MULTIPLE SITE REMOTE LASER POINTER
INVENTORS: EDWIN R. LEONARD, HANS TEIN-SHIN KU
FIELD OF THE INVENTION
[0001] The present invention relates to synchronously controlling a laser
projector in a remote location using a local handheld laser pointer in a different location.
BACKGROUND OF THE INVENTION [0002]Video and computer-based teleconferencing between persons in remote
locations is now a common form of communication. A common feature of all of these systems is some type of visual display system in which the images from the remote locations are displayed for viewing by the local participants. This enables the local participants to see the other participants in the distant location. But beyond merely seeing each other, video conferencing systems allow the participants to display items and objects to the other remote participants. For example, participants in one location can display drawings, documents, models, or any other physical object, for other participants to see. Further, many video- and computer-based conferencing systems allow as an input computer graphics displays from workstations (e.g., software applications, graphics, animations, or the like)/ and likewise separate document camera inputs. One such application is the motion picture industry's digital dailies where both the local and remote audiences view and discuss the same digital movie input played back simultaneously on local and remote digital display devices. This rich Variety of different inputs allows all of the participants to collaborate and discuss the commonly viewed information, whether it is displayed documents, models, movies, or computer graphics.

[0003] In order to efficiently collaborate with each other when discussing some
displayed information, such as a document from a document camera or computer display, it is beneficial for the participants to be able to visually indicate on their displays particular items of interest. For example, when discussing a document that is displayed to the participants in the various remote locations, it is desirable for a speaker to be able to visually highlight a paragraph or sentence. Similarly, if the participants are all viewing a computer image or software application, again it is desirable for the participants to be able to visually indicate a portion of the image to draw attention to a particular detail or characteristic of the image. The ability to indicate some item of interest often depends on where that item is located. Thus, for a speaker in the same location as the document under discussion, he can easily use a pen to directly draw on the document. But participants in the remote location conventionally have much more limited options, since they are not physically in the same location. Where the item of interest is a computer application, participants in the same location as the computer running the application can easily control and manipulate the application as well as draw attention to items of interest within the application using an on-screen cursor controlled by a computer mouse or other similar input device. Remote viewers, however, may have no ability to control or interact with the application. [0004]To provide both local and remote participants the ability to direct others'
attention to specific areas of interest in a video or computer mediated conference, a number of limited interfaces and devices exist. For computer mediated conferences, where the item of interest is generated by a source computer (a "digital exhibit"), the various participants at different remote locations can each take control of the source computer, and thereby control the location of an on-screen cursor using a mouse or other similar input device. This simple approach only serves to give control of the source computer to different ones of the participants.

[0005] More sophisticated systems provide the ability to participants at either site
to overlay graphics onto a shared video signal. In this way, an on-screen cursor can be used in conjunction with any video source regardless of its origin. With this approach, a participant in one location can use the on-screen cursor to draw attention to and/ or "markup"an item of interest on the display for participants in all locations to see, This frees the participant from having to be in the same location as the item of interest. This feature is helpful for marking up sports telecasts and document camera feeds, for example, whose video sources are generally not compatible with the other digital pointing devices.
[0006] These devices impose several problems and limitations upon the
presenter. For example, the resolution of the display system limits the fidelity and
accuracy of the digital pointer as subpixel precision cannot be achieved. The pointer
may also blend into the foreground or background of a presentation and become less
evident to an audience. This occurs because the pointer is generated and presented as
part of a video signal and therefore cannot attain a color, contrast, or brightness greater
than what is within the capabilities of the video display. In addition, it is difficult to
efficiently share the pointing device among several participants at the same time.
[0007] A particularly significant problem is that these types of systems are not
designed to support interaction by a large number of participants at a location, such as a large audience in a theater setting that may be viewing the images from a remote location. The difficulty arises from inherent limitations in the pointing systems which typically have only a single device to move the pointer attached to the presentation
r
computer; it would be cumbersome for an audience of more than four or five participants to effectively share the input device, and considerably more impractical for an audience of twenty or one hundred. Even if multiple instances of the pointing devices can be used to control a single presentation computer, the cost and

impracticality of distributing the devices to each participant in a large audience makes the option prohibitively unattractive.
[0008)Another problem occurs in the presentation of a physical exhibit such as a
maquette, poster board, piece of furniture, article of clothing, livestock, etc. While the local audience can directly highlight particular areas of interest on the exhibit using a laser pointer, for example, the remote audience, who perhaps sees only a video representation of the local exhibit that has been transmitted over a video teleconferencing system, cannot do so.
[0009] Apart from video conferencing systems, presenters often use laser
pointers to direct an audience's attention to particular aspects of displayed information
during a presentation. Laser pointers are useful in these circumstances since they can
instantly project a highly visible colored spot, that can be seen on objects in close
proximity or dozens of feet away without requiring any adjustment to be visible.
However, in the context of video and computer-based teleconferencing, the problem
with laser pointers becomes apparent. The audience direction conveyed by the use of a
laser pointer does not translate well to remote audiences, who are not physically in the
same room as the presenter's laser pointer, and thus do not see where the presenter is
pointing the device. Further, the remote audience cannot use a laser pointer to produce
a point in the source location in order to collaborate with the presenter.
[0010] This problem of conveying direction to a remote audience is exacerbated
in settings such as multi-site network operations, mission control, or immersive video conferencing centers. These centers often aggregate information onto a place of common view for its participants through the use of multiple displays mounted on a single wall. The displays typically have independent, heterogeneous sources and may even be heterogeneous in type and size from each other, as is the case in mission control centers. The multiplicity and heterogeneity of the displays and sources makes it challenging, if not impossible, for a presenter to use a shared computer-controlled

cursor or video markup system to direct the attention of an audience in the same location, let alone a remote location. A laser pointer is not affected by these differences, and a presenter can easily use one to direct the attention of the local audience. Participants at a remote location sharing the same display arrangement and respective sources, however, may not be able to see where the presenter is pointing nor can the remote participants use a laser pointer in the remote location to direct the attention of the presenter.
[0011] Thus, it is desired to provide a way of using a laser pointer in one location
and reproduce it in one or more geographically remote locations, for example, to allow participants in the one location to direct the attention of other participants in the remote locations,
SUMMARY OF THE INVENTION
[0012] The present invention provides various embodiments in which a
geographically remote laser projector is synchronized with a handheld laser pointer in a
different location. At a first location, a machine vision camera captures a video stream
of images that include the laser point. A laser tracking system analyzes the images and
determines the laser path traced out by a handheld laser pointer, and expresses it as
■ control information. The control information is transmitted over a network to a remote
laser control system and laser projector system at a second location. Using the control
information from the first location, the second location's laser control system uses the
control information to drive the laser projector system to project a laser beam at the
second location which accurately reproduces the laser path traced by the laser pointer at
*,
the first location.
[0013]In a second embodiment, a two way laser tracking system is provided.
Here, the second location includes a camera and laser tracking system which operates to determine the path of a second laser pointer being used at the second location and

transmit control information to the first location. At the first location a laser control system and laser projector system again reproduce the laser path of the second laser pointer.
[0014] Either the laser tracking elements or the laser control elements can be
independently extended to any number of locations, in one-to-many, many-to-one, or many-to-many relationships. Thus, for example, a laser tracking system at a first location may be used to control the laser control and projector systems at multiple different locations. Conversely, laser tracking systems at multiple locations can provide their control information to a single location with laser control and laser projector systems to replicate the multiple laser paths.
[0015] The area upon which a laser pointer is directed and from which the
camera captures the video stream can be a physical area or object of interest can be a
projected image or may be a computer driven presentation. This allows participants to
reference and discuss any variety of different content or exhibits.
[0016] In one aspect, the laser control system transforms the control information
so that the coordinate information received from the laser tracking system is expressed as coordinate information that can be used to drive the laser projector system. Thus, even if the physical dimensions of the two locations are entirely different in terms of the size of the room, the size of the region of interest, and/ or the distance of the camera from the region of interest, the laser path information in the second location is appropriately transformed and scaled.
[0017] The present invention has embodiments in various system architectures,
equipment configurations for sites, software products for controlling the laser control systems, methods of interactions between participants at the locations, nature and content of the exhibit or presentation, and calibration methodologies for calibrating the laser tracking and laser control systems.

DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a concept diagram illustrating a one-way remote laser pointer
system.
[0019] FIG. 2 is a concept diagram illustrating a two-way remote laser pointer
system.
[0020] FIG. 3 is a concept diagram illustrating another embodiment of a one-way
remote laser pointer system including a presentation system.
[0021] FIG. 4 is a concept diagram illustrating another embodiment of a two-way
remote laser pointer system including a presentation system.
[0022] FIG. 5 is a concept diagram illustrating another embodiment of a two-way
remote laser pointer system including a video conferencing system
[0023] FIG. 6 is a concept diagram illustrating another embodiment of a two-way
remote laser pointer system including a video conferencing system and multiple,
heterogeneous displays
[0024] FIG. 7 is a block diagram illustrating a system architecture for a one-way
remote laser pointer system,
[0025] FIG. 8 is a block diagram illustrating a system architecture for a two-way
remote laser pointer system.
[0026] FIG. 9 is a block diagram illustrating a system architecture for a remote
laser pointer system including a presentation system.
[0027] FIG. 10 is a block diagram illustrating a system architecture for a two-way
remote laser pointer system including a video conferencing system.
[0028] FIG. 11 is a block diagram illustrating a system architecture for a multi-
way remote laser pointer system in a multiple site configuration.
[0029] FIG. 12 is a flowchart illustrating the functions of a laser tracking system
and a laser control system.

[0030] In the following discussion of the figures, reference numbers without
subscript (e.g., "114") are understood to refer generally to all instances of items having the same reference number, while reference numbers with subscripts (e.g., "114a'7) are understood to refer to a specific item.
[0031]The above figures illustrate configurations, systems, architectures, and
methods in various embodiments of the invention for the purposes of explanation only. Those of skill in the art will appreciate that other configurations, systems, architectures, and methods can be constructed and implemented in accordance with the teachings of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0032] The present invention can be used in a large number of different
configurations for collaboration between two or more locations. To better explain the
invention, a variety of these configurations will be described first, followed by a
description of the underlying system architecture.
[0033] FIG. 1 illustrates schematically a basic configuration for the present
invention, for a one-way remote laser pointer system. At two sites, Site A and Site B,
■
are two participants, a presenter and viewer respectively. At both sites there is a region of interest (ROI) 114a and 114b that the participants are discussing. In this first configuration, the ROI 114a is a physical exhibit such as a map, diagram, model, or any other physical item with ROI 114b being substantially a copy of ROI 114a (though
perhaps differing in size, color, etc.). The participants communicate with each other
»
over conventional telephones 112 and telephone network 113.
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[0034] The presenter at Site A has a laser pointer 110a, which he uses to point to
specific areas on the ROI 114a, variously tracing a laser path 116a (heavy dashed lines in the figures indicate the path of the laser pointer's beam originating from site A) as the laser point 126a moves over the ROI 114a. A machine vision camera 102a is mounted at

Site A and oriented towards the ROI 114a and adapted to image the entire ROI 114a.
The camera 102a captures a video stream of the ROI 114a, and passes the video stream
130 to a laser tracking system 106a. The laser tracking system 106a determines from the
video stream the location of the laser point 126a or the laser path 116a, The location or
path information may be in terms of an (x,y) position or trajectory in the image space of
the camera, in a corresponding geometric space, or any equivalent transformation
useful for describing the laser point 126a or laser path 116a, The laser tracking system
106a transmits this control information 132 over a network 120 to Site B.
[0035] At Site B, a laser control system 108b is connected to the network 120 and
receives the control information. The laser control system 108b derives from the control
information the appropriate control signals 134 for controlling a laser projector system
104b, which may include mapping the control signals 134 onto a local geometry space
for the ROI 114b. The laser projector system 104b projects its laser beam on the ROI
114b, recreating the laser point 126b at the same location relative to ROI 114a as the
original laser point 126a on ROI 114a, and thus tracing a similar laser path 116b. Thus,
the viewer at Site B can see what the presenter is referring to during their discussion.
[0036] FIG, 2 illustrates a two-way remote laser pointer system in which both
sites enable laser tracking and laser projection. This configuration extends the one-way configuration of FIG. 1 as follows. Site B includes a machine vision camera 102b oriented on the ROI 114b for capturing a video stream thereof, including the laser point 128b from laser pointer 110b, as it traces laser path 118b (dotted-dashed lined lines in the figures indicate the path of the laser pointer's beam originating from site B). A laser tracking system 106b is provided in addition to the laser control system 108b for analyzing the video stream from the machine vision camera 102b in the manner described above and transmitting control information for the laser pointer llOb's
position back to Site A over the network 120. In this and the remaining illustrations, the
> laser tracking system 106 is illustrated as being separate from the laser control system

108 merely for convenience; in practice these systems may operate, at least in part,
using a common computer apparatus. At Site A, laser control system 108a receives the
control information and provides control signals to a laser projector system 104a, which
projects a laser point 128a along laser path 118a on the ROl 114a, mirroring the path of
the laser pointer 110b. Thus, both participants can now use their laser pointers 110 to
point to specific areas on their respective ROI114, and have such laser paths recreated
at the other site. The two-way configuration further enhances the ability of the
participants to collaborate with each other, as each can both point to the ROI and see
what the other participant is pointing at.
[00371 The one-way and two-way configurations of FIGS. 1 and 2 illustrate the
system with an identical physical ROI 114a and 114b at each site. A variant
■
configuration includes a video displayed ROI at either or both sites. FIG. 3 illustrates a one-way remote laser pointer system with two video-displayed ROIs 114. This configuration is similar to the one-way configuration of FIG, 1, with additional elements. At Site A, a presentation projector 140a is coupled to a presentation system 144a, to project an image onto the ROI 114a. The use of a projector 140 is preferred to provide a very large image, but the ROI may also be displayed with other presentation display technologies, including rear projection systems, video walls, flat panel displays, and so forth. The projected image on ROI 114a can be computer generated from the presentation system 144a (e.g., graphics, documents, presentations, and the like). The presentation system 144a is coupled over a network 146 to another presentation system 144b, which drives presentation projector 140b, to display the same image onto ROI 114b, thereby allowing both participants to view the same presentation image. As with the configuration of FIG. 1, the presenter has a laser pointer 110a, which he uses to project a laser point 126a on the now projected image on the ROI 114a. As before, the machine vision camera 102a captures a video stream of the ROI 114a, the laser tracking system 106a derives and transmits control information from the video stream to the

laser control system 108b which controls the laser projector system 104b to project a laser point 126b tracing out laser path 116b onto the projected image on ROI 114b. Thus, again both participants can see what the presenter is pointing at on the projected image on their respective ROIs 114.
[0038] A two-way remote laser pointer system using projected ROIs is another
configuration, combining the two-way laser projection and tracking elements of FIG. 2, with the projection elements of FIG. 3. FIG. 4 illustrates this combination, in which the elements operate as previously described. As can be appreciated, in this configuration, both participants can see the projected images for the presentation and use their laser pointers 110 to direct the other participant's attention to portions of the image, thereby further enhancing their collaboration.
[0039] FIG. 5 illustrates another configuration, a variant of the two-way remote
laser pointer system with single projected ROI 114a. In this configuration, one of the sites, for example Site B, has a physical ROI 114b, such as a large diagram, storyboard, map, and so forth. The participant uses her laser pointer 110b to point to something of interest in the ROI 114b, tracing a laser path 118b with the laser pointer 110b as before. A camera 102b is oriented towards the physical ROI 114b and captures a video stream thereof. The video stream thus contains both the physical ROI and the laser point 128b. Preferably, the camera 102b can be moved to capture any particular portion of the ROI 114b, thereby forming a dynamic region of interest 115. The video stream is passed to an audio-video (AV) encoder/decoder 152b along with audio signals captured at microphone 150b where they are encoded and then passed to AV gateway 154b for transmission over a network 156 to Site A. Any suitable, commercially available videoconferencing type system can be used to perform the video and audio capture, encoding, and transmission,
[0040] At Site A, the AV signal is received at an AV gateway 154a and provided
to a complementary AV encoder/decoder 152a. The AV encoder/decoder 152a

decodes the signals into a video stream and an audio stream and provides the video stream to presentation projector 140a, which projects the images onto the ROI 114a, and the audio stream to audio speakers 170a, which produces the audio output. Note that the projected image corresponds to the dynamic ROI 115 from Site B and not to the entire ROI 114b at Site B. As these images show laser path 118a/ the participant at Site A can readily see what the participant at Site B is pointing at. The participant at Site A can use his laser pointer 110a to point to the projected image on ROI 114a, tracing laser path 116a. As in FIG. 1, Site A includes the machine vision camera 102a and laser tracking system 106a, which capture and determine the position of the laser point 126a and transmit the control information back to Site B. As in FIG. 1, Site B includes the laser control system 108b, which uses the control information to control laser projector system 104b to project the laser point 126b onto the ROI 114b, tracing laser path 116b that corresponds to the laser path 116a at Site A. Thus, again the participants can use their laser pointers 110 to point to the ROI 114 and see the other participant's laser point as well.
[0041]FIG. 5 also illustrates a videoconferencing system coupling the two sites,
in one preferred embodiment of this configuration. Here, each site includes a video
camera 162 oriented at the participant at the site. The camera 162 provides a video
signal to the A V encoder 152, which encodes the signal and provides it to gateway 154
for transmission to the other site. The received video signal is decoded at decoder 152
and output on a presentation monitor 160. In this manner, the participants can see each
other as they discuss and collaborate over the exhibit in the ROI 114.
[0042] FIG. 6 illustrates another videoconferencing system coupling two sites. In
this embodiment, there are multiple displays, including ROI 114 and display monitors 121 and 123 at each site, having independent, heterogeneous data sources. As above the projectors 140 are driven by respective presentation systems 144, while display monitors 121,123 are driven with data from an independent computer system 180. In

this configuration, the participants are thus observing multiple sources of information from the independent sources. However, using the two-way remote laser tracking systems, both participants are able to point at any portion of these displays 114,121,123 with their laser pointers 110 and have that laser path information reproduced at the other site. In this embodiment, the camera 102 can image all of the displays 114,121,
123, and thereby capture the laser point 128 across any of these areas; the laser projector
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system 104 is likewise configured to project a laser beam on any of the displays 114,121,
123. Alternatively, a one-way remote laser tracking system such as the one shown in
FIG. 1 may be used with the multiple display features of this embodiment These
configurations are thus beneficial at sites such as control rooms where multiple
independent data sources and presentation systems are to used to present information
to participants, where it is desirable to direct other participants' attention to specific
information the displays, by eliminating the low-level computer integration typically
needed to control a computer cursor across the multiple displays and systems.
[0043] The above configurations illustrate just some of the possible variations
and combinations of elements in accordance with the principles of the present
invention, and those of skill in the art can easily devise further configurations. For
example, the presentation system elements of FIG. 3 can be combined with the
videoconference system elements of FIG. 5, to provide a highly sophisticated video
conferencing and presentation system with two-way remote laser pointing.
[0044] Further, the invention is not limited to use with two sites as illustrated,
but can be readily extended to three or more sites, each including a laser tracking system 106 and laser control system 108 as needed. In these multi-site configurations, each participant can use a red (or other color) laser pointer 110 in their local site, while the laser projector system 104 is either a poly-chromatic laser, supporting multiple colors, or multiple separate lasers, or a combination thereof with each color representing a particular remote site.

[0045] Turning now to FIG. 7, there is shown the system architecture for the basic
one-way remote laser pointing system of FIG. 1, In FIG. 7, Site A comprises the laser pointer 110a, machine vision camera 102a, laser tracking system 106a, and Site B comprises the laser control system 108b, laser projector system 104b, and a network 120 connecting the two sites,
[0046] FIG. 8 illustrates the system architecture used in various ones of the two-
way remote laser pointer configurations discussed above. Here, each site includes both the laser tracking elements and the laser projection elements, In addition, in a two-way system, a 532 nm green laser projector system is preferred to help both the audience and the machine vision camera 102 distinguish the remote laser point 128 from the 650 nm red local laser point 126.
[0047] FIG. 9 illustrates the system architecture for a remote laser pointer system
including a presentation system for providing a video-based ROI 114, as illustrated in FIGS. 3 and 4. The presentation system comprises a conventional computer system executing presentation, graphics, word processing, or any other applications useful for presenting graphic displays. The presentation systems 144 at the various systems communicate over the network, for example, using TCP/IP over Ethernet. Presentation control software (e.g., Microsoft Corporation's Netmeeting™) allows the various participants to each control the presentation. The presentation system 144 at each site outputs VGA, SVGA, or other common graphics resolution signals to a presentation display 140. The presentation display system 140 can be a format compatible projector that projects the image onto the ROI 114. Alternatively, the presentation display system 140 may be a format compatible monitor, direct view television, rear projection display television, flat panel display, or the like, which itself would thus serve as the ROI 114. 10048]FIG. 10 illustrates a system architecture for a remote laser pointer system
using a video conferencing system used to communicate between two (or more) sites, such as used in FIG. 5. In this architecture, at least one site includes the laser tracking

system 106, and at least one site includes the laser control system 108. In addition, both sites include AV inputs, such as video cameras 162, microphones 150, AV outputs 160, AV encoder/ decoders 152, and AV gateways 154, as commonly used by those of skill in the art. For highest performance, the video conferencing system provides a high resolution signal path, including HD cameras, such as a Panasonic AK HC900 HD camera, an MPEG-2 encoder/decoder, such an Astra Wavestar, and a suitable AV gateway such as a Path 1 Network Technologies Inc;s CxlOOO IP video gateway. Other embodiments can use H.263-based video conferencing architecture, H.320 (ISDN-based videoconferencing), H.324 (POTS-based videotelephony), H.323 (LAN or IP-based videoconferencing), or H.264 (advanced video coding).
[0049)FIG. 11 illustrates a system architecture for a remote laser pointer system
in a multiple site configuration. In this embodiment each of three sites, Sites A, B, and C include the machine vision cameras 102, laser tracking systems 106, laser control systems 108, and laser projector systems 104. At each site, at least one participant uses a laser pointer 110 to direct a laser upon a local ROI 114, and this laser is tracked by the local laser tracking system 106. The control information derived by the laser tracking system 106 is provided to the laser control system 108 at each of the other sites, which uses the information to generate local control signals 134 for controlling the local laser projector system 104. As each site is to project two laser paths, the laser projector systems 104 are preferably polychromatic, and the control system 108 is adapted to drive the laser projector system 104 with the appropriate signals for projecting both
laser paths.
[0050] The various system elements of one embodiment are now discussed in
more detail
[0051] As the only unattached, mobile part of the system, the handheld laser
pointer is the most likely to be lost or broken, and so should be easily replaceable. Any low cost, commercially available laser pointer can be used, which enables participants

to use their own personal laser pointers without having to rely on a dedicated laser
pointer 110. Preferably, the laser pointer 110 is 650 nm, <5 mW, class IIIA, TEM00,
continuous wave red laser pointer, which is desirable for its low cost and widespread
commercial availability. The laser pointer 110 creates a laser point 126 approximately 2
mm in diameter. Typical usage includes holding the laser point stationary or moving
the pointer slowly or rapidly in a circular or zigzag motion creating a laser path. The
participant may also turn the pointer on and off. The machine vision camera 102
comprises a black and white Instrumentation & Industrial Digital Camera (IIDC) Digital
Camera Specification (DCAM) compliant digital video camera such as the DCAM
compliant PixeLINK PL-A741 Machine Vision Camera. DCAM complaint cameras
allow for plug and play operation with standardized host interface methods such as
IEEE 1394 (FireWire). The machine vision camera 102 sends captured frames over an
IEEE 1394 interface obviating the need for frame grabber hardware. Of course, an
alterative embodiment can use an NTSC type camera, in conjunction with a frame
grabber, sampling the video at 60 Hz (or alternatively, a PAL camera with a 50 Hz
sample rate). It is preferable to use a progressive scan (non-interlaced) video camera to
avoid image tearing and/or disappearance of the laser point between interlaced frames.
Increasing frame capture resolution and rate improves spatial accuracy and temporal
accuracy, respectively. Increasing frame capture rate also reduces the statistical
significance of a single detected laser point coordinate thereby reducing the unwanted
influence of a spurious detection event. Both resolution and rate increases however
» provide diminishing returns, and should be bounded by the limits of human perception
and persistence of vision, Resolution and rate are also limited by the camera
hardware's capabilities and the host computer system's ability to process each frame in
real time without falling behind. A progressive scan frame capture with rolling shutter
at about 100 fps and 640x480 pixels per frame is sufficient to capture enough
information to reproduce the appearance and effect of the handheld laser pointer, The

PixeLINK PL-A741 MV camera supports this combination of resolution and rate and produces a data stream of about 31 megabytes per second (MBps) from camera to host computer. An example of a host computer that can process the data in real time is the HP xw8000 w/dual 3.06 GHz Intel Xeon processors.
[0052] Standard systemic CCD noise reduction methodologies and algorithms
are preferably employed at the camera 102, or its associated processing hardware, to improve laser point detection and include fixed pattern noise (FPN) reduction using gain/offset correction and photo-response non-uniformity (PRNU) reduction using flat-field correction.
[0053] To improve identification of the laser point, a filter of the appropriate
wavelength may be mounted on the camera 102. For example, for a 650nm red laser, a
650 nm central wavelength (CWL) thin-film Fabry-Perot interference narrow bandpass
filter may be mounted to the camera to better isolate the laser pointer's wavelength.
The Fabry-Perot efficiently rejects light from the presentation projector, display device
and other incident light while allowing the desired 650 nm wavelength from the laser
pointer to pass through to the CCD of the camera 102. Standard digital image
processing techniques such as threshold convolution further isolate the laser point.
[0054] Referring now to FIG. 12, there is shown a flowchart of the laser tracking
and laser control operations of the laser tracking system 106 and laser control system 108 in one embodiment of the present invention. The laser tracking system 106 receives 1202 the captured images from the camera 104a, and tracks 1204 the path 116 of the laser point 126 and its velocity using either point or path sampling strategies. Both strategies begin with segments of the laser path traced out by the laser pointer, The point sampling strategy reproduces the path using discreet point input data. The length of the laser path segment sampled approaches zero, the length of a point, as sampling rate increases and exposure time decreases. Therefore the success of this strategy is improved by maximizing sample rate while minimizing exposure time. A suitable laser

tracking system 106 includes the Model 150 Laser Tracker from Newton Research Labs, Inc. of Renton, WA.
[0055] The original detected pixel locations of the sample exist in the camera's
coordinate space and are translated to the ROI's coordinate space. An initial calibration
process 1200 defines the boundaries of the ROI within the camera's coordinate space
and establishes a relationship between them. Using a transform constructed from the
initial calibration of the machine vision camera, the pixel locations of the sample are
corrected 1208 for geometric distortion and normalized 1210 to device independent
coordinates , as further explained below. To retain subpixel location information, all
calculations and resulting coordinate and/or spline data are floating point
[0056] In the point sampling strategy, a single coordinate is produced from each
frame by taking the area mean of the set of, pixels representing the laser point. These points are identified by a thresholding operation to identify the brightest pixels in the image. For laser points occupying more than a single pixel, as is often the case, subpixel precision can be achieved by weighting each adjoined and neighboring pixel by its intensity value when calculating the mean location. This requires that 2-bit or greater bit depth in the captured frame data exists and survives the threshold convolution or other image processing techniques used to isolate the laser path from its background. A Kalman filter, spline smoothing, or similar means of removing spatial and temporal jitter and noise using a trailing set of sampled coordinates can be applied as well. The path sampling strategy is similar in many respects to the point sampling strategy except that a contiguous splint is produced from each frame rather than a single coordinate. A set of adjoining pixels now represents a line rather than a point. A spline is fitted to the set of pixels in each frame using best-fit analysis, Subpixel precision is achieved by weighting each adjoined and neighboring pixel by its intensity value in the best fit calculation. Again, the presence of 2-bit or greater depth is required.

As with point sampling, a Kalman filter can be utilized with a trailing set of fitted splines.
[0057] The final device independent control information 132 (e.g., splines
and/ or coordinates) are packaged and transmitted 1212 over an Ethernet or similar network to the laser control system 108. A sequence number and velocity data for each point or spline is preferably included in the packet. The sequence number allows the receiving system to detect lost packets and ensure their correct ordering. Velocity information, calculated as the length of the spline over the time elapsed from the previous sample is also included in the packet.
[0058] At the receiving site, the laser control system 108 comprises a combination
of elements for receiving 1214 the control information 132 and deriving control signals
134 to control the laser projector system 104. In one embodiment the laser control
system 108 includes a laser controller board and a laser control program (e.g., Pangolin
Laser Systems, Inc. QM2000 controller board and LD2000 laser control program)
running on a conventional computer for mapping the control information to local
control signals. Generally, the laser control program takes the device independent
coordinate and velocity information described in the control information 132,
denormalizes 1216 the coordinate space information, and determines 1218 a
corresponding coordinate in the coordinate space used by the laser projector system
104. The laser control software uses a set of coordinate transforms which map the local
ROI boundary information to the device independent coordinates, derived from an
initial calibration of the laser projector system. The laser projector system 104 is
automatically blanked whenever a lapse in packet transmission occurs.
[0059] Because the laser projector system 104 has a resolution and speed several
orders of magnitude faster than the sampling rate, it could easily jump from point-to-point producing dots rather than a perceived path. Thus it is desirable to constrain the laser projector's movement between points with the velocity information provided by

the laser tracking system. Due to human persistence of vision, the velocity constraint enables the system to reproduce the perception of a line drawn out by the laser pointer. [0060]The laser projector system 104 can be any commercially available,
computer controllable laser projector system suitable for laser projection in the presence of observers, such as commonly used for laser shows and the like. In one embodiment, the laser projector system 104 comprises an ILDA compliant, PCAOM type, XY scanning laser projector. A suitable laser projector system 104 (e.g., MediaLas Laserproducts GmbH's CatWeazle VX laser projector) uses a 532 nm, 5 mW, class II, TEM00, continuous wave, modulatable green laser. The 532 nm green laser is desirable because the human eye is over 8 times more sensitive to 532 nm green light than it is to 650 nm red light permitting the use of a lower power 532 nm green laser in the projector. The machine vision camera typically has a more even sensitivity to both 532 nm and 650 nm light and thus allows the use of a simple threshold convolution algorithm to separate the 532 nm laser point from the 650 nm laser point. Using the control signals 134 from the laser control system 108, the laser projector system 104 reproduces the laser path 118 on the ROI114.
[0061] Initial calibration of the machine vision cameras 102 and laser projectors
104 is used to the accurately capture and reproduce the laser path from one site to the other. Both the projector system 104 and the camera 102 are calibrated 1200 to compensate for intrinsic and extrinsic distortions and misalignments, In addition, the ROIs 114 at both sites are assumed to be proportionately equivalent requiring only an X and Y scaling factor to translate coordinates between them once geometric distortion is removed. The calibration methodology presented here seeks to enable the System to accurately capture a world referenced coordinate and project that coordinate in a world referenced coordinate space in a different location.
[0062] Specifically in one embodiment, a world referenced coordinate (Ui, Vi) in
the local region of interest ROI 114, is captured by the machine vision camera 102 as (XC/

Yc) with camera distortion described by the transform, Tc. The distortion introduced by
the camera 102 is compensated for by the inverse of the camera distortion transform,
Tc-1, producing an undistorted camera coordinate, (Xc', Yc'). The undistorted coordinate
is converted into a device independent normalized coordinate, (X, Y), by dividing Xc' by
ROIi's maximum Xc' value, and dividing Yc' by ROI1's maximum Yc' value. The device
independent coordinate, (X, Y), is then scaled for projection to the projector distorted
coordinate (Xp, YP) by multiplying X by the remote region of interest's (ROh) maximum
Xp1 value and multiplying Y by ROI's maximum Yp1 value. The distorted projector
coordinate is corrected using the inverse of the projector's distortion transform, Tp1,
producing the undistorted coordinate (Xp1, Yp'). (Xp', Yp') is then projected as a world
referenced coordinate (U2, V2) where (U2 V2) = (U1, V1) if ROh = ROI1. This process
works correctly for situations in which ROh is proportionally equivalent to ROh as
well. The transforms are appropriately stored and used by the laser tracking system
106 to convert the device dependent coordinate information into the device
independent control information 132, and likewise used by the laser control system 108
to convert the control information 132 into the control signals 134.
[0063] The laser projector system 104 is intrinsically calibrated using, as an
example of one method, a variety of tuning procedures defined by the ILDA and its ILDA B Test Pattern. These tuning procedures ensure the accuracy of the laser projector's mechanical scanner response.
[0064] The laser control program is also configured to perform extrinsic
calibration of the laser projector system 104. The laser control software operates the laser projector system 104 to project a grid on the ROI114. The projector's vertical and horizontal scan angles are then adjusted such that the grid just encompasses the height and width of the ROI 114. Geometric distortion is then corrected and the compensating transform (Tp) stored along with the origin and maximum values of the ROI

[0065] Once the laser projected grid is distortion free, it is used as a target for the
calibration of the machine vision camera 102. The field of view (FOV) of the camera 102 is manually adjusted to encompass the grid by adjusting the pan, tilt, and zoom of the camera. An image of the grid is then captured by the camera 102. The laser control program analyzes the image to extract the coordinates of the grid intersections. The set of observed coordinates are passed through a geometric distortion modeling algorithm which determines a transform for mapping the observed coordinates with the original grid coordinates projected by the laser projector system 104. A suitable modeling methodology is disclosed in L. Ma, Y. Chen, and K. Moore,7/A Family of Simplified Geometric Distortion Models for Camera Calibration/ Center for Self-Organizing and Intelligent Systems (CSOIS), Dept. of Electrical and Computer Engineering, Utah State University, and available at http://arxiv.org/abs/cs/0308003. The distortion present in the image is modeled and a compensating transform (Tc) generated and stored along with the origin and maximum values of the ROI.
[0066] The camera and projector calibrations are performed at both sites
independently. Transformation of coordinates into normalized device independent
coordinate space allows any number of sites to capture and accurately reproduce laser
paths. Once these calibrations are complete, the transforms are stored by the laser
control program, and used to convert the received control information 132 into the
appropriate control signal 134 for the laser projector system 104,
[0067] In summary then, the present invention provides a remote laser pointing
system that can be used with two, threg or more sites. Each site includes either laser tracking, or laser control components, or both, to provide one-way or two-way remote Uic-i pointing. The remote laser pointing system can be used to point at physical or displayed regions of interest, thereby allowing participants at the various sites to more specifically identify aspects of the regions of interest for discussion and collaboratioa The flexibility of the present invention allows it to be integrated with a variety of

different and compatible teleconferencing, videoconferencing, and presentation systems, and enhances the operations of all such systems.
[0068] The present invention has been described in particular detail with respect
to one possible embodiment. Those oi skill in the art will appreciate that the invention
may be practiced in other embodiments. First, the particular naming of the
components, system elements, capitalization of terms, the attributes, data structures, or
any other programming or structural aspect is not mandatory or significant, and the
mechanisms that implement the invention or its features may have different names,
formats, or protocols. Further, the system may be implemented via a combination of
hardware and software, as described, or entirely in hardware elements. Also, the
particular division of functionality between the various system components described
herein is merely exemplary, and not mandatory; functions performed by a single
system component may instead be performed by multiple components, and functions
performed by multiple components may instead performed by a single component.
[0069] Some portions of above description present the features of the present
invention in terms of algorithms and symbolic representations of operations on
information. These algorithmic descriptions and representations are the means used by
those skilled in the data processing arts to most effectively convey the substance of their
work to others skilled in the art. These operations, while described functionally or
logically, are understood to be implemented by computer programs. Furthermore, it
has also proven convenient at times, to refer to these arrangements of operations as
modules or by functional names, without loss of generality.
{0070] Uidess specifically stated otherwise as apparent from the above
discussion, it is appreciated that throughout the description, discussions utilizing terms such as "processing* or ''computing" or "calculating" or "determining" or "displaying" or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical

(electronic) quantities within the computer system memories or registers or other such information storage, transmission or display devices.
[0071] Certain aspects of the present invention include process steps and
instructions described herein in the form of an algorithm. It should be noted that the process steps and instructions of the present invention could be embodied in software, firmware or hardware, and when embodied in software, could be downloaded to reside on and be operated from different platforms used by real time network operating systems.
[0072] The present invention also relates to an apparatus for performing the
operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored on a computer readable medium that can be accessed by the computer. Such a computer program may be stored in a computer readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, application specific integrated circuits (ASICs), or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus, Furthermore, the computers referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability.
(0073) The algorithms and operations presented herein are not inherently related
to any particular computer or other apparatus. Various general-purpose systems may also be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will be apparent to those of skill in the art, along with equivalent variations.

[0074] The present invention is well-suited to a wide variety of computer
network systems over numerous topologies. Within this field, the configuration and management of large networks comprise storage devices and computers that are communicatively coupled to dissimilar computers and storage devices over a network, such as the Internet.
[0075) Finally, it should be noted that the language used in the specification has
been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

1. A remote laser pointer system, comprising:
a camera for capturing an image of a source location containing a laser point;
a laser tracking system that determines a position of the la9er point in the image, and
generates control information corresponding to the determined position; a laser control system at a remote location from the souice location, that receives the
control information and determines a control signal in response to the control
information; and a laser projector at the remote location that projects a laser point in response to the
control signal at a position in the remote location corresponding to the
position of the laser point in the source location.
2. The system of claim 1, wherein the laser control system comprises:
a laser control program that receives the control information and converts the control information from a coordinate system associated with
THE camera to a coordinate system associated with the laser projector; and
a laser control interface that couples the control signal to the laser projector.
3. The system of claim 2, wherein the laser tracking system generates the control
information by:
applying an inverse camera distortion transform to the captured image to produce undistorted camera coordinates for the laser point; and
normalizing the undistorted camera coordinates into device independent normalized coordinates.
4. The system of claim 3, wherein the laser tracking system normalizes the undistorted camera coordinates (XcV Yc') by dividing the camera coordinates by respective maximum camera coordinates (Xcmax', YCAX') for a region of interest at the source location.
5. The system of claim 3, wherein the laser control system determines a control signal
scaling the device independent normalized coordinates by maximum projector coordinates for a region of interest at the remote location; and

applying an inverse projector distortion transform to the scaled coordinates to produce projection coordinates for the laser projector.
6. The system of claim 1, further comprising;
a plurality of presentation displays, each presentation display driven by a separate presentation system, wherein the camera captures an image of the plurality of presentation systems, and wherein the laser tracking system determines the position of the laser point in the image corresponding to a laser point projected on any of the presentation systems.
7. A remote laser pointer system, comprising;
a first location, comprising:
a first camera for capturing an image containing a first laser point;
a first laser tracking system that determines a position of the first laser point in
the image and generates first control information corresponding to the
determined position of the first laser point; a second location/ remote from the first location, comprising:
a first laser control system for receiving the first control information and
determining a first control signal in response to the control information; a first laser projector for projecting a first laser point in response to the first
control signal; a second camera for capturing an image of the source location containing a
second laser point; a second laser tracking system that determines a position of the second laser
point in the image and generates the second control information
corresponding to the determined position of the second laser point; the first location further comprising:
a second laser control system for receiving the second control information from
the second laser tracking system and determining a second control signal
in response to the second control information; and a second laser projector for projecting a second projected laser point in response
to the second control signal.

8. The system of claim 7, wherein each laser control system comprises:
a laser control program for receiving the control information and converting the control information from a coordinate system associated with the camera to a coordinate system associated with the laser projector; and
a laser control interface for coupling the control signal to the laser projector.
9. The system of claim 7, wherein:
the first location further comprises a plurality of fast presentation displays, each first presentation display driven by a first presentation system, wherein the first camera captures an image of the plurality of first presentation systems, and wherein the first laser tracking system determines the position of the laser point in the image corresponding to a laser point projected on any of the presentation systems; and
the second location further comprises a plurality of second presentation displays, each second presentation display driven by a second presentation system, and wherein the first laser projector projects the first laser point on the second presentation displays.
10. A remote laser pointer system comprising a plurality of locations; each location
distant from the other locations, each location comprising:
a camera for capturing an image containing a laser point;
a laser tracking system for determining a position of the laser point in the image and
generating control information corresponding to the determined position for
transmission to the other locations; a laser control system for receiving control information from the other locations,
determining control signals in response to the control information; and a laser projector for projecting at least one laser point in response to the control
signals.

11. The system of claim 10, wherein each laser control system comprises:
a laser control program for receiving the control signal and converting the control information from a coordinate system associated with the camera to a coordinate system associated with the laser projector; and
a laser control interface/ for coupling the control signal to the laser projector,
12. The system of claim 10, wherein each laser projector comprises:
a polychromatic laser projector adapted to project a plurality of different colored laser beams, each colored laser beam associated with a received control signal from another location.
13. The system of claim 10, wherein each location further comprises;
a video camera for capturing an image of a participant at the location as video
signals; an audio-video encoder coupled to the video camera for encoding the video signals; an audio-video gateway coupled to audio-video encoder for transmitting encoded
audio-video signals to at least one other of the locations and receiving
encoded audio-video signals from at least one other of the locations; an audio-video decoder coupled to the audio-video gateway for decoding the
received encoded audio-video signals; and a video presentation system, coupled to the audio-video decoder for displaying the
decoded video signals.
14. A remote laser pointer system comprising:
a first location, comprising:
a first presentation system, including a first presentation source, and a first presentation display for displaying first presentation content from the first presentation source;
a first camera for capturing an image of the presentation display, the image containing a laser point projected on the first presentation display;

a first tracking system that determines a position of the laser point in the image, and providing a control signal in response to the determined position; and a second location, comprising:
a second presentation display for receiving and displaying the first presentation content;
a first laser projector system for receiving the control signal, and in response to the control signal, projecting a laser point on the second presentation display corresponding to the laser point projected on the first presentation display.
15. The remote laser pointer system of claim 14, wherein;
the first location further comprises:
a first videoconferencing system coupled to the first presentation system for transmitting the content from the first presentatiQn source; and the second location further comprises:
a second videoconferencing system coupled over a network connection to the first videoconferencing system to receive the presentation content and provide the presentation content to the second presentation display.
16. The remote laser pointer system of claim 14, wherein:
the second location further comprises:
a second camera for capturing an image of the second presentation display, the
image containing a laser point projected on the second presentation
display; a second tracking system that determines a position of the laser point in the
image and provides a control signal in response to the determined
position; and the first location further comprises:
a second laser projector system for receiving the control signal from the second
tracking system, and in response to the control signal, projecting a laser

point on the first presentation display corresponding to the laser point projected on the second presentation display.
17. A method for conducting a meeting between participants at a first location and a
second location remote from the first location, the method comprising;
directing a laser pointer along a first laser path on a presentation area observable to
participants at the first location; and projecting on a presentation area observable to participants at the second location a
laser beam along a second laser path corresponding to the first laser path.
18. The method of claim 17, further comprising;
capturing at the first location images containing the first laser path;
determining the laser path in the captured images and generating control
information corresponding to the determined path; determining control signals in response to the control information; and projecting the second laser path in response to the control signals,
19. The method of claim 18, wherein determining control signals comprises;
converting the control information from a first coordinate system associated with
captured images to a second coordinate system associated with the second
location.
20. The method of claim 18, wherein generating control information comprises:
applying an inverse camera distortion transform to the captured images to produce
undistorted camera coordinates for the laser path; and normalizing the undistorted camera coordinates into device independent normalized coordinates.

21. The method of claim 20, wherein normalizing the undistorted camera coordinates (Xc, Yc) comprises dividing the camera coordinates by respective maximum camera coordinates (Xc.max', Yc,max') fox the first region of interest at the first location.
22. The method of claim 20, wherein determining a control signal comprises:
scaling the device independent normalized coordinates by maximum projector coordinates for a second region of interest at the second location; and
applying an inverse projector distortion transform to the scaled coordinates to produce projection coordinates for projecting the second laser path.
23. A method for operating a laser, the method comprising:
at a first site, indicating with a laser pointer a location on a first presentation area;
and at a second site remote from the first location, directing a laser beam to a
corresponding point on a second presentation area corresponding to the first
presentation area.
24. The method of claim 23, further comprising:
observing the laser pointer at the first site; and
wherein directing the laser beam at the second site is in response to the observed laser pointer at the first site.
25. The method of claim 23, wherein:
the laser pointer traces a first laser path on the first presentation area; and directing the laser beam comprises tracing a second laser path on the second presentation area that corresponds to the first laser path.
26. A method of providing a remote laser point, the method comprising:
capturing images of a source location, the images containing a laser point;
determining positions of the laser point in the images, and generating control
information corresponding to the determined positions; determining a control signal in response to the control information; and

projecting at the remote location a laser point in response to the control signal at a position in the remote location corresponding to the position of the laser point in the source location.
27. The method of claim 26, wherein determining a control signal comprises:
converting the control information from a first coordinate system associated with the
captured image to a second coordinate system associated with the remote location.
28. The method of claim 26, wherein generating control information comprises:
applying an inverse camera distortion transform to the captured image to produce
undistorted camera coordinates for the laser point; and normalizing the undistorted camera coordinates into device independent normalized coordinates.
29. The method of claim 26, wherein normalizing the undistorted camera coordinates (Xc', Yc') comprises dividing the camera coordinates by respective maximum camera coordinates(Xcmax,'yc,max) for a region of interest at the source location.
30. The method of claim 26, wherein determining a control signal comprises;
scaling the device independent normalized coordinates by maximum projector coordinates for a region of interest at the remote location; and
applying an inverse projector distortion transform to the scaled coordinates to produce projection coordinates.
31. A method of providing at a local location a laser point controlled from a remote
location, the method comprising:
receiving at the local location control information from the remote location corresponding to the position of a laser point at the remote location;
determining at the local location a control signal in response to the control information; and

projecting at the local location a laser point in response to the control signal at a position at the local location corresponding to the position of the laser point at the remote location.
32. The method of claim 31, wherein determining control signals comprises:
converting the received control information from a first coordinate system associated
with the remote location to a second coordinate system associated with the local location.
33. The method of claim 31, further comprising:
capturing images of a remote location/ the images containing a laser point; and determining positions of the laser point in the images and generating control information corresponding to the determined positions.
34. A method for providing a remote laser point at a plurality of locations, each location
distant from the other locations, the method comprising, at each location:
capturing images containing a laser point;
determining a position of the laser point in the captured image and generating
control information corresponding to the determined position; transmitting the control information to the other locations; receiving control information from the other locations; determining control signals in response to the received conh-ol information; and projecting at least one laser point in response to the control signals, each projected
laser point corresponding to control information from another location.
35. The method of claim 34, wherein determining control signals comprises:
converting the received control'information from a first coordinate system associated
with the other location to a second coordinate system associated with a laser projector at the location.

36. The method of claim 34, wherein projecting at least one laser point comprises:
projecting a plurality of differently colored laser beams, each laser beam associated
with another of the locations.
37. A method of providing a remote laser point, the method comprising:
at a first location:
displaying first presentation content on a first presentation display;
capturing images of the first presentation content, the image containing a laser
point; determining positions of the laser point in the captured images and providing
control signals in response to the determined positions; and at a second location:
receiving and displaying the first presentation content on a second presentation
display; receiving the control signals; and projecting in response to the control signal a laser point on the second
presentation display corresponding to the laser point projected on the
first presentation display.
38. The method of claim 37, further comprising:
at the second location:
capturing images of the second presentation display, the images containing a
laser point projected on the second presentation display; determining positions of the laser point in the captured image, and providing
control signals in response to the determined positions; and at the first location:
receiving the control signal from the second location; and
projecting in response to the control signals a laser point on the first presentation
display corresponding to the laser point projected on die second
presentation display.

39. A computer program product, comprising computer readable instructions stored on
a computer readable medium, for controlling a laser control system at a first location by
performing the operations of:
receiving control information corresponding to coordinate information for a laser point at a 9econd location remote from the first location;
converting the control information from a first coordinate system associated with the laser point to a second coordinate system associated with a laser projector at the first location to provide coordinate information for a laser point in the first location; and
providing to a laser projector control signals corresponding to the coordinate information for the laser point in the first location/ to thereby cause projection of the laser point at the first location.
40. A computer implemented method for controlling a laser control system at a first
location, the method comprising:
receiving control information corresponding to coordinate information for a laser point at a second location remote from the first location;
converting the control information from a first coordinate system associated with the laser point to a second coordinate system associated with a laser projector at the fast location to provide coordinate information for a laser point in the first location; and
providing to a laser projector control signals corresponding to the coordinate information for the laser point in the first location, to thereby cause projection of the laser point at the first location.
41. A remote laser pointer system, comprising:
a camera for capturing an image of a source location containing a laser point;
a laser tracking means, coupled to the camera, for determining a position of the laser
point in the image, and generates control information corresponding to the
determined position;

a laser control means at a remote location from the 6ource location, coupled to the laser tracking means for receiving the control information and determining a control signal in response to the control information; and
a laser projecting means at the remote location, coupled to the laser control means, for projecting a laser point in response to the control signal at a position in the remote location corresponding to the position of the laser point in the source location.