1.TECHNICAL FIELD
The present invention relates to the field of remote controlling, and more particularly,
to remote controlling over a delayed communication link via a vision display.
2. DISCUSSION OF THE RELATED ART
Prior to setting forth the background of the related art, it may be helpful to set forth
definitions of certain terms that will be used hereinafter.
The term "remotely piloted aircraft" (RPA) or "unmanned aerial vehicle" (UAV/RPA)
as used herein in this application, refers to an aircraft flying without a human pilot. A
UAV/RPA may be remotely controlled or fly autonomously based on pre
programmed flight plans or more complex dynamic automation systems. UAVs/RPAs
are currently used in a number of military roles, including reconnaissance. They are
also used in a small but growing number of civil applications such as firefighting
when a human observer would be at risk, police observation of civil disturbances and
crime scenes, and reconnaissance support in natural disasters.
The term "payload" as used herein in this application, is the load carried by an
UAV/RPA exclusive of what is necessary for its operation. The payload may
comprise, inter alia, an imaging apparatus that provides the user of the UAV/RPA
with a dynamic vision display (e.g. a video sequence). The vision display may
comprise a predefined point that corresponds with the general pointing point of the
payload. The pointing point may be indicated in a particular graphic manner (e.g., a
cross) so that the user will be informed of the current pointing direction of the
payload.
The term "transponder" as used herein in this application, refers to a communication
relay unit, usually in the form of a communication satellite that enables long range
communication between the user and the remotely controlled UAV/RPA.

FIG. I is a high level schematic diagram showing a communication link between a
user and a remote controlled unmanned aerial vehicle (UAV/RPA). A user (not
shown) is in operative association with a control station 10 that is in direct
communication with a transponder such as a communication satellite 20.
Communication satellite 20 is in direct communication with UAV/RPA 30 that carries
a payload such as an imaging apparatus 35. Between imaging apparatus 35 and a
potential target 40 there is a direct line of sight. In operation, imaging apparatus 35
repeatedly captures images that may contain potential target 40. These images are
transmitted to communication satellite 20 which in turn, transmits them to control
station 10 thereby providing the user with a dynamic vision display (e.g. video
sequence) associated with the pointing direction of imaging apparatus 35.
Remote controlling a UAV/RPA via a transponder, as discussed above usually results
in a substantial delay in the communication link. The delay is constituted of two parts.
The first part is an uplink delay which is the delay from the time a control command is
given (and transmitted) by the user until the control command reaches the payload.
The second part is a downlink delay which is a delay from the time of a particular
image of the video sequence is captured until the time that particular image reaches
the user.
Consequently, controlling a payload on a UAV/RPA over a delayed communication
link may pose substantial challenges for UAV/RPA users. Many UAV/RPA
operations require the payload to be pointed directly at user identified targets seen on
the vision display.
BRIEF SUMMARY
In embodiments of the present invention, there is provided a method of enabling a
user to control a pointing direction of an imaging apparatus over a delayed
communication link. The method comprises: enabling the user to track a user-
identified target on a currently presented image of periodically transmitted images
from the imaging apparatus; calculating a distance between the estimated location of
the user-identified target in view of the user's tracking and the estimated location of
the pointing point of the imaging apparatus at said future time, wherein the estimation
relate to a future time by which a command control currently transmitted by the user

reaches the imaging apparatus; and calculating a command control required for
directing the pointing point of the imaging apparatus onto the user-identified target,
based on said calculated distance and further based on all previous control commands
that had been already transmitted by the user but have not yet affected the currently
presented image due to the delay in the communication link.
According to one aspect of the invention there is provided a computer implemented
method of enabling a user to control a pointing direction of an imaging apparatus over
a communication link exhibiting an uplink delay and a downlink delay, by
periodically transmitting a control command for directing the imaging apparatus,
wherein the imaging apparatus periodically transmits to the user an image, and
wherein the transmitted image is presented to the user and contains a pointing point of
the imaging apparatus, the method comprising: enabling the user to track a user-
identified target on a currently presented image of the periodically transmitted images;
estimating a location of the user-identified target in view of the user's tracking, at a
future time corresponding with the uplink delay, wherein the uplink delay is a time
required for a command control currently transmitted by the user to reach the imaging
apparatus; estimating a location of the a pointing point of the imaging apparatus,
at a future time related to the uplink delay; calculating a distance between the
estimated location of the user-identified target and the estimated location of the
pointing point of the imaging apparatus at said future time; and calculating a
command control required for spatially directing the pointing point of the imaging
apparatus onto the user-identified target, based on said calculated distance and taking
into account all previous control commands that had been already transmitted by the
user but have not yet affected the currently presented image.
These, additional, and/or other aspects and/or advantages of the present invention are
set forth in the detailed description which follows; possibly inferable from the detailed
description; and/or learnable by practice of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention and to show how the same may be carried
into effect, reference will now be made, purely by way of example, to the
accompanying drawings in which like numerals designate corresponding elements or
sections throughout.

In the accompanying drawings:
FIG. 1 is a high level schematic diagram of a unmanned aerial vehicle (UAV/RPA)
controlled via a satellite according to the existing art;
FIG. 2 is a high level flowchart showing an aspect of the method according to some
embodiments of the invention;
FIG. 3 is a timing diagram showing an aspect of the method according to some
embodiments of the invention;
FIG. 4 is a schematic diagram of a vision display according to some embodiments of
the invention;
FIG. 5 is a timing diagram showing an aspect of the method according to some
embodiments of the invention; and
FIG. 6 and FIG. 7 show a high level flowchart illustrating an aspect of a method
according to some embodiments of the invention.
The drawings together with the following detailed description make apparent to those
skilled in the art how the invention may be embodied in practice.
DETAILED DESCRIPTION
With specific reference now to the drawings in detail, it is stressed that the particulars
shown are by way of example and for purposes of illustrative discussion of the
preferred embodiments of the present invention only, and are presented in the cause of
providing what is believed to be the most useful and readily understood description of
the principles and conceptual aspects of the invention. In this regard, no attempt is
made to show structural details of the invention in more detail than is necessary for a
fundamental understanding of the invention, the description taken with the drawings
making apparent to those skilled in the art how the several forms of the invention may
be embodied in practice.
Before explaining at least one embodiment of the invention in detail, it is to be
understood that the invention is not limited in its application to the details of
construction and the arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is applicable to other

embodiments or of being practiced or carried out in various ways. Also, it is to be
understood that the phraseology and terminology employed herein is for the purpose
of description and should not be regarded as limiting.
The present invention, in embodiments thereof, provides a method of enabling a user
to effectively control a remotely located imaging apparatus over a communication link
exhibiting a delay. Embodiments of the present invention take into account the delays
involved in computing the optimal commands that need to be transmitted at any given
time in order to direct the imaging device on a target identified by the user. In addition
to a visual display (e.g., a video sequence exhibiting consecutive images) constantly
transmitted to the user by the imaging device, the user is provided with an interface
enabling him or her to track a target he or she identifies on the visual display. The
tracking of the target is then used by the proposed method to estimate the location and
velocity of the identified target on an image currently presented to the user, at a future
time which corresponds with the time by which commands executed by the user at a
current time will reach the imaging apparatus. Together with the estimation of the
location of the pointing point of the imaging device at the aforementioned future time,
the proposed method may calculate the required commands in order to direct the
imaging apparatus onto the target. According to embodiments of the present
invention, the calculated commands further take into account all previous commands
that had been transmitted by the user but have not yet affected the image currently
presented to the user.
FIG. 2 is a high level flowchart showing an aspect of the method according to some
embodiments of the invention. The flowchart shows a method of enabling a user to
control a spatial direction of an imaging apparatus over a communication link
exhibiting an uplink delay and a downlink delay. The method comprises: periodically
transmitting a control command for spatially directing the imaging apparatus, wherein
the imaging apparatus periodically transmits to the user an image, and wherein the
user is presented with the transmitted image which contains a pointing point of the
imaging apparatus 210; enabling the user to track a user-identified target on a
currently presented image of the periodically transmitted images 220 in real time;
estimating a location of the user-identified target in view of the user's tracking and the
command control which directed the presented image, at a future time corresponding
with the uplink delay, wherein the uplink delay is a time required for a command

control currently transmitted by the user to reach the imaging apparatus 230;
estimating a location of the a pointing point of the imaging apparatus, at a future time
related to the uplink delay 240; calculating a distance between the location of the
user-identified target and the location of the pointing point of the imaging apparatus at
said future time 250; and calculating a command control required for spatially
directing the pointing point of the imaging apparatus onto the user-identified target,
based on said calculated distance and further based on all previous control commands
that had been already transmitted but have not yet affected the currently presented
image due to the downlink and the uplink delays 260.
FIG. 3 is a timing diagram showing an aspect of the method according to some
embodiments of the invention. Timing diagram 300 shows a time-scale exhibiting
periods or cycles of operation 1-14. In each cycle, a new image from the imaging
apparatus is presented to the user and further, a command control from the user may
be transmitted to the imaging apparatus. As explained above, due to the delayed
communication link there is a time difference between transmitting a command by the
user 310 and receiving it by the imaging apparatus 312. This delay is denoted as the
uplink delay 320, 340. There is also a delay due to the time difference between
transmitting the image by the imaging apparatus 312 and receiving it by the user 314.
This delay is denoted as the downlink delay 340. For the sake of simplicity, in the
aforementioned example, receiving the command by the imaging apparatus and
transmitting an image by the imaging apparatus occur at the same time.
In operation, an image that is currently presented to the user in time t=l0 was actually
obtained by the imaging apparatus and transmitted by the UAV/RPA at time t=4.
Additionally, any command that is currently transmitted by the user at time t=10 will
only reach the imaging apparatus at time t=13. Embodiments of the present invention
overcome these two types of delays by taking them into account while calculating, at
any given time, the required command for directing the pointing point of the imaging
apparatus onto the user-identified target.
Since during the uplink delay both the pointing point of the imaging apparatus and the
user-identified target will change their position, it is necessary to determine both their
location at time t=13.

According to some embodiments of the invention, the position of the pointing point of
the imaging apparatus is easily determined by summing up all the previous commands
that have been already transmitted. In addition, the location of the user-identified
target may be estimated by first calculating it's momentary and then average velocity
under the assumption that it's velocity (a vector incorporating speed and direction)
does not change substantially during the uplink delay. The momentary velocity is
calculated by comparing the location of both user-identified target and pointing point
of the imaging apparatus in a currently presented image to their location in a
previously presented image (one period/cycle earlier). Thus an average velocity may
also be calculated - several momentary velocities averaged over a predefined time
such as the total delay, uplink and downlink added together.
According to some embodiments of the invention, the location of the user-identified
target is determined by enabling the user to track it independently. By successfully
tracking the target, the user determines at any given time and for each transmitted
image, the location of the user-identified target. The tracking is enabled, by providing
a graphical user interface as explained below.
FIG. 4 is a schematic diagram of a vision display according to some embodiments of
the invention. Vision display 400 comprises a dynamically changing image, on a
cycle-by cycle basis (period-by-period). Vision display 400 may be a video sequence
exhibiting the optical image taken by the imaging apparatus or any other imaging
technology, including radar, infrared (IR) and the like. Vision display 400 presents the
images taken by the imaging apparatus which may contain a target 420 identifiable by
the user. Vision display 400 also presents a pointing point which represents the
pointing point of the imaging apparatus. In addition, according to some embodiments
of the invention a command curser 430 is also presented to the user over vision
display 400.
In operation, the user is enabled to move command curser 430 towards user-identified
target 420. By tracking user-identified target 420, the user determines the location of
user-identified target 420 in any given image. Thus, the location of user-identified
target 420 in a currently presented image may be used for estimating it's future
location at a time corresponding to the current time plus the uplink delay. In the case
where the user-identified target 420 is not automatically identifiable, embodiments of
the present invention enable the determination of the location of user-identified target

420 by assuming that the user will successfully track user-identified target 420 using
command curser 430 after a predefined time.
Alternatively, the location of the user identified target may be determined
automatically using machine vision techniques or by an external tracker. In these
embodiments, the user may be enabled to provide an initial indicating only of the
target upon identifying it, leaving the actual tracking for the aforementioned
automatic tracking means.
FIG. 5 is timing diagram showing an aspect of the method according to some
embodiments of the invention. Similarly to FIG. 3, timing diagram 500 shows a time-
scale exhibiting periods or cycles of operation 1-14. In each cycle, a new image from
the imaging apparatus is presented to the user and further, a command control from
the user may be transmitted to the imaging apparatus. As explained above, due to the
delayed communication link there is a time difference between transmitting a
command by the user 310 and receiving it by the imaging apparatus 312. This delay is
denoted as the uplink delay 320, 340. There is also a delay due to the time difference
between transmitting the image by the imaging apparatus 312 and receiving it by the
user 314. This delay is denoted as the downlink delay 340. For the sake of simplicity,
in the aforementioned example, receiving the command by the imaging apparatus and
transmitting an image by the imaging apparatus occur at the same time.
Given that the currently presented image is at time t=10 510, the currently presented
image was actually obtained and transmitted at time r=4 and therefore it only reflects
the command (in axis X and Y) that has been transmitted by time t=l. This is because
it takes an uplink delay 320 for a transmitted command to reach the imaging
apparatus. Thus, commands that have been transmitted at time cycles t=2, 3,4, 5, 6, 7,
8, and 9 would not affect the currently presented image of time t=10. Therefore, while
calculating the required command to be transmitted at time t=10, two delays need to
be taken into consideration. First, an estimation of the distance between the locations
of both the pointing point of the imaging apparatus and the user-identified target at
time t=13 (taking into account uplink delay 340) is performed in view of their
respective locations in the currently presented image of time t=10 and the velocity of
the user-defined target. Second, a summation of all previous commands that had been
already transmitted but have net yet affected the currently presented image needs to be
taken into account.

According to some embodiments of the invention, calculating a command control
required for directing the pointing point of the imaging apparatus is followed by
transmitting the calculated command to the imaging apparatus.
According to some embodiments of the invention, each image comprises an array of
pixels and wherein distances are calculated by calculating the difference in the
location of the corresponding pixels.
According to some embodiments of the invention, the differences are calculated in
angular terms.
According to some embodiments of the invention, the pointing point of the imaging
apparatus is located in the center of the image of the visual display.
According to some embodiments of the invention, enabling the user to track a user-
identified target on a currently presented image of the periodically transmitted images
is achieved and implemented by presenting a command cursor over the visual display,
wherein the user is enabled to move the command curser towards the user-identified
target thereby tracking it.
According to some embodiments of the invention, initially, the command cursor is
located on the pointing point of the imaging apparatus.
In the reminder of the description, a potential implementation of the aforementioned
method is depicted in detail according to some embodiments of the invention. The
example described herein illustrates in a non-limiting manner a possible
implementation of the location estimation mechanism of both the pointing point of the
imaging apparatus and the user-identified target at a time that is advanced by an
uplink delay from the current time.
The proposed algorithm makes use of the aforementioned user interface of a
command indicator that may be moved by the user at any given time. The algorithm
starts with calculating the distance between the location of the command cursor and
the pointing point at the current time t. it then goes to measure the same distance in a
previous cycle (period) t-1 and calculates the difference between the current and
previous location distance.

Then the momentary velocity (per cycle) of the target is estimated in accordance with
the following formula:

Wherein, in the aforementioned formula (1), Velocity is a vector denoting the velocity
of the user-identified target at time t for each axis j (X and Y); Command denotes all
the commands in each j axis that were transmitted at time t-N; wherein N is the total
delay (uplink and downlink summed up); and wherein Difference denotes the
difference between the distance between the locations of the command cursor and the
pointing point at time t and the respective distance at time t-1.
Then, the estimated average velocity per cycle (period) for each axis j is being
calculated in accordance with the following formula:

Wherein, in the aforementioned formula (2), EstVelocity is a vector denoting the
estimated average velocity of the user-identified target at time t in each axis j;
Velocity is a vector denoting the velocity of the user-identified target at time t, and N
denotes the number of cycles used for estimating the average velocity which is
preferably set to the number of cycles in the total delay (uplink and downlink summed
up). The summation in formula (2) is over the number of cycles used for estimating
the average velocity which is as noted, set to the number of cycles in the total delay.
Then, the estimated location of the target in relation to the location of the pointing
point of the imaging apparatus, at time t=t+uplink-l is calculated in accordance with
the following formula:


Wherein, in the aforementioned formula (3), ForecastDist is an estimated distance
between the user identified target and the pointing point of the imaging apparatus at
the time the current command reaches the imaging apparatus, wherein Dist is the
current distance between the user-identified target and the pointing point and
EstVelocity is a vector denoting the estimated average velocity of the user-identified
target at time t in each axis j.
Then, all commands that had been already transmitted by the user and have not yet
been affected in the currently presented image are calculated in accordance with the
following formula:

Wherein, in the aforementioned formula (4), NotYetAffected denotes a summation of
all commands that had been already transmitted and have not yet been affected in the
currently presented image.
Then, the estimated distance between the estimated location of the pointing point of
the imaging apparatus and the estimated location user-identified target, at time
t+uplink-1 which represent one cycle before the time in which presently transmitted
commands reach the imaging apparatus, is calculated in accordance with the
following formula:

Wherein, in the aforementioned formula (5), ForecastTotDist is an estimated distance
between the estimated location of the pointing point of the imaging apparatus and the
estimated location of the user-identified target; ForecastDist is an estimated distance
between the user identified target and the pointing point of the imaging apparatus one
cycle before the time the current command reaches the imaging apparatus; and
NotYetAffected denotes a summation of all commands that had been already
transmitted by the user and have not yet been affected in the currently presented
image.

Then, the required command for directing the imaging apparatus onto the user-
identified target at time t is calculated in accordance with the following formula:

Wherein, in the aforementioned formula (6), ForecasTotDist is the estimated distance
between the estimated location of the pointing point of the imaging apparatus and the
estimated location of the user-identified target; EstVelocity is a vector denoting the
estimated average velocity of the user-identified target at time t in each axis j; and
CyclesToOvertake is the number of cycles that is set for closure of the distance
between the estimated location of the pointing point of the imaging apparatus and the
estimated location of the user-identified target.
FIG. 6 and FIG. 7 show a high level flowchart illustrating an implementation of the
aforementioned algorithm according to some embodiments of the invention. The
flowchart shows a computer implemented method of controlling an imaging apparatus
over a delayed communication link, by periodically transmitting a control command
to the imaging apparatus, the method comprises: presenting a user with a visual
display operatively associated with images periodically obtained by the imaging
apparatus, the visual display comprising a sequence of images, each image associated
with a particular cycle, wherein each image contains a pointing point of the imaging
apparatus, and a command curser 600; enabling the user, in each particular cycle, to
direct the command curser towards a user-identified target contained within a
particular image, thereby tracking the user-identified target 610; calculating, in each
particular cycle, a first distance exhibiting a distance between the command cursor
and the indicator of the pointing point of the imaging apparatus 620;
calculating, in each particular cycle, a difference between the first distance at the
particular cycle and the first distance in a previous cycle 630; estimating, in each
particular cycle, a velocity of the user-identified target by adding the calculated
difference to the control command transmitted at a cycle preceding the particular
cycle by a total delay being the delay required for a transmitted command to affect an
image presented to the user 640; calculating, in each particular cycle, an average over

a predefined time, of the estimated velocity of the user-identified target 650;
estimating, in each particular cycle, a second distance between the estimated location
of the user-identified target at a future cycle , one cycle before commands transmitted
will reach the imaging apparatus and the location of the pointing point of the imaging
apparatus at the particular cycle, by adding the distance between the command cursor
and the pointing point of the imaging apparatus at the particular cycle, to the average
velocity of the target multiplied by the total delay-1 660; summing up, in each
particular cycle, all previous commands that had been already transmitted but have
not been yet affected the image presented in the particular cycle 670; calculating, in
each particular cycle, a third distance between the estimated location of the pointing
point of the imaging apparatus and the estimated location of the user-identified target
at a future cycle, one cycle before commands transmitted by the user will reach the
imaging apparatus, by subtracting the summed up all previous commands from the
second distance 680; and calculating, in each particular cycle, a control command
required for directing the imaging device onto the user-identified target by adding the
estimated average velocity of the target to the third distance divided by a predefined
time set for overtaking the user-identified target 690.
According to some embodiments of the invention, calculating, in each particular
cycle, a control command required for directing the pointing point of the imaging
apparatus is followed by transmitting the calculated command to the imaging
apparatus.
According to some embodiments of the invention, the command cursor is initially
located on the pointing point of the imaging apparatus.
According to some embodiments of the invention, the pointing point of the imaging
apparatus is located in the center of each image.
According to some embodiments of the invention, the velocity and distances are
calculated in angular terms.
According to some embodiments of the invention, the averaged estimated velocity is
averaged over the total delay.
According to some embodiments of the invention, the predefined time set for over-
taking the user-identified target is set to the total delay.

Advantageously, the present invention is aimed for the unmanned aerial vehicle
market (UAV/RPAs). However, it is understood that the necessary modification may
be performed in order to support any kind of remote controlling of a device that is
equipped with an imaging apparatus, over a delayed communication link, be it
manned or unmanned. Such devices may comprise, but are not limited to: remote
controlled weaponry, aerospace related device, submarines, surface vehicles and the
like.
According to some embodiments of the invention, the disclosed method may be
implemented in digital electronic circuitry, or in computer hardware, firmware,
software, or in combinations thereof.
Suitable processors may be used to implement the aforementioned method. Generally,
a processor will receive instructions and data from a read-only memory or a random
access memory or both. The essential elements of a computer are a processor for
executing instructions and one or more memories for storing instructions and data.
Generally, a computer will also include, or be operatively coupled to communicate
with, one or more mass storage devices for storing data files. Storage devices suitable
for tangibly embodying computer program instructions and data include all forms of
non-volatile memory, including by way of example semiconductor memory devices,
such as EPROM, EEPROM, and flash memory devices.
In the above description, an embodiment is an example or implementation of the
inventions. The various appearances of "one embodiment," "an embodiment" or
"some embodiments" do not necessarily all refer to the same embodiments.
Although various features of the invention may be described in the context of a single
embodiment, the features may also be provided separately or in any suitable
combination. Conversely, although the invention may be described herein in the
context of separate embodiments for clarity, the invention may also be implemented
in a single embodiment.
Reference in the specification to "some embodiments", "an embodiment", "one
embodiment" or "other embodiments" means that a particular feature, structure, or
characteristic described in connection, with the embodiments is included in at least
some embodiments, but not necessarily all embodiments, of the inventions.

It is to be understood that the phraseology and terminology employed herein is not to
be construed as limiting and are for descriptive purpose only.
The principles and uses of the teachings of the present invention may be better
understood with reference to the accompanying description, figures and examples.
It is to be understood that the details set forth herein do not construe a limitation to an
application of the invention.
Furthermore, it is to be understood that the invention can be carried out or practiced in
various ways and that the invention can be implemented in embodiments other than
the ones outlined in the description above.
It is to be understood that the terms "including", "comprising", "consisting" and
grammatical variants thereof do not preclude the addition of one or more components,
features, steps, or integers or groups thereof and that the terms are to be construed as
specifying components, features, steps or integers.
If the specification or claims refer to "an additional" element, that does not preclude
there being more than one of the additional element.
It is to be understood that where the claims or specification refer to "a" or "an"
element, such reference is not be construed that there is only one of that element.
It is to be understood that where the specification states that a component, feature,
structure, or characteristic "may", "might", "can" or "could" be included, that
particular component, feature, structure, or characteristic is not required to be
included.
Where applicable, although state diagrams, flow diagrams or both may be used to
describe embodiments, the invention is not limited to those diagrams or to the
corresponding descriptions. For example, flow need not move through each illustrated
box or state, or in exactly the same order as illustrated and described.
Methods of the present invention may be implemented by performing or completing
manually, automatically, or a combination thereof, selected steps or tasks.
The term "method" may refer to manners, means, techniques and procedures for
accomplishing a given task including, but not limited to, those manners, means,

techniques and procedures either known to, or readily developed from known
manners, means, techniques and procedures by practitioners of the art to which the
invention belongs.
The descriptions, examples, methods and materials presented in the claims and the
specification are not to be construed as limiting but rather as illustrative only.
Meanings of technical and scientific terms used herein are to be commonly
understood as by one of ordinary skill in the art to which the invention belongs, unless
otherwise defined.
The present invention may be implemented in the testing or practice with methods and
materials equivalent or similar to those described herein.
Any publications, including patents, patent applications and articles, referenced or
mentioned in this specification are herein incorporated in their entirety into the
specification, to the same extent as if each individual publication was specifically and
individually indicated to be incorporated herein. In addition, citation or identification
of any reference in the description of some embodiments of the invention shall not be
construed as an admission that such reference is available as prior art to the present
invention.
While the invention has been described with respect to a limited number of
embodiments, these should not be construed as limitations on the scope of the
invention, but rather as exemplifications of some of the preferred embodiments.
Other possible variations, modifications, and applications are also within the scope of
the invention. Accordingly, the scope of the invention should not be limited by what
has thus far been described, but by the appended claims and their legal equivalents.

We Claim:
1. A method of spatially directing an imaging apparatus over a communication link
exhibiting an uplink delay and a downlink delay, by periodically transmitting a
control command for directing the imaging apparatus, wherein the imaging apparatus
periodically transmits to the user an image, and wherein the transmitted image is
presented to the user and contains a pointing point of the imaging apparatus, the
method comprising:
enabling the user to track a user-identified target on a currently presented image
of the periodically transmitted images;
estimating a location of the user-identified target based on a tracking by the
user, at a future time corresponding with the uplink delay, wherein the uplink delay is
a time required for a command control currently transmitted by the user to reach the
imaging apparatus;
estimating a location of a pointing point of the imaging apparatus, at a future
time corresponding with the uplink delay;
calculating a distance between the estimated location of the user-identified
target and the estimated location of the pointing point at the future time; and
calculating a command control that will direct the pointing point onto the user-
identified target, based on the calculated distance and all previous control commands
that have been transmitted to the imaging apparatus but have not yet affected the
currently presented image,
wherein at least one of: the presenting, the estimating, and the calculating is
performed by at least one computer.
2. The method according to claim 1, further comprising transmitting the calculated
command to the imaging apparatus, after the calculating a command control.
3. The method according to claim 1, wherein each image comprises an array of
pixels, and wherein distances are calculated by calculating differences in locations of
corresponding pixels of successive images.

4. The method according to claim 1, wherein the differences are calculated in
angular terms.
5. The method according to claim 1, wherein the pointing point of the imaging
apparatus is located in a center of the image of a visual display.
6. The method according to claim 1, wherein the enabling is implemented by
receiving an initial indication relating to the position of the user-identified target, and
wherein the tracking is implemented automatically using machine vision techniques.
7. The method according to claim 1, wherein the enabling is implemented by
receiving an initial indication relating to the position of the user-identified target, and
wherein the tracking is implemented automatically using an external tracking means.
8. The method according to claim 1, wherein the enabling is implemented by
presenting a command cursor over a visual display, and wherein the user permitted to
move the command curser towards the user-identified target.
9. The method according to claim 8, wherein, initially, the command cursor is
located on the pointing point of the imaging apparatus.
10. A computer program product for controlling an imaging apparatus over a delayed
communication link, by periodically transmitting control commands to the imaging
apparatus, the computer program product comprising:
a computer readable storage medium having computer readable program
embodied therewith, the computer readable program comprising:
computer readable program configured to present a user, via a visual display,
with a sequence of images periodically obtained by the imaging apparatus, each image
associated with a particular cycle, wherein each image includes a pointing point of the
imaging apparatus, and a command curser;
computer readable program configured to enable the user, in each particular
cycle, to move the command curser towards a user-identified target within an
associated image, thereby tracking the user-identified target;

computer readable program configured to calculate, for each particular cycle, a
first distance that is between the command cursor and the indicator of an orientation
of the imaging apparatus;
computer readable program configured to calculate, for each particular cycle, a
difference between a first distance in the particular cycle and the first distance in a
previous cycle;
computer readable program configured to estimate, for each particular cycle, a
velocity of the user-identified target by adding the calculated difference to a control
command transmitted at a cycle preceding the particular cycle by a total delay that is
required for a transmitted command to affect an image presented to the user;
computer readable program configured to calculate, for each particular cycle,
an average over a predefined time, of the estimated velocity of the user-identified
target;
computer readable program configured to estimate, for each particular cycle, a
second distance that is between the estimated location of the user-identified target in
a future cycle in which commands transmitted by the user will reach the imaging
apparatus and the location of the pointing point of the imaging apparatus at the
particular cycle, by adding the distance between the command cursor and the pointing
point of the imaging apparatus at the particular cycle, to the average velocity of the
target multiplied by the total delay;
computer readable program configured to sum-up, in each particular cycle, all
previous commands that have been transmitted by the user but have not yet affected
the image presented in the particular cycle;
computer readable program configured to calculate, for each particular cycle, a
third distance that is between the estimated location of the pointing point of the
imaging apparatus and the estimated location of the user identified target at a future
cycle in which commands transmitted by the user will reach the imaging apparatus, by
subtracting the summed up all previous commands from the second distance; and
computer readable program configured to calculate, for each particular cycle, a
control command that will direct the imaging device onto the user-identified target by
adding the estimated average velocity of the target to the third distance divided by a
predefined time set for overtaking the user-identified target.

11. The computer program product according to claim 10, further comprising
computer readable program configured to initiate transmission the calculated
command to the imaging apparatus.
12. The computer program product according to claim 10, wherein, the command
cursor is initially located on the pointing point of the imaging apparatus.
13. The computer program product according to claim 10, wherein the pointing point
of the imaging apparatus is located in the center of each image.
14. The computer program product according to claim 10, wherein the velocity and
distances are calculated in angular terms.
15. The computer program product according to claim 10, wherein the averaged
estimated velocity is averaged over the total delay.
16. The computer program product according to claim 10, wherein the predefined
time set for overtaking the user-identified target is set to the total delay.
17. A system for spatially directing an imaging apparatus over a communication link
exhibiting an uplink delay and a downlink delay, by periodically transmitting a
control command for directing the imaging apparatus, wherein the imaging apparatus
periodically transmits to the user an image, and wherein the transmitted image is
presented to the user and contains a pointing point of the imaging apparatus, the
system comprising:
a user interface configured to enable the user to track a user-identified target on
a currently presented image of the periodically transmitted images; and
a processor configured to:
estimate a location of the user-identified target based on a tracking by
the user over the user interface, at a future time corresponding with the uplink
delay, wherein the uplink delay is a time required for a command control
currently transmitted by the user to reach the imaging apparatus;
estimate a location of a pointing point of the imaging apparatus, at a
future time corresponding with the uplink delay;

calculate a distance between the estimated location of the user-
identified target and the estimated location of the pointing point at the future
time; and
calculate a command control that will direct the pointing point onto the
user-identified target, based on the calculated distance and all previous control
commands that have been transmitted to the imaging apparatus but have not
yet affected the currently presented image.
18. The system according to claim 17, further comprising a transmitting module
configured to transmit the calculated command to the imaging apparatus, after the
calculating a command control.
19. The system according to claim 17, wherein each image presented over the user
interface comprises an array of pixels, and wherein distances are calculated by
calculating differences in locations of corresponding pixels of successive images.

Method that includes: enabling the user to track a user-identified target on a
currently presented image of periodically transmitted images from an imaging
apparatus; calculating a distance between the estimated location of the user-
identified target in view of the user's tracking and the estimated location of the
pointing point of the imaging apparatus at said future time, wherein the estimation
relate to a future time by which a command control currently transmitted by the user
reaches the imaging apparatus; and calculating a command control required for
directing the pointing point of the imaging apparatus onto the user-identified target,
based on said calculated distance, the estimated average velocity of the user-
identified target and further based on all previous control commands that had been
already transmitted by the user but have not yet affected the currently presented
image due to the delay in the communication link.