THREE-DIMENSIONAL IMAGING DEVICE AND METHOD, AS WELL AS PROGRAM
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a three-dimensional imaging
device and a three-dimensional imaging method for obtaining two or
more images to be used for three-dimensional display by imaging a
subject from different positions, as well as a program for causing
a computer to carry out the three-dimensional imaging method.
Description of the Related Art
It has been known that stereoscopic viewing using a parallax
can be achieved by combining two or more images and
three-dimensionally displaying the combined images. Such
stereoscopic viewing can be provided by taking two or more images
of the same subject from different positions using two or more cameras,
and three-dimensionally displaying the two or more images by using
a parallax between the subject images contained in the images.
Specifically, if the stereoscopic viewing is achieved by
parallel viewing with naked eyes, the three-dimensional display can
be achieved by arranging the images side by side. Further, the
three-dimensional display may be achieved by combining the images,
for example, by overlapping the images with providing the images
with different colors, such as red and blue, or by overlapping the
images with providing the images with different polarization
directions. In these cases, the stereoscopic viewing can be achieved
by using image separating glasses, such as red-and-blue glasses or
polarization glasses, to provide a merged view of the
three-dimensionally displayed images, which is attained via the
automatic focusing function of the eyes (anaglyph system,
polarization filter system).
The stereoscopic viewing can also be achieved without using
the polarization glasses, or the like, by displaying the images on
a three-dimensional display monitor which can provide stereoscopic
viewing, such as a monitor of a parallax barrier system or a lenticular
system. In this case, the three-dimensional display is achieved by

cutting the images into vertical strips and alternately arranging
the vertical strips of the images. Moreover, a system for providing
the three-dimensional display by alternately displaying left and
right images with changing directions of light beams from the left
and right images through the use of image separation glasses or by
attaching an optical element on the liquid crystal display has been
proposed (scanning backlight system).
Further, stereoscopic cameras provided with two or more
imaging units to carry out imaging for the above-described
three-dimensional display have been proposed. This type of
stereoscopic camera includes two or more imaging units disposed apart
from each other by a predetermined distance and generates an image
for three-dimensional display from the images obtained by the two
or more imaging units. The thus generated image for three-dimensional
display can be three-dimensionally displayed on a monitor. In
addition, a method for use with this type of stereoscopic camera
for successfully providing stereoscopic viewing by changing
positions of the two or more images depending on a parallax level
between corresponding areas in the two or more images has been
proposed (see Japanese Unexamined Patent Publication No.
8(1996)-009421, hereinafter "Patent Document 1").
In the case where imaging is carried out using the stereoscopic
camera, a live view image is three-dimensionally displayed on the
monitor before the release button is pressed. At this time, an angle
of view to be imaged can be changed using a zoom function of each
imaging unit. In this case, the photographer can image a subject
at a desired size by making a zoom control operation on the
stereoscopic camera while viewing the three-dimensionally displayed
live view image.
As described above, when the stereoscopic camera carries out
a zoom operation, the angle of view is changed. During the zoom
operation,.the subject may often be out of focus. Further, since
the stereoscopic camera includes the two or more imaging units, the
zoom operation is carried out synchronously at the two or more imaging
units. However, due to individual variability of a motor and a

mechanism for performing the zoom function at each imaging unit,
it is very difficult to achieve completely synchronous zoom operation
at the imaging units. The three-dimensional display uses optical
illusion to stereoscopically display the images. Therefore, when
the zoom operation is carried out while the live view image is
three-dimensionally displayed, the subject may be out of focus or
the angle of view may vary at each imaging unit. Thus, during the
zoom operation, the stereoscopic effect of the three-dimensionally
displayed image may change or the stereoscopic effect may appear
or disappear, and this makes it very hard to perform stereoscopic
viewing.
SUMMARY OF THE INVENTION
In view of the above-described circumstances, the present
invention is directed to alleviating uncomfortable feeling felt when
stereoscopic viewing cannot be performed during a zoom operation
when two or more images are taken for three-dimensional display.
A three-dimensional imaging device according to the invention
includes:
two or more imaging means for obtaining two or more images
having a parallax therebetween by imaging a subject from different
positions, the two or more imaging means having an optical zoom
function;
three-dimensional processing means for applying
three-dimensional processing for three-dimensional display to the
two or more images;
display means for carrying out various types of display
including three-dimensional display of the two or more images; and
display control means for carrying out three-dimensional
display with a reduced parallax between the two or more images or
two-dimensional display while the imaging means carry out a zoom
operation.
The "three-dimensional display with a reduced parallax"
refers to three-dimensional display carried out with reducing a
stereoscopic effect, which has been felt while the
three-dimensionally displayed image is viewed before the zoom

operation, and the "two-dimensional display" refers to display with
no stereoscopic effect, i.e., with no parallax.
In the three-dimensional imaging device according to the
invention, the three-dimensional processing means may carry out the
three-dimensional processing with a reduced parallax while the
imaging means carry out the zoom operation.
The three-dimensional display with a reduced parallax or the
two-dimensional display may be achieved by reducing a distance
between the two or more imaging means.
In the three-dimensional imaging device according to the
invention, in a case where an object is three-dimensionally displayed
with being superposed on the three-dimensionally displayed image,
the display control means may carry out three-dimensional display
with a reduced parallax or two-dimensional display of the object
while the imaging means carry out the zoom operation.
The object herein refers to an image displayed on the display
means other than images obtained through imaging. Specifically,
examples of the object includes imaging conditions, such as F value
and shutter speed, the number of images taken and imaging time and
date, icons representing modes, such as image stabilizing mode, flash
on/off, person mode, etc., pictograms, and menus for various
operations.
The three-dimensional imaging device according to the
invention may further include notification means for notifying that
the three-dimensional display with a reduced parallax or the
two-dimensional display is being carried out.
In the three-dimensional imaging device according to the
invention, the display control means may gradually reduce the
parallax after the zoom operation is started until the parallax
becomes 0 to finally carry out the two-dimensional display.
In the three-dimensional imaging device according to the
invention, the display control means may gradually reduce the
parallax after the zoom operation is started until the parallax
becomes a predetermined parallax to finally carry out the
three-dimensional display with a reduced parallax.

A three-dimensional imaging method according to the invention
is a three-dimensional imaging method for use with a
three-dimensional imaging device including two or more imaging means
for obtaining two or more images having a parallax therebetween by
imaging a subject from different positions, the two or more imaging
means having an optical zoom function, three-dimensional processing
means for applying three-dimensional processing for
three-dimensional display to the two or more images, and display
means for carrying out various types of display including
three-dimensional display of the two or more images, the method
including:
carrying out three-dimensional display with a reduced
parallax between the two or more images or two-dimensional display
while the imaging means carry out a zoom operation.
The three-dimensional imaging method according to the
invention may be provided in the form of a program for causing a
computer to carry out the three-dimensional imaging method.
According to the invention, while the imaging means carry out
the zoom operation, the three-dimensional display with a reduced
parallax between the two or more images or the two-dimensional
display is carried out. Therefore, when the photographer makes a
zoom control operation, the stereoscopic effect of the
three-dimensional display can be reduced. In this manner, even when
stereoscopic viewing cannot be performed during the zoom operation,
variation of the stereoscopic effect is smaller, thereby alleviating
the uncomfortable feeling felt during the zoom operation. In
particular, by carrying out three-dimensional display with no
stereoscopic effect by reducing the parallax to 0, i.e.,
two-dimensional display, no variation of stereoscopic effect occurs
during the zoom operation, thereby reliably alleviating the
uncomfortable feeling felt during the zoom operation.
Further, by carrying out the three-dimensional processing
with a reduced parallax while the imaging means carry out the zoom
operation, the reduction of stereoscopic effect can be achieved
without increasing the components of the device, thereby preventing

the device configuration from being complicated.
Furthermore, in the case where an object is
three-dimensionally displayed with being superposed on the
three-dimensionally displayed image, the object may be
three-dimensionally displayed with a reduced parallax or
two-dimensionally displayed while the imaging means carry out the
zoom operation. Thus, the stereoscopic effect of the object in the
three-dimensional display can be reduced when the photographer makes
a zoom control operation. In this manner, even when stereoscopic
viewing cannot be performed during the zoom operation, variation
of the stereoscopic effect of the object is smaller, thereby
alleviating the uncomfortable feeling felt during the zoom
operation.
Moreover, by notifying that the three-dimensional display
with a reduced parallax or the two-dimensional display is being
carried out, the photographer can recognize based on the notification
that the three-dimensional display with a reduced parallax or the
two-dimensional display is being carried out.
In addition, by gradually reducing the parallax after the zoom
operation is started until the parallax becomes 0 to finally carry
out the two-dimensional display, or gradually reducing the parallax
after the zoom operation is started until the parallax becomes a
predetermined parallax to finally carry out the three-dimensional
display with a reduced parallax, abrupt change of the stereoscopic
effect when the zoom operation is started can be prevented, thereby
achieving further alleviation of the uncomfortable feeling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram illustrating the internal
configuration of a stereoscopic camera, to which a three-dimensional
imaging device according to an embodiment of the present invention
is applied,
FIG. 2 is a diagram illustrating the configuration of an
imaging unit,
FIG. 3 is a diagram illustrating stereoscopic effects when
display is switched,

FIG. 4 is another diagram illustrating stereoscopic effects
when display is switched,
FIG. 5 is a flow chart illustrating a process carried out in
the embodiment,
FIG. 6 is a diagram illustrating an image displayed with
objects superposed thereon,
FIG. 7 is a diagram illustrating a state where a "2D" mark
is displayed,
FIG. 8 is a diagram illustrating stereoscopic effects when
display is switched in a case where a reduced parallax is used,
FIG. 9 is another diagram illustrating stereoscopic effects
when display is switched in a case where a reduced parallax is used,
and
FIG. 10 is a diagram for explaining changes of a baseline length
and a convergence angle of imaging units.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, an embodiment of the present invention will be
described with reference to the drawings. FIG. 1 is a schematic block
diagram illustrating the internal configuration of a stereoscopic
camera, to which a three-dimensional imaging device according to
the embodiment of the invention is applied. As shown in FIG. 1, the
stereoscopic camera 1 according to this embodiment includes two
imaging units 21A and 21B, an imaging control unit 22, an image
processing unit 23, a compression/decompression unit 24, a frame
memory 25, a media control unit 26, an internal memory 27, and a
display control unit 28. The imaging units 21A and 21B are positioned
to be able to photograph a subject with a predetermined baseline
length and a convergence angle.
FIG. 2 illustrates the configuration of the imaging units 21A
and 21B. As shown in FIG. 2, the imaging units 21A and 21B include
focusing lenses 10A and 10B, zoom lenses 11A and 11B, aperture
diaphragms 12A and 12B, shutters 13A and 13B, CCDs 14A and 14B, analog
front ends (AFE) 15A and 15B and A/D converting units 16A and 16B,
respectively. The imaging units 21A and 21B further include focusing
lens driving units 17A and 17B for driving" the focusing lenses 10A

and iOB and zoom lens driving units 18A and 18B for driving the zoom
lenses 11A and 11B.
The focusing lenses 10A and 10B are used to focus on the subject,
and are movable along the optical axis directions by the focusing
lens driving units 17A and 17B, each of which is formed by a motor
and a motor driver. The focusing lens driving units 17A and 17B control
the movement of the focusing lenses 10A and 10B based on focus data
obtained through AF processing, which will be described later,
carried out by the imaging control unit 22.
The zoom lenses 11A and 11B are used to achieve a zoom function,
and are movable along the optical axis directions by the zoom lens
driving units 18A and 18B, each of which is formed by a motor and
a motor driver. The zoom lens driving units 18A and 18B control the
movement of the zoom lenses 11A and 11B based on zoom data obtained
at the CPU 33 upon operation of a zoom lever.
Aperture diameters of the aperture diaphragms 12A and 12B are
adjusted by an aperture diaphragm driving unit (not shown) based
on aperture value data obtained through AE processing carried out
by the imaging control unit 22.
The shutters 13A and 13B are mechanical shutters, and are
driven by a shutter driving unit (not shown) according to a shutter
speed obtained through the AE processing.
Each of the CCDs 14A and 14B includes a photoelectric surface,
on which a large number of light-receiving elements are arranged
two-dimensionally. Light from the subject is focused on each
photoelectric surface and is subjected to photoelectric conversion
to provide an analog imaging signal. Further, a color filter formed
by regularly arranged R, G and B color filters is disposed on the
front side of each CCD 14A, 14B.
The AFEs 15A and 15B process the analog imaging signals fed
from the CCDs 14A and 14B to remove noise from the analog imaging
signals and adjust gain of the analog imaging signals (this operation
is hereinafter referred to as "analog processing").
The A/D converting units 16A and 16B convert the analog imaging
signals, which have been subjected to the analog processing by the

AFEs 15A and 15B, into digital signals. The image represented by
digital image data obtained by the imaging unit 21A is referred to
as a first image Gl, and the image represented by digital image data,
obtained by the imaging unit 21B is referred to as a second image
G2.
The imaging control unit 22 includes an AF processing unit
and an AE processing unit (not shown) . When a release button included
in the input unit 34 is half-pressed, the imaging units 21A and 21B
obtain preliminary images, and the AF processing unit determines
focused areas and focal positions for the lenses 10A and 10B based
on the preliminary images, and outputs them to the imaging units
21A and 21B. The AE processing unit determines an aperture value
and a shutter speed based on the preliminary images, and outputs
them to the imaging units 21A and 21B.
As the method used to detect the focal points through the AF
processing, a passive method may be used, for example. In the passive
method, the focus position is detected based on characteristics that
an image containing a desired subject being focused has a higher
contrast value. More specifically, each preliminary image is divided
into a plurality of AF areas, and an image in each AF area is filtered
using a high-pass filter. Then, an AF evaluation value is calculated
for each AF area, and the AF area having the highest evaluation value,
i.e., the highest output value from the filter, is detected as the
focused area.
When the release button is fully pressed, the imaging control
unit 22 instructs the imaging units 21A and 21B to carry out actual
imaging to obtain actual images of the first and second images Gl
and G2. It should be noted that, before the release button is operated,
the imaging control unit 22 instructs the imaging unit 21A to
successively obtain a live view image, which has fewer pixels than
the first and second images Gl and G2, at a predetermined time interval
(for example, at an interval of 1/30 seconds) for checking imaging
range of the imaging unit 21A.
It should be noted that the imaging control unit 22 also carries
out the AF processing while the live view image is taken. The AF

processing in this case is achieved by a simpler calculation than
the AF processing based on the preliminary images.
The image processing unit 23 applies image processing, such
as white balance adjustment, tone correction, sharpness correction
and color correction, to the digital image data of the first and
second images Gl and G2 obtained by the imaging units 21A and 21B.
In this description, the first and second images which have been
processed by the image processing unit 23 are also denoted by the
same reference symbols Gl and G2 as the unprocessed first and second
images.
The compression/decompression unit 24 applies compression
processing according to a certain compression format, such as JPEG,
to the image data representing an image for three-dimensional display,
which is generated, as will be described later, from the actual images
of the first and second images Gl and G2 processed by the image
processing unit 23, and generates a three-dimensional image file
used for three-dimensional display. The three-dimensional image file
contains the image data of the first and second images Gl and G2
and the image data of the image for three-dimensional display. A
tag storing associated information, such as photographing time and
date, is added to the image file based on the Exif format, or the
like.
The frame memory 25 is a work memory used to carry out various
types of processing, including the above-described processing
carried out by the image processing unit 23, applied to the image
data representing the first and second images Gl and G2 obtained
by the imaging units 21A and 21B.
The media control unit 26 accesses a recording medium 29 and
controls writing and reading of the three-dimensional image file,
etc.
The internal memory 27 stores various constants to be set in
the stereoscopic camera 1, a program executed by the CPU 33, etc.
The display control unit 28 causes the first and second images
Gl and G2 stored in the frame memory 25 during imaging to be
two-dimensionally displayed on the monitor 20, or causes the first

and second images Gl and G2 recorded in the recording medium 29 to
be two-dimensionally displayed on the monitor 20. The display control
unit 28 is also able to cause the first and second images Gl and
G2, which have been subjected to the three-dimensional processing,
as will be described later, to be three-dimensionally displayed on
the monitor 20, or to cause the three-dimensional image file recorded
in the recording medium 29 to be three-dimensionally displayed on
the monitor 20. Switching between the two-dimensional display and
the three-dimensional display may automatically be carried out, or
may be carried out according to instructions from the photographer
via the input unit 34, which will be described later. During the
three-dimensional display, a live view image of the first and second
images Gl and G2 is three-dimensionally displayed on the monitor
20 until the release button is pressed.
It should be noted that, when the display mode is switched
to three-dimensional display, both the first and second images Gl
and G2 are used for the display, as will be described later. In
contrast, when the display mode is switched to two-dimensional
display, one of the first and second images Gl and G2 is used for
the display. In this embodiment, the first image Gl is used for the
two-dimensional display.
Further, when the imaging units 21A and 21B carry out the zoom
operation during three-dimensional display of the live view image,
as will be described later, the display control unit 28 switches
the display to two-dimensional display.
The stereoscopic camera 1 according to this embodiment further
includes a three-dimensional processing unit 30. The
three-dimensional processing unit 30 applies the three-dimensional
processing to the first and second images Gl and G2 to allow
three-dimensional display of the first and second images Gl and G2
on the monitor 20. The three-dimensional display technique used in
this embodiment may be any of known techniques. For example, the
stereoscopic viewing may be achieved by parallel viewing with naked
eyes by displaying the first and second images Gl and G2 side by
side, or the three-dimensional display may be achieved using a

lenticular system, where a lenticular lens is attached on the monitor
20, and the images G1 and G2 are displayed at predetermined positions
on the display surface of the monitor 20 so that the first and second
images Gl and G2 are respectively viewed by the left and right eyes.
Further, which the three-dimensional display may be achieved using
a scanning backlight system, where optical paths of backlights of
the monitor 20 are optically separated correspondingly to the left
and right eyes in an alternate manner, and the first and second images
Gl and G2 are alternately displayed on the display surface of the
monitor 20 synchronously with the separation of the backlights to
the left or the right.
The three-dimensional processing unit 30 applies the
three-dimensional processing depending on the type of
three-dimensional display to the first and second images Gl and G2.
For example, if the three-dimensional display is achieved by parallel
viewing with naked eyes, the three-dimensional processing is
achieved by generating a stereoscopic image by arranging the first
and second images Gl and G2 side by side on the left and right is
carried out. If the three-dimensional display is achieved with a
lenticular system, the three-dimensional processing is achieved by
generating a stereoscopic image by cutting the first and second
images Gl and G2 into vertical strips and alternately arranging the
vertical strips of the images. If the three-dimensional display is
achieved with a scanning backlight system, three-dimensional
processing to alternately output the first and second images Gl and
G2 to the monitor 20 synchronously with separation of backlights
of the monitor 20 to the left and right is carried out.
The monitor 20 is modified according to the type of the
three-dimensional processing carried out by the three-dimensional
processing unit 30. For example, if the system of the
three-dimensional display is a lenticular system, a lenticular lens
is attached on the display surface of the monitor 20. If the system
of the three-dimensional display is a scanning backlight system,
an optical element for changing directions of the light beams from
the left and right images is attached on the display surface of the

monitor 20.
In this embodiment, when the photographer makes a zoom control
operation using a zoom lever 34A while the live view image of the
first and second images G1 and G2 is displayed, the imaging units
21A and 21B carry out a zoom operation, and the display control unit
28 switches the display from three-dimensional display to
two-dimensional display. Specifically, in place of the image for
three-dimensional display generated by the three-dimensional
processing unit 30, the first image Gl is displayed on the monitor
20. In this case, driving of the imaging unit 21B may be stopped
so that only the imaging unit 21A images the subject to obtain the
first image G1. It should be noted that, at the three-dimensional
processing unit 30, an image for two-dimensional display may be
generated by morphing the first and second images Gl and G2 so that
a parallax between subject images contained in the first and second
images Gl and G2 becomes 0, and the thus generated image for
two-dimensional display may be two-dimensionally displayed on the
monitor 20. Further, when the imaging units 21A and 21B end the zoom
operation, the display control unit 28 switches the display from
two-dimensional display to three-dimensional display. FIG. 3 is a
diagram illustrating stereoscopic effects when the display is
switched. As shown in FIG. 3, when the photographer starts the zoom
control operation, the display is switched from three-dimensional
display to two-dimensional display and the stereoscopic effect
becomes 0. Then, when the photographer finishes the zoom control
operation, the display is switched from two-dimensional display to
three-dimensional display and the stereoscopic effect appears.
It should be noted that switching of the display from
three-dimensional display to two-dimensional display and from
two-dimensional display to three-dimensional display may be carried
out such that the stereoscopic effect is gradually changed. In this
case, as shown in FIG. 4, when the photographer starts the zoom control
operation, the display is gradually switched from three-dimensional
display to two-dimensional display, and the stereoscopic effect
gradually becomes 0. Then, when the photographer finishes the zoom

control operation, the display is gradually switched from
two-dimensional display to three-dimensional display, and the
stereoscopic effect gradually appears.
Change of the stereoscopic effect when the display is switched
from three-dimensional display to two-dimensional display may be
achieved by applying the three-dimensional processing to gradually
reduce the parallax, i.e., an amount of disparity, between first
and second images G1 and G2. In contrast, change of the stereoscopic
effect when the display is switched from two-dimensional display
to three-dimensional display may be achieved by applying the
three-dimensional processing to gradually restore the original
parallax, i.e., the original amount of disparity, between the first
and second images Gl and G2.
In addition to changing the amount of disparity between the
first and second images Gl and G2, gradual change of the stereoscopic
effect may be achieved by sequentially generating interpolation
images from the first and second images Gl and G2 with using the
first image Gl as a reference such that the parallax between the
subject images contained in the first and second images Gl and G2
is gradually reduced, and carrying out, each time the interpolation
image is generated, the three-dimensional processing using the first
image Gl and each interpolation image and display of the image for
three-dimensional display generated through the three-dimensional
processing.
The CPU 33 controls the units of the stereoscopic camera 1
according to signals inputted via the input unit 34, which includes
the release button, etc.
The data bus 35 is connected to the units forming the
stereoscopic camera 1 and the CPU 33, and communicates various data
and information in the stereoscopic camera 1.
Next, a process carried out in this embodiment is described.
FIG. 5 is a flow chart illustrating the process carried out in this
embodiment. It is assumed here that the live view image of the first
and second images Gl and G2 is three-dimensionally displayed on the
monitor 20 of the stereoscopic camera 1 through the three-dimensional

processing applied by the three-dimensional processing unit 30 to
the first and second images G1 and G2 obtained by the imaging units
21A and 21B. Since the invention is characterized by a process carried
out during the zoom operation of the imaging units 21A and 21B, only
a process that is carried out when the zoom control operation is
made using the zoom lever 34A while the live view image is displayed
is described.
The CPU 33 monitors whether or not the photographer has
operated the zoom lever 34A (step ST1) . If the determination in step
ST1 is affirmative, the imaging units 21A and 21B start the zoom
operation, and the display control unit 28 switches the display to
two-dimensional display where only the first image Gl is displayed
on the monitor 20 (step ST2). Then, the CPU 33 starts monitoring
whether or not the photographer has ended the zoom control operation
(step ST3). If the determination in step ST3 is affirmative, the
imaging units 21A and 21B stop the zoom operation, and the imaging
control unit 22 performs the AF processing of the imaging units 21A
and 21B (step ST4).
Subsequently, the display control unit 28 switches the display
on the monitor 20 to three-dimensional display of the live view image
(step ST5), and the process returns.
Then, when the release button is pressed to carry out imaging,
the imaging units 21A and 21B obtain the actual images of the first
and second images Gl and G2. Then, the three-dimensional processing
unit 30 generates the image for three-dimensional display from the
first and second images Gl and G2, the compression/decompression
unit 24 generates the three-dimensional image file formed by image
data of the first and second images Gl and G2 and the image for
three-dimensional display, and the media control unit 26 records
the three-dimensional image file in the recording medium 29.
As described above, in this embodiment, two-dimensional
display is carried out while the imaging units 21A and 21B carry
out the zoom operation. Therefore, no variation of the stereoscopic
effect of the image displayed on the monitor 20 occurs during the
zoom operation, thereby reliably alleviating the uncomfortable

feeling felt due to variation of the stereoscopic effect during the
zoom operation.
After the zoom operation is ended, the AF processing of the
imaging units 21A and 21B is carried out, and then the display is
switched to three-dimensional display. Therefore, the
three-dimensional display is carried out with the first and second
images G1 and G2 being in focus. Thus, after the zoom operation is
ended, stereoscopic viewing can be achieved successfully.
It should be noted that, in the above-described embodiment,
while the live view image is displayed, objects may be superposed
on the image. FIG. 6 is a diagram illustrating an image displayed
with objects superposed thereon. Here, a state where objects are
superposed on a two-dimensional image is shown for the purpose of
explanation. As shown in FIG. 6, on the image displayed on the monitor
20, an object of an icon representing emission of flash light is
superposed at the upper-left corner, an object of the number of images
taken so far is superposed at the upper-right corner, an object of
an F value and a shutter speed is superposed at the lower-left corner,
and an object of a text showing the photographing date is superposed
at the lower-right corner.
In this case, the objects can be three-dimensionally displayed
to allow stereoscopic viewing by arranging the objects on each of
the first and second images Gl and G2 such that a parallax is provided
therebetween. In the case where the objects are three-dimensionally
displayed like this, display of the objects may be switched from
three-dimensional display to two-dimensional display while the
imaging units 21A and 21B carry out the zoom operation, in the same
manner as the first and second images Gl and G2. Thus, variation
of the stereoscopic effect of the objects becomes small, thereby
alleviating the uncomfortable feeling felt during the zoom
operation.
Further, since stereoscopic viewing cannot be performed when
the display is switched from three-dimensional display to
two-dimensional display in the above-described embodiment, the
photographer may misunderstand this to be a failure of the device

1. Therefore, as shown in FIG. 7, the display control unit 28 may
display a "2D" mark MO on the monitor 20 to notify the photographer
of the fact that two-dimensional display is being carried out. In
this case, the display control unit 28 corresponds to a notification
means. In this manner, the photographer can recognize, based on the
mark MO, that two-dimensional display is being carried out.
Alternatively, in place of displaying the mark MO, the device 1 may
be provided with a sound output unit to use a sound to notify the
photographer of the fact that two-dimensional display is being
carried out. Further alternatively, both the sound and display of
the mark MO may be used to notify the photographer of the fact that
two-dimensional display is being carried out.
Further, although the display is switched from
three-dimensional display to two-dimensional display when the
photographer has started the zoom control operation in the
above-described embodiment, three-dimensional display with a
smaller parallax may be carried out, in place of the two-dimensional
display, by applying the three-dimensional processing with a reduced
parallax between the first and second images G1 and G2.
The three-dimensional processing with a reduced parallax can
be achieved by reducing a parallax, i.e., an amount of disparity,
between subject images contained in the first and second images Gl
and G2. The three-dimensional processing with a reduced parallax
can also be achieved by morphing the first and second images Gl and
G2 using the first image Gl as a reference to generate an interpolation
image with a reduced parallax between subject images contained in
the first and second images Gl and G2, and carrying out the
three-dimensional processing using the first image Gl and the
interpolation image.
FIG. 8 is a diagram illustrating stereoscopic effects when
the display is switched in the case where the three-dimensional
processing with a reduced parallax is carried out. As shown in FIG.
8, when the photographer has started the zoom control operation,
the stereoscopic effect of the three-dimensional display is reduced.
Then, when the photographer has ended the zoom control operation,

the stereoscopic effect is increased. In this case, the stereoscopic
effect may be switched gradually, as shown in FIG. 9.
The parallax between the first and second images G1 and G2
can also be reduced by reducing a distance between the imaging units
21A and 21B. That is, as shown in FIG. 10, reduction of the parallax
between the first and second images Gl and G2 can be achieved by
changing, when the zoom control operation is started, a baseline
length K1 and a convergence angle α1 between the imaging units 21A
and 21B before the photographer starts the zoom control operation
to a baseline length K2 and a convergence angle α2. The distance
between the imaging units 21A and 21B may be changed using a known
mechanism.
Further, although the stereoscopic camera 1 is provided with
the two imaging units 21A and 21B and three-dimensional display is
carried out using the two images Gl and G2 in the above-de scribed
embodiment, the invention is also applicable to a case where the
stereoscopic camera 1 is provided with three or more imaging units
and three-dimensional display is carried out using three or more
images.
One embodiment of the present invention has been described.
The invention may also be implemented in the form of a program for
causing a computer to function as means corresponding to the display
control unit 28 and the three-dimensional processing unit 30
described above and carry out the process as shown in FIG 5. The
invention may also be implemented in the form of a computer-readable
recording medium containing such a program.

CLAIMS
1. A three-dimensional imaging device comprising:
two or more imaging means for obtaining two or more images
having a parallax therebetween by imaging a subject from different
positions, the two or more imaging means having an optical zoom
function;
three-dimensional processing means for applying
three-dimensional processing for three-dimensional display to the
two or more images;
display means for carrying out various types of display
including three-dimensional display of the two or more images; and
display control means for carrying out three-dimensional
display with a reduced parallax between the two or more images or
two-dimensional display while the imaging means carry out a zoom
operation.
2. The three-dimensional imaging device as claimed in claim
1, wherein the three-dimensional processing means carries out the
three-dimensional processing with a reduced parallax while the
imaging means carry out the zoom operation.
3. The three-dimensional imaging device as claimed in claim
1 or 2, wherein in a case where an object is three-dimensionally
displayed with being superposed on the three-dimensionally displayed
image, the display control means carries out three-dimensional
display with a reduced parallax or two-dimensional display of the
object while the imaging means carry out the zoom operation.
4. The three-dimensional imaging device as claimed in any one
of claims 1 to 3, further comprising notification means for notifying
that the three-dimensional display with a reduced parallax or the
two-dimensional display is being carried out.
5. The three-dimensional imaging device as claimed in any one
of claims 1 to 4, wherein the display control means gradually reduces
the parallax after the zoom operation is started until the parallax
becomes 0 to finally carry out the two-dimensional display.
6. The three-dimensional imaging device as claimed in any one
of claims 1 to 4, wherein the display control means gradually reduces

the parallax after the zoom operation is started until the parallax
becomes a predetermined parallax to finally carry out the
three-dimensional display with a reduced parallax.
7. A three-dimensional imaging method for use with the
three-dimensional imaging device as claimed in claims 1 including
two or more imaging means for obtaining two or more images having
a parallax therebetween by imaging a subject from different
positions, the two or more imaging means having an optical zoom
function, three-dimensional processing means for applying
three-dimensional processing for three-dimensional display to the
two or more images, and display means for carrying out various types
of display including three-dimensional display of the two or more
images, the method comprising:
carrying out three-dimensional display with a reduced
parallax between the two or more images or two-dimensional display
while the imaging means carry out a zoom operation.
8. A program for causing a computer to function as the
three-dimensional imaging device as claimed in claim 1.

An uncomfortable feeling felt when stereoscopic viewing
cannot be performed during a zoom operation is alleviated when two
or more images for three-dimensional display is taken. A
three-dimensional processing unit (30) applies three-dimensional
processing to first and second images (G1, G2) obtained by imaging
units (21A, 21B), and a display control unit (28) three-dimensionally
displays an image for three-dimensional display, which is obtained
by three-dimensional processing, on a monitor (20) . When a zoom
operation of the imaging units (21A, 21B) is started, the display
control unit (28) displays only the first image (Gl) on the monitor
(20). When the zoom operation of the imaging units (21A, 21B) is
ended, the image for three-dimensional display is again
three-dimensionally displayed on the monitor (20).