JP2015043607A - Image processing apparatus, image processing method, image processing program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of controlling parallax while keeping a desired stereoscopic effect especially in viewpoint images photographed as a moving image for stereoscopic vision.SOLUTION: An image processing apparatus comprises a parallax control processing unit that changes a parallax amount between viewpoint images photographed from different directions using a focal length of an imaging lens in photographing each viewpoint image.

Description

  The present invention relates to an image processing apparatus, an image processing method, an image processing program, and a recording medium that perform predetermined image processing on a plurality of viewpoint images corresponding to stereoscopic viewing.

  In recent years, image processing apparatuses that perform processing for changing (enlarging or reducing) the amount of parallax between stereoscopic viewpoint images, that is, left and right viewpoint images (left viewpoint image, right viewpoint image) have been developed (for example, patents). Reference 1). Note that the amount of parallax here corresponds to the amount of shift in the horizontal position of the image in the left and right viewpoint images, and the stereoscopic effect varies depending on the amount of this amount of parallax. In Patent Document 1, a retinal image difference (disparity) corresponding to parallax is detected from left and right viewpoint images, and the entire image is horizontally shifted based on the disparity (specifically, the average value of disparity) to generate parallax. Image processing is performed to change the amount. Such a change control of the amount of parallax makes it possible to change the stereoscopic effect during video display.

JP 07-167633 A

  However, in the image processing method of Patent Document 1, there is no means for determining the change control amount of the parallax amount, and the change control amount is set to a fixed value (a constant value) or manually by an observer (user). It is adjusted with. Here, the amount of parallax is relatively large when a certain subject is photographed at telephoto, but is relatively small when photographed at wide angle. Similarly, the amount of parallax differs between when a close subject is photographed and when a distant subject is photographed.

  For this reason, for example, when the shooting condition (focal length or the like) changes in time series by so-called zooming, the amount of parallax itself also changes. Therefore, if the parallax amount is changed with a constant control amount for each viewpoint image when a moving image is shot by zooming, the following problem occurs. That is, when each viewpoint image after change control is displayed as a moving image, the stereoscopic effect changes during the movement (zooming), resulting in an unnatural image.

  The present invention has been made in view of such problems, and an object thereof is an image processing apparatus capable of performing parallax control while maintaining a desired stereoscopic effect, particularly in a viewpoint image shot as a stereoscopic moving image. Another object is to provide an image processing method, an image processing program, and a recording medium.

  An image processing apparatus according to the present invention includes a parallax control processing unit that changes a parallax amount between viewpoint images using a focal length of an imaging lens when shooting the viewpoint images in a plurality of viewpoint images shot from different directions. It is equipped with.

  The image processing method and the image processing program of the present invention change the amount of parallax between viewpoint images using a focal length of an imaging lens when shooting each viewpoint image in a plurality of viewpoint images taken from different directions. Includes steps.

  The recording medium of the present invention is a computer-readable medium on which the image processing program of the present invention is recorded.

  In the image processing apparatus, the image processing method, the image processing program, and the recording medium of the present invention, the amount of parallax between the viewpoint images is changed using the focal length of the imaging lens when the viewpoint images are captured. The amount of parallax varies depending on the shooting conditions such as the focal length, but this is the case when shooting is performed while changing the shooting conditions in time series, such as when shooting while zooming using the focal length. However, appropriate parallax control according to the change is performed.

  According to the image processing device, the image processing method, the image processing program, and the recording medium of the present invention, the amount of parallax between the viewpoint images is changed using the focal length of the imaging lens when the viewpoint images are captured. Therefore, appropriate parallax control according to the change is also possible for each viewpoint image acquired by changing the shooting conditions such as moving images in time series. Therefore, parallax control can be performed while maintaining a desired stereoscopic effect, particularly in a viewpoint image shot as a stereoscopic moving image.

It is a figure showing the whole imaging device composition concerning a 1st embodiment of the present invention. FIG. 2 is a functional block diagram illustrating a detailed configuration of an image processing unit illustrated in FIG. 1. FIG. 2 is a schematic diagram for explaining an imaging position of a subject when a left viewpoint image is acquired in the imaging apparatus shown in FIG. 1. FIG. 2 is a schematic diagram for explaining an imaging position of a subject when a right viewpoint image is acquired in the imaging apparatus shown in FIG. 1. It is a schematic diagram for demonstrating the parallax between the right-and-left viewpoint images acquired using the imaging device shown in FIG. It is a schematic diagram for demonstrating an example (parallax expansion process) of a parallax control processing operation. It is a schematic diagram showing the parallax amount and parallax range in the image before parallax control processing. It is a schematic diagram showing the parallax amount and parallax range in the image after parallax control processing. It is a figure showing the whole structure of the imaging device which concerns on the 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the received light image in the case of 2D imaging | photography (without optical path switching). It is a schematic diagram for demonstrating the principle of the left viewpoint image acquisition in the imaging device shown in FIG. It is a schematic diagram for demonstrating the principle of right viewpoint image acquisition in the imaging device shown in FIG. It is a schematic diagram for demonstrating the parallax between the right-and-left viewpoint images acquired using the imaging device shown in FIG. It is a schematic diagram for demonstrating the imaging | photography conditions and distance between gravity centers of the imaging device shown in FIG. It is a schematic diagram for demonstrating the parallax control process (parallax reduction process) which concerns on the modification 1. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. First embodiment (example of parallax control processing based on photographing information when a twin-lens camera is used)
2. Second embodiment (example using a monocular camera)
3. Modification 1 (example of parallax reduction processing)
4). Modification 2 (example in which only focal length is used as shooting information)

<First Embodiment>
[Overall Configuration of Imaging Device 1]
FIG. 1 shows the overall configuration of an imaging apparatus (imaging apparatus 1) according to a first embodiment of the present invention. The imaging device 1 captures a subject from a plurality of different viewpoint directions, and acquires a plurality of viewpoint images (here, two viewpoint images on the left and right) in time series as moving images (or still images). The imaging apparatus 1 uses a so-called binocular camera having imaging lenses 10a1 and 10b and imaging lenses 10a2 and 10b for each optical path for acquiring light beams LL and LR from the left and right viewpoint directions. is there. The imaging lens 10b is a common component for each optical path. The imaging apparatus 1 also includes shutters 11a and 11b for each optical path, and includes an image sensor 12 as a common component for each optical path, and further includes an image processing unit 13, a lens driving unit 14, a shutter driving unit 15, and an image. A sensor driving unit 16 and a control unit 17 are provided.

  The image processing unit 13 corresponds to the image processing apparatus of the present invention. The image processing program of the present invention is a software implementation of each image processing function in the image processing unit 13. In this case, the software is composed of a program group for causing each computer to execute each image processing function. Each program may be used by being incorporated in advance in dedicated hardware, for example, or installed in a general-purpose personal computer or the like from a network or a recording medium.

  The imaging lenses 10a1 and 10b are lens groups for acquiring the light beam LL in the left viewpoint direction, and the imaging lenses 10a2 and 10b are the lens group for acquiring the light beam LR in the right viewpoint direction. A shutter 11a is disposed between the imaging lenses 10a1 and 10b, and a shutter 11b is disposed between the imaging lenses 10a2 and 10b. Although the arrangement of the shutters 11a and 11b is not particularly limited, it is ideally arranged on the pupil plane of the imaging lens group or the position of a diaphragm (not shown).

  These imaging lenses 10a1 and 10b (imaging lenses 10a2 and 10b) function as a so-called zoom lens as a whole. In the imaging lenses 10a1 and 10b (imaging lenses 10a2 and 10b), the lens distance and the like are adjusted by the lens driving unit 14, so that the focal length is variable. Each lens group is composed of one or more lenses. Information regarding zooming (for example, focal length, subject distance, etc.) in the imaging lenses 10a1 and 10b (imaging lenses 10a2 and 10b) is input to the image processing unit 13 via the control unit 17 as shooting information Df. It has become.

  A mirror 110 is disposed between the imaging lens 10a1 and the shutter 11a, a mirror 111 is disposed between the imaging lens 10a2 and the shutter 11b, and a mirror 112 is disposed between the shutters 11a and 11b. The mirrors 110 to 112 allow the light beams LL and LR to enter the imaging lens 10b after passing through the shutters 11a and 11b, respectively.

  The shutters 11a and 11b are for switching transmission and blocking in the left and right optical paths, and are controlled to switch between an open state (translucent state) and a closed state (light-shielded state) for each shutter 11a and 11b. ing. The shutters 11a and 11b may be mechanical shutters as long as the optical paths can be switched as described above, and may be electrical shutters such as liquid crystal shutters.

  The image sensor 12 is a photoelectric conversion element that outputs a light reception signal based on the light beam LL that has passed through the imaging lenses 10a1 and 10b and the shutter 11a or the light beam LR that has passed through the imaging lenses 10a2 and 10b and the shutter 11b. The image sensor 12 includes, for example, a plurality of photodiodes (light receiving pixels) arranged in a matrix, and reads a signal from the plurality of photodiodes in a line-sequential manner. ). For example, R, G, and B color filters (not shown) having a predetermined color arrangement may be disposed on the light receiving surface side of the image sensor 12.

(Configuration of the image processing unit 13)
The image processing unit 13 performs predetermined image processing on the captured images (left and right viewpoint images) based on the imaging data output from the image sensor 12, and stores various types of imaging data before or after image processing. Includes memory. However, the image data after image processing may be output to an external display or the like without being recorded.

  FIG. 2 shows a detailed configuration of the image processing unit 13. The image processing unit 13 includes a parallax control processing unit 131 and a disparity map generation unit 133, and image correction processing units 130 and 132 are provided upstream and downstream of the parallax control processing unit 131. The parallax control processing unit 131 changes the parallax amount with respect to the images (left viewpoint image L1, right viewpoint image R1) based on the imaging data (left viewpoint image data D0L, right viewpoint image data D0R) input from the image sensor 12. It is something to control.

  The disparity map generation unit 133 generates a so-called disparity map based on the imaging data (left viewpoint image data D0L, right viewpoint image data D0R). Specifically, a disparity (disparity: phase difference, phase shift) between the left and right viewpoint images is calculated for each pixel, and a map in which the calculated disparity is associated with each pixel is generated. However, as the disparity map, as described above, the disparity may be obtained for each pixel and held for each pixel, but the disparity is obtained for each pixel block including a predetermined number of pixels, and the obtained disparity is calculated. You may make it hold | maintain corresponding to each pixel block. The disparity map generated by the disparity map generation unit 133 is output to the parallax control processing unit 131 as map data DD.

  Although details will be described later, in the present embodiment, the parallax control processing unit 131 changes and controls the parallax amount between the input left and right viewpoint images to a desired value based on the shooting information Df. . For example, appropriate parallax control is performed even when the amount of parallax changes in accordance with zooming shooting conditions. By changing (enlarging or reducing) the amount of parallax, the subject image can be observed on the near side (side closer to the observer) or on the reverse side (on the side farther from the observer). The stereoscopic effect can be changed. In particular, when changing the parallax amount (enlargement in the present embodiment), it is possible to enlarge not only the parallax amount but also the parallax range by using the map data DD.

  In this specification, “parallax amount” represents the amount of positional deviation (phase deviation amount) in the horizontal direction of the screen, and “parallax range” refers to the observation point closest to the depth direction of the screen to the deepest observation point. It represents the dynamic range of.

  The image correction processing unit 130 performs correction processing such as noise reduction and demosaic processing, and the image correction processing unit 132 performs correction processing such as gamma correction processing.

  The lens driving unit 14 is an actuator for shifting a predetermined lens in the imaging lenses 10a1, 10a2, and 10b along the optical axis to change the focal length.

  The shutter driving unit 15 performs opening / closing switching driving for each of the shutters 11a and 11b. Specifically, the shutter 11a is driven so that the shutter 11b is closed when the shutter 11a is open, and the shutter 11b is opened when the shutter 11a is closed. Further, when each viewpoint image is acquired as a moving image, driving is performed so that the open state and the closed state are alternately switched in a time division manner for each of the shutters 11a and 11b.

  The image sensor driving unit 16 drives the image sensor 12 and controls its light receiving operation. For example, when the image sensor 12 is a rolling shutter type CMOS image sensor as described above, the image sensor 12 is driven so that the exposure operation and the signal readout operation are performed in a line sequential manner.

  The control unit 17 controls each operation of the image processing unit 13, the lens driving unit 14, the shutter driving unit 15, and the image sensor driving unit 16 at a predetermined timing. As the control unit 17, for example, a microcomputer or the like is used. Used.

[Operation and Effect of Imaging Device 1]
(1. Basic operation)
In the imaging apparatus 1 as described above, based on the control of the control unit 17, the lens driving unit 14 drives the imaging lenses 10a1 and 10b under a predetermined zooming shooting condition, and the shutter driving unit 15 opens the shutter 11a. The shutter 11b is switched to the closed state. Further, in synchronization with these operations, the image sensor driving unit 16 drives the image sensor 12 to receive light. As a result, the left optical path corresponding to the left viewpoint direction is selected (switched to the left optical path), and the image sensor 12 receives light based on the light beam LL among the incident light beams from the subject side, and obtains the left viewpoint image data D0L. Is done.

  Subsequently, the lens driving unit 14 drives the imaging lenses 10a2 and 10b under photographing conditions by predetermined zooming, and the shutter driving unit 15 switches the shutter 11b to the open state and the shutter 11a to the closed state. Further, in synchronization with these operations, the image sensor driving unit 16 drives the image sensor 12 to receive light. As a result, the right optical path corresponding to the right viewpoint direction is selected (switched to the right optical path), and the image sensor 12 receives light based on the light beam LR among the incident light beams from the subject side, and acquires the right viewpoint image data D0R. Is done.

  The shooting conditions (focal length f, subject distance S, etc.) by zooming at the time of acquiring each viewpoint image are taken as shooting information Df to the image processing unit 13 (specifically, the parallax control processing unit 131) via the control unit 17. Entered.

  By alternately performing switching driving of the imaging lenses 10a1 and 10a2 and the shutters 11a and 11b as described above in time division, imaging data corresponding to the left viewpoint image and the right viewpoint image are alternately acquired in time series, A set of these left and right viewpoint images is sequentially input to the image processing unit 13.

  The image processing unit 13 performs predetermined image processing on the captured images (left viewpoint image L1 and right viewpoint image R1 described later) based on the left viewpoint image data D0L and the right viewpoint image data D0R acquired as described above. For example, left and right viewpoint images for stereoscopic viewing (left viewpoint image L2 and right viewpoint image R2 described later) are generated. The generated left viewpoint image L2 and right viewpoint image R2 are recorded in the image processing unit 13 or output to the outside.

(Principle of viewpoint image acquisition)
Here, the principle of acquiring the left and right viewpoint images will be described in detail with reference to FIGS. FIGS. 3 and 4 are equivalent to views of the imaging apparatus 1 as viewed from above, but for the sake of simplicity, the light path from the subject to the sensor surface (light receiving surface) S2 of the image sensor 12 is changed by a mirror or the like. Shown without consideration. Moreover, illustration of components other than the imaging lenses 10a1 and 10a2 is omitted, and the imaging lenses 10a1 and 10a2 are also simplified. The subjects are two subjects arranged at different positions in the depth direction, specifically, the subject A (person) on the focusing surface S1 of the imaging lenses 10a1 and 10a2, and the back side of the subject A ( Take subject B (mountain) located on the opposite side of the imaging lens as an example.

(Left viewpoint image)
When the optical path is switched between right and left for the two subjects A and B having such a positional relationship, the way the image is reflected on the sensor surface S2 is as follows. For example, as shown in FIG. 3, when the left optical path corresponding to the left viewpoint direction (the optical path through which the incident light to the imaging lens 10a1 passes) is transmission, the right optical path corresponding to the right viewpoint direction is Shaded. In this case, on the sensor surface S2, the subject A is formed as an image focused (focused) at the position A1 _L , and the subject B is defocused (blurred) at the position B1 _L. Form an image. Note that the center of gravity of each subject image is used as the imaging position of each subject (the same applies hereinafter).

(Right viewpoint image)
On the other hand, as shown in FIG. 4, when the right optical path corresponding to the right viewpoint direction (the optical path through which the incident light to the imaging lens 10a2 passes) is transmitted, the left optical path is shielded. In this case, on the sensor surface S2, the subject A is formed as an image focused on the position A1 _R , while the subject B is formed as an image defocused on the position B1 _R.

(Parallax between left and right viewpoint images)
As described above, the imaging device 1 can acquire the left viewpoint image and the right viewpoint image by switching the two optical paths corresponding to the left viewpoint direction and the right viewpoint direction, respectively. Further, as schematically shown in FIGS. 5A and 5B, in the obtained left viewpoint image L1 and right viewpoint image R1, the defocused image (the image of the subject B) is a focused image ( With respect to the image of the subject A) shifted in the opposite horizontal directions.

The left viewpoint image L2 and the right viewpoint image R2 based on the left viewpoint image L1 and the right viewpoint image R1 are displayed by using a predetermined 3D display method such as a polarization method, a frame sequential method, a projector method, or the like. The observer can feel a stereoscopic effect corresponding to the following parallax in the observed video. However, at this time, the display is performed such that the positions A1 _L and A1 _{R of} the subject A are in the same position (overlapping) in the horizontal direction. As a result, a positional shift (phase difference) occurs in the horizontal direction between the positions B1 _L and B1 _R of the subject B, and this positional shift becomes the left and right parallax. When displayed in this manner, the subject A (person) has no parallax and is observed on the display screen (reference plane), but the subject B (mountain) has parallax as described above, Observation is made with a three-dimensional effect corresponding to the amount of parallax (in this case, a three-dimensional effect as if existing behind the reference surface).

(Relation between parallax amount and shooting conditions)
Here, in the binocular imaging apparatus 1, the parallax amount Wb1 of the subject B when the display is performed so that the subject A is observed on the reference plane as described above is the horizontal between the positions B1 _L and B1 _R. Corresponds to the distance along the direction. The parallax amount Wb1 can be defined as in the following expression (1) using the shooting conditions. However, the base line length (distance between the optical axes between the imaging lenses 10a1 and 10a2) is L, and the focal lengths of the imaging lenses 10a1 and 10a2 (specifically, the focal lengths of the imaging lenses 10a1 and 10b and the imaging lenses 10a2 and 10b). f, the subject distance is S, and the distance between the subjects A and B is dep. The actual stereoscopic effect of the subject B is affected by the display screen size, the distance between the observer and the display screen, and the like. ).

(2. Parallax control processing: parallax control using shooting information)
In the present embodiment, the image processing unit 13 performs change control (enlargement here) on the amount of parallax between the left viewpoint image L1 and the right viewpoint image R1 as described above. Specifically, in the image processing unit 13, the image correction processing unit 130 performs processing such as noise reduction as described above on the left viewpoint image data D0L and D0R input from the image sensor 12. Thereafter, for the image data D1 (left viewpoint image data D1L, right viewpoint image data D1R) after the image correction processing by the image correction processing unit 130, the parallax control processing unit 131 uses the shooting information Df to determine the amount of parallax. Control is performed so that it is expanded to a desired value.

  On the other hand, the disparity map generation unit 133 generates a disparity map to be used when changing the parallax amount and the parallax range, which will be described later, based on the input left viewpoint image data D0L and right viewpoint image data D0R. Specifically, the disparity between the left and right viewpoint images is calculated for each pixel, and a map that holds the calculated disparity in association with each pixel is generated. However, as the disparity map, each disparity may be obtained and held for each pixel as described above, but the disparity is obtained for each predetermined number of pixel blocks, and the obtained disparity is assigned to each pixel. You may make it hold | maintain in association with a block. The disparity map generated by the disparity map generation unit 133 is output to the parallax control processing unit 131 as map data DD.

(Comparative example)
Here, the parallax control process according to the comparative example of the present embodiment will be described. In the comparative example, for example, when the parallax amount after the parallax control for the subject B is Wb ₁₀₀ , the parallax amount Wb ₁₀₀ is expressed by the following equation (2) using the constant α. However, α is a fixed value (constant) set in advance for parallax change control or a value set manually by the observer. That is, in the comparative example, the change control amount (for example, the enlargement amount) of the parallax amount Wb1 for the subject B is uniquely set by the constant α.

  However, the left and right parallax amounts differ when shooting a plurality of subjects, when shooting a subject in the foreground and when shooting a subject in the distance. . Even for the same subject, it is relatively large when taken at a telephoto position and relatively small when taken at a wide angle. That is, when the shooting conditions such as the focal length and subject distance change due to zooming or the like, the parallax amount also changes accordingly.

  For this reason, for example, when moving image shooting is performed while zooming, the amount of parallax changes in time series even for the same subject. Therefore, if the parallax amount is changed and controlled uniquely (with a constant change control amount) for each of the viewpoint images constituting such a moving image, the following problem occurs. That is, when each viewpoint image after the change control is displayed as a moving image, the amount of parallax (stereoscopic effect) changes during the movement (zooming), and the observer tends to feel an unnatural stereoscopic effect. For example, if you increase the amount of parallax with a certain amount of control for a movie that gradually zooms up on a certain subject image, you may feel unsatisfactory proximity while the subject image is on the back side, On the front side, the feeling of popping out becomes greater than necessary. Therefore, the observer may feel tired or display an image that lacks realism and power.

(Parallax enlargement process considering shooting conditions)
Therefore, in the present embodiment, the parallax control processing unit 131 performs change control of the parallax amount between the viewpoint images in consideration of such shooting conditions by zooming. Specifically, the amount of parallax is based on the above-described constant (α) for changing the parallax and the following equation (3) using the coefficient α (S, f) including, for example, the focal length f and the subject distance S as parameters. Change (enlarge) control. That is, when the parallax amount after change control (the parallax amount of the output image) is Wb2, the coefficient α (S, f) is set so that the parallax amount Wb2 is expanded to a desired value.

  For example, when it is desired to increase the amount of parallax so that the value of the amount of parallax does not change due to shooting conditions (for example, focal length f), the coefficient α (S, f) is expressed by the following equation (4). Use what is done. Substituting this into equation (3) yields equation (5). By performing the parallax control based on the equation (5), the parallax amount Wb2 can be controlled to be enlarged regardless of the focal length f. That is, it is possible to suppress an unnatural change in the amount of parallax (stereoscopic effect) during zooming as described above, and to generate an image that is easy for an observer to observe. However, the coefficient α (S, f) is not limited to this, and may include other parameters selected so as to correspond to a desired amount of parallax.

  The parallax control processing unit 131 then positions (phase, centroid position) of the image of the subject B in the left viewpoint image L1 and the right viewpoint image R1 so that the amount of parallax for the subject B is expanded from Wb1 to Wb2. Shift along the horizontal direction. At this time, as described below, it is desirable to perform processing using a disparity map. In the above description, the parallax control for the subject B has been described, but the same applies to other subjects. That is, the coefficient α (S, f) may be set for each subject (here, for each of the subjects B and C) so that a desired amount of parallax is obtained.

(Parallax expansion operation using disparity map)
Further, in the present embodiment, the map data DD supplied from the disparity map generation unit 133 is used in the parallax control process in consideration of the shooting conditions as described above. Hereinafter, in addition to the above-described subject A (person) and subject B (mountain), viewpoints of photographing a total of three subjects, that is, subject C (flower) arranged on the near side (imaging lens 10 side) of subject A An image will be described as an example. That is, as shown in FIGS. 6A and 6B, the images of the subjects B and C in each of the left viewpoint image L1 and the right viewpoint image R1 so that the parallax amounts of the subjects B and C are increased. The position is shifted along the horizontal direction (X direction). However, here, the positions A1 _L and A1 _R of the subject A having no parallax are not changed (the parallax amount remains unchanged at 0), and the left viewpoint image L2 and the right viewpoint image R2 are arranged at the same positions. To.

Specifically, the object B, from the position B1 _L of the left-viewpoint image L1 to the position B2 _L in the left-viewpoint image L2, X direction negative (-) is shifted in the direction of (solid arrow). On the other hand, from the position B1 _R in the right viewpoint image R1 to the position B2 _R in the right viewpoint image R2, it is shifted in the direction of the X-direction positive (+) (dashed arrows). Thereby, the parallax amount for the subject B can be expanded from the parallax amount Wb1 to the parallax amount Wb2 set in consideration of the shooting conditions as described above. On the other hand, the parallax amount of the subject C is increased in the same manner. However, the subject C is shifted in the positive X direction (dotted arrow) from the position C1 _L in the left viewpoint image L1 to the position C2 _L in the left viewpoint image L2. On the other hand, the position is shifted in the X direction negative (−) from the position C1 _R in the right viewpoint image R1 to the position C2 _R in the right viewpoint image R2 (solid arrow).

  As described above, in this embodiment, by using the deparity map, the parallax amount can be enlarged and controlled for each subject. For example, as described above, the parallax control for each subject, such as increasing the parallax amount of only the subjects B and C by shifting the positions of the specific subjects B and C among the subjects A to C in different directions. Is possible. As a result, not only the amount of parallax in the horizontal direction but also the range of parallax in the depth direction can be expanded as described below.

(Expansion of parallax range)
FIG. 7 is a schematic diagram showing the parallax amount and the parallax range in the left viewpoint images L1 and R1 corresponding to the left viewpoint image data D0L and the right viewpoint image data D0R, and FIG. 8 is a parallax amount in the left viewpoint images L2 and R2. It is a schematic diagram showing a parallax range. As shown in FIG. 7, when the parallax amount of the subject B is Wb1 and the parallax amount of the subject C is Wc1 between the left viewpoint image L1 and the right viewpoint image R1, the depths of the images of the subjects A to C in the depth direction. The observation position is as follows. That is, the image of the subject A is the position A1 ′ on the display screen (reference plane) S3, the image of the subject B is the position B1 ′ farther from the subject A by the distance Dab1, and the image of the subject C is the distance from the subject A. It is observed at the position C1 ′ on the near side by Dac1. Accordingly, the parallax range between the left viewpoint image L1 and the right viewpoint image R1 before the enlargement control process is a distance D1 obtained by adding the distances Dab1 and Dac1.

  On the other hand, when the enlargement control process as described above is performed, the parallax amount of the subject B is Wb2 and the parallax amount of the subject C is Wc2 between the left viewpoint image L2 and the right viewpoint image R2, as shown in FIG. Further, each observation position in the depth direction of the subjects A to C changes as follows. That is, the image of the subject A is a position A2 ′ (= A1 ′) on the display screen (reference plane) S3, and the image of the subject B is a position B2 ′ on the back side by a distance Dab2 (> Dab1) from the position A2 ′. The image of the subject C is observed at a position C2 ′ on the near side by a distance Dac2 (> Dac1) from the position A2 ′. Accordingly, the parallax range between the left viewpoint image L2 and the right viewpoint image R2 after the parallax enlargement process is the total distance D2 of the distances Dab2 and Dac2, and the parallax range D2 is larger than the parallax range D1. Is done.

  Thus, by using the disparity map, not only the amount of parallax in the horizontal direction but also the range of parallax in the depth direction can be expanded. As a result, for example, as described above, the subject B on the back side of the reference plane S3 is deeper and the subject C on the front side protrudes to the front side and is observed, that is, for each subject. It is possible to perform parallax control that enhances the stereoscopic effect. In other words, the sense of distance in the depth direction between the subjects B and C observed on one screen can be expanded. If the disparity map is not used, the phase shift for each subject (for each pixel and each pixel block) as described above cannot be performed, so the parallax range cannot be expanded, and the distance in the depth direction between each subject is Each subject image is shifted while keeping it constant. In such parallax control, all subject images can only be shifted collectively to either the back side or the near side, and the change in stereoscopic effect tends to be monotonous (the degree of freedom in parallax control is poor). .

  The left viewpoint image L2 and the right viewpoint image R2 that have been subjected to the parallax enlargement process as described above are input to the image correction processing unit 132 as image data D2. The image correction processing unit 132 performs the above-described gamma correction processing or the like on the input image data D2, and outputs the image data Dout to a storage unit (not shown) or transmits it to an external display device or the like.

  As described above, in this embodiment, the left viewpoint image L1 and the right viewpoint image R1 are subjected to the parallax amount enlargement control process using the shooting information Df related to the shooting conditions, thereby focusing as described above. Even when the shooting conditions such as the distance change, an appropriate parallax control process according to the change can be performed. Therefore, unlike the case where the change control amount of the parallax amount is constant, it is possible to perform the parallax control while maintaining a desired stereoscopic effect even with respect to the viewpoint image shot as a stereoscopic moving image.

<Second Embodiment>
[Overall Configuration of Imaging Device 3]
FIG. 9 shows the overall configuration of an imaging apparatus (imaging apparatus 3) according to the second embodiment of the present invention. Similar to the imaging device 1 of the first embodiment, the imaging device 3 captures a subject from a plurality of (here, left and right) viewpoint directions, and makes the left and right viewpoint images time-sequentially as a moving image (or still image). To get to. However, the imaging apparatus 3 according to the present embodiment uses a so-called monocular camera, and can switch the left and right optical paths by shutter control. The imaging device 3 includes imaging lenses 10a and 10b, a shutter 11, an image sensor 12, an image processing unit 13, a lens driving unit 18, a shutter driving unit 19, an image sensor driving unit 16, and a control unit 17. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The imaging lenses 10a and 10b are a lens group for acquiring light rays from a subject, and a shutter 11 is disposed between the imaging lenses 10a and 10b. The arrangement of the shutter 11 is not particularly limited, but ideally, it is desirably arranged on the pupil plane of the imaging lenses 10a and 10b or the position of a diaphragm (not shown). The imaging lenses 10a and 10b function as a so-called zoom lens like the imaging lens in the first embodiment, and the focal distance can be changed by adjusting the lens interval and the like by the lens driving unit 18. Yes. Information regarding zooming in the imaging lenses 10a and 10b is input to the image processing unit 13 via the control unit 17 as shooting information Df.

  The shutter 11 is divided into two left and right regions, and transmission and blocking are controlled to be switched for each of the divided regions. The shutter 11 may be a mechanical shutter or an electric shutter such as a liquid crystal shutter as long as it can be switched between opening and closing for each left and right region.

  As in the first embodiment, the image processing unit 13 performs predetermined image processing on the input left and right viewpoint images, and includes image correction processing units 130 and 132, a parallax control processing unit 131, and A disparity map generation unit 133 is provided. Further, the parallax control processing unit 131 performs a parallax amount change control process on the left viewpoint image L1 and the right viewpoint image R1. However, in this embodiment, although the details will be described later, the parallax control processing unit 131 in the image processing unit 13 controls the amount of parallax using the photographing condition in the monocular camera.

  The lens driving unit 18 is an actuator that shifts predetermined lenses in the imaging lenses 10a and 10b along the optical axis.

  The shutter drive unit 19 performs opening / closing switching drive of each area in the shutter 11. Specifically, driving is performed so that the right region is closed when the left region of the shutter 11 is open, and conversely when the left region is closed, the right region is open. When shooting a moving image, the shutter 11 is driven so that the left and right areas are alternately opened and closed in a time-sharing manner.

[Operation and Effect of Imaging Device 3]
(1. Basic operation)
In the imaging device 3, based on the control of the control unit 17, the lens driving unit 18 drives the imaging lenses 10a and 10b under photographing conditions by predetermined zooming, and the shutter driving unit 19 opens the left region in the shutter 11, and the right side Each region is switched to the closed state. Further, in synchronization with these operations, the image sensor driving unit 16 drives the image sensor 12 to receive light. As a result, switching to the left optical path is performed, and the image sensor 12 acquires left viewpoint image data D0L based on light rays incident from the left viewpoint direction.

  Subsequently, the shutter drive unit 19 switches the right region of the shutter 11 to the open state and the left region to the closed state, and the image sensor drive unit 16 drives the image sensor 12 to receive light. Thereby, switching to the right optical path is performed, and the image sensor 12 acquires the right viewpoint image data D0R based on the light ray incident from the right viewpoint direction.

  The zooming conditions (focal length f, subject distance S, etc.) at the time of acquiring each viewpoint image are the imaging information Df via the control unit 17 (details) as in the first embodiment. Is input to the parallax control processing unit 131).

  Then, by performing the opening / closing switching operation in the shutter 11 and the light receiving operation in the image sensor 12 in a time-sharing manner, imaging data corresponding to the left viewpoint image and the right viewpoint image are alternately acquired in time series, and these The sets are sequentially input to the image processing unit 13.

  The image processing unit 13 performs predetermined image processing on the captured images (left viewpoint image L1, right viewpoint image R1) based on the left viewpoint image data D0L and right viewpoint image data D0R acquired as described above, For example, a left viewpoint image L2 and a right viewpoint image R2 for stereoscopic viewing are generated. The generated left viewpoint image L2 and right viewpoint image R2 are recorded in the image processing unit 13 or output to the outside.

(Principle of viewpoint image acquisition)
Here, with reference to FIG. 10 to FIG. 12, the principle of acquiring the left and right viewpoint images when using a monocular camera will be described. 10 to 12 are equivalent to views of the imaging device 3 as viewed from above, but for the sake of simplicity, illustration of components other than the imaging lenses 10a and 10b, the shutter 11, and the image sensor 12 is omitted. The imaging lenses 10a and 10b are also simplified.

  First, as shown in FIG. 10, a light reception image (how to be reflected on the image sensor 12) when the left and right optical paths are not switched (in the case of normal 2D imaging) will be described. Here, three subjects (subjects A to C) arranged at different positions in the depth direction will be described as an example of the subject. As described above, the subject A (person) is on the focusing surface S1 of the taking lenses 10a and 10b, the subject B (mountain) is on the back side of the subject A, and the subject C (flower) is on the near side of the subject A. Each is arranged. In this case, the subject A forms an image near the center on the sensor surface S2, for example. On the other hand, the subject B located behind the focus surface S1 forms an image in front of the sensor surface S2 (on the imaging lens 10b side), and the subject C is behind the sensor surface S2 (on the opposite side to the imaging lens 10b). To form an image. That is, on the sensor surface S2, the subject A is focused (focused) (A0), and the subject B and subject C are defocused (blurred) images (B0, C0).

(Left viewpoint image)
When the optical path is switched between right and left for the three subjects A to C having such a positional relationship, the way the image is reflected on the sensor surface S2 changes as follows. For example, when the shutter drive unit 19 is driven so that the left region SL of the shutter 11 is in the open state and the right region SR is in the closed state, as shown in FIG. The light path is shielded. In this case, the subject A on the focus surface S1 is focused and imaged on the sensor surface S2 (A0) even if the right optical path is shielded, as in the case where the optical path is not switched. However, with respect to the subjects B and C that are out of the focus plane S1, the images defocused on the sensor plane S2 are images that are moved in opposite directions (d1, d2) in the horizontal direction ( B0 ′, C0 ′).

(Right viewpoint image)
On the other hand, when the shutter drive unit 19 is driven to open the right region SR of the shutter 11 and close the left region SL, as shown in FIG. The light path is shielded. Also in this case, the subject A on the focus surface S1 forms an image on the sensor surface S2, and the subjects B and C at positions away from the focus surface S1 are in opposite directions (d3, d4) on the sensor surface S2. ) Is reflected as an image (B0 ", C0"). However, these moving directions d3 and d4 are opposite to the moving directions d1 and d2 in the left viewpoint image, respectively.

(Parallax between left and right viewpoint images)
As described above, also in the imaging device 3, by switching the opening and closing of each region in the shutter 11, the optical paths corresponding to the left and right viewpoint directions are switched as in the imaging device 1 of the first embodiment. The left viewpoint image L1 and the right viewpoint image R1 can be acquired. In addition, since the subject image defocused as described above shifts in the horizontal direction opposite to each other between the left and right viewpoint images, the positional deviation amount (phase difference) along the horizontal direction becomes the parallax amount. For example, as shown in FIGS. 14A and 14B, when focusing on the subject B, the position (B1 _L ) of the image B0 ′ in the left viewpoint image L1 and the position (B1) of the image B0 ″ in the right viewpoint image R1 _R ) in the horizontal direction is the amount of parallax for the subject B. Similarly, when attention is paid to the subject C, the position (C1 _L ) of the image C0 ′ in the left viewpoint image L1 and the right viewpoint image The amount of horizontal displacement Wc1 from the position (C1 _R ) of the image C0 ″ in R1 is the amount of parallax for the subject C.

  Therefore, also in the present embodiment, as in the first embodiment, such left and right viewpoint images are displayed toward the viewer using a predetermined 3D display technique, so that the viewer can A stereoscopic effect corresponding to the amount of parallax of each subject image can be felt in the observed video. For example, in the above-described example, the subject A (person) having no parallax is observed on the display screen (reference plane), while the subject B (mountain) appears to be deeper than the reference plane, and the subject C (flower) is It is observed with a three-dimensional effect that protrudes from the reference plane.

(Relation between parallax amount and shooting conditions)
Here, when attention is paid to the parallax amount Wb1 of the subject B between the left viewpoint image L1 and the right viewpoint image R1, in the monocular imaging device 3, the parallax amount Wb1 is expressed by the following equation (6) using a shooting condition. Can be defined as However, as shown in FIG. 14A, the focal length of the imaging lenses 10a and 10b is f, the subject distance is S, and the distance between the subjects A and B is dep. As shown in FIG. 14B, the distance between the centroids GL and GR of the left and right regions on the pupil plane is G (distance between centroids), and the pupil diameter is D. As described above, also in the present embodiment (monocular type), the parallax amount Wb1 is expressed by an equation using the same shooting conditions as in the first embodiment (binocular type), and the above equation (1) This is equivalent to the one obtained by replacing the base line length L in FIG. Further, the relative stereoscopic effect of the actual subject B with respect to the subject A is determined by equation (6).

(2. Parallax control processing)
In the present embodiment, as in the first embodiment, the image processing unit 13 controls to change the amount of parallax between the left viewpoint image L1 and the right viewpoint image R1. Specifically, the parallax control processing unit 131 in the image processing unit 13 enlarges and controls the parallax amount and the parallax range using the shooting information Df for the left viewpoint image L1 and the right viewpoint image R1.

(Parallax enlargement process considering shooting conditions)
Also in the present embodiment, the parallax control processing unit 131 performs enlargement control of the parallax amount between the viewpoint images in consideration of the shooting conditions by zooming as described above. Specifically, the parallax amount is controlled to be enlarged based on the following equation (7) using a coefficient α (S, f) including, for example, the focal length f and the subject distance S as parameters. That is, for example, when attention is paid to the subject B, the coefficient α (S, f) is set so that the parallax amount Wb2 after the enlargement control becomes a desired value. As in the case of the first embodiment, the coefficient α (S, f) can be calculated by using the above-described equation (in the case where it is desired to increase the amount of parallax so that the value of the amount of parallax does not change due to shooting conditions) What is represented by 4) can be used. Thereby, also in this Embodiment, it can suppress that the amount of parallax (three-dimensional effect) changes unnaturally in the middle of the above zooming. However, the distance G between the centers of gravity is expressed by the following equation (8) using the pupil diameter D, and the pupil diameter D is expressed by using the focal length f and the F number F. It can also be expressed as 9). That is, in addition to the focal length f and the subject distance S, the pupil diameter D and the F number F may be used as parameters.

(Use of disparity map)
In such parallax control processing, the parallax amount can be enlarged for each subject by using the map data DD as in the first embodiment. As a result, not only the amount of parallax in the horizontal direction but also the range of parallax in the depth direction can be expanded. Therefore, as in the first embodiment, the subject B on the far side is deeper and the subject C on the near side protrudes further, that is, the stereoscopic effect for each subject is more emphasized. Such parallax control is possible.

  The left viewpoint image L2 and the right viewpoint image R2 that have been subjected to the parallax enlargement processing in this way are subjected to predetermined image correction processing by the image correction processing unit 132, and then are stored as image data Dout as a storage unit (not shown). Or output to an external display device or the like.

  As described above, also in the present embodiment, as in the first embodiment, the parallax amount enlargement control is performed on the left viewpoint image L1 and the right viewpoint image R1 by using the shooting information Df regarding the shooting conditions. By performing the above, it is possible to perform an appropriate parallax amount control process corresponding to the change even when the shooting condition changes. Therefore, an effect equivalent to that of the first embodiment can be obtained.

  Hereinafter, modified examples (modified examples 1 and 2) of the imaging devices according to the first and second embodiments will be described. In the following description, the same components as those in the imaging devices of the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

<Modification 1>
In the first and second embodiments, the enlargement control process has been described as an example of the parallax amount change control process, but it is also possible to perform change control that reduces the parallax amount. That is, for the left viewpoint image L1 and the right viewpoint image R1 acquired in the same manner as described above, the following reduction control is performed using the disparity map in the parallax control using the shooting information Df. Also good. That is, as shown in FIGS. 15A and 15B, in the left viewpoint image L1 and the right viewpoint image R1, the images of the subjects B and C so that the parallax amounts of the subjects B and C are reduced. Is shifted along the horizontal direction (X direction). However, also here, the positions A1 _L and A1 _R of the subject A having no parallax are not changed (the parallax amount is kept 0), and the left viewpoint image L2 and the right viewpoint image R2 are also arranged at the same position. To do.

Specifically, the object B, from the position B1 _L of the left-viewpoint image L1 to the position B2 _L in the left-viewpoint image L2, is shifted in the direction of the X-direction positive (+) (dashed arrows). On the other hand, from the position B1 _R in the right viewpoint image R1 to the position B2 _R in the right viewpoint image R2, X direction negative (-) is shifted in the direction of (solid arrow). Thereby, the parallax amount for the subject B can be reduced from the parallax amount Wb1 to the parallax amount Wb3 smaller than the parallax amount Wb1. Also in this modification, the parallax amount Wb3 is set using the shooting information Df (focal length f, subject distance S, etc.). On the other hand, the parallax amount of the subject C is reduced in the same manner. However, the subject C is shifted in the negative X direction (−) from the position C1 _L in the left viewpoint image L1 to the position C2 _L in the left viewpoint image L2. On the other hand, the X-direction positive (+) direction is shifted from the position C1 _R in the right viewpoint image R1 to the position C2 _R in the right viewpoint image R2 (broken arrow).

  Thus, also in this modification, the disparity amount can be reduced for each subject by using the disparity map. For example, as described above, the parallax control for each subject such as shifting the positions of specific subjects B and C among the subjects A to C in different directions to reduce only the parallax amount of the subjects B and C is performed. It becomes possible. Thereby, for the same reason as described above, not only the amount of parallax in the horizontal direction but also the parallax range in the depth direction can be reduced. Therefore, for example, it is possible to observe each subject image observed on the back side and the near side closer to the reference plane, that is, to reduce the stereoscopic effect for each subject.

<Modification 2>
In the first and second embodiments, the focal length f and the subject distance S are used as the shooting information Df, and the parallax control is performed using the coefficient α (S, f) using these S and f as parameters. Although the processing is performed, the parameters used as the photographing information Df are not limited to these. As the shooting information Df, for example, other parameters may be used as described above, or only the focal length f may be used as in the present modification.

  That is, since S >> f is obtained in a focus range in a general camera, the parallax amount Wb2 can be expressed by the following expression (10) in consideration of this. Therefore, as in the first and second embodiments, when it is desired to change (enlarge or reduce) the parallax amount so that the value of the parallax amount does not change due to the shooting conditions, the coefficient α (S, f ) May be expressed by the following formula (11). As a result, as in the first and second embodiments, it is possible to suppress an unnatural change in the amount of parallax (three-dimensional effect) during zooming.

  Although the present invention has been described with reference to the embodiment and the modification examples, the present invention is not limited to the embodiment and the like, and various modifications can be made. For example, in the above-described embodiment and the like, the case where predetermined image processing is performed on the left and right viewpoint images acquired by switching the left and right optical paths has been described as an example, but the viewpoint direction is left and right (horizontal direction). The upper and lower sides (vertical direction) are not limited. In addition, the optical path may be switched to three or more, and three or more multi-view images may be acquired.

  In the above-described embodiment and the like, the image processing unit 13 acquires the shooting information Df from the imaging lens side via the control unit 17. However, for example, a separate device from the camera body (including the imaging lens and the image sensor). When image processing including parallax control processing is executed, the following may be performed. That is, the shooting information Df may be acquired directly from the camera body, or the shooting information may be obtained as pixel data of a pixel of each viewpoint image (for example, a pixel that is normally arranged at the corner of the image sensor and does not affect image display). Df may be stored. Furthermore, it may be stored in the header of the line memory so that the parallax control process can be performed at an opportunity different from that at the time of shooting.

  Furthermore, in the above-described embodiment, the subject B on the back side of the subject A is observed on the back side, and the subject C on the near side is observed on the near side (or vice versa). Although the parallax control is performed so as to emphasize (or relax) the feeling, the present invention is not limited to this, and it can be controlled so as to have various appearances according to a desired stereoscopic effect. Further, although the image position of the subject A is not shifted from the reference position, the subject A may also be shifted so that it can be observed from the reference plane on the back side (or the near side). Further, the number of subjects to be subject to parallax control is not limited to three as described above, and may be two or less or four or more.

  The series of image processing in the image processing unit 13 can be executed in hardware, software, or a combination of both. When executing processing by software, the program recording the processing sequence is installed in a memory in a computer incorporated in dedicated hardware and executed, or the program is executed on a general-purpose computer capable of executing various processing. It can be installed and run. For example, the program can be recorded in advance on a recording medium. In addition to installing on a computer from a recording medium, the program can be received via a network such as a LAN (Local Area Network) or the Internet and installed on a recording medium such as a built-in hard disk.

  DESCRIPTION OF SYMBOLS 1,3 ... Imaging device, 10a, 10a1, 10a2, 10b ... Imaging lens (group), 11, 11a, 11b ... Shutter, 12 ... Image sensor, 13 ... Image processing part, 14, 18 ... Lens drive part, 15, DESCRIPTION OF SYMBOLS 19 ... Shutter drive part, 16 ... Image sensor drive part, 17 ... Control part, L1, L2 ... Left viewpoint image, R1, R2 ... Right viewpoint image, Df ... Shooting information.

Claims (10)

An image processing apparatus comprising: a parallax control processing unit that changes a parallax amount between viewpoint images using a focal length of an imaging lens when shooting each viewpoint image in a plurality of viewpoint images taken from different directions. The image processing device according to claim 1, wherein the parallax control processing unit expands or reduces a parallax amount in the horizontal direction between the viewpoint images based on a phase difference between the viewpoint images. The image processing apparatus according to claim 2, wherein the parallax control processing unit further changes the parallax amount using a subject distance. The image processing apparatus according to claim 3, wherein the parallax control processing unit changes the parallax amount for each subject. The parallax control processing unit performs a depth direction between viewpoint images based on a disparity map in which a phase difference detected for each pixel or each pixel block including a plurality of pixels is associated with each pixel or each pixel block. The image processing apparatus according to claim 2, wherein the parallax range in is enlarged or reduced. An imaging unit for acquiring the plurality of viewpoint images;
The image processing apparatus according to claim 1, wherein the parallax control processing unit changes a parallax amount between the viewpoint images in the plurality of viewpoint images acquired by the imaging unit. The imaging unit
An imaging lens;
The image processing apparatus according to claim 6, further comprising: a shutter that switches between transmission and blocking in each of the plurality of optical paths. An image processing method, comprising: changing a parallax amount between viewpoint images using a focal length of an imaging lens when capturing each viewpoint image in a plurality of viewpoint images captured from different directions. An image processing program for causing a computer to execute a step of changing a parallax amount between viewpoint images using a focal length of an imaging lens when shooting each viewpoint image in a plurality of viewpoint images taken from different directions. In a plurality of viewpoint images taken from different directions, an image processing program is recorded that causes the computer to execute a step of changing the amount of parallax between the viewpoint images using the focal length of the imaging lens when the viewpoint images are taken. ing,
Computer-readable recording medium.

Images