JP4533735B2 - Stereo imaging device - Google Patents

Description

    The present invention relates to a stereoscopic image photographing apparatus such as a digital camera provided with a plurality of imaging units.

  In recent years, digital cameras have become widespread. The digital camera includes an imaging unit including a photographing lens, a diaphragm, an image sensor, and the like, and image data acquired by the imaging unit is digitized and recorded on an information recording medium such as a memory card. The image sensor is configured by a solid-state imaging device such as a CCD (Charge Coupled Device) type or a CMOS (Complementary Metal Oxide Semiconductor) type that photoelectrically converts a subject image formed by a photographing lens.

Among such digital cameras, there are two-lens cameras that include first and second imaging units and can acquire two images for stereoscopic viewing (for example, Patent Documents 1 and 2 below). reference). In this two-lens digital camera, the same subject is simultaneously photographed by each imaging unit, and two types of images with different parallaxes are obtained for the right-eye image and the left-eye image. By using a stereoscopic display, the acquired right-eye image is guided to the right eye and the left-eye image is guided to the left eye, thereby realizing stereoscopic display.
JP 2001-281754 A JP 2001-142166 A

  However, Patent Documents 1 and 2 do not disclose a specific operation method of automatic focusing (AF) at the time of photographing with a twin-lens digital camera. Since the two image capturing units of the twin-lens digital camera capture the same subject at the same time, it is inefficient in time to perform the AF operation independently of each other.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a stereoscopic image capturing apparatus that includes a plurality of imaging units and can perform an AF operation efficiently in a short time.

  In order to achieve the above object, a stereoscopic image capturing apparatus of the present invention includes a first imaging unit having a first focus lens that moves in a range from a near point to a far point along an optical axis, and an optical axis. The AF evaluation value is calculated by integrating the high-frequency component of the luminance value from each image data obtained by the second imaging unit having the second focus lens moving in the range from the near point to the far point, and the AF evaluation value is In a stereoscopic image photographing apparatus that performs an AF operation for positioning the first and second focus lenses at a position that is substantially maximum, in the AF operation, the first and second focus lenses are simultaneously driven, and each predetermined feed amount is obtained. The AF evaluation value is calculated, and the other focus lens is set at the position of the focus lens where the maximum value of the AF evaluation value is detected first.

  In the AF operation, it is preferable that one of the first and second focus lenses is driven from the near point to the far point and the other is driven from the far point to the near point.

  In the AF operation, one movement start position of the first and second focus lenses is set as a near point or a far point, and the other movement start position is set between the near point and the far point, and both are in the same direction. It is also suitable to move to.

  Further, the distance between the optical axes of the first and second focus lenses is variable, and in the AF operation, the movement start position and the movement direction of the first and second focus lenses are set according to the distance between the optical axes. It is also suitable to determine.

  Further, the angle between the optical axes of the first and second focus lenses is variable, and in the AF operation, the movement start position and the movement direction of the first and second focus lenses are set according to the angle between the optical axes. It is also suitable to determine.

  Further, the image processing apparatus includes a parallax calculation unit that calculates a parallax of a subject from each image data obtained by the first and second imaging units, and the first operation is performed according to the parallax calculated by the parallax calculation unit in the AF operation. It is also preferable to determine the movement start position and movement direction of the second focus lens.

  In the AF operation, one of the first and second imaging units is driven from one of the near point or the far point toward the other, and the AF evaluation value is calculated for each first feed amount to obtain the maximum value. After the detection, both the first and second imaging units are driven only within a range determined to include the position of the focus lens where the maximum value is obtained, and the second feed smaller than the first feed amount. It is also preferable to detect the maximum value by calculating the AF evaluation value for each amount.

  Further, in the AF operation, one of the first and second imaging units is finely moved from a predetermined position toward a near point and a far point, and a focus lens is moved in a direction in which the AF evaluation value increases, thereby performing the AF evaluation. After detecting the maximum value, both the first and second imaging units are driven only within a range determined so as to include the position of the focus lens from which the maximum value was obtained, for each predetermined feed amount. It is also preferable to detect the maximum value by calculating the AF evaluation value.

  Furthermore, the first and second imaging units include first and second diaphragms for restricting light beams, respectively, and the aperture values of the first and second diaphragms are set to different values, and then the aperture values are changed. It is also preferable to perform photometry and set the aperture value of the other aperture to the aperture value of the aperture for which the optimum value has been detected first.

  The stereoscopic image capturing apparatus according to the present invention drives the first and second focus lenses simultaneously in the AF operation, calculates an AF evaluation value for each predetermined feed amount, and detects the maximum AF evaluation value first. Since the other focus lens is set at the lens position, the AF operation can be completed efficiently in a short time.

  In FIG. 1, on the front surface of the stereoscopic camera 1 to which the first embodiment of the present invention is applied, a first lens barrel 3 a that holds the first imaging unit 2 a and a second lens barrel 3 b that holds the second imaging unit 2 b. In addition to being incorporated, the strobe device 4 and the like are exposed. The first and second lens barrels 3a and 3b are arranged in parallel in the horizontal direction at a constant interval so that the lens optical axes L1 and L2 of the first and second imaging units 2a and 2b are parallel to each other. The first and second lens barrels 3a and 3b are extended forward from the camera body as shown by a solid line in the drawing at the time of photographing, and retracted into the camera body as shown by a dotted line in the drawing when the power is turned off or when an image is reproduced. Further, a shutter button 5 used for a shutter release operation is provided on the upper surface of the stereoscopic camera 1.

  In FIG. 2, an input operation unit 9 including a zoom button 6, a menu button 7, a cursor button 8, and the like and an LCD (Liquid Crystal Display) 10 are provided on the back of the stereoscopic camera 1. By appropriately operating the input operation unit 9, the power is turned on / off, various modes (shooting mode, playback mode, etc.) are switched, zooming, and the like are performed. The LCD 10 is a 3D monitor of a parallax barrier type or a lenticular lens type, and is used as an electronic viewfinder at the time of image shooting, and performs stereoscopic display of image data obtained by shooting at the time of image reproduction.

  FIG. 3 shows an electrical configuration of the stereoscopic camera 1. The first imaging unit 2a includes a first zoom lens 11, a first diaphragm 12, a first focus lens 13, and a first image sensor 14 arranged along the lens optical axis L1. A lens motor 15 is connected to the first zoom lens 11, an iris motor 16 is connected to the first diaphragm 12, a lens motor 17 is connected to the first focus lens 13, and a timing generator (TG) is connected to the first image sensor 14. ) 18 is connected. The operations of the motors 15 to 17 and the TG 18 are controlled by the CPU 19.

  The lens motor 15 moves the first zoom lens 11 along the lens optical axis L1 to the NEAR side (feed-out side) or the INF side (retract-side) according to the zoom operation from the input operation unit 9, and the zoom magnification. To change. The iris motor 16 performs exposure adjustment by changing the aperture value (aperture value) of the first diaphragm 12 to limit the light beam during AE (Auto Exposure) operation. The lens motor 17 moves the first focus lens 13 to the NEAR side or the INF side along the lens optical axis L1 during AF (Auto Focus) operation to change the focus position and perform focus adjustment.

  The first image sensor 14 receives subject light imaged by the first zoom lens 11, the first diaphragm 12, and the first focus lens 13, and accumulates photocharges corresponding to the amount of received light in the light receiving element. The photocharge accumulation / transfer operation of the first image sensor 14 is controlled by the TG 18, and the electronic shutter speed (photocharge accumulation time) is determined by a timing signal (clock pulse) input from the TG 18. The first image sensor 14 acquires an image signal for one screen at a predetermined period and sequentially inputs it to the correlated double sampling circuit (CDS) 28 in the photographing mode.

  The second imaging unit 2b has the same configuration as the first imaging unit 2a. The second zoom lens 20 to which the lens motor 24 is connected, the second diaphragm 21 to which the iris motor 25 is connected, and the lens motor 26 are connected. The second focus lens 22 and a second image sensor 23 to which a timing generator (TG) 27 is connected. The operations of the motors 24 to 26 and the TG 27 are controlled by the CPU 19. The first imaging unit 2a and the second imaging unit 2b basically operate in conjunction with each other, but can also be operated individually. Incidentally, as the first and second image sensors 14 and 23, CCD type or CMOS type image sensors are used.

  The imaging signals output from the first and second image sensors 14 and 23 are input to a correlated double sampling circuit (CDS) 28. The CDS 28 inputs R, G, B image data accurately corresponding to the accumulated charge amount of each light receiving element of the first and second image sensors 14, 23 to the amplifier (AMP) 29. The AMP 29 amplifies the input image data and inputs it to the A / D converter 30. The A / D converter 30 converts the input image data from analog to digital. Through the CDS 28, the AMP 29, and the A / D converter 30, the imaging signal of the first image sensor 14 is the first image data (right eye image data), and the imaging signal of the second image sensor 23 is the second image data (left eye data). Image data).

  The image signal processing circuit 31 performs various image processing such as gradation conversion, white balance correction, and γ correction processing on the first and second image data input from the A / D converter 30. The frame memory 32 temporarily stores the first and second image data subjected to various image processing by the image signal processing circuit 31.

  The evaluation value calculation circuit 33 calculates an AF evaluation value and an AE evaluation value from each of the first and second image data stored in the frame memory 32. The AF evaluation value is calculated by integrating high-frequency components of the luminance value for the entire region or predetermined region (for example, the central portion) of each image data, and represents the sharpness of the image. The high-frequency component of the luminance value is a sum of luminance differences (contrast) between adjacent pixels in a predetermined area. Further, the AE evaluation value is calculated by integrating the luminance values over the entire area or a predetermined area (for example, the central portion) of each image data, and represents the brightness of the image. The AF evaluation value and the AE evaluation value are respectively used in an AF operation and an AE operation that are executed during an imaging preparation process described later.

  The stereoscopic image processing circuit 34 combines the first and second image data stored in the frame memory 32 with stereoscopic image data for the LCD 10 to perform stereoscopic display. When the LCD 10 is used as an electronic viewfinder in the shooting mode, the stereoscopic image data synthesized by the stereoscopic image processing circuit 34 is displayed on the LCD 10 as a through image via the LCD driver 35.

  The compression / decompression processing circuit 36 performs compression processing on the first and second image data stored in the frame memory 32 in a compression format such as the JPEG method. The media controller 37 records each image data compressed by the compression / decompression processing circuit 36 on a recording medium 38 such as a memory card.

  When the first and second image data thus recorded on the recording medium 38 are reproduced and displayed on the LCD 10, each image data on the recording medium 38 is read by the media controller 37 and decompressed by the compression / decompression processing circuit 36. After being processed and converted into stereoscopic image data by the stereoscopic image processing circuit 34, it is displayed as a reproduced image on the LCD 10 via the LCD driver 35.

  Although the detailed structure of the LCD 10 is not shown, the LCD 10 includes a parallax barrier display layer on the surface thereof. The LCD 10 generates a parallax barrier having a pattern in which light transmitting portions and light shielding portions are alternately arranged at a predetermined pitch on the parallax barrier display layer when performing stereoscopic display, and an image display surface below the parallax barrier. The strip-shaped image fragments showing the left and right images are alternately arranged and displayed to enable stereoscopic viewing.

  The CPU 19 comprehensively controls the overall operation of the stereoscopic camera 1. In addition to the shutter button 5 and the input operation unit 9 described above, an EEPROM 39 that is a nonvolatile memory is connected to the CPU 19. The EEPROM 39 stores various control programs and setting information. The CPU 19 executes various processes based on this program and setting information.

  The shutter button 5 has a two-stage push switch structure. When the shutter button 5 is lightly pressed (half-pressed) during the shooting mode, an AF operation and an AE operation are performed, and a shooting preparation process is performed. In this state, when the shutter button 5 is further pressed (fully pressed), shooting processing is performed, and the first and second image data for one screen are transferred from the frame memory 32 to the recording medium 38 and recorded. .

  As will be described in detail later, in the AF operation, the CPU 19 controls the lens motors 17 and 26 to move the first and second focus lenses 13 and 22 in predetermined directions, respectively, and the first and second images obtained sequentially. This is done by obtaining the maximum AF evaluation value calculated by the evaluation value calculation circuit 33 from each piece of data. In the AE operation, after the AF operation is completed, the CPU 19 controls the iris motors 18 and 27 and the TGs 18 and 27 based on the AE evaluation value calculated by the evaluation value calculation circuit 33, and the first and second apertures 12 and 21 are controlled. And the electronic shutter speeds of the first and second image sensors 14 and 23 are set.

  Next, the operation of the present invention will be described with reference to FIGS. FIG. 4 shows the operation of the shooting mode provided in the stereoscopic camera 1. When the power of the stereoscopic camera 1 is turned on and the photographing mode is set by the operation of the input operation unit 9, a standby state is detected in which it is detected whether or not the shutter button 5 is half-pressed (step S100). At this time, a through image is displayed on the LCD 10. When the photographer frames the subject and presses the shutter button 5 halfway, the AF operation starts (step S101). First, the first and second focus lenses 13 and 22 are moved to the search start positions (movement start positions) shown in FIG. ) Is set (step S102). The search start position of the first focus lens 13 is set to the NEAR end (position Pn (near point)), and the search start position of the second focus lens 22 is set to the INF end (position Pi (far point)). Note that the first and second focus lenses 13 and 22 each move in a range from the NEAR end to the INF end.

  Thereafter, an AF search is executed (step S103). The first focus lens 13 is moved in the direction of arrow A in the figure along the lens optical axis L1, and the second focus lens 22 is moved in the direction of arrow B in the figure along the lens optical axis L2. At this time, the first and second focus lenses 13 and 22 are moved at a constant speed, and the AF evaluation values of the first and second image data are calculated each time the first and second focus lenses 13 and 22 are moved by the feed amount d (see FIG. 6). (Step 104). The feed amount d is set so that a sufficient number of AF evaluation value calculation points can be obtained between the NEAR end and the INF end.

  When the first and second focus lenses 13 and 22 are at the same position, the AF evaluation values of the first and second image data are almost the same. When the AF evaluation values of the first and second image data follow the graph of FIG. 6, for example, the position (peak position) Pm at which the AF evaluation value is maximized is located on the INF end side, and therefore AF in the direction of arrow B The second imaging unit 2b that performs the search detects the maximum AF evaluation value before the first imaging unit 2a that performs the AF search in the direction of arrow A. The detection of the maximum value is determined by increasing or decreasing the AF evaluation value.

  In this way, when either the first imaging unit 2a or the second imaging unit 2b detects the maximum value of the AF evaluation value (Yes in step S105), the AF search ends, and the first and second focus The lenses 13 and 22 are stopped on the spot (step 106). At this time, the focus lens of the imaging unit (the second imaging unit 2b in the example of FIG. 6) that has detected the maximum AF evaluation value is stopped at the peak position Pm, but the other imaging unit (in the example of FIG. 6). The focus lens of the first imaging unit 2a) is not stopped at the peak position Pm. Thereafter, when the focus lens of the other imaging unit is moved and set to the peak position Pm (step S107), the AF operation ends (step S108).

  When the AF operation is completed, the AE operation is subsequently started (step S109), and the AE evaluation value is calculated from the first and second image data acquired at the peak position Pm. When the exposure amount is determined based on the AE evaluation value (step S110), the aperture values of the first and second diaphragms 12 and 21 and the electronic shutter speeds of the first and second image sensors 14 and 23 are set. The AE operation ends (step S111). Thereafter, a standby state is detected for detecting whether or not the shutter button 5 has been fully pressed (step S112). When the shutter button 5 is fully pressed, shooting is performed, and the first and second image data for one screen acquired at this time is recorded on the recording medium 38 (step S113).

  In the first embodiment, as shown in FIG. 5, the search start position of the first focus lens 13 is the NEAR end, and the search start position of the second focus lens 22 is the INF end. The search start position of the first focus lens 13 may be the INF end, and the search start position of the second focus lens 22 may be the NEAR end, contrary to the above.

  As described above, in the stereoscopic camera 1 to which the first embodiment of the present invention is applied, during the AF operation, one search start position of the first and second focus lenses 13 and 22 is the NEAR end, and the other search start position. Since the AF search is performed by moving each in the opposite direction after setting the INF end, the AF operation can be completed efficiently in a short time.

  In the first embodiment, the first and second focus lenses 13 and 22 are sometimes moved in opposite directions to perform the AF search. Instead, the first and second focus lenses 13 and 22 are replaced with each other. Even if the AF search is performed by moving 22 in the same direction, the same effect as described above may be obtained as described below.

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, an AF search is performed by moving the first and second focus lenses 13 and 22 in the same direction, and the search start position is different from that in the first embodiment. In the figure, the search start position of the first focus lens 13 is the NEAR end, the search start position of the second focus lens 22 is a position shifted by a distance δ from the NEAR end (position Pn + σ), and both search directions are toward the INF end side. In the same direction (arrows A and B in the figure). The shift amount σ is preferably a half distance from the NEAR end to the INF end.

  The operations other than the search start position and search direction of the first and second focus lenses 13 and 22 are the same as those in the first embodiment. When the AF evaluation values of the first and second image data are as shown in the graph of FIG. 8, the second imaging unit 2b first detects the peak position Pm. On the other hand, when the peak position Pm is located between the position Pn and the position Pn + σ, the first imaging unit 2a first detects the peak position Pm. As described above, in the second embodiment of the present invention, as in the first embodiment, one of the first and second imaging units 2a and 2b detects the peak position Pm first during the AF search. The AF operation can be completed efficiently in a short time.

  In the second embodiment, the search start positions of the first and second focus lenses 13 and 22 are set as shown in FIG. 8, but the search start positions may be reversed. In the second embodiment, the first and second focus lenses 13 and 22 are moved from the INF end side to the NEAR end side during the AF search, but are moved from the NEAR end side to the INF end side. May be.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, either one of the first and second lens barrels 3a and 3b is configured to be slidable by a rail or the like, and the distance between the optical axes (base line) while keeping the lens optical axes L1 and L2 in parallel. Long) W is variable. The search start positions and search directions of the first and second focus lenses 13 and 22 are determined according to the magnitude of the optical axis distance W. Other configurations are the same as those in the first embodiment. In the figure, the first lens barrel 3a is slidable, and a voltage decoder 40 for detecting the amount of displacement of the first lens barrel 3a is provided. The detection result of the voltage decoder 40 (that is, the optical axis distance W) is transmitted to the CPU 19.

  The photographer determines the approximate distance to the subject and manually slides the first lens barrel 3a. Usually, when the subject is far away, the optical axis distance W is small, and when the subject distance is short, the optical axis distance W is set large. The CPU 19 determines whether or not the optical axis distance W detected by the voltage decoder 40 is larger than a predetermined length S. If the optical axis distance W is smaller than the length S (W <S), The search start positions of the first and second focus lenses 13 and 22 are both set to the NEAR end, the search direction is the direction from the NEAR end toward the INF end, and the optical axis distance W is greater than the length S (W> S), the search start positions of the first and second focus lenses 13 and 22 are both set to the INF end, and the search direction is the direction from the INF end toward the NEAR end.

  When W <S, the peak position Pm of the AF evaluation value is positioned on the NEAR end side. Conversely, when W <S, the peak position Pm of the AF evaluation value is positioned on the INF end side. By setting the position and the search direction, the peak position Pm can be detected at an early stage, and the AF operation can be completed efficiently in a short time.

  In the third embodiment, the first lens barrel 3a is slidable. Alternatively, the second lens barrel 3b may be slidable, and the first and second lens barrels 3a, 3b may be slidable. Both may be slidable.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, one of the first and second lens barrels 3a and 3b is configured to be rotatable by a hinge or the like, and the angle between the optical axes (convergence angle) θ is variable. The search start positions and search directions of the first and second focus lenses 13 and 22 are determined in accordance with the magnitude of the optical axis angle θ. Other configurations are the same as those of the first embodiment. In the figure, the first lens barrel 3a is rotatable, and an angle decoder 41 for detecting the rotation angle of the first lens barrel 3a is provided. The detection result of the angle decoder 41 (that is, the optical axis angle θ) is transmitted to the CPU 19.

  The photographer determines the approximate distance to the subject and manually rotates the first lens barrel 3a. Usually, when the subject is far, the optical axis angle θ is small, and when the subject distance is short, the optical axis angle θ is set large. The CPU 19 determines whether or not the optical axis angle θ detected by the angle decoder 41 is larger than a predetermined angle Δ, and when the optical axis angle θ is larger than the angle Δ (θ> Δ), the first is performed. When the search start position of both the second focus lenses 13 and 22 is set to the NEAR end, the search direction is the direction from the NEAR end toward the INF end, and the optical axis angle θ is smaller than the angle Δ (θ <Δ). In this case, the search start positions of the first and second focus lenses 13 and 22 are both set to the INF end, and the search direction is the direction from the INF end toward the NEAR end.

  When θ> Δ, the peak position Pm of the AF evaluation value is located on the NEAR end side. Conversely, when θ <Δ, the peak position Pm of the AF evaluation value is located on the INF end side. By setting the position and the search direction, the peak position Pm can be detected at an early stage, and the AF operation can be completed efficiently in a short time.

  In the fourth embodiment, the first lens barrel 3a is rotatable. Alternatively, the second lens barrel 3b may be rotatable, and the first and second lens barrels 3a. , 3b may be rotatable.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS. In the fifth embodiment, as shown in FIG. 11, a parallax calculation circuit 42 that performs feature extraction from the first and second image data stored in the frame memory 32 and obtains the parallax of the subject is provided. The search start positions and search directions of the first and second focus lenses 13 and 22 are determined according to the magnitude of the parallax. Other configurations are the same as those in the first embodiment. Assume that the subject 43 is in a positional relationship as shown in FIG. When the AF operation is started (step S101 in FIG. 4), the first and second image data as shown in FIG. The parallax calculation circuit 42 extracts the characteristic part (face, trunk, etc.) of the subject 43 from the first and second image data, and calculates the subject parallax P from the difference in the horizontal position (in the case of FIG. = X2-X1). The subject parallax P is transmitted to the CPU 19.

  The CPU 19 determines whether or not the subject parallax P calculated by the parallax calculation circuit 42 is larger than the predetermined parallax α. If the subject parallax P is larger than the parallax α (P> α), the first and second When the search start positions of the focus lenses 13 and 22 are both set to the NEAR end, the search direction is the direction from the NEAR end toward the INF end, and the subject parallax P is smaller than the parallax α (P <α), the first The search start positions of the second focus lenses 13 and 22 are both set to the INF end, and the search direction is the direction from the INF end toward the NEAR end.

  When P> α, the peak position Pm of the AF evaluation value is positioned on the NEAR end side. Conversely, when P <α, the peak position Pm of the AF evaluation value is positioned on the INF end side. By setting the position and the search direction, the peak position Pm can be detected at an early stage, and the AF operation can be completed efficiently in a short time.

  Next, a sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, at the start of the AF operation, one of the first and second imaging units 2a and 2b first performs AF search (hereinafter referred to as AF rough search) with a relatively large first feed amount d1, and AF evaluation is performed. After the approximate peak position Pm ′ of the value is detected, an AF search (hereinafter referred to as an AF detailed search) is performed with a second feed amount d2 smaller than the first feed amount d1, using both the first and second imaging units 2a and 2b. ), The more accurate peak position Pm of the AF evaluation value is detected.

  The shooting mode follows the flowchart of FIG. 14 instead of the flowchart of FIG. 4 of the first embodiment. The flowchart in FIG. 14 is the same as the flowchart in FIG. 4 except for steps S202 to S205. When the AF operation is started (step S201), the first focus lens 13 is set to the NEAR end, and the AF rough search is performed with the first feed amount d1 toward the INF end side (step S202). Thereby, as shown in FIG. 15A, the approximate peak position Pm 'is detected. Then, the search range R of the AF detailed search is determined so as to include the detected approximate peak position Pm '(step S203). As shown in the figure, the search range R is set to a range from the position Pm′−d1 to the position Pm ′ + d1.

  Thereafter, the search start positions of the first and second focus lenses 13 and 22 are set to the NEAR end side (position Pm′−d1) of the search range R (step S204), and the search range R is moved toward the INF side. An AF detailed search is performed with the second feed amount d2 (step S205). Then, by the same procedure as described above, a more accurate peak position Pm is detected as shown in FIG. 15B (steps S206 and S207).

  As described above, in the sixth embodiment of the present invention, after one imaging unit performs AF rough search, all the imaging units perform AF detailed search on a limited area, so that AF operation can be efficiently performed in a short time. In addition to being able to be completed, the time for performing the AF search can be substantially shortened, and the overall power consumption can be reduced.

  In the sixth embodiment, the first imaging unit 2a performs the AF rough search. Instead, the second imaging unit 2b may perform the AF rough search. Further, although the search start position of the AF rough search is set as the NEAR end, this may be set as the INF end. Further, although the search start position at the time of the AF detailed search is set to the NEAR end side of the search range R for both the first and second focus lenses 13 and 22, this may be set to the INF end side of the search range R. One of the first and second focus lenses 13 and 22 may be the NEAR end side of the search range R, and the other may be the INF end side of the search range R.

  Next, a seventh embodiment of the present invention will be described with reference to FIG. In the seventh embodiment, a continuous AF search is used in place of the AF rough search of the sixth embodiment. The flowchart in FIG. 16 is the same as the flowchart in FIG. 14 except for step S302. In step S302, only the first imaging unit 2a among the first and second imaging units 2a and 2b operates. The first imaging unit 2a finely moves the first focus lens 13 from a predetermined position to the NEAR end side and the INF end side, and then moves the first focus lens 13 in a direction in which the AF evaluation value increases, thereby approximately the approximate peak position. Pm ′ is detected.

  When the approximate peak position Pm ′ is detected, the search range R of the AF detailed search is determined (step S303), the first and second focus lenses 13 and 22 are set to predetermined search start positions (step S304), An AF detailed search is performed within the search range R (step S305). Then, a more accurate peak position Pm is detected by the same procedure as described above (steps S306 and S307).

  As described above, in the seventh embodiment of the present invention, after one imaging unit performs a continuous AF search, all the imaging units perform an AF detailed search on a limited area, so that it is efficient in a short time. In addition to being able to complete the AF operation, the time for performing the AF search can be substantially shortened, and the overall power consumption can be reduced.

  Next, an eighth embodiment of the present invention will be described with reference to FIG. The AE operation in the first to seventh embodiments may be performed according to the procedure shown in FIG. When the AE operation starts, the aperture value of the first aperture 12 is set to the maximum (open aperture state), and the aperture value of the second aperture 21 is set to the minimum (small aperture state) (step S400). Subsequently, while the aperture value of the first diaphragm 12 is decreased and the second diaphragm 21 is increased, the AE evaluation value is calculated to perform photometry (step S403), and the first imaging unit 2a or the second imaging unit 2b. When either of these detects the optimal AE evaluation value (optimum value) (Yes in step S403), the increase / decrease in the aperture value is stopped. Thereafter, the aperture of the other imaging unit that has not detected the optimal value is set to the aperture value of the aperture of the imaging unit that has detected the optimal value (step S404), and the AE operation ends. In step S401, contrary to the above, the aperture value of the first diaphragm 12 may be set to the minimum, and the aperture value of the second diaphragm 21 may be set to the maximum.

  Thus, in the eighth embodiment of the present invention, one of the first and second apertures 12 and 21 changes the aperture value from one open aperture state to the small aperture state and the other changes the aperture value from the small aperture state to the open aperture state. Since the evaluation value is calculated, the AE operation can be completed efficiently in a short time.

  In the first to eighth embodiments, the stereoscopic camera 1 is provided with the two imaging units, the first and second imaging units 2a and 2b. However, three or more imaging units may be provided. . In addition, although the digital still camera that captures a still image is illustrated as the stereoscopic image capturing device of the present invention, the present invention is not limited thereto, and the present invention can also be applied to a digital video camera that captures a moving image. .

It is an external view of the front side of a stereoscopic camera. It is an external view of the back side of a stereoscopic camera. It is a block diagram which shows the electrical structure of a stereo camera. It is a flowchart which shows operation | movement of imaging | photography mode. It is a figure explaining the operation | movement of the 1st and 2nd focus lens at the time of AF operation | movement. It is a graph which shows an example of AF evaluation value obtained for every predetermined feed amount. It is a schematic block diagram which shows 2nd Embodiment of this invention. It is a graph which shows an example of AF evaluation value obtained by a 2nd embodiment of the present invention. It is a schematic block diagram which shows 3rd Embodiment of this invention. It is a schematic block diagram which shows 4th Embodiment of this invention. It is a block diagram which shows 5th Embodiment of this invention. It is a figure which shows a mode that a to-be-photographed object is image | photographed with a stereo camera. It is a figure which shows the 1st and 2nd image data obtained by imaging | photography. It is a flowchart which shows 6th Embodiment of this invention. It is a graph which shows an example of AF evaluation value obtained in a 6th embodiment of the present invention. It is a flowchart which shows 7th Embodiment of this invention. It is a flowchart which shows 8th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stereo camera 2a 1st imaging part 2b 2nd imaging part 3a 1st lens barrel 3b 2nd lens barrel 10 LCD
11 First Zoom Lens 12 First Aperture 13 First Focus Lens 14 First Image Sensor 19 CPU
20 second zoom lens 12 second aperture 22 second focus lens 23 second image sensor 32 frame memory 33 evaluation value calculation circuit 34 stereoscopic image processing circuit 40 position decoder 41 angle decoder 42 parallax calculation circuit

Claims (4)

A first imaging unit having a first focus lens that moves in the range from the near point to the far point along the optical axis; and a second focus lens that moves in the range from the near point to the far point along the optical axis. An AF evaluation value is calculated by integrating high-frequency components of luminance values from each image data obtained by the second imaging unit, and the first and second focus lenses are positioned at a position where the AF evaluation value is substantially maximum. In a stereoscopic image capturing apparatus that performs an AF operation,
In the AF operation, the first and second focus lenses are simultaneously driven, the AF evaluation value is calculated for each predetermined feed amount, and the maximum value of the AF evaluation value is detected at the position of the focus lens previously detected. Control means for setting the other focus lens ;
Parallax calculating means for calculating the parallax of the subject from each image data obtained by the first and second imaging units,
The stereoscopic image capturing apparatus , wherein the control means determines a movement start position and a movement direction of the first and second focus lenses according to the parallax calculated by the parallax calculation means . When the parallax of the subject calculated by the parallax calculation unit is greater than a predetermined value, the control unit sets the movement start positions of the first and second focus lenses as near points and sets the movement direction as a near point. When the parallax of the subject calculated by the parallax calculation means is smaller than a predetermined value, the movement start positions of the first and second focus lenses are both set as the far point and the movement direction. The stereoscopic image capturing apparatus according to claim 1, wherein a direction from a far point to a near point is set. The stereoscopic image capturing apparatus according to claim 1, wherein the parallax calculation unit extracts a feature portion of the subject from each of the image data, and calculates the parallax of the subject from a difference in position. The first and second imaging units include first and second diaphragms for restricting light beams, respectively, and the aperture values of the first and second diaphragms are set to different values, and then photometry is performed while changing each aperture value. performed, the three-dimensional image photographing apparatus in accordance with claim 1, characterized in that to set the aperture value of the other diaphragm aperture value of the aperture obtained by detecting the optimum value previously 3.

Images