JP2018129822A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a subject detecting ability using an output from a focus detection pixel.SOLUTION: An imaging apparatus includes: a first image pickup device for capturing an image of a subject formed by an optical system and outputting a signal; a second image pickup device that has a plurality of microlenses transmitting a luminous flux from the subject transmitted through the optical system, and a plurality of light-receiving elements respectively corresponding to the microlenses, and that outputs a plurality of signals by each microlens; a first image generation part for generating a first image based on the signal by the first image pickup device; a second image generation part for generating a second image based on at least one signal output by each microlens of the second image pickup device; a detection part for detecting the position of the subject image in the first image corresponding to a template image, from the second image and the template image that is based on an image selected from images preliminarily captured by the first image pickup device; and a display part for displaying the first image as overlapping an indicator indicating the position of the subject image corresponding to the template image detected by the detection part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus.

  Conventionally, when there is an imaging device in which an imaging pixel and a focus detection pixel having a deeper depth of focus than the imaging pixel are arranged and subject detection cannot be performed based on an output from the imaging pixel, the focus detection pixel A camera that detects a subject based on an output from the camera is known (for example, Patent Document 1).

JP 2010-68439 A

  However, the focus detection pixel on the same element as the image pickup element of the above document is structurally only capable of obtaining about twice the depth of focus compared to the image pickup pixel, and the focus detection pixel is discretely formed on the subject element. Since they are arranged, subject detection is performed using an image having a rough sampling pitch, and there is a problem that sufficient detection capability cannot be obtained.

  The imaging apparatus according to claim 1, wherein a first imaging element that captures an image of a subject formed by an optical system and outputs a signal, and a plurality of microlenses that allow a light flux from the subject that has passed through the optical system to pass therethrough. A plurality of light receiving elements for each of the microlenses, a second image sensor that outputs a plurality of signals for each of the microlenses, and a first image based on a signal from the first image sensor. A first image generation unit to generate, a second image generation unit to generate a second image based on one or more of the signals output for each of the microlenses of the second image sensor, and the first The position of the subject image corresponding to the template image in the first image is detected from the template image based on the image selected from the images obtained by the image pickup element and the second image. Having a detection unit that, the index indicating the position of the image of the object corresponding to the template image detected by the detection unit, the first image, and a display unit for displaying superimposed.

  According to the present invention, the imaging optical system generated based on a part of the first light receiving signals among the plurality of light receiving signals from the plurality of light receiving elements provided corresponding to the plurality of microlenses, respectively. The position of a specific subject image detected in a pan focus image having a depth of subject deeper than the subject image formed on the image sensor is displayed on the observation means, and the location of the subject can be confirmed on the blurred image. it can.

1 is a main part configuration diagram of a digital camera according to a first embodiment of the present invention. The perspective view of the focus detection unit with which the digital camera by an embodiment is provided Sectional view schematically showing how the subject light enters the microlens array and the light receiving element array The flowchart explaining a process in case the specific object recognition process of the digital camera by embodiment is set effectively The principal part block diagram of the digital camera by the 2nd Embodiment of this invention

-First embodiment-
An imaging apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram for explaining a main configuration of a digital camera 1 that is an image pickup apparatus according to the first embodiment. For convenience of explanation, as shown in FIG. 1, a coordinate system including an x axis, a y axis, and a z axis is set. The digital camera 1 is a so-called single-lens reflex camera that includes a camera body 20 and a lens barrel 10 that can be attached to and detached from the camera body 20 via a lens mount 9.

  The lens barrel 10 includes an imaging optical system 11 and a diaphragm 12. The imaging optical system 11 is an optical system for forming a subject image on a predetermined planned focal plane, and is composed of a plurality of lenses including a focus adjustment lens. The focus adjustment lens is driven back and forth in the direction of the optical axis L, that is, the x-axis direction of FIG. 1 by the operation of a lens driving motor (not shown). In FIG. 1, for convenience of illustration, the imaging optical system 11 is schematically shown as a single lens. The diaphragm 12 limits a light beam passing through the imaging optical system 11, that is, an incident light amount.

  Inside the camera body 20, there are a quick return mirror 21, an image sensor 22, a sub mirror 23, a focus detection unit 25, a control device 26, a mat screen 27, a pentaprism 28, an eyepiece lens 29, and a display. A half mirror 31, a condenser lens 32, and a pattern display element 33 are provided. On the back surface of the camera body 20, a back monitor 30 constituted by a display device such as a liquid crystal display is provided. The camera body 20 is provided with an operation unit 40.

  The quick return mirror 21 is a partial half mirror provided at a position indicated by a solid line in FIG. 1 during non-exposure, and a part of incident light (subject light) from the imaging optical system 11 is reflected on the camera body 20 by a reflecting surface. Is reflected on the upper part (z-axis direction in FIG. 1). The subject light reflected by the quick return mirror 21 forms an image on a mat screen 27 provided in the upper part of the camera body 20. A user of the digital camera 1 can visually recognize a subject image formed on the mat screen 27 by the imaging optical system 11 via the pentaprism 28, the display half mirror 31, and the eyepiece lens 29. In other words, the user can observe the subject image via the optical viewfinder including the mat screen 27, the quick return mirror 21, and the eyepiece lens 29.

  The pattern display element 33 is provided above the display half mirror 31 and is substantially flush with the mat screen 27 due to the action of the condenser lens 32. The pattern display element 33 is, for example, a small liquid crystal display element with a backlight, and displays a predetermined pattern according to control by the control device 26 described later. The displayed pattern passes through the condenser lens 32, is reflected by the display half mirror 31, and is guided to the eyepiece lens 29. The pattern display element 33 is apparently provided on substantially the same plane as the mat screen 27, so that the user can observe the displayed pattern superimposed on the subject image.

  The sub mirror 23 is disposed on the back surface of the quick return mirror 21, that is, the surface opposite to the surface on which the subject light from the imaging optical system 11 is incident. The sub mirror 23 has at least the width of the photographing screen, that is, a size that can cover the entire image sensor 22. As described above, the quick return mirror 21 is constituted by a partial half mirror, and therefore, part of the subject light from the imaging optical system 11 that is partially transmitted through the reflection surface of the quick return mirror 21 is subject light. The light is reflected by the sub-mirror 23 and travels in the z-axis + direction, and enters a focus detection unit 25 provided at the lower part of the camera body 20. The structure of the focus detection unit 25 will be described later.

  At the time of exposure, the quick return mirror 21 and the sub mirror 23 are retracted to a position indicated by a broken line in FIG. 1 by a drive mechanism (not shown) (mirror up). By subjecting the mirror up, subject light from the imaging optical system 11 enters the image sensor 22.

  The image pickup device 22 is a solid-state image pickup device such as a CCD or a CMOS, for example, and is arranged so that the image pickup surface is positioned on the planned focal plane of the imaging optical system 11. The image sensor 22 captures a subject image formed on the imaging surface by the imaging optical system 11 and outputs an image signal to the control device 26. Although not shown in FIG. 1, various optical filters such as an infrared cut filter are provided on the imaging surface of the imaging element 22.

  The control device 26 is composed of a microprocessor and its peripheral circuits and the like, and by reading and executing a control program stored in advance in a storage medium (not shown) (for example, a flash memory), each part of the digital camera 1 is controlled. Control. The control device 26 performs various image processing on the imaging signal output from the imaging element 22 to generate image data of the subject image, and generates the image data on a portable storage medium (not shown) (for example, a memory card). Record image data. The control device 26 performs focus adjustment by driving the focus adjustment lens of the imaging optical system 11 according to the defocus amount calculated based on the output of the focus detection unit 25, and the pattern display element 33 and the rear monitor 30. By displaying the current focus state of the front pin, the rear pin, etc., the manual focus adjustment by the user is supported. Furthermore, the control device 26 displays a setting menu for setting an image captured by the image sensor 22, shooting parameters, an operation mode of the digital camera 1, and the like. Note that the control device 26 may be configured by an electronic circuit having a function equivalent to that of the control program.

  The control device 26 includes a focus adjustment unit 261, an image generation unit 262, a subject specifying unit 263, and a display control unit 264 as functions. The focus adjustment unit 261 performs the focus adjustment by calculating the defocus amount and driving the focus adjustment lens. The image generation unit 262 uses the output of the focus detection unit 25 to generate an image having a deeper subject depth (hereinafter referred to as a pan focus image) than the image that the imaging optical system 11 connects to the image sensor 22. The subject specifying unit 263 recognizes a specific subject using the generated pan focus image. The display control unit 264 controls the pattern display element 33 to display a position corresponding to the recognized position of the specific subject using, for example, a rectangular frame. The processing of the focus adjusting unit 261, the image generating unit 262, the subject specifying unit 263, and the display control unit 264 will be described later.

  The operation unit 40 includes various switches provided corresponding to various operation members operated by the user, and outputs an operation signal corresponding to the operation of the operation member to the control device 26. The operation member determines, for example, a release button, a menu button for displaying a menu screen on the rear monitor 30, a cross key operated when selecting and operating various settings, a setting selected by the cross key, and the like. And a mode switching button for switching the operation of the digital camera 1 between the shooting mode and the playback mode. In addition, the operation unit 40 can set the validity / invalidity of the specific subject identification function. The specific subject identification function is a function that recognizes a specific subject in the object scene before focus adjustment and recognizes the position of the recognized subject on the screen via an index or the like. is there.

  The focus detection unit 25 will be described with reference to FIG. In FIG. 2, a coordinate system including the x axis, the y axis, and the z axis is set in the same manner as in FIG. As shown in the perspective view of FIG. 2, the focus detection unit 25 is arranged in parallel with each other in the order of the microlens array 52 and the light receiving element array 53 when viewed from the sub mirror 23 side. In the microlens array 52, a plurality of microlenses 54 that are positive lenses are two-dimensionally arranged on the surface facing the sub mirror 23. Each outline of the plurality of microlenses 54 is formed in a rectangular shape. As described above, the subject light reflected by the sub mirror 23 and traveling in the z-axis + direction enters the light receiving element array 53 via the microlens array 52.

  A plurality of rectangular light receiving elements (photoelectric conversion elements) 55 are squarely arranged on the imaging surface of the light receiving element array 53 (that is, the surface facing the microlens array 52). The light receiving element 55 is formed smaller than the microlens 54, and a plurality of light receiving elements 55 are included in a range where one microlens 54 is projected onto the light receiving element array 53. That is, a plurality of light receiving elements 55 are arranged in association with one microlens 54. In the focus detection unit 25 having the above-described configuration, the front main surface of the microlens array 52 is disposed in the vicinity of a predetermined focal plane, that is, a plane conjugate with the imaging surface of the imaging element 22.

  In FIG. 2, for the convenience of illustration, the number of microlenses 54 and light receiving elements 55 is smaller than the actual number. That is, the focus detection unit 25 includes more microlenses 54 and light receiving elements 55 than shown in FIG. Although not shown in FIG. 2, a light-shielding coating is applied to each boundary surface of each microlens 54 for the purpose of preventing the occurrence of crosstalk. Further, the interval between the microlens array 52 and the light receiving element array 53 is determined so that the imaging surface of the light receiving element array 53 is positioned near the focal position of each microlens 54.

  FIG. 3 is a cross-sectional view schematically showing how the subject light enters the microlens array 52 and the light receiving element array 53. The microlens array 52 and the light receiving element array 53 are arranged so that an image formed by the microlens 54 of each light receiving element 55 is connected to the element imaging surface 56. The element imaging plane 56 is located closer to the subject than the apex of each microlens 54. Ideally, the position of the image of each light receiving element 55, that is, the element imaging plane 56 coincides with the exit pupil of the imaging optical system 11, but in a range where the blurred image on the exit pupil plane is sufficiently small. Deviation is allowed.

  A focus adjustment process performed by the focus adjustment unit 261 using the light reception signal output from the focus detection unit 25 will be described. The focus adjustment unit 261 is configured to receive light beams that have passed through the microlenses 54 from the light receiving element 55 for (Ln−L1 + 1) microlenses 54 up to the microlenses 54_L1 to 54_Ln (Ln> Ln> 1). A pair of signal sequences is generated using the received light signal. That is, the focus adjustment unit 261 uses the light reception signal output from the light receiving element 55 in the positional relationship (first positional relationship) where the relative positional relationship with respect to each of the plurality of microlenses 54 is the same as the first light reception signal sequence, A light reception signal output from the light receiving element 55 in which the relative positional relationship with respect to each of the plurality of microlenses 54 is different from the first positional relationship is defined as a second signal sequence.

  In the example illustrated in FIG. 3, the third light receiving element 55a1 from the left end is selected from among the plurality of light receiving elements 55 corresponding to the micro lens 54_L1. Similarly, the third light receiving elements 55a2 to 55an from the left end are selected for each of the micro lenses 54_L2 to 54_Ln. The focus adjustment unit 261 generates the first signal sequence {a (i)} using the light reception signals output from the light receiving elements 55a1 to 55an.

  Further, the third light receiving element 55b1 from the right end (sixth from the left end) among the plurality of light receiving elements 55 corresponding to the micro lens 54_L1 is selected. Similarly, the third light receiving elements 55b2 to 55bn from the right end are selected for each of the microlenses 54_L2 to 54_Ln. The focus adjustment unit 261 generates the second signal sequence {b (i)} using the light reception signals output from the light receiving elements 55b1 to 55bn. The first signal sequence {a (i)} and the second signal sequence {b (i)} pass through different pupils of the imaging optical system 11 to each other, and virtual pixels 56 a to 56 f on the element imaging surface 56. It corresponds to the luminous flux from the subject passing through.

  The focus adjustment unit 261 performs an image shift calculation using the first signal sequence {a (i)} and the second signal sequence {b (i)}, and calculates a defocus amount by a known method. The focus adjustment unit 261 calculates a drive amount of the focus adjustment lens based on the calculated defocus amount. Here, the focus adjustment unit 261 calculates the lens drive amount by calculating the lens target position that is the target of the drive position of the focus adjustment lens. The lens target position corresponds to the position of the focus adjustment lens where the defocus amount is zero.

  The focus adjustment unit 261 outputs a drive control signal to a lens drive motor (not shown) based on the calculated lens drive amount, that is, the lens target position with respect to the focus adjustment lens. In response to the drive control signal, the lens drive motor drives the focus adjustment lens to the lens target position, thereby adjusting the focus of the imaging optical system 11.

  Hereinafter, an operation when the specific subject identification function is set to be effective in the digital camera 1 according to the present embodiment will be described. When preparation for shooting is instructed by a half-press operation of the release button by the user, the image generation unit 262 of the control device 26 generates a pan-focus image using the light reception signal output from the focus detection unit 25. The subject specifying unit 263 of the control device 26 performs specific subject recognition processing using the generated pan focus image. The display control unit 264 causes the pattern display element 33 to perform display processing so that the user can recognize the position of the recognized specific subject via the eyepiece lens 29. The following description will be divided into pan-focus image generation processing, specific subject recognition processing, and display processing.

1. Pan Focus Image Generation Processing The image generation unit 262 starts pan focus image generation processing when the user performs a half-press operation on the release button. The image generation unit 262 extracts a predetermined light reception signal from the light reception signals output from the plurality of light receiving elements 55 constituting the focus detection unit 25. In the present embodiment, as an example, the image generation unit 262 receives the light reception signals from the light receiving elements 55 arranged substantially at the center of the range in which the light transmitted through the microlenses 54 is incident. To extract.

  In the example illustrated in FIG. 3, the light reception signal from the fourth light receiving element 55c1 from the left end among the plurality of light receiving elements 55 corresponding to the micro lens 54_L1 is extracted. Similarly, the light reception signals from the fourth light receiving elements 55c2 to 55cn from the left end are extracted for each of the micro lenses 54_L2 to 54_Ln. The image generation unit 262 generates, as a pan focus image, image data in which the received light signals extracted corresponding to the respective microlenses 54 are arranged according to the arrangement of the microlenses 54.

  As described above, in the focus detection unit 25, one microlens 54 has a configuration that covers a large number of light receiving elements 55, so the size of the light receiving surface of one light receiving element 55 is one micrometer. Compared with the size of the entrance surface of the lens 54, it is a fraction of the size. For this reason, when converted into the f-number, the number of f-numbers defined by one microlens 54 is several times in one light-receiving element 55. In the example shown in FIG. 3, it is 10 times or more the f number of one microlens 54. As a result, a photographic image corresponding to the minimum aperture of the aperture 12 of the imaging optical system 11 and focused on almost all the subjects in the screen is generated in a pseudo manner as a pan focus image. In other words, the pan-focus image is an image that has a sufficiently deep depth of field than the image that the imaging optical system 11 connects to the image sensor 22.

  Note that the pan focus image is not limited to the one in which the pan focus image is generated by using the light receiving signal from one light receiving element 55 for one micro lens 54, and the pan focus image is generated by expanding the range from which the light receiving signal is extracted. The case of increasing the number of received light signals per one microlens 54 is also included in one embodiment of the present invention. In this case, it is preferable to increase the number of received light signals so that a depth of field of 3 or more can be obtained compared to the depth of field of the image connected to the image sensor 22. Further, the light receiving signal from the light receiving element 55 arranged substantially in the center of the range in which the transmitted light of the microlens 54 is incident is not limited, and the vicinity of the outer edge of the range in which the transmitted light is incident. You may extract the light reception signal from the light receiving element 55 currently arranged. For example, the pan focus image may be generated using the light reception signals output from the light receiving elements 55a1 to 55an or the light receiving elements 55b1 to 55bn shown in FIG.

  As described above, the image generation unit 262 performs a pan-focus image as described above every predetermined period, that is, every time the focus detection unit 25 outputs a light reception signal while the release button is half-pressed by the user. Is generated. That is, a pan-focus image is generated until the user does not operate the release button or until the user gives a shooting instruction after the release button is fully pressed.

2. Specific Subject Recognition Processing The subject specifying unit 263 recognizes a specific subject using a technique such as template matching for the pan-focus image generated by the image generation unit 262. In the present embodiment, the subject specifying unit 263 calculates the similarity between the template image registered in advance and the pan focus image, and sets an image area having a similarity equal to or greater than a predetermined value on the pan focus image as the position of the subject. Detect as. The template image may be stored in a predetermined storage area (not shown) when the digital camera 1 is shipped. In this case, it is possible to detect a person's face in general from the pan focus image. Further, the template image may be set according to a setting operation by the user from the generated image data and stored in a predetermined storage area (not shown). In this case, it is possible to detect a specific person or a person in a specific costume.
Note that the specific subject recognition processing by the subject specifying unit 263 is not limited to the method using the template matching method, and various known methods can be used.

3. Display Processing The display control unit 264 causes the pattern display element 33 to display an image area detected by the subject specifying unit 263, that is, an index indicating the position of the recognized subject. In the present embodiment, a rectangular frame surrounding the detected subject is displayed as an index. The display control unit 264 converts the position of the image area detected by the subject specifying unit 263 into a position on the pattern display element 33, and displays an index of the pixel of the pattern display element 33 arranged at the position. Make a display. Since the index displayed on the pattern display element 33 is guided to the eyepiece lens 29 through the condenser lens 32 and the display half mirror 31 as described above, the user confirms the position where the subject exists in the optical viewfinder. can do.

  In addition, it is not limited to what displays a rectangular frame as a parameter | index, Any shape, such as a polygon and a circle, may be sufficient as the shape of a frame. Also, the index is not limited to a frame displayed, and any mark or arrow may be used as long as the user can confirm the position of the subject using the optical viewfinder.

  When a plurality of subjects are recognized in the specific subject recognition process, indicators may be displayed at all recognized subject positions, or indicators may be displayed at any one of the subject positions. The index may be displayed at the positions of a predetermined number of subjects. In this case, the index may be displayed corresponding to one or a predetermined number of subjects located near the center of the shooting screen. Alternatively, the index may be displayed in correspondence with one closest to the digital camera 1 or a predetermined number of subjects. In which aspect the index is displayed, it is preferable that the user can set the index from the menu screen, for example.

  When the specific subject is not recognized in the specific subject recognition process, the display control unit 264 of the present embodiment does not cause the pattern display element 33 to display the index. Note that the display control unit 264 includes an indicator that displays an index only when the presence of a specific subject is detected at a position corresponding to a focus detection area set in accordance with a user operation. .

  The processing of the digital camera 1 when the specific subject identification function is set to be effective will be described with reference to the flowchart shown in FIG. The process shown in FIG. 4 is performed by executing a program in the control device 26. This program is stored in a memory (not shown), and is activated and executed by the control device 26 when the release button is pressed halfway by the user.

  In step S1, the image generation unit 262 generates a pan focus image by the above-described pan focus image generation process using the light reception signal output from the focus detection unit 25, and proceeds to step S2. In step S2, the subject specifying unit 263 performs a specific subject recognition process for recognizing a specific subject on the generated pan focus image, and proceeds to step S3.

  In step S3, it is determined whether or not a specific subject has been recognized by the specific subject recognition process. If a specific subject is recognized, an affirmative determination is made in step S3 and the process proceeds to step S4. In step S4, the display control unit 264 causes the pattern display element 33 to display an index and proceeds to step S6. If the specific subject is not recognized, a negative determination is made in step S3 and the process proceeds to step S5. In step S5, the display control unit 264 does not display the index on the pattern display element 33 and proceeds to step S6.

  In step S6, the focus adjustment unit 261 calculates the defocus amount as described above using the light reception signal output from the focus detection unit 25, and drives the focus lens according to the calculated defocus amount. Thus, the focus is adjusted and the process proceeds to step S7. When a specific subject is recognized by the specific subject recognition process, the defocus amount is calculated using a light reception signal from the light receiving element 55 arranged corresponding to the position of the recognized subject. When a specific subject is not recognized by the specific subject recognition process, defocusing is performed using a light reception signal from the light receiving element 55 arranged at a position corresponding to a focus detection area set in accordance with a user operation. What is necessary is just to calculate quantity.

  In step S7, it is determined whether or not the half-press operation of the release button by the user is continued. If the half-press operation of the release button by the user continues, an affirmative determination is made in step S7 and the process returns to step S1. If the half-press operation of the release button by the user has not been continued, a negative determination is made in step S7 and the process ends. Note that when the release button is half-pressed by the user fully pressing the release button, the control device 26 causes the image sensor 22 to output an imaging signal, and generate and record image data. The process ends.

According to the digital camera according to the first embodiment described above, the following operational effects can be obtained.
(1) The focus detection unit 25 includes a microlens array 52 in which a plurality of microlenses 54 are arranged, and a plurality of light receiving elements 55 for each of the plurality of microlenses 54, and a light beam from the imaging optical system 11. And a light receiving element array 53 that outputs a plurality of light receiving signals for each micro lens 52. The image generation unit 262 generates a subject image that the imaging optical system 11 forms on the image sensor 22 based on a part of the light reception signals output from the plurality of light reception signals corresponding to the plurality of microlenses 54. A pan focus image having a deeper subject depth is generated. The subject specifying unit 263 recognizes a specific subject in the generated pan focus image, and the display control unit 264 causes the pattern display element 33 to display the position of the recognized specific subject. In this process, since the pan focus image corresponds to an image acquired with a small aperture, the number of subjects in focus on the screen increases, and the possibility of recognizing a specific subject can be improved.

  In addition, a desired subject image can be very displayed on the optical viewfinder, such as when the subject moves, the digital camera 1 touches, the panning is intentionally performed, or the digital camera 1 is initially held. Even when it is difficult to visually recognize due to blur, the index can be displayed overlapping the blur image, so that the subject can be continuously captured. For this reason, the user adjusts the position and posture of the digital camera 1 while keeping the desired subject in the desired position and waiting for a photo opportunity, that is, maintaining the relative direction between the subject direction and the digital camera 1. Even in such a case, the chance of missing a photo opportunity can be reduced. In particular, even when the subject is moving violently, the user can determine the composition by confirming at a glance the position where the desired subject exists in the scene.

  When a telephoto lens is used as the imaging optical system 11 and a relatively distant subject is photographed, the depth of field is shallow, the amount of blur of the subject image when the subject is not in focus is large, and the angle of view is narrow. Become. In such a case, even if the actual amount of movement of the subject is very small, the amount of movement of the subject image within the range that can be observed through the optical viewfinder becomes large, and on the blurred image through the optical viewfinder. Although it is difficult to continue capturing the subject, the position of the subject image can be confirmed by the index, so that the chances of losing sight of the subject and missing a photo opportunity can be reduced.

(2) The image generation unit 262 generates a pan-focus image using a light reception signal output from the light receiving element 55c arranged in the vicinity of the center among the plurality of light receiving elements 55 corresponding to each of the plurality of microlenses 54. Generated. As a result, the pan focus image is an image acquired with the minimum aperture, that is, an image in which almost all the subjects in the screen are in focus, so that the accuracy for recognizing a specific subject can be improved. it can.

(3) The focus adjusting unit 261 detects the focus state of the imaging optical system 11 using a plurality of light reception signals output from the plurality of light receiving elements 55. It is possible to use both the dedicated sensor for detecting the focus state and the dedicated sensor for generating the pan focus image, and the space occupancy can be reduced compared to the case where each dedicated sensor is installed. This contributes to the miniaturization of the digital camera 1.

-Second Embodiment-
A digital camera according to the second embodiment of the present invention will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the first embodiment. This embodiment is different from the first embodiment in that an optical finder is not provided.

  FIG. 5 is a block diagram illustrating a configuration of a main part of the digital camera 100 according to the second embodiment. In FIG. 5 as well, as in FIGS. 1 and 2, a coordinate system including the x axis, the y axis, and the z axis is set. A lens barrel 10 is detachably attached to the camera body 101 of the digital camera 100 via a lens mount 9. Inside the camera body 101, an image sensor 22, a focus detection unit 25, a control device 26, and a half mirror 102 are provided.

  The half mirror 121 is constituted by a pellicle mirror, for example, and divides the subject light beam from the imaging optical system 11 into two. A part of the subject light beam is reflected by the half mirror 121 and guided to the image sensor 22 disposed inside the camera body 101 (on the x axis + side in FIG. 5). As in the case of the first embodiment, the imaging element 22 captures the subject image formed by the imaging optical system 11 and outputs an imaging signal. The other part of the subject luminous flux passes through the half mirror 121 and enters the focus detection unit 25 arranged on the inner back side of the camera body 101 (the z axis + side in FIG. 5). The focus detection unit 25 has the same structure as that of the first embodiment shown in FIG. 2, and outputs a light reception signal.

  When still image shooting is performed, the live view image is displayed on the rear monitor 30 until the start of shooting is instructed in response to the user fully pressing the release button. That is, the control device 26 sequentially generates image data using an imaging signal output at a predetermined cycle (for example, 1/60 seconds, 1/30 seconds, etc.) from the imaging element 22 and generates a live view image. It is displayed on the rear monitor 30. In other words, the user can observe the subject image with the live view image displayed on the rear monitor 30.

The focus detection unit 25 outputs a light reception signal at a predetermined cycle. Note that the period in which the focus detection unit 25 outputs the light reception signal may be the same as or different from the period in which the imaging element 22 outputs the imaging signal for generating the live view image. When the specific subject identification function is set to be effective, the control device 26 performs pan focus image generation processing, specific subject recognition processing, and display processing in the same manner as in the first embodiment. However, during the display process, the display control unit 264 causes the rear monitor 30 to display an index indicating the position of a specific subject. That is, the display control unit 264 converts the position of the subject specified in the specific subject recognition process into a position on the rear monitor 30, and superimposes the index on the image data displayed as the live view image. As a result, even when the desired subject image is very blurred and difficult to see on the rear monitor 30, the index is displayed overlapping the blurred image, so that the subject can be continuously captured, and the shutter chance is increased. Opportunities to miss can be reduced.
The control device 26 continues the above operation until the release button is fully pressed by the user and the start of shooting is instructed.

  In the case of moving image shooting, when an instruction to start moving image shooting is given by the user, the control device 26 outputs an imaging signal output from the imaging device 22 at a predetermined cycle (for example, 1/60 seconds, 1/30 seconds, etc.). Then, image data is sequentially generated and displayed on the rear monitor 30 as a moving image. As in the case where the live view image is displayed, the focus detection unit 25 outputs a light reception signal at a predetermined cycle, and when the specific subject identification function is enabled, the control device 26 In the same manner as in the first embodiment, pan focus image generation processing, specific subject recognition processing, and display processing are performed. However, in the display process, the display control unit 264 converts the position of the subject specified in the specific subject recognition process into a position on the rear monitor 30, and superimposes an index on the image data displayed as a moving image. Let

  The control device 26 continues the above operation until the user instructs the stop of moving image shooting. The instruction to start / stop moving image shooting may be performed by the user operating a dedicated button, or by pressing the release button fully with the moving image shooting mode selected as the shooting mode. Also good.

  According to the second embodiment described above, even in the digital camera 100 that does not include an optical finder, the position of the specified subject is indicated by superimposing an index on the image displayed on the rear monitor 30. be able to. As a result, the same operational effects as those of the digital camera 1 according to the first embodiment can be obtained.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(1) The image generation unit 262 is not limited to the one that generates a pan-focus image using a part of the received light signal, and a technique for synthesizing an image of an arbitrary focal plane in a so-called light field camera is applied. A pan-focus image may be generated by connecting pixels extracted from the corresponding focal plane composite image for each point. In this case, in order to synthesize one pixel in the pan focus image, the light receiving elements 55 respectively covered with the plurality of microlenses 54 are used, so that a pan focus image with less noise is generated and a specific subject is generated. Can increase the probability of being recognized.

(2) The control device 26 performs only display processing instead of performing display processing and focus adjustment processing according to the position of the specific subject recognized by the subject specifying unit 263 after the specific subject recognition processing. Is also included in one embodiment of the present invention. That is, focus adjustment may be performed according to a manual operation by a user who has confirmed the position of a specific subject based on an index using an optical finder. The digital cameras 1 and 100 include a mode for automatically adjusting the focus according to the result of the specific subject recognition process, and a mode for performing the focus adjustment according to a manual operation. You may be comprised so that selection is possible by operating.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

1, 100 ... Digital camera, 22 ... Image sensor,
25 ... focus detection unit, 26 ... control device,
29 ... eyepiece, 30 ... rear monitor,
31 ... half mirror for display, 32 ... condenser lens,
33 ... pattern display element, 40 ... operation unit,
52 ... Micro lens array, 53 ... Light receiving element array,
54 ... micro lens, 55 ... light receiving element,
261: Focus adjustment unit, 262: Image generation unit,
263 ... Subject specifying unit, 264 ... Display control unit

Claims (7)

A first image sensor that captures an image of a subject formed by the optical system and outputs a signal;
A plurality of microlenses that allow a light beam from the subject that has passed through the optical system to pass therethrough, and a plurality of light receiving elements for each of the microlenses, and that outputs a plurality of signals for each of the microlenses. An image sensor;
A first image generation unit that generates a first image based on a signal from the first image sensor;
A second image generation unit that generates a second image based on one or more of the signals output for each of the microlenses of the second image sensor;
A position of an image of a subject corresponding to the template image in the first image is detected from a template image based on an image selected from images obtained by the first image sensor in advance and the second image. A detector to perform,
An index indicating the position of the image of the subject corresponding to the template image detected by the detection unit, the display unit displaying the first image in an overlapping manner,
An imaging apparatus having The imaging apparatus according to claim 1,
An imaging device in which the subject corresponding to the template image is a specific person. The imaging apparatus according to claim 1, wherein:
The display device displays an index indicating a position of an image of a subject corresponding to the template image during imaging of a moving image by the imaging device. In the imaging device according to any one of claims 1 to 3,
When the detection unit detects images of a subject corresponding to the plurality of template images, the display unit displays the plurality of indices. In the imaging device according to any one of claims 1 to 3,
When the detection unit detects images of a subject corresponding to the plurality of template images, the display unit displays the index at the position of the subject image corresponding to the template image located near the center. In the imaging device according to any one of claims 1 to 3,
When the image of the subject corresponding to the plurality of template images is detected by the detection unit, the display unit displays the index at the position of the image of the subject corresponding to the template image located closest to the imaging device. An imaging device. In the imaging device according to any one of claims 1 to 6,
An imaging apparatus including a focus detection unit that detects a focus state of an imaging optical system using two or more light reception signals output for each of the plurality of microlenses.

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