JP5966299B2 - FOCUS DETECTION DEVICE AND IMAGING DEVICE HAVING THE SAME - Google Patents

Description

  The present invention relates to a focus adjustment apparatus and an imaging apparatus including the same.

  2. Description of the Related Art Conventionally, a technique for detecting a focus state for a plurality of focus detection positions set in an image plane of an optical system by a phase difference detection method has been performed. In such a technique, a specific subject as a focus state detection target is recognized, a focus state is detected at a focus detection position corresponding to the recognized specific subject position, and focus adjustment is performed based on the detected focus state. A technique for performing is known (see, for example, Patent Document 1).

JP 2008-298934 A

  In the above prior art, normally, a plurality of pairs of light receiving element arrays for performing focus detection by the phase difference detection method are provided for each of a plurality of focus detection positions, and a recognized specific subject is captured. Focus detection is performed on the basis of outputs from a plurality of pairs of light receiving element arrays corresponding to a focus detection position. However, in the above-described prior art, depending on the position of the recognized specific subject, there may be a case where only a part of the light receiving element arrays overlapped among the plurality of pairs of light receiving element arrays provided corresponding to the focus detection positions. However, even in such a case, the focus detection calculation is performed using the output of the light receiving element array at a position that does not overlap the recognized specific subject. Therefore, the focus detection is performed due to the influence of the output from the light receiving element array. There has been a problem that may not be performed properly.

  The problem to be solved by the present invention is to provide a focus detection apparatus capable of performing focus detection satisfactorily.

  The present invention solves the above problems by the following means. In the following description, the reference numerals corresponding to the drawings showing the embodiments of the present invention are used for explanation, but these reference numerals are only for facilitating the understanding of the present invention and are not intended to limit the invention. Absent.

[1] The focus detection apparatus of the present invention is a first focus in which a plurality of focus detection pixels that are arranged in at least two rows in the first direction and receive light incident through the optical system and output signals are arranged. A plurality of focus detection pixels, which are arranged in at least two rows in a second direction that intersects the first direction with detection pixel rows and receives light incident through the optical system and outputs a signal, are arranged. a light receiving element have a second focus detection pixel row, the second focus detection pixel row to be disposed in the first focus detection pixel row and the at least two rows which are arranged in at least two rows intersect the optical A recognition unit for recognizing a specific subject among images by the system, and the first focus detection pixel row or the second focus detection pixel row at a position corresponding to a position in the image plane of the subject recognized by the recognition unit. from the signal to be output to the serial optical system from Comprising a detector for detecting a shift amount between the light receiving surface of the imaging surface and the light receiving element of the image.

[2] In the focus detection apparatus of the present invention, the detection unit overlaps a position in the image plane of the subject recognized by the recognition unit in the first focus detection pixel row or the second focus detection pixel row. The shift amount can be detected from a signal output from the focus detection pixel row at the position.

[3] In the focus detection device of the present invention, the detection unit may detect the shift amount from a signal output from at least two focus detection pixel columns of the first focus detection pixel column or the second focus detection pixel column. Can be configured to detect.

[4] In the focus detection apparatus of the present invention, the detection unit outputs from at least two focus detection pixel rows having the same arrangement direction in the first focus detection pixel row or the second focus detection pixel row. The shift amount can be detected from a signal to be detected.

[5] The focus detection apparatus of the present invention includes a control unit that controls an accumulation time or a gain of the first focus detection pixel column or the second focus detection pixel column, and the control unit is recognized by the recognition unit. The accumulation time or gain is controlled based on the positional relationship between the position of the subject in the image plane and the position of the first focus detection pixel array or the second focus detection pixel array in the image plane. can do.

[6] In the focus detection apparatus of the present invention, the light receiving element control unit includes a position in the image plane of the subject recognized by the recognition unit in the first focus detection pixel row or the second focus detection pixel row. The accumulation time or the gain can be determined based on the output from the first focus detection pixel row or the second focus detection pixel row at a position overlapping with the first focus detection pixel row.

[7] In the focus detection apparatus of the present invention, the light receiving element may be configured to include a plurality of the first focus detection pixel columns and the second focus detection pixel columns.

  [8] An imaging apparatus of the present invention includes the focus detection apparatus.

  According to the focus detection apparatus of the present invention, focus detection can be performed satisfactorily.

FIG. 1 is a block diagram showing a single-lens reflex digital camera 1 according to this embodiment. FIG. 2 is a diagram showing the focus detection module shown in FIG. FIG. 3 is a diagram illustrating an arrangement example of a plurality of focus detection areas set in the photographing screen of the photographing optical system. FIG. 4 is a diagram showing an example of the arrangement of line sensor pairs in the photographing screen of the photographing optical system in the present embodiment. FIG. 5 is a flowchart showing the operation of the camera according to the present embodiment. FIG. 6 is a flowchart showing tracking control initial processing according to the present embodiment. FIG. 7 is a flowchart showing the tracking calculation process according to the present embodiment. FIGS. 8A to 8D are diagrams showing an example of how the tracking subject area overlaps with the detection areas by the line sensor pairs H1, H2, V1, and V2.

  In the following, an embodiment in which the present invention is applied to a single-lens reflex digital camera will be described with reference to the drawings. However, the present invention can also be applied to other imaging devices such as a silver salt film camera.

  FIG. 1 is a block diagram showing a single-lens reflex digital camera 1 according to the present embodiment. The illustration and description of a general configuration of the camera other than the configuration related to the focus detection apparatus and the imaging apparatus of the present invention are partially omitted. To do.

  The single-lens reflex digital camera 1 of this embodiment (hereinafter simply referred to as the camera 1) includes a camera body 100 and a lens barrel 200, and the camera body 100 and the lens barrel 200 are detachably coupled. In the camera 1 of the present embodiment, the lens barrel 200 is replaceable depending on the purpose of shooting.

  The lens barrel 200 incorporates a photographing optical system including lenses 211, 212, 213 and a diaphragm 220.

  The focus lens 212 is provided so as to be movable along the optical axis L1 of the lens barrel 200, and its position is adjusted by the focus lens drive motor 230 while its position is detected by the encoder 260.

  The specific configuration of the moving mechanism along the optical axis L1 of the focus lens 212 is not particularly limited. For example, a rotating cylinder is rotatably inserted into a fixed cylinder fixed to the lens barrel 200, a helicoid groove (spiral groove) is formed on the inner peripheral surface of the rotating cylinder, and the focus lens 212 is fixed. The end of the lens frame is fitted into the helicoid groove. Then, by rotating the rotating cylinder by the focus lens drive motor 230, the focus lens 212 fixed to the lens frame moves straight along the optical axis L1. The lens barrel 200 is provided with lenses 211 and 213 other than the focus lens 212. Here, the embodiment will be described by taking the focus lens 212 as an example.

  As described above, the focus lens 212 fixed to the lens frame by rotating the rotating cylinder with respect to the lens barrel 200 moves straight in the direction of the optical axis L1, but the focus lens drive motor 230 as the drive source is the lens. The lens barrel 200 is provided. The focus lens drive motor 230 and the rotating cylinder are connected by, for example, a transmission including a plurality of gears. When the drive shaft of the focus lens driving motor 230 is driven to rotate in any one direction, it is transmitted to the rotating cylinder at a predetermined gear ratio. Then, when the rotating cylinder rotates in any one direction, the focus lens 212 fixed to the lens frame moves straight in any direction of the optical axis L1. When the drive shaft of the focus lens drive motor 230 is rotated in the reverse direction, the plurality of gears constituting the transmission also rotate in the reverse direction, and the focus lens 212 moves straight in the reverse direction of the optical axis L1. .

  The position of the focus lens 212 is detected by the encoder 260. As described above, the position of the focus lens 212 in the direction of the optical axis L1 correlates with the rotation angle of the rotating cylinder, and can be obtained, for example, by detecting the relative rotation angle of the rotating cylinder with respect to the lens barrel 200.

  As the encoder 260 of the present embodiment, an encoder that detects the rotation of a rotating disk coupled to the rotational drive of the rotating cylinder with an optical sensor such as a photo interrupter and outputs a pulse signal corresponding to the number of rotations, or a fixed cylinder And the contact point of the brush on the surface of the flexible printed wiring board provided on either one of the rotating cylinders, and the brush contact provided on the other, the amount of movement of the rotating cylinder (in either the rotational direction or the optical axis direction) A device that detects a change in the contact position according to the detection circuit using a detection circuit can be used.

  The focus lens 212 moves in the direction of the optical axis L1 from the end portion (also referred to as the closest end) on the camera body 100 side to the end portion (also referred to as the infinite end) on the subject side by the rotation of the rotating cylinder described above. Can do. Incidentally, the current position information of the focus lens 212 detected by the encoder 260 is sent to the camera control unit 170 described later via the lens control unit 250. Then, the drive amount Δd of the focus lens 212 calculated based on this information is sent from the lens drive control unit 165 via the lens control unit 250, and based on this, the focus lens drive motor 230 is driven.

  The aperture 220 has an aperture diameter centered on the optical axis L1 in order to limit the amount of light flux that passes through the imaging optical system and reaches the image sensor 110 provided in the camera body 100 and adjusts the amount of blur. It is configured to be adjustable. The adjustment of the aperture diameter by the diaphragm 220 is performed, for example, by sending an appropriate aperture diameter calculated in the automatic exposure mode from the camera control unit 170 via the lens control unit 250. Further, the set aperture diameter is input from the camera control unit 170 to the lens control unit 250 by a manual operation by the operation unit 150 provided in the camera body 100. The aperture diameter of the aperture 220 is detected by an aperture sensor (not shown), and the lens controller 250 recognizes the current aperture diameter.

  On the other hand, the camera body 100 includes a mirror system 120 for guiding the light flux from the subject to the image sensor 110, the finder 135, the photometric sensor 137, and the focus detection module 161. The mirror system 120 includes a quick return mirror 121 that rotates by a predetermined angle between the observation position and the photographing position of the subject around the rotation axis 123, and the quick return mirror 121 that is pivotally supported by the quick return mirror 121. And a sub mirror 122 that rotates in accordance with the rotation. In FIG. 1, a state where the mirror system 120 is at the observation position of the subject is indicated by a solid line, and a state where the mirror system 120 is at the photographing position of the subject is indicated by a two-dot chain line.

  The mirror system 120 is inserted on the optical path of the optical axis L1 in the state where the subject is in the observation position, while rotating so as to retract from the optical path of the optical axis L1 in the state where the subject is in the photographing position.

  The quick return mirror 121 is composed of a half mirror, and in a state where the subject is at the observation position, the quick return mirror 121 reflects a part of the light flux (optical axes L2 and L3) from the subject (optical axis L1). Then, the light is guided to the finder 135 and the photometric sensor 137, and a part of the light beam (optical axis L4) is transmitted and guided to the sub mirror 122. On the other hand, the sub mirror 122 is configured by a total reflection mirror, and guides the light beam (optical axis L4) transmitted through the quick return mirror 121 to the focus detection module 161.

  Therefore, when the mirror system 120 is at the observation position, the light flux (optical axis L1) from the subject is guided to the finder 135, the photometric sensor 137, and the focus detection module 161, and the subject is observed by the photographer and exposure calculation is performed. And the focus adjustment state of the focus lens 212 is detected. When the photographer fully presses a release button (not shown), the mirror system 120 is rotated to the photographing position, and all the light flux (optical axis L1) from the subject is guided to the image sensor 110, and the photographed image data is illustrated. Do not save to memory.

  The light beam from the subject reflected by the quick return mirror 120 forms an image on a focusing screen 131 disposed on a surface optically equivalent to the image sensor 110 and can be observed through the pentaprism 133 and the eyepiece lens 134. It has become. At this time, the transmissive liquid crystal display 132 superimposes and displays a focus detection area mark on the subject image on the focusing screen 131 and relates to shooting such as the shutter speed, aperture value, and number of shots in an area outside the subject image. Display information. As a result, the photographer can observe the subject, its background, and photographing related information through the finder 135 in the photographing preparation state.

  The photometric sensor 137 is composed of a two-dimensional color CCD image sensor or the like, and divides the photographing screen into a plurality of regions and outputs a photometric signal corresponding to the luminance of each region in order to calculate an exposure value at the time of photographing. The photometric sensor 137 also serves as an image sensor for recognizing a subject, converts a subject image formed on the focusing screen 131 by a photographing optical system into an electrical signal, and outputs an image signal. A signal detected by the photometric sensor 137 is output to the camera control unit 170 and used for automatic exposure control and subject recognition processing.

  The focus detection module 161 is a focus detection element for executing automatic focusing control by a phase difference detection method using subject light, and the imaging surface of the imaging element 110 of the light beam (optical axis L4) reflected by the sub-mirror 122. It is fixed at an optically equivalent position.

  FIG. 2 is a diagram illustrating a configuration example of the focus detection module 161 illustrated in FIG. The focus detection module 161 of this embodiment includes a condenser lens 161a, a diaphragm mask 161b in which a pair of openings are formed, a pair of re-imaging lenses 161c, and a pair of line sensors 161d, and the exit pupils of the focus lens 212 are different. The focus adjustment state is detected by obtaining a phase shift of a pair of image signals obtained by receiving a pair of light beams passing through the pair of regions by a line sensor 161d by a known correlation calculation.

  As shown in FIG. 2, when the subject P is imaged on the equivalent surface (scheduled imaging surface) 161e of the image sensor 110, a focused state is achieved. If the image point shifts from the equivalent surface 161e toward the subject (referred to as a front pin) or shifts toward the camera body 100 (referred to as a rear pin), a focus shift state occurs.

  When the imaging point of the subject P is shifted from the equivalent surface 161e toward the subject, the interval W between the pair of image signals detected by the pair of line sensors 161d becomes shorter than the interval W in the focused state, and vice versa. If the imaging point of the subject image P is shifted to the camera body 100 side, the interval W between the pair of image signals detected by the pair of line sensors 161d becomes longer than the interval W in the focused state.

  That is, in the in-focus state, the image signals detected by the pair of line sensors 161d overlap with the center of the line sensor, but in the out-of-focus state, each image signal is shifted from the center of the line sensor, that is, the phase difference is Therefore, focusing is performed by moving the focus lens 212 by an amount corresponding to the phase difference (deviation amount).

  Here, FIG. 3 shows an arrangement example of a plurality of focus detection areas set in the photographing screen 50 of the photographing optical system. As shown in FIG. 3, a plurality of focus detection areas AFP are set in the shooting screen 50 of the shooting optical system. As will be described later, the focus detection module 161 corresponds to each focus detection area AFP. Each of the four pairs of line sensors 161d includes a plurality of line sensors 161d so that an image signal in each focus detection area AFP can be acquired. In this embodiment, as indicated by AFP1 to AFP11 in FIG. 3, eleven focus detection areas AFP are provided, and each position corresponds to a predetermined position in the imaging range of the image sensor 110. The number and arrangement of the focus detection areas AFP are not limited to the mode shown in FIG.

  FIG. 4 shows an arrangement example of the line sensor 161d in the photographing screen 50 of the photographing optical system in the present embodiment. In the present embodiment, as shown in FIG. 4, the focus detection module 161 is provided with a plurality of four pairs of line sensors 161d corresponding to each focus detection area AFP. An image signal in the area AFP can be acquired. Specifically, the focus detection area AFP2 shown in FIG. 3 will be described as an example. As shown in FIG. 4, four pairs of line sensors provided corresponding to the focus detection area AFP2 in the shooting screen 50 are shown. , H1, H2, V1, and V2. In other words, the position of each pair of line sensors 161d in the shooting screen 50 (the position in the shooting screen 50 where each pair of line sensors 161d can capture the subject) is represented by H1, H2, in FIG. The image signals in the focus detection area AFP2 can be acquired by these four pairs of line sensors 161d. Similarly, in AFP1, AFP3 to AFP11 other than the focus detection area AFP2, as shown in FIGS. 3 and 4, four pairs of line sensors 161d are arranged corresponding to each focus detection area AFP, Thereby, the image signal in each focus detection area AFP can be acquired. In the example shown in FIG. 4, an example is shown in which four pairs of line sensors 161d are arranged for each focus detection area AFP, but the number of line sensors 161d is not limited to four pairs. , Can be any number. In the present embodiment, the line sensor pairs corresponding to these H1, H2, V1, and V2 are hereinafter referred to as line sensor pairs H1, H2, V1, and V2.

  Of line sensor pairs H1, H2, V1, and V2, line sensors H1 and H2 that have the same horizontal direction and V1 and V2 that have the same vertical direction have averaged outputs. An average value is obtained by processing, or an addition value can be calculated by adding the outputs.

  Returning to FIG. 1, the AF-CCD control unit 162 controls the gain and accumulation time of the line sensor 161 d of the focus detection module 161 in the autofocus mode. The line sensor 161 d provided in the focus detection module 161 controls the AF-CCD control unit 162. The detected image signal is read in correspondence with each focus detection area AFP, and is output to the defocus calculation unit 163.

  The defocus calculation unit 163 converts the shift amount of the image signal corresponding to each focus detection area 51 sent from the AF-CCD control unit 162 into a defocus amount df, and outputs this to the lens drive amount calculation unit 164. To do.

  Based on the defocus amount sent from the defocus calculation unit 163, the lens drive amount calculation unit 164 calculates a lens drive amount Δd corresponding to the defocus amount, and outputs this to the lens drive control unit 165. .

  Based on the lens drive amount Δd sent from the lens drive amount calculation unit 164, the lens drive control unit 165 sends a drive command to the focus lens drive motor 230 via the lens control unit 250, and the lens drive amount Δd. Only the focus lens 212 is moved.

  The image sensor 110 is provided on the optical axis L1 of the light beam from the subject of the camera body 100 and at a position that is a planned focal plane of the photographing optical system including the lenses 211, 212, and 213, and a shutter 111 is provided on the front surface thereof. Is provided. The image sensor 110 is a two-dimensional array of a plurality of photoelectric conversion elements, and can be constituted by a two-dimensional CCD image sensor, a MOS sensor, a CID, or the like. The electrical image signal photoelectrically converted by the image sensor 110 is subjected to image processing by the camera control unit 170 and then stored in a memory (not shown). Note that the memory for storing the photographed image can be constituted by a built-in memory or a card-type memory.

  The operation unit 150 includes a shutter release button and an input switch for the photographer to set various operation modes of the camera 1, and selects a continuous shooting mode, switching between an automatic exposure mode / manual exposure mode, Switching between the auto focus mode / manual focus mode, and even in the auto focus mode, the subject tracking mode for recognizing and tracking a specific subject can be set. The shutter release button switch includes a first switch SW1 that is turned on when the button is half-pressed and a second switch SW2 that is turned on when the button is fully pressed. The shutter release button switches SW1 and SW2 and various modes set by the operation unit 150 are transmitted to the camera control unit 170.

  The camera body 100 is provided with a camera control unit 170. The camera control unit 170 includes a microprocessor and peripheral components such as a memory, and is electrically connected to the lens control unit 250. The lens control unit 250 receives lens information including information on the focus adjustment range of the lens barrel 200. And information such as a defocus amount and an aperture control signal is transmitted to the lens control unit 250. The camera control unit 170 reads out image information from the image sensor 110 as described above, performs predetermined information processing as necessary, and outputs the information to a memory (not shown). Further, when the subject tracking mode is selected by the operation unit 150, the camera control unit 170 receives an image signal from the photometric sensor 137 and exists in the shooting screen 50 based on the received image signal. A subject tracking process for detecting a specific subject and tracking it is performed. In addition to these, the camera control unit 170 controls the entire camera 1 such as correction of captured image information and detection of a focus adjustment state and an aperture adjustment state of the lens barrel 200.

  Next, an operation example of the camera 1 according to this embodiment will be described. 5-7 is a flowchart which shows operation | movement of the camera 1 which concerns on this embodiment. Hereinafter, the focus adjustment operation when the subject tracking mode is selected by the operation unit 150 will be described.

  First, in step S1, the camera control unit 170 determines whether the photographer has pressed the shutter release button halfway (the first switch SW1 is turned on). If the first switch SW1 is turned on, the process proceeds to step S2. If the first switch SW1 is not turned on, the process waits in step S1.

  In step S2, it is determined whether or not the tracking control initial process shown in FIG. 6 has been executed. When the tracking control initial process is not executed, the process proceeds to step S3, and the tracking control initial process is performed. On the other hand, if the tracking control initial process has already been executed, the process proceeds to step S4. For example, immediately after the first switch SW1 is turned on, it is determined that the tracking control initial process has not been executed, and the process proceeds to step S3.

  If it is determined in step S2 that the tracking control initial process is not executed, the process proceeds to step S3, and the tracking control initial process shown in FIG. 6 is executed. Specifically, first, in step S301 shown in FIG. 6, the photometric sensor 137 acquires an initial image for subject tracking.

  Next, in step S302, an image at a position corresponding to the position of the focus detection area AFP where the specific subject (for example, a person's face) exists in the tracking initial image acquired by the photometry sensor 137 by the camera control unit 170. Is stored as subject color information (color information and luminance information).

  In step S303, the camera control unit 170 performs processing for detecting the same color information region indicating the same color information as the subject color information stored in step S302 in the peripheral portion of the position of the focus detection area AFP where the specific subject exists. .

  In step S304, the camera control unit 170 performs processing for setting the same color information area detected in step S303 as an initial tracking subject area.

  In step S305, the camera control unit 170 performs a process of storing the image of the tracking subject area in the tracking initial image as a template image used for the next tracking process.

  In step S306, the camera control unit 170 performs processing for setting an area enlarged by predetermined pixels (for example, two pixels) in the front, rear, left, and right directions around the tracking subject area set in step S304 as a search area. As described above, the tracking control initial process is executed.

  On the other hand, if it is determined in step S2 shown in FIG. 5 that the above-described tracking control initial process is being executed, the process proceeds to step S4, and the tracking calculation process shown in FIG. 7 is executed. Specifically, first, in step S401 shown in FIG. 7, an image for subject tracking is acquired by the photometric sensor 137.

  Next, in step S402, the camera control unit 170 sequentially cuts out a region having the same size as the template image stored in the camera control unit 170 from the tracking image search region, and the cut-out image and the template image correspond to corresponding pixels. Every time, a difference between image information (color information and luminance information) is calculated, and a process for obtaining a sum of differences for all pixels is performed.

  Next, in step S403, the camera control unit 170 selects a clipped image having the smallest sum of image information differences, and sets the selected clipped image area as a new tracking subject area. Here, a newly set tracking subject area image may be set as a new template image.

  In step S404, the camera control unit 170 performs processing for setting an area enlarged by predetermined pixels (for example, two pixels) in the front, rear, left, and right directions around the tracking subject area set in step S403 as a search area. The tracking calculation process is executed as described above.

Next, in step S5, the camera control unit 170 performs processing for detecting an overlap between the tracking subject region set in step S304 or step S403 described above and the detection region by each line sensor pair H1, H2, V1, and V2. Done. In the following, the focus detection area AFP that overlaps the tracking subject area set in step S304 or S403 described above among the focus detection areas AFP shown in FIG. 3 will be described as the subject capture area _{AFP_obj} . Here, FIGS. 8A to 8D are diagrams illustrating an example of how the tracking subject area overlaps with the detection areas by the line sensor pairs H1, H2, V1, and V2. 8A to 8D illustrate a rectangular area as an example of the tracking subject area, but the shape is not particularly limited to such a shape.

For example, in the scene shown in FIG. 8A, the camera control unit 170 determines that the tracking subject area and all the line sensor pairs H1, H2, V1, and V2 provided corresponding to the subject capturing area _{AFP_obj.} Judge that they overlap. On the other hand, in the scene shown in FIG. 8B, the camera control unit 170 selects the line sensor pair H1, among the line sensor pairs H1, H2, V1, and V2 provided corresponding to the subject capturing area _{AFP_obj} . Only H2 and V1 overlap with the tracking subject area, and it is determined that the line sensor pair V2 does not overlap with the tracking subject area. In the scene shown in FIG. 8C, the camera control unit 170 tracks only the line sensor pair H1, H2 among the line sensor pairs H1, H2, V1, V2 corresponding to the subject capturing area _{AFP_obj.} It is determined that the line sensor pair V1 and V2 does not overlap the tracking object area. Further, in the scene shown in FIG. 8D, the camera control unit 170 has only the line sensor pair H1 among the line sensor pairs H1, H2, V1, and V2 provided corresponding to the focus detection area AFP. It is determined that the line sensor pair H2, V1, and V2 does not overlap with the tracking subject area. As described above, in step S5, the camera control unit 170 detects an overlap between the tracking subject area and the detection areas by the line sensor pairs H1, H2, V1, and V2. In FIGS. 8A to 8D, of the detection areas by the line sensor pairs H1, H2, V1, and V2, those that overlap with the tracking subject area are hatched. . In the present embodiment, it is determined that the tracking subject area and the detection area of each line sensor pair overlap each other at least partially. However, for example, the overlapping area is predetermined. When the area is less than the area (for example, less than an area where it can be determined that focus detection is possible), it may be determined that these do not overlap.

  Next, in step S6, the AF-CCD control unit 162 sets the accumulation time of the line sensor 161d of the focus detection module 161 and adjusts the gain. Based on this, charge accumulation is performed by the line sensor 161d. .

Here, in the present embodiment, the accumulation times and gains of the respective line sensor pairs H1, H2, V1, and V2 corresponding to the focus detection area AFP (subject capture area _{AFP_obj} ) that overlaps the tracking subject area are described above. It is determined based on the detection result of step S5. Specifically, in the present embodiment, when the accumulation times and gains of the line sensor pairs H1, H2, V1, and V2 corresponding to the subject capturing area _{AFP_obj} are set based on the detection result of step S5 described above. The priority of the pair of line sensors to be used is set, and the accumulation time and gain are set based on the set priority. Table 1 shows an example of a method for setting the priority of the line sensor pair.

That is, for example, in the scene shown in FIG. 8A, the camera control unit 170 has all the line sensor pairs H1, H2, V1, and V2 corresponding to the subject capturing area _{AFP_obj} overlap the tracking subject region. The priority is set to “high” for all the line sensor pairs H1, H2, V1, and V2. In the scene shown in FIG. 8B, the camera control unit 170 has only the line sensor pair H1, H2, and V1 overlapped with the tracking subject area, and the line sensor pair V2 overlapped with the tracking subject area. Therefore, the priority is set to “high” for the line sensor pair H1, H2, and V1, while the priority is set to “low” for the line sensor pair V2. Similarly, in the scene shown in FIG. 8C, the priority is set to “high” for the line sensor pair H1 and H2, while the priority is set to “low” for the line sensor pair V1 and V2. Further, in the scene shown in FIG. 8D, the priority is set to “high” for the line sensor pair H1, while the priority is set to “low” for the line sensor pair V1. Set to.

In this embodiment, for example, according to the above method, the output from the line sensor pair whose priority is set to “high” among the line sensor pairs H1, H2, V1, and V2 is appropriate. In addition, the accumulation times and gains of all line sensor pairs H1, H2, V1, and V2 corresponding to the focus detection area AFP overlapping the tracking subject area are set. Specifically, among the line sensor pairs H1, H2, V1, and V2, the line sensor pairs H1, H2, and V1 are based on the output of the line sensor pair that has been determined to be “high” in the previous processing. , V2 accumulation time and gain are set. That is, for example, in the scene shown in FIG. _8C , the subject capturing area _{AFP_obj} is based on the output of the line sensor pair H1, H2, V1, and V2 only during the previous processing of the line sensor pair H1 and H2. The accumulation times and gains of all line sensor pairs H1, H2, V1, and V2 corresponding to are set.

  In step S7, the AF-CCD control unit 162 reads out the signal information accumulated by the line sensor 161d in correspondence with each focus detection area AFP set in the imaging screen 50, and outputs it to the defocus calculation unit 163. .

  In step S8, the defocus calculation unit 163 calculates an image shift amount by the phase difference detection method for each focus detection area AFP set in the shooting screen 50 of the shooting optical system, and defocuses each focus detection area. A focus amount df is calculated. The calculated defocus amount df is output to the camera control unit 170 and the lens drive amount calculation unit 164.

Here, in the present embodiment, when calculating the defocus amount df in the focus detection area AFP (subject capture area _{AFP_obj} ) overlapping the tracking subject region, the detection result in step S5 described above is taken into consideration. Perform the calculation. Specifically, in the present embodiment, the priority is set and set for each of the line sensor pairs H1, H2, V1, and V2, based on the detection result of step S5 described above, similarly to step S6 described above. Based on the priority, the defocus amount df is calculated.

For example, in the scene shown in FIG. 8A, the priority of all line sensor pairs H1, H2, V1, and V2 provided corresponding to the subject capturing area _{AFP_obj} is set to “high”. The defocus amount df is calculated based on the outputs of all the line sensor pairs H1, H2, V1, and V2. Specifically, in the scene shown in FIG. 8A, the output of the pair of line sensors H1, H2 having the same horizontal direction is subjected to a simple averaging process, and the vertical direction is the same. A process of simply averaging the outputs of a certain line sensor pair V1, V2 is performed. In the scene shown in FIG. 8A, the defocus amount df is based on the obtained simple average value of the output of the line sensor pair H1, H2 and the simple average value of the output of the line sensor pair V1, V2. Is calculated.

  On the other hand, in the scene shown in FIG. 8B, the priority is set to “high” for the line sensor pair H1, H2, and V1, while the priority is set to “low” for the line sensor pair V2. Set to Therefore, in the scene shown in FIG. 8B, the defocus amount df is calculated based on the outputs of the pair of line sensors H1, H2, and V1 having the priority “high”. Specifically, in the scene shown in FIG. 8B, a process of simply averaging the outputs of the pair of line sensors H1 and H2 having the same horizontal direction is performed. In the scene shown in FIG. 8B, the defocus amount df is calculated based on the obtained simple average value of the outputs of the line sensor pair H1 and H2 and the output value of the line sensor pair V1. That is, in the scene shown in FIG. 8B, when the defocus amount df is calculated, the line sensors having the same horizontal direction and the priority set to “high” are used. For the pair H1 and H2, the output is simply averaged, and the obtained simple average value is used. On the other hand, for the line sensor pair V1 and V2 whose alignment direction is the vertical direction, the priority of the line sensor pair V2 is “ Therefore, only the output value of the line sensor pair V1 is used without using the output of the line sensor pair V2.

  In the scene shown in FIG. 8C, the priority is set to “high” for the line sensor pair H1, H2, while the priority is “low” for the line sensor pair V1, V2. Set to Therefore, in the scene shown in FIG. 8C, the defocus amount df is calculated based on the outputs of the pair of line sensors H1 and H2 having the priority “high”. Specifically, in the scene shown in FIG. 8C, a process of simply averaging the outputs of the pair of line sensors H1 and H2 having the same horizontal direction is performed. In the scene shown in FIG. 8C, the defocus amount df is calculated based on the obtained simple average value of the outputs of the line sensor pairs H1 and H2. That is, in the scene shown in FIG. 8C, the output sensor is simply averaged for the line sensor pairs H1 and H2 that have the same horizontal direction and both have a high priority. The defocus amount df is calculated using only the obtained simple peace value, and the priority is “low” for the line sensor pair V1 and V2 whose arrangement direction is the vertical direction. These line sensor pairs V1 and V2 are not used for calculating the defocus amount df.

  Further, in the scene shown in FIG. 8D, the priority is set to “high” for the line sensor pair H1, while the priority is “low” for the line sensor pairs H2, V1, and V2. Set to Therefore, in the scene shown in FIG. 8D, the defocus amount df is calculated based only on the output value of the line sensor pair H1 having the priority “high”. That is, in the scene shown in FIG. 8D, the defocus amount df is calculated using only the output value of the line sensor pair H1 having the priority “high”, and the priority is “ The line sensor pairs H2, V1, and V2 that are “low” are not used to calculate the defocus amount df.

In the present embodiment, the defocus amount df in the subject capturing area _{AFP_obj} is calculated as described above. In the above-described example, the configuration in which the outputs are simply averaged for the line sensor pairs having the same arrangement direction and the priority of both is “high” is illustrated. Instead of this, a configuration in which addition processing or addition averaging processing is performed may be employed.

  Next, in step S9, it is determined whether or not the defocus amount calculation has been completed for a predetermined number of focus detection areas in the focus detection area AFP shown in FIG. If the defocus amount calculation is completed for a predetermined number of focus detection areas, the process proceeds to step S11. If not, the process returns to step S7. In steps S7 and S8, AFF is performed. -The readout of the CCD signal and the defocus amount calculation are repeatedly executed. Whether or not the defocus amount calculation has been completed for a predetermined number of focus detection areas determined in advance is determined by, for example, the defocus amount calculation for all focus detection areas AFP overlapping the tracking subject area. The determination may be made based on whether or not the defocus amount calculation has been completed for all the focus detection areas AFP (total 11 points) shown in FIG. Also good.

In step S10, the camera control unit 170 performs a process of determining a focus detection area to be used for focus adjustment from the focus detection area AFP shown in FIG. 3 based on the defocus amount df calculated in step S8. It is. In the present embodiment, for example, when there is a focus detection area AFP (subject capture area _{AFP_obj} ) that overlaps the tracking subject area, the subject capture area _{AFP_obj} is determined as a focus detection area for use in focus adjustment. can do. When there are a plurality of subject capture areas _{AFP_obj} , for example, the subject capture area _{AFP_obj} whose focus state is closest to the closest side is _used for focus adjustment based on the defocus amount df calculated in step S8. It can be determined as a focus detection area for use. If the subject capture area _{AFP_obj} does not exist, the focus detection in which the defocus amount closest to the defocus amount df calculated in the focus detection area AFP overlapping the tracking subject region is calculated before the previous process. The area can be determined as a focus detection area for use in focus adjustment, or the focus detection area AFP in which the focus state is located closest to the focus detection area can be determined as a focus detection area for use in focus adjustment.

  In step S11, the lens drive amount calculation unit 164 calculates a lens drive amount Δd corresponding to the defocus amount df of the focus detection area to be used for the focus adjustment selected in step S10, and this is calculated as a lens drive control unit. To 165.

  In step S12, the lens drive control unit 165 sends a drive command to the focus lens drive motor 230 via the lens control unit 250 based on the lens drive amount Δd calculated in step S11. A move is made. And it returns to step S1 again and the process mentioned above is performed repeatedly.

  As described above, the camera 1 according to this embodiment operates.

  In the present embodiment, when the defocus amount df in the focus detection area AFP that overlaps the tracking subject area is calculated, the tracking subject area overlaps the detection areas by the line sensor pairs H1, H2, V1, and V2. Among the line sensor pairs H1, H2, V1, and V2, those that overlap the tracking subject area are set to priority “high”, and those that do not overlap are set to priority “low”. Based on the set priority, the defocus amount df is calculated. Specifically, the defocus amount df is calculated using only the line sensor pair set to the priority “high” among the line sensor pairs H1, H2, V1, and V2. Therefore, according to the present embodiment, when calculating the defocus amount df in the focus detection area AFP that overlaps the tracking subject area, the line that does not overlap the tracking subject area and is set to the priority “low”. The sensor pair can be removed from the defocus amount df, so that the defocus amount df can be calculated without being affected by the data from the line sensor pair that does not overlap the tracking subject area. As a result, the calculation accuracy of the defocus amount df can be improved. In addition, the line sensor pair that does not overlap with the tracking subject area and has the priority “low” is excluded from the defocus amount df, thereby calculating the output data of the line sensor pair that has the priority “low”. The load can be reduced, and thereby the calculation time for calculating the defocus amount df can be shortened.

  In addition, in the present embodiment, when setting the accumulation time and gain (light receiving condition) of each line sensor pair H1, H2, V1, and V2 in the focus detection area AFP that overlaps the tracking subject area, the tracking subject area The accumulation time and the gain are set on the basis of the output of the pair of line sensors set to the priority “high” in the previous process. Therefore, according to the present embodiment, it is possible to set an appropriate accumulation time and gain for the line sensor pair used when calculating the defocus amount df, and accordingly, an image signal based on the tracking subject can be appropriately set. As a result, the calculation accuracy when calculating the defocus amount df can be improved.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, when calculating the defocus amount df in the focus detection area AFP that overlaps the tracking subject area, only the line sensor pair set to the priority “high” is used to determine the defocus amount. Although an example of calculating df has been illustrated, the defocus amount df is calculated using the line sensor pair set to the priority “low” in addition to the line sensor pair set to the priority “high”. It is good also as an aspect.

  That is, for example, in the scene shown in FIG. 8B, the priority “high” is applied to the line sensor pair V1 and V2 having the same vertical direction and the priorities “high” and “low”, respectively. ”And the output of the line sensor pair V2 having the priority“ low ”may be weighted and added or averaged. Specifically, the weight of the output of the line sensor pair V1 having the priority “high” is set higher than the weight of the output of the line sensor pair V2 having the priority “low”, and these are added or averaged. Such processing may be performed.

  Further, for example, in the scene shown in FIG. 8C, the simple average value (or the addition value) of the outputs of the line sensor pair V1 and V2 having the same vertical direction and the priority “low”. Or the addition average value), and the horizontal direction is the same as the simple average value (or addition value or addition average value) of the outputs of the pair of line sensors V1 and V2, and both have a high priority. The defocus amount df may be calculated based on the simple average value of the outputs of the line sensor pair H1, H2. In this case, priority is given to the simple average value of the output of the line sensor pair H1, H2 having the priority “high” over the simple average value of the output of the line sensor pair V1, V2 having the priority “low”. It is desirable to perform such processing. Further, in the scene shown in FIG. 8D, it is of course possible to make the same as in FIGS. 8B and 8C.

  Alternatively, as a result of calculating the defocus amount df based on the line sensor pair having the priority “high” in each of the scenes illustrated in FIGS. 8B, 8 </ b> C, and 8 </ b> D, The defocus amount df may be calculated based on the line sensor pair having the priority “low” only when the defocus amount having high reliability is not obtained.

  In the above-described embodiment, the focus detection module 161 for performing focus detection by the phase difference detection method is illustrated separately from the image sensor 110. For example, the image forming the image sensor 110 is illustrated. A part of the pixels is replaced with a focus detection pixel row for performing focus detection by the phase difference detection method, so that the focus detection pixel row is arranged at a position as shown in FIG. It is good also as an aspect.

  Furthermore, in the above-described embodiment, the lens-integrated digital camera 1 has been described as an example. However, the present invention can also be applied to a lens interchangeable digital camera, a small camera module built in a mobile phone, or the like. .

DESCRIPTION OF SYMBOLS 1 ... Single-lens reflex digital camera 100 ... Camera body 110 ... Image pick-up element 150 ... Operation part 161 ... Focus detection module 161d ... Line sensor H1, H2, V1, V2 ... Line sensor pair 162 ... AF-CCD control part 163 ... Defocus calculation 164: Lens drive amount calculation unit 165 ... Lens drive amount control unit 170 ... Camera control unit 200 ... Lens barrel 212 ... Focus lens 230 ... Focus lens drive motor 250 ... Lens control unit

Claims (8)

A first focus detection pixel array that is arranged in at least two rows in the first direction and receives a plurality of focus detection pixels that receive light incident through the optical system and output signals; and the first direction; arranged in at least two rows in a second direction crossing, it has a second focus detection pixel row to the focus detection pixels for outputting a signal by receiving the light incident through the optical system has a plurality of arranged, A light receiving element that intersects the first focus detection pixel rows arranged in at least two rows and the second focus detection pixel rows arranged in at least two rows ;
A recognizing unit for recognizing a specific subject in the image by the optical system;
An image formation plane of an image by the optical system from a signal output from the first focus detection pixel row or the second focus detection pixel row at a position corresponding to the position in the image plane of the subject recognized by the recognition unit. And a focus detection device including a detection unit that detects a shift amount between the light receiving element and the light receiving surface of the light receiving element . The focus detection apparatus according to claim 1,
The detection unit is output from a focus detection pixel column at a position overlapping with a position in the image plane of the subject recognized by the recognition unit in the first focus detection pixel column or the second focus detection pixel column. A focus detection device that detects the shift amount from a signal. The focus detection apparatus according to claim 1 or 2,
The said detection part is a focus detection apparatus which detects the said deviation | shift amount from the signal output from at least 2 focus detection pixel row | line | column among the said 1st focus detection pixel row | line | column or the said 2nd focus detection pixel row | line | column. The focus detection apparatus according to claim 3,
The detection unit detects the shift amount from a signal output from at least two focus detection pixel rows having the same arrangement direction in the first focus detection pixel row or the second focus detection pixel row. apparatus. In the focus detection apparatus in any one of Claims 1-4,
A control unit for controlling an accumulation time or gain of the first focus detection pixel row or the second focus detection pixel row;
The control unit is based on a positional relationship between a position in the image plane of the subject recognized by the recognition unit and a position in the image plane of the first focus detection pixel row or the second focus detection pixel row. A focus detection device for controlling the accumulation time or gain. The focus detection apparatus according to claim 5,
The light receiving element control unit includes the first focus detection pixel at a position overlapping with a position in the image plane of the subject recognized by the recognition unit in the first focus detection pixel row or the second focus detection pixel row. A focus detection apparatus that determines the accumulation time or the gain based on an output from the column or the second focus detection pixel column. In the focus detection apparatus in any one of Claims 1-6,
The focus detection device, wherein the light receiving element includes a plurality of the first focus detection pixel rows and the second focus detection pixel rows.   An imaging apparatus comprising the focus detection apparatus according to claim 1.

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