JP2016224372A - Focus detection device, imaging device and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which when a plurality of subject images different in a distance from a camera is included in an image of a subject to be detected by a phase difference AF method AF sensor, a focus adjustment to a desired position cannot be made in technology making the focus adjustments using a partial area of the AF sensor.SOLUTION: A focus detection device includes: a plurality of light reception units that receives a light flux passing through a pupil area different in an optical system by each of a plurality of pixels; and a detection unit that detects a focus state of the optical system on the basis of a deviation of an image of the different pupil area received by the light reception unit. The detection unit is configured to detect the focus state of the optical system on the basis of the deviation of the image of the different pupil area received by the light reception unit other than the light reception unit receiving a plurality of images different in the deviation.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a focus detection device, an imaging device, and an electronic apparatus.

  When the subject image detected by the phase difference AF sensor includes a plurality of subject images with different distances from the camera (referred to as perspective conflict), focus adjustment is performed using a part of the AF sensor. A technique is known (for example, Patent Document 1).

JP 2013-29803 A

  The prior art has a problem that focus adjustment may not be performed at a desired position.

In the first invention, based on a plurality of light receiving portions that receive light beams that have passed through different pupil regions of the optical system by a plurality of pixels, and deviations of images of the different pupil regions received by the light receiving portions, A detection unit that detects a focus state of the optical system, and the detection unit detects a shift of the images of the different pupil regions received by the light receiving unit other than the light receiving unit that has received a plurality of images having different shifts. The focus state of the optical system is detected based on
In the second invention, the imaging device has the focus detection device of the first invention.
In a third invention, an electronic apparatus has the focus detection device of the first invention.

It is a figure which shows the structure of the imaging device which has the focus detection apparatus which concerns on 1st Embodiment. It is a schematic diagram which superimposes an imaging screen and a some focus detection area. It is a figure which shows the micro lens array which covers a focus detection sensor and a focus detection sensor. It is a figure which shows the correspondence of a focus detection pixel and a micro lens. It is a flowchart of the focus adjustment process performed by a control apparatus. It is a figure which shows an example in which two subject images are included in the focus detection area. It is a flowchart of the perspective conflict determination process performed by a control apparatus. It is a figure showing the change of the focus detection signal value of a pair of focus detection signal sequence with respect to the focus detection pixel position in a focus detection area. It is a figure showing the state which shifted a pair of focus detection signal sequence relatively by the specific shift amount which gives the minimum value of the correlation amount of a pair of focus detection signal sequence. It is a figure for demonstrating the division | segmentation process of a pair of focus detection signal sequence. It is a flowchart of the focus adjustment process performed by a control apparatus. It is a flowchart of the focus adjustment process performed by a control apparatus. It is a flowchart of the first tracking process performed by a control apparatus. It is a flowchart of the tracking calculation process performed by a control apparatus. It is a figure which shows the structure of the imaging device which has another focus detection apparatus. It is a figure which shows the structure of the imaging device which has another focus detection apparatus. It is a front view which shows the detailed structure of an image pick-up element. It is a front view which shows the detailed structure of an image pick-up element. It is a front view which shows the detailed structure of an image pick-up element.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of an imaging apparatus 100 according to the first embodiment. The imaging device 100 includes a focus detection device 50, a liquid crystal display element 1, an imaging device 2, an imaging optical system 4, a lens driving unit 5, a half mirror 7, a focus adjustment device 8, and a storage device 15. Including. The focus detection device 50 includes a focus detection sensor 6 that is a focus detection unit, a microlens array 9, and a control device 3.

  The imaging optical system 4 forms an object image on an imaging surface (for example, the imaging surface of the image sensor 2). The imaging optical system 4 includes a plurality of lenses and a diaphragm. The lens driving unit 5 moves the focus adjustment lens among the plurality of lenses in the direction of the optical axis 10 of the imaging optical system 4.

  The half mirror 7 is a thin mirror such as a pellicle mirror. The half mirror 7 is located in the optical path along the optical axis 10 as shown in FIG. The half mirror 7 reflects a part of the incident light beam that has passed through the imaging optical system 4 in the direction of the optical axis 10 a, that is, toward the microlens array 9. The half mirror 7 transmits the remainder of the incident light beam that has not been reflected. The reflected light beam reflected by the half mirror 7 passes through the microlens array 9 and enters the focus detection sensor 6. The transmitted light beam that has passed through the half mirror 7 enters the image sensor 2. The microlens array 9 has a plurality of microlenses arranged two-dimensionally. The microlens array 9 is disposed on the imaging plane of the imaging optical system 4. The position of the microlens array 9 is optically equivalent to the position of the imaging surface of the imaging device 2.

  A plurality of focus detection pixels are arranged in the focus detection sensor 6. Each focus detection pixel generates an electrical focus detection signal in accordance with the received light beam. A large number of focus detection areas are provided on the imaging screen. The focus detection sensor 6 can generate a pair of electrical focus detection signal sequences corresponding to the subject image for each of the plurality of light receiving units corresponding to the plurality of focus detection areas of the imaging screen.

  When generating the pair of focus detection signal sequences described above, the control device 3 performs photoelectric conversion control of the focus detection sensor 6. Examples of photoelectric conversion control include exposure control of a plurality of focus detection pixels, readout control of a plurality of focus detection signals, and / or amplification control of a plurality of read focus detection signals. A pair of focus detection signal sequences generated by the focus detection sensor 6 is output to the control device 3.

  The control device 3 executes the focus adjustment process of the imaging optical system 4 based on the pair of focus detection signal sequences output by the focus detection sensor 6. The control device 3 performs focus detection by a so-called pupil division type phase difference detection method. The control device 3 detects a shift amount (phase difference amount) between the pair of focus detection signal sequences. The control device 3 calculates a defocus amount from the detected deviation amount. The control device 3 calculates the lens driving amount of the focus adjustment lens of the imaging optical system 4 based on the calculated defocus amount. The control device 3 transmits the calculated lens driving amount to the focus adjustment device 8. The focus adjustment device 8 drives the focus adjustment lens of the imaging optical system 4 by the received lens drive amount via the lens drive unit 5.

  During the imaging process, the half mirror 7 retreats from the optical path by jumping up so as to cover the focus detection sensor 6. After retraction of the half mirror 7, all incident light beams that have passed through the imaging optical system 4 are incident on the imaging device 2. A subject image is formed on the light receiving surface of the image sensor 2. A plurality of imaging pixels are arranged in a two-dimensional manner on the imaging element 2. Each of the plurality of imaging pixels receives incident light flux and performs photoelectric conversion. The plurality of imaging pixels generate a plurality of electrical imaging signals corresponding to the subject image formed by the imaging optical system 4. The imaging element 2 outputs the generated plurality of imaging signals to the control device 3.

  The control device 3 generates image data of the subject image based on the plurality of imaging signals output by the imaging element 2. The control device 3 displays an image based on the generated image data on the liquid crystal display element 1 as a through image. The control device 3 records the generated image data in the storage device 15 at the time of imaging processing executed in accordance with an imaging instruction from the user.

  FIG. 2 is a schematic diagram illustrating the imaging screen 400 and a plurality of focus detection areas 410 superimposed on each other. In the imaging screen 400, a total of 25 focus detection areas 410 of 5 vertical × 5 horizontal are provided in advance. In FIG. 2, the focus detection areas 410 are independent from each other, but the focus detection areas 410 may be adjacent to each other or may partially overlap each other. The plurality of light receiving sections of the focus detection sensor 6 can generate a pair of focus detection signal sequences corresponding to the partial subject images in the focus detection area 410 for each of the plurality of focus detection areas 410. In the following description, a pair of focus detection signal sequences corresponding to partial subject images in a specific focus detection area 410 is simply referred to as a pair of focus detection signal sequences corresponding to the focus detection area 410.

  FIG. 3 is a diagram showing the focus detection sensor 6 and the microlens array 9 that covers the focus detection sensor 6. FIG. 3A shows an enlarged view of the focus detection sensor 6 and the microlens array 9 in the vicinity of the optical axis 10a shown in FIG. A plurality of focus detection pixels 60 are two-dimensionally arranged in the focus detection sensor 6. In the microlens array 9, a plurality of microlenses 90 are arranged two-dimensionally (in a honeycomb shape) at a pitch of 100 μm or less. Although the peripheral shape of the microlens 90 is illustrated as a sphere, it may be a hexagon in accordance with the honeycomb arrangement.

  FIG. 3B is a diagram in which the microlens array 9 and the focus detection sensor 6 on the other side are overlapped when viewed from directly above the microlens array 9. In the example of FIG. 3B, each microlens 90 corresponds to a plurality of focus detection pixels 60 composed of 5 pixels in the vertical direction × 5 pixels in the horizontal direction. The reflected light beam from the half mirror 7 (FIG. 1) passes through the microlens array 9 and enters the focus detection sensor 6. The light beam that has passed through each microlens 90 is received by a plurality of focus detection pixels 60 including a total of 25 pixels of 5 pixels in the vertical direction and 5 pixels in the horizontal direction corresponding to each microlens 90. The plurality of focus detection pixels 60 convert incident light into an electrical focus detection signal by photoelectric conversion. The plurality of focus detection pixels 60 corresponding to each microlens 90 is not limited to a total of 25 pixels of 5 pixels in the vertical direction × 5 pixels in the horizontal direction.

  FIG. 4 is a diagram illustrating a correspondence relationship between the plurality of focus detection pixels 60 and the microlens 90. FIGS. 4A and 4B are plan views of the plurality of focus detection pixels 60 and the microlens 90. FIG. In the example shown in FIGS. 4A and 4B, the plurality of focus detection pixels 60 corresponding to each microlens 90 is a total of 25 pixels of 5 pixels in the vertical direction × 5 pixels in the horizontal direction.

  In the focus detection area 410, there are a plurality of focus detection pixels 60 each having 25 pixels. The control device 3 defines a pair of focus detection pixel groups for each of the 25 pixel focus detection pixels 60. The pair of focus detection pixel groups receive a pair of light beams among the light beams incident on the focus detection sensor 6 via the microlens array 9. The pair of focus detection pixel groups photoelectrically convert the received pair of light beams to generate a pair of electrical focus detection signal sequences corresponding to the subject image. In the example of the focus detection pixels 60 of 25 pixels in total of 5 pixels in the vertical direction and 5 pixels in the horizontal direction corresponding to each microlens 90 shown in FIG. 4A, a pair of focus detection pixel groups 610a and 610b are hatched. ing. The pair of focus detection pixel groups 610a and 610b includes three focus detection pixels at the center among five focus detection pixels included in each of the two vertical focus detection pixel rows located at both ends in the horizontal direction. Pixel.

  In the example of the focus detection pixel 60 of 25 pixels in total of 5 pixels in the vertical direction and 5 pixels in the horizontal direction corresponding to each microlens 90 shown in FIG. 4B, a pair of focus detection pixel groups 620a and 620b are hatched. ing. The pair of focus detection pixel groups 620a includes five focus points included in each of the vertical focus detection pixel column positioned at the left end in the horizontal direction and the vertical focus detection pixel column adjacent thereto. Among the detection pixels, there are three focus detection pixels at the center. The pair of focus detection pixel groups 620b includes five focus points included in each of the vertical focus detection pixel column positioned at the right end and the vertical focus detection pixel column adjacent to the horizontal direction. Among the detection pixels, there are three focus detection pixels at the center. As shown in FIG. 4B, each of the pair of focus detection pixel groups 620a and 620b has a total of six focus points by arranging three focus detection pixels arranged in the vertical direction adjacent to each other in two horizontal rows. Includes detection pixels.

  4 (c) and 4 (d) show the focus detection pixels 60 and the microlens 90 of 25 pixels in total of 5 pixels in the vertical direction × 5 pixels in the horizontal direction shown in FIGS. 4 (a) and 4 (b), respectively. It is sectional drawing when a top view is cut | disconnected by the dashed-dotted lines S1 and S2 extended in a horizontal direction through the focus detection pixel located in the center of the focus detection pixel 60 of 25 pixels. In FIG. 4C, a pair of focus detection pixel groups 610a and 610b receive a pair of light beams 11 and 12 passing through a pair of pupil regions and a microlens 90 which are different pupil regions of the imaging optical system 4, and photoelectrically A pair of electrical focus detection signals is generated by the conversion. FIG. 4A illustrates five combinations of 25-pixel focus detection pixels 60 and microlenses 90. Therefore, a focus detection signal sequence including five focus detection signals generated by the five focus detection pixel groups 610a and a focus detection signal sequence including five focus detection signals generated by the five focus detection pixel groups 610b. These two focus detection signal sequences form a pair of focus detection signal sequences. Similarly, in FIG. 4D, the pair of focus detection pixel groups 620a and 620b receive the pair of light beams 13 and 14 passing through the pair of pupil regions and the microlens 90 of the imaging optical system 4, and perform photoelectric conversion. A pair of electrical focus detection signals is generated. FIG. 4B illustrates five combinations of the focus detection pixels 60 and the microlenses 90 of 25 pixels, but the number of combinations is not five, but may be four or less or six or more. Therefore, a focus detection signal sequence generated by the focus detection pixel group 620a and a focus detection signal sequence generated by the focus detection pixel group 620b are obtained, and these two focus detection signal sequences are a pair of focus detection signal sequences. Form.

  The focus adjustment of the imaging optical system 4 can be performed based on the shift amount (phase difference) of the pair of focus detection signal sequences obtained in this way or the defocus amount calculated based on the shift amount (phase difference). . Note that the distance between the pair of focus detection pixel groups 610a and 610b shown in FIG. 4C is larger than the distance between the pair of focus detection pixel groups 620a and 620b shown in FIG. Therefore, the size of the opening angle formed by the pair of light beams 11 and 12 shown in FIG. 4C is larger than the size of the opening angle formed by the pair of light beams 13 and 14 shown in FIG. In either case, the present embodiment provides the effects described later, but the larger the opening angle, the easier it is to detect the difference in focus detection signal value change caused by the perspective conflict described later. It is more preferable to adopt a configuration with a large opening angle as shown in FIG.

  FIG. 5 is a flowchart of the focus adjustment process performed by the control device 3. The control device 3 is a computer composed of, for example, a CPU and a memory. When the CPU executes the computer program stored in the memory, the process of each step constituting the focus adjustment process shown in FIG. 5 is performed.

  Prior to the focus adjustment process, the user designates one focus detection area 410 as a focus adjustment target from the plurality of focus detection areas 410 illustrated in FIG. The control device 3 sets a partial subject existing at the position of the focus detection area 410 designated by the user as a focus adjustment target. In the following description, the focus detection area 410 designated as a focus adjustment target by the user is referred to as a selection area. When the user performs a predetermined focus adjustment operation with an operation member (not shown), the control device 3 starts executing the focus adjustment process shown in FIG. For example, an operation member (not shown) is a shutter release button, and a focus adjustment operation is a half-press operation of the shutter release button.

  The process of each step constituting the focus adjustment process shown in FIG. 5 will be described using the example of the imaging screen 250 shown in FIG. In FIG. 6, the entire imaging screen 250 includes two subject images formed by the imaging optical system 4, that is, a background subject image 210 including trees and a person subject image 220. A selection area 200 is superimposed on the imaging screen 250 shown in FIG. The selection area 200 includes a background subject image 210 including a tree located far from the imaging apparatus 100 and a subject image 220 of a person located nearby.

  In the following description, as in the selection area 200 shown in FIG. 6, the focus detection area 410 including a plurality of subject images whose distances from the imaging device 100 are relatively different by a certain amount or more is referred to as a perspective conflict state. .

  In step S <b> 100, the control device 3 performs photoelectric conversion control of the focus detection sensor 6. As photoelectric conversion control of the focus detection sensor 6, for example, exposure control of a plurality of focus detection pixels 60 arranged in the focus detection sensor 6, read control of a plurality of focus detection signals, and / or a plurality of read focus detection signals. Amplification control is performed.

  In step S110, the control device 3 acquires a pair of focus detection signal strings based on the plurality of focus detection signals read in step S100. The control device 3 acquires a pair of corresponding focus detection signal sequences not only for the selection area 200 but also for all focus detection areas 410.

  In step S120, the control device 3 calculates a defocus amount for each of the pair of focus detection signal sequences acquired in step S110. For example, the pair of focus detection signal sequences are {a [i]} and {b [j]}. The controller 3 sequentially changes the correlation amount C (k) while changing the interval between the pair of focus detection signal sequences {a [i]} and {b [j]} (shifting the phase relatively by a predetermined shift amount). Calculate. Here, k is a relative (phase) shift amount of the pair of focus detection signal sequences {a [i]} and {b [j]}. The control device 3 specifies the minimum value C (k) _min of the correlation amount C (k). The control device 3 acquires a specific shift amount X0 of the pair of focus detection signal sequences {a [i]} and {b [j]} that gives the minimum value C (k) _min. The control device 3 calculates a defocus amount as a focus detection amount parameter based on the shift amount X0.

  In step S130, the control device 3 executes a perspective conflict determination process to be described later. By this process, it is determined whether or not the selected area 200 is in a perspective conflict state. For example, as shown in FIG. 6, when the selection area 200 includes a background subject image 210 including a tree located far from the imaging device 100 and a subject image 220 of a person located nearby, the control is performed. The device 3 determines that the selected area 200 is in a perspective conflict state.

  In step S140, the control device 3 determines whether or not it is determined that the selected area 200 is in the perspective conflict state. If the determination is affirmative, the process proceeds to step S190. In step S190, the control device 3 selects one target area from the focus detection area 410 in which the defocus amount calculated in step S120 is the front pin among the focus detection areas 410 positioned around the selection area 200. To do. That is, the target area is selected so that the subject located on the near side of the current in-focus position is in focus. Note that, in all of the focus detection areas 410 located around the selection area 200, when the reliability of the calculated defocus amount is low and it is determined that focus detection is not possible, the target area is not selected. Thereafter, the process proceeds to step S200. If a negative determination is made in step S140, the process proceeds to step S150.

  In step S150, the control device 3 determines whether or not focus detection has succeeded in the selection area 200, that is, whether or not a highly reliable defocus amount has been calculated. If the determination is negative, the process proceeds to step S180. In step S <b> 180, the control device 3 selects one target area from the focus detection area 410 located around the selection area 200. Note that, in all of the focus detection areas 410 located around the selection area 200, when the reliability of the calculated defocus amount is low and it is determined that focus detection is not possible, the target area is not selected. Thereafter, the process proceeds to step S200. If the determination is affirmative in step S150, the process proceeds to step S160.

  In step S160, the control device 3 determines whether or not the defocus amount calculated in the selection area 200 is within a predetermined range. The predetermined range is, for example, a range in which the subject can move back and forth of the imaging apparatus 100 during a focus detection cycle (for example, 1/60 second). That is, the determination in step S160 is a determination for confirming whether or not the subject that has been the focus adjustment target has deviated from the selection area 200 when performing repeated focus detection. Note that this determination is always affirmative at the first focus detection. If the determination is affirmative, the process proceeds to step S170. In step S170, the control device 3 sets the selection area 200 as a target area. Thereafter, the process proceeds to step S200. In the case of negative determination in step S160, the process proceeds to step S180. For example, if a defocus amount that is far from the defocus amount that was calculated at the previous focus adjustment is calculated, it is considered that the subject that was the target of focus adjustment is out of the selection area 200, and the process proceeds to step S180. move on.

  In step S200, the control device 3 determines whether or not a target area has been selected. If the determination is affirmative, the process proceeds to step S210. In step S210, the control device 3 calculates the lens driving amount of the imaging optical system 4 based on the defocus amount of the target area calculated in step S120. In step S220, the control device 3 transmits the lens driving amount calculated in step S210 to the focus adjustment device 8. The control device 3 controls the focus adjustment device 8 so as to cause the focus adjustment device 8 to drive the lens of the imaging optical system 4 via the lens drive unit 5. When the process of step S220 is completed, this process ends. In the case of negative determination in step S200, the process proceeds to step S230. In step S230, the control device 3 performs a scanning operation. When the process of step S230 is completed, this process ends.

  FIG. 7 is a flowchart showing details of the perspective conflict determination process performed by the control device 3 in step S130 of FIG. This process is a process for determining whether or not the selected area 200 is in a perspective conflict state. In step S300, the control device 3 determines whether or not the minimum value C (k) _min of the correlation amount C (k) specified at the time of calculating the defocus amount is smaller than a predetermined threshold C (k) _th. . If the determination is affirmative, the control device 3 advances the process to step S400. In step S400, the control device 3 determines that the selected area 200 is not in the perspective conflict state, and ends this process. In the case of negative determination in step S300, the process proceeds to step S310.

  As shown in FIG. 6, when the selection area 200 includes a background subject image including a tree located far away and a subject image of a person located nearby, the correlation amount C (k) The distance between the pair of focus detection signal sequences {a [i]} and {b [j]} is changed by a specific shift amount (X0) that gives the minimum value C (k) _min (shifting the relative phase). Even if it makes it, a pair of focus detection signal sequence {a [i]} and {b [j]} will not correspond over the whole focus detection area, and the section which does not correspond partially will arise (FIG. 8). Will be described later). Therefore, the minimum value C (k) _min of the correlation amount C (k) is away from 0. On the contrary, in the focus detection area 200, when a background subject image including a tree located far away and a subject image of a person located nearby are not mixed, or a background subject including a tree located far away When the difference between the image and the subject image of a person located nearby from the imaging device 100 is small, the minimum value C (k) _min of the correlation amount C (k) is a background including a tree located far away. It approaches 0 compared with the case where the difference of the distance from the imaging device 100 with a subject image of a person and a subject image of a person located nearby is large. In such a case, an affirmative determination is made in step S300, and the control device 3 determines that the selected area 200 is not in a perspective conflict state.

  In step S <b> 310, the control device 3 determines whether the brightness of the subject image including the background subject image 210 including the tree and the subject image 220 of the person is darker than the predetermined brightness within the selection area 200. . In the case of an affirmative determination, that is, when the brightness of the subject image is darker than the predetermined brightness, there is a possibility that amplification control is performed with a large amplification degree with respect to the focus detection signal in step S100 of FIG. When amplification control is performed with a large amplification degree, noise superimposed on the focus detection signal is also amplified. In such a case, the reason why the minimum value C (k) _min of the correlation amount C (k) is not smaller than the predetermined threshold value C (k) _th is not because of the near-far competition state but because the noise is amplified. It is thought that. Therefore, the control device 3 advances this process to step S400. If a negative determination is made in step S310, the control device 3 advances the process to step S320.

  As the brightness determination index in step S310 of FIG. 7, for example, the magnitude of the amplification degree of the amplification control performed in step S100 of FIG. 5 is used. When the amplification degree is less than the predetermined value, the control device 3 determines that the brightness of the entire subject image is not darker than the predetermined brightness, that is, a negative determination is made in step S310.

  In step S320, the control device 3 relates the pair of focus detection signal sequences {a [i]} and {b [j]} corresponding to the selection area 200 acquired in step S110 by a specific shift amount X0. The absolute values | a [i] −b [j] | of the differences between the focus detection signals are sequentially calculated to obtain a plurality of differences. That is, the control device 3 determines the absolute value | a [i] of the difference between the focus detection signals for the pair of focus detection signal sequences {a [i]} and {b [j]} shifted to the state where the correlation is the highest. -B [j] | is calculated. In step S330, the control device 3 calculates an average value of absolute values of differences between the focus detection signals calculated in step S320.

  In step S340, the control device 3 relates the pair of focus detection signal sequences {a [i]} and {b [j]} corresponding to the selection area 200 acquired in step S110 by a specific shift amount X0. And a pair of partial signal sequences corresponding to a near subject image (personal subject image 220) and a pair of partial signal sequences corresponding to a distant subject image (background subject image 210 including a tree). Is divided into two pairs of partial signal sequences. For example, the control device 3 determines that each of a plurality of differences obtained by sequentially calculating the absolute value | a [i] -b [j] | of the difference in step S320 is the average value calculated in step S330. Based on whether or not this is the case, the division processing in step S340 is performed. Details will be described later with reference to FIG.

  In step S350, the control device 3 calculates the maximum luminance value for each pair of the two pairs of partial signal sequences obtained in step S340. That is, the control device 3 calculates the maximum value of the luminance value of the distant subject image (background subject image 210 including the tree) and the maximum value of the luminance value of the nearby subject image (personal subject image 220). In step S360, the control device 3 determines whether or not the difference between the maximum luminance values calculated in step S350 is greater than or equal to a predetermined amount. If the determination is affirmative, the process proceeds to step S390. In step S390, the control device 3 determines that the selected area 200 is in the perspective conflict state, and ends this process. That an affirmative determination is made in step S360 means that the selected area 200 is considered to be in a perspective competition state from the minimum value C (k) _min of the correlation amount C (k) and the luminance value. It is. In other words, both the correlation amount and the luminance value indicate that the selected area 200 is in a perspective conflict state. Therefore, the control device 3 determines that the selected area 200 is in a perspective conflict state. In the case of negative determination in step S360, the process proceeds to step S370.

  In step S370, the control device 3 calculates an interval (phase difference amount) between each pair of partial signal sequences of the two pairs of partial signal sequences obtained in step S350. The two intervals (phase difference amounts) X1 and X2 corresponding to the two pairs of partial signal sequences calculated in this way are a kind of focus detection parameters. The control device 3 calculates two defocus amounts D1 and D2 based on these two intervals (phase difference amounts) X1 and X2. The two defocus amounts D1 and D2 corresponding to the two pairs of partial signal sequences are also a kind of focus detection parameters.

  In step S380, the control device 3 determines whether or not the difference between the two defocus amounts D1 and D2 calculated in step S370 is greater than or equal to a predetermined amount. That is, in step S380, it is determined whether or not the two pairs of partial signal sequences correspond to subjects that are apart from each other by a certain distance. If the determination is affirmative, the process proceeds to step S390, and the control device 3 determines that the selected area 200 is in a perspective conflict state. In step S380, in the case of negative determination, the process proceeds to step S370, and the control device 3 determines that the selected area 200 is not in the perspective conflict state.

  That a negative determination is made in step S360, that is, it is considered that the selected area 200 is in a perspective conflict state from the minimum value C (k) _min of the correlation amount C (k), but is selected from the luminance value. That is, it is considered that the area 200 is not in a perspective conflict state. In other words, the correlation amount indicates that the selected area 200 is in a perspective conflict state, but the luminance value indicates that it is not. In this case, the control device 3 branches to step S370, and further calculates the defocus amounts D1 and D2, thereby more precisely determining whether the selected area 200 is in the perspective conflict state. Finally, if there is a difference of a predetermined amount or more between the actually calculated defocus amounts D1 and D2, the control device 3 determines that the selected area 200 is in a perspective conflict state, and the defocus amounts D1 and D2 are close to each other. If so, it is determined that the selected area 200 is not in the perspective conflict state.

  FIG. 8 corresponds to the example of the imaging screen 250 shown in FIG. 6, and a pair of focus detection signal sequences {a [i] for the focus detection pixel position in the selection area 200 having a length of about 50 pixels in the horizontal direction. } And {b [j]} are diagrams illustrating changes in focus detection signal values. The pair of focus detection signal sequences 655a and 655b that are the pair of focus detection signal sequences {a [i]} and {b [j]} shown in FIG. 8 are the pair of focus detection signals acquired in step S100 of FIG. Corresponds to the column. In FIG. 8, a section 310 of horizontal focus detection pixel positions 1 to 13 in the focus detection area 200 corresponds to a subject image 220 of a person close to the imaging device 100 shown in FIG. 6. In this section, One focus detection signal sequence 655a of the pair of focus detection signal sequences 655a and 655b is shifted to the left with respect to the other focus detection signal sequence 655b. In FIG. 8, a section 320 of horizontal focus detection pixel positions 14 to 46 in the focus detection area 200 corresponds to the background subject image 210 including a tree at a position far from the imaging device 100 shown in FIG. 6. In the section, one focus detection signal sequence 655a of the pair of focus detection signal sequences 655a and 655b is shifted to the right with respect to the other focus detection signal sequence 655b.

  In FIG. 8, in the section corresponding to the subject image 220 of the person close to the imaging device 100, the focus detection signal sequence 655a is shifted to the left with respect to the focus detection signal sequence 655b, and is far from the imaging device 100. In the section corresponding to the background subject image 210 including the tree, the focus detection signal sequence 655a is shifted to the right with respect to the focus detection signal sequence 655b, and the shift of the focus detection signal sequence differs depending on the subject image. The shift of the focus detection signal sequence is different in this way because the distance of the person from the imaging device 100 and the distance from the background imaging device 100 including the trees are different, and thus the light receiving unit of the focus detection sensor 6. This is because the difference between the images of the different pupil regions due to the subject image of the person received at the difference between the image of the different pupil regions due to the background subject image including the tree received by the light receiving unit of the focus detection sensor 6 is different. .

  In FIG. 8, a human subject image and a background subject image including a tree are taken as an example of an image received by the light receiving unit of the focus detection sensor 6, but an image received by the light receiving unit of the focus detection sensor 6 is a predetermined image. As long as the focus detection signal has a brightness change of a predetermined value or more as shown in FIG. 8 may be natural objects such as animals and plants other than trees, and artificial objects such as cars, trains, and buildings. Further, the number of specific subjects may be not only one person in FIG. 8 but also a plurality of objects such as a plurality of persons or a plurality of trees.

  Further, the difference in image shift between different pupil regions is when the distance of a specific subject from the imaging apparatus 100 differs by a predetermined value or more as shown in FIG.

  In FIG. 8, when the correlation amount C (k) shows the minimum value C (k) _min due to the relative shift of the specific shift amount (X0) with respect to the pair of focus detection signal sequences 655a and 655b. A pair of focus detection signal sequences 660a and 660b which are a pair of focus detection signal sequences {a [i]} and {b [j]} are illustrated in FIG.

  FIG. 9 shows a relative shift by a specific shift amount X0 that gives the minimum value C (k) _min of the correlation amount C (k) of the pair of focus detection signal sequences {a [i]} and {b [j]}. It is a figure showing the state which shifted a pair of focus detection signal sequence {a [i]} of 8 and {b [j]}. Since the contrast is higher in the section 320 corresponding to the background subject image 210 including the tree than the section 310 corresponding to the person subject image 220 shown in FIG. 8, the correlation between the pair of focus detection signal sequences 655a and 655b. But higher. In this case, since the specific shift amount X0 may be greatly influenced by the background subject image 210 including the tree, the pair of focus detection signal sequences {a [i] in FIG. ]} And {b [j]} are shifted, as shown in FIG. 9, the horizontal focus detection pixel positions 14 to 46 in the focus detection area 200 corresponding to the background subject image 210 including the tree. In the section 320, the pair of focus detection signal trains 660a and 660b may be close to matching. As shown in FIG. 9, in the section 310 of the focus detection pixel positions 1 to 13 in the horizontal direction within the focus detection area 200 corresponding to the subject image 220 of the person, there is a shift between the pair of focus detection signal sequences 660a and 660b. (Phase difference) has occurred. The entire section 300 in the horizontal direction of the focus detection area 200 is divided into a section 310 corresponding to the above-described person subject image 220 and the background subject image 210 including trees between the focus detection pixel positions 13 and 14. A method for identifying the boundary 350 that is divided into the corresponding section 320 will be described with reference to FIG.

  FIG. 10 is a diagram for explaining the division processing of the pair of focus detection signal sequences {a [i]} and {b [j]} shown in FIG. 8, and corresponds to the processing in step S340 in FIG. . 10 shows a pair of focus detection signals in the state of FIG. 9 in which the pair of focus detection signal sequences {a [i]} and {b [j]} in FIG. 8 are relatively shifted by a specific shift amount X0. For each horizontal focus detection pixel position in the focus detection area 200, the absolute value | a [i] -b [j] | of the difference between the corresponding focus detection signals in the columns 660a and 660b is sequentially calculated. The obtained variation of the plurality of differences 671 is shown.

  In the entire section 300 in the horizontal direction of the focus detection area 200, in the section 320 corresponding to the background subject image 210 including the tree, the change in the horizontal focus detection pixel position in the focus detection area 200 is performed. The variation of the absolute value | a [i] −b [j] | In the section 310 corresponding to the human subject image 220 described above, the absolute value | a [i] −b [j] of the difference every time the horizontal focus detection pixel position in the focus detection area 200 increases by one pixel. | Has increased or decreased dramatically. When an average value of a plurality of differences 671 across the entire section 300 in the horizontal direction of the focus detection area 200 is obtained, in the section 320 corresponding to the background subject image 210 including the tree, the absolute value of the difference indicating a value greater than the average value is obtained. The value | a [i] −b [j] | does not exist, but in the section 310 corresponding to the subject image 220 of the person, the absolute value | a [i] −b [j] of the difference indicating a value equal to or greater than the average value There are many | Therefore, in FIG. 10, with respect to the change in the focus detection pixel position in the horizontal direction in the focus detection area 200, each of the plurality of differences 671 changes below the average value of the plurality of differences 671, that is, the focus. The section of the detection pixel positions 14 to 46 can be specified as the section 320, and the boundary 350 can be specified such that the boundary 350 is located between the focus detection pixel positions 13 and 14. Of the entire section 300, the section of the focus detection pixel positions 1 to 13 that is the section opposite to the section 320 across the boundary 350 can be specified as the section 310. Based on this result, in step S340 in FIG. 7, the pair of focus detection signal sequences 655a and 655b shown in FIG. 8 representing the current focus state are divided into the focus detection pixel positions 1 to 13 corresponding to the human subject image 220. It can be divided into a pair of partial signal sequences 310 and a pair of partial signal sequences in the section 320 of the focus detection pixel positions 14 to 46 corresponding to the background subject image 210 including the tree.

According to the embodiment described above, the following operational effects can be obtained.
(1) The focus detection sensor 6 receives a pair of light beams that have passed through a pair of pupil regions of the imaging optical system 4 in each of a plurality of focus detection areas 410 provided on the imaging screen, and a pair of focus detection signal sequences. The control device 3 that functions as a photoelectric conversion unit that outputs a signal for the selection area 200 of the plurality of focus detection areas 410 is based on a pair of focus detection signal sequences corresponding to the selection area 200. It functions as a perspective conflict detection unit that detects When the selection area 200 is in a perspective conflict state, the control device 3 functions as a focus adjustment unit that performs focus adjustment based on a pair of focus detection signal sequences corresponding to another focus detection area 410 different from the selection area 200. Since it did in this way, the focus adjustment apparatus by which focus adjustment is not made to the to-be-photographed object which a user does not intend can be provided.

(2) When the selection area 200 is not in a perspective conflict state, the control device 3 performs focus adjustment based on a pair of focus detection signal sequences corresponding to the selection area 200. Since it did in this way, focus adjustment can be accurately performed with respect to the subject which a user desires.

(3) The control device 3 detects the near-far conflict state based on the correlation amount and signal level of the pair of focus detection signal sequences corresponding to the selection area 200. Since it did in this way, a near-far conflict state can be detected more accurately than in the case where only the correlation amount is used.

(4) The control device 3 estimates that the pair of focus detection signal sequences corresponding to the selection area 200 correspond to the first pair of partial signal sequences and the second subject estimated to correspond to the first subject. It functions as a dividing unit that divides the second pair of partial signal sequences into at least two pairs of partial signal sequences. The control device 3 compares the correlation amount of the pair of focus detection signal sequences corresponding to the selection area 200 with the signal level of the first pair of partial signal sequences and the signal level of the second pair of partial signal sequences. , Focus adjustment is performed. Since it did in this way, a perspective competition state can be detected accurately.

(5) The control device 3 functions as a calculation unit that calculates a shift amount (phase difference amount) for a pair of focus detection signal sequences corresponding to the selection area 200. The control device 3 sequentially calculates a difference between the corresponding focus detection signals in the pair of focus detection signal sequences when the pair of focus detection signal sequences are relatively shifted by the shift amount (phase difference amount). It functions as a part. The control device 3 divides the pair of focus detection signal sequences corresponding to the selection area 200 into two pairs of partial signal sequences based on a plurality of differences. When the first subject and the second subject exist in the selection area 200, the difference between the focus detection signals is greatly different between the subjects. It is possible to accurately divide the signal into two pairs of partial signal sequences respectively corresponding to the subject.

(6) When the correlation amount of the pair of focus detection signal sequences corresponding to the selection area 200 is less than the predetermined amount, the control device 3 determines that the selection area 200 is not in the perspective conflict state. Since it did in this way, when it can be considered that it is clearly not a perspective competition state from the correlation amount, the amount of calculation can be suppressed low.

(7) The control device 3 is such that the correlation amount of the pair of focus detection signal sequences corresponding to the selection area 200 is not less than a predetermined amount, and the maximum value (extreme value) of the signal level of the first pair of partial signal sequences When the difference between the maximum value (extreme value) of the signal level of the second pair of partial signal trains is equal to or greater than a predetermined amount, it is determined that the selected area 200 is in a perspective conflict state. Since it did in this way, a perspective competition state can be detected accurately.

(8) When the selection area 200 is in the perspective conflict state, the control device 3 outputs a pair of focus detection signal sequences indicating that the other focus detection areas 410 are pins ahead of the selection area 200. Focus adjustment is performed based on a pair of focus detection signal sequences corresponding to the focus detection area 410. Since it did in this way, focus adjustment can be accurately performed on the subject desired by the user.

(Second Embodiment)
In the first embodiment, the imaging apparatus that performs focus adjustment based on the selection area 200 selected in advance by the user has been described. In the imaging apparatus according to the second embodiment, the imaging apparatus automatically performs focus adjustment based on the plurality of focus detection areas 410 without the user specifying the selection area 200. Hereinafter, a description will be given focusing on differences from the imaging apparatus according to the first embodiment. In the following description, the same parts as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  FIG. 11 is a flowchart of the focus adjustment process performed by the control device 3 according to the second embodiment. When the user performs a predetermined focus adjustment operation with an operation member (not shown), the control device 3 starts executing the focus adjustment process shown in FIG. For example, an operation member (not shown) is a shutter release button, and a focus adjustment operation is a half-press operation of the shutter release button.

  In step S100, the control device 3 performs photoelectric conversion control of the focus detection sensor 6 (FIG. 3). As photoelectric conversion control of the focus detection sensor 6, for example, exposure control of a plurality of focus detection pixels 60 (FIG. 3) arranged in the focus detection sensor 6, readout control of a plurality of focus detection signals, and / or a plurality of readout readouts. Amplification control of the focus detection signal is performed.

  In step S110, the control device 3 acquires a pair of focus detection signal strings based on the plurality of focus detection signals read in step S100. The control device 3 acquires a pair of corresponding focus detection signal sequences not only for the selection area 200 but also for all focus detection areas 410. A pair of corresponding focus detection signal sequences may be acquired for each of the focus detection areas 410 of all the focus detection areas 410.

  In step S120, the control device 3 calculates a defocus amount for each of the pair of focus detection signal sequences acquired in step S110. For example, the pair of focus detection signal sequences are {a [i]} and {b [j]}. The controller 3 sequentially changes the correlation amount C (k) while changing the interval between the pair of focus detection signal sequences {a [i]} and {b [j]} (shifting the phase relatively by a predetermined shift amount). Calculate. Here, k is a relative (phase) shift amount of the pair of focus detection signal sequences {a [i]} and {b [j]}. The control device 3 specifies the minimum value C (k) _min of the correlation amount C (k). The control device 3 acquires a specific shift amount X0 of the pair of focus detection signal sequences {a [i]} and {b [j]} that gives the minimum value C (k) _min. The control device 3 calculates a defocus amount as a focus detection amount parameter based on the shift amount X0.

  In step S500, the control device 3 executes the perspective conflict determination process of FIG. The content of the process is the same as that of the first embodiment, but the control device 3 of the present embodiment executes the perspective conflict determination process for all focus detection areas 410. With this processing, it is determined whether or not the focus detection area 410 is in a perspective conflict state for all focus detection areas 410. Note that the near / far conflict determination process may be executed for some of the focus detection areas 410 out of all the focus detection areas 410.

  In step S510, the control device 3 determines whether or not the focus detection area 410 determined to be in the perspective conflict state exists. If the determination is affirmative, the process proceeds to step S520. In step S520, the control device 3 selects one target area from the focus detection area 410 that is determined not to be in the perspective conflict state. For example, the focus detection area 410 having the smallest absolute value of the defocus amount is selected as the target area. Alternatively, the focus detection area 410 closest to the closest end is selected as the target area. Note that, in all of the focus detection areas 410 determined not to be in the perspective conflict state, the reliability of the calculated defocus amount is low, and if it is determined that focus detection is not possible, the target area is not selected. Thereafter, the process proceeds to step S200. In the case of negative determination in step S510, the process proceeds to step S530. In step S530, the control device 3 tries to select a target area from all the focus detection areas 410. Thereafter, the process proceeds to step S200.

  In step S200, the control device 3 determines whether or not a target area has been selected. If the determination is affirmative, the process proceeds to step S210. In step S210, the control device 3 calculates the lens driving amount of the imaging optical system 4 based on the defocus amount of the target area calculated in step S120. In step S220, the control device 3 transmits the lens driving amount calculated in step S210 to the focus adjustment device 8. The control device 3 controls the focus adjustment device 8 so as to cause the focus adjustment device 8 to drive the lens of the imaging optical system 4 via the lens drive unit 5. When the process of step S220 is completed, this process ends. In the case of negative determination in step S200, the process proceeds to step S230. In step S230, the control device 3 performs a scanning operation. When the process of step S230 is completed, this process ends.

According to the embodiment described above, in addition to the function and effect of the first embodiment, the following function and effect can be obtained.
(9) The control device 3 detects, for each of the predetermined number of focus detection areas 410 out of the plurality of focus detection areas 410, that the focus detection areas 410 are in a perspective conflict state. The control device 3 performs focus adjustment based on a pair of focus detection signal sequences corresponding to focus detection areas 410 that are not in the perspective conflict state among the predetermined number of focus detection areas 410. Since it did in this way, focus adjustment can be accurately performed on the subject desired by the user.

(Third embodiment)
The image pickup apparatus according to the third embodiment performs focus adjustment in consideration of whether or not the subject is in the perspective competition state when performing subject tracking using a technique such as template matching. Hereinafter, a description will be given focusing on differences from the imaging apparatus according to the first embodiment. In the following description, the same parts as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  FIG. 12 is a flowchart of the focus adjustment process performed by the control device 3 according to the third embodiment. Prior to the focus adjustment process, the user designates one focus detection area 410 to be a focus adjustment target. The control device 3 uses the subject existing at the position of the focus detection area 410 designated by the user as a tracking target, and performs focus adjustment so that the partial subject is continuously in focus. When the user performs a predetermined focus adjustment operation using an operation member (not shown), the control device 3 repeatedly executes the focus adjustment process shown in FIG. For example, an operation member (not shown) is a shutter release button, and a focus adjustment operation is a half-press operation of the shutter release button. The control device 3 repeatedly executes the focus adjustment process shown in FIG. 12 while the half-press operation is continued.

  In step S <b> 100, the control device 3 performs photoelectric conversion control of the focus detection sensor 6. As photoelectric conversion control of the focus detection sensor 6, for example, exposure control of a plurality of focus detection pixels 60 arranged in the focus detection sensor 6, read control of a plurality of focus detection signals, and / or a plurality of read focus detection signals. Amplification control is performed.

  In step S110, the control device 3 acquires a pair of focus detection signal strings based on the plurality of focus detection signals read in step S100. The control device 3 acquires a pair of corresponding focus detection signal sequences not only for the selection area 200 but also for all focus detection areas 410.

  In step S120, the control device 3 calculates a defocus amount for each of the pair of focus detection signal sequences acquired in step S110. For example, the pair of focus detection signal sequences are {a [i]} and {b [j]}. The controller 3 sequentially changes the correlation amount C (k) while changing the interval between the pair of focus detection signal sequences {a [i]} and {b [j]} (shifting the phase relatively by a predetermined shift amount). Calculate. Here, k is a relative (phase) shift amount of the pair of focus detection signal sequences {a [i]} and {b [j]}. The control device 3 specifies the minimum value C (k) _min of the correlation amount C (k). The control device 3 acquires a specific shift amount X0 of the pair of focus detection signal sequences {a [i]} and {b [j]} that gives the minimum value C (k) _min. The control device 3 calculates a defocus amount as a focus detection amount parameter based on the shift amount X0.

  In step S500, the control device 3 executes the perspective conflict determination process of FIG. The content of the process is the same as that of the first embodiment, but the control device 3 of the present embodiment executes the perspective conflict determination process for all focus detection areas 410. With this processing, it is determined whether or not the focus detection area 410 is in a perspective conflict state for all focus detection areas 410.

  In step S600, the control device 3 determines whether or not the tracking operation has been started. A negative determination is made when the focus adjustment process is executed for the first time, and an affirmative determination is made when the focus adjustment process is executed for the second time and thereafter. If the determination is negative, the process proceeds to step S610. In step S610, the control device 3 executes an initial tracking process of FIG. By the initial tracking process, a tracking area and a search area are determined in the imaging screen. The tracking area is an area indicating a part of the subject image specified for tracking the subject. The search area is an area indicating a range in which a subject image is searched when the tracking area is updated. Thereafter, the process proceeds to step S630. If the determination is affirmative in step S600, the process proceeds to step S620. In step S620, the control device 3 executes a tracking calculation process of FIG. The tracking area and the search area are updated by the tracking calculation process. Thereafter, the process proceeds to step S630.

  In step S630, the control device 3 calculates whether the focus detection is successful in at least one focus detection area 410 of the focus detection area 410 at least partially overlapping with the tracking region, that is, a reliable defocus amount is calculated. It is determined whether or not it has been done. If the determination is negative, the process proceeds to step S660. In step S660, the control device 3 selects the previous target area as a new target area. Note that in the previous selection area, when the reliability of the calculated defocus amount is low and it is determined that focus detection is not possible, the target area is not selected. Thereafter, the process proceeds to step S200. In step S630, if the determination is affirmative, the process proceeds to step S640.

  In step S640, the control device 3 determines whether or not the calculated defocus amount is within a predetermined range in at least one focus detection area 410 among the focus detection areas 410 at least partially overlapping with the tracking region. judge. The predetermined range is, for example, a range in which the subject can move back and forth of the imaging apparatus 100 during a focus detection cycle (for example, 1/60 second). That is, the determination in step S640 is a determination for confirming whether or not the subject that has been subject to focus adjustment has deviated from the tracking region when performing repeated focus detection. Note that this determination is always affirmative at the first focus detection. If the determination is affirmative, the process proceeds to step S650. In step S650, the control device 3 selects a target area from the focus detection area 410 in which the calculated defocus amount is within a predetermined range among the focus detection areas 410 that overlap at least partially with the tracking area. . Thereafter, the process proceeds to step S200. In the case of negative determination in step S640, the process proceeds to step S660.

  In step S200, the control device 3 determines whether or not a target area has been selected. If the determination is affirmative, the process proceeds to step S210. In step S210, the control device 3 calculates the lens driving amount of the imaging optical system 4 based on the defocus amount of the target area calculated in step S120. In step S220, the control device 3 transmits the lens driving amount calculated in step S210 to the focus adjustment device 8. The control device 3 controls the focus adjustment device 8 so as to cause the focus adjustment device 8 to drive the lens of the imaging optical system 4 via the lens drive unit 5. When the process of step S220 is completed, this process ends. In the case of negative determination in step S200, the process proceeds to step S230. In step S230, the control device 3 performs a scanning operation. When the process of step S230 is completed, this process ends.

  FIG. 13 is a flowchart of the initial tracking process called from step S610 of FIG. In step S <b> 700, the control device 3, among the sensor outputs (image outputs) from the focus detection sensor 6, an image of a region corresponding to the focus adjustment area 410 designated as a focus adjustment target by the user, that is, a tracking target. Stores subject color information. In step S710, the control device 3 detects the same color area having the same color information as the color information stored in step S700 in the peripheral portion of the focus adjustment area 410 designated as the focus adjustment target by the user. In step S720, the control device 3 determines the detected same color area as the tracking area. In step S730, the control device 3 stores the image of the tracking region in the sensor output (image output) from the focus detection sensor 6 as a template image used for the subsequent tracking processing. In step S740, the control device 3 determines an area obtained by enlarging the tracking area up, down, left, and right by a predetermined amount as a search area.

  FIG. 14 is a flowchart of the tracking calculation process called from step S620 of FIG. In step S800, the control device 3 performs a so-called template difference calculation. That is, an area having the same size as the template image is sequentially cut out from the search area of the sensor output (image output) from the focus detection sensor 6, the cut-out image and the template image are compared, and the difference in color information for each pixel. Is calculated. In step S810, the control device 3 searches for an area with the smallest difference in color information, and determines that area as a new tracking area. Here, the image information of the template image may be updated using the image information of the new tracking area. In step S820, the control device 3 sets, as a search area, an area obtained by enlarging a new tracking area by a predetermined amount vertically and horizontally.

  Note that the subject tracking process in FIGS. 13 and 14 described above can be performed not on the sensor output (image output) from the focus detection sensor 6 but on the output from the image sensor 2.

According to the embodiment described above, in addition to the function and effect of the first embodiment, the following function and effect can be obtained.
(10) The control device 3 functions as a tracking area setting unit that sets an area where the main subject exists in the imaging screen as a tracking area. The control device 3 functions as a tracking unit that tracks the main subject based on the image output corresponding to the tracking area. The control device 3 detects, for each of the focus detection areas 410 located in the tracking region among the plurality of focus detection areas 410, that the focus detection area 410 is in a perspective conflict state. The control device 3 performs focus adjustment based on a pair of focus detection signal sequences corresponding to the focus detection area 410 that is not in the perspective competition state among the focus detection areas 410 located in the tracking region. Since it did in this way, focus adjustment can be performed at a position closer to the center position (center of gravity position) of the subject to be tracked.

  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.

(Modification 1)
The perspective conflict determination process shown in FIG. 7 is an example, and the perspective conflict state may be detected by a process different from this. For example, if the difference between the maximum luminance values is not equal to or greater than the predetermined amount, that is, if a negative determination is made in step S360, the processing of step S370 and step S380 is not executed, and the process immediately proceeds to step S400. Also good.

(Modification 2)
In the above-described embodiment, as illustrated in FIG. 6, an example in which two subject images are included in the focus detection area 410 has been described. However, even if three or more subject images are included in the focus detection area 410. Good. In this case, for example, in step S340 of FIG. 7, the pair of focus detection signal sequences may be divided into three or more pairs of partial signal sequences.

(Modification 3)
The method of dividing the pair of focus detection signal sequences may be different from the above-described embodiment. For example, the control device 3 calculates differential values of the plurality of differences 671. The differential value is calculated by calculating the difference between the absolute values | a [i] −b [j] | between two adjacent focus detection pixel positions in the horizontal direction in the selected area 200. Obtained over a full range of 1 to 46.

  As described above, referring to FIG. 10, in the entire section 300 in the horizontal direction of the focus detection area 200, the section 320 corresponding to the background subject image 210 including the above-described tree is within the selection area 200. The variation of the absolute value | a [i] −b [j] | of the difference with respect to the change in the focus detection pixel position in the horizontal direction is generally small. Therefore, the magnitude of the differential value in this section 320 is less than a predetermined value close to zero. In the section 310 corresponding to the human subject image 220 described above, the absolute value | a [i] −b [j] | of the difference every time the focus detection pixel position in the horizontal direction within the selection area 200 increases by one pixel. Has increased or decreased dramatically. Therefore, the magnitude of the differential value in this section 310 is not less than the predetermined value described above. That is, in step S340 of FIG. 7, the control device 3 determines the differential value that is the difference between the absolute values | a [i] −b [j] | adjacent to each other in the plurality of differences 671 obtained in step S320. A pair of focus detection signal sequences 655a and 655b based on whether or not the magnitude of the image is less than a predetermined value, a pair of partial signal sequences corresponding to the subject image 220 of a person located near the imaging device 100, and The image may be divided into a pair of partial signal sequences corresponding to the background subject image 210 including a tree located far from the imaging device 100.

(Modification 4)
In step S310 of FIG. 7 of the embodiment described above, the control device 3 determines whether the brightness of the entire subject image including the background subject image 210 including the tree and the person subject image 220 is darker than the predetermined brightness. Determine whether. As described above, in the case where the brightness of the entire subject image is darker than the predetermined brightness, noise superimposed on the focus detection signal is also amplified. Therefore, in step S320, a plurality of processes are not performed in step S310. When the difference is obtained, the absolute value | a [i] −b of the difference indicating a value equal to or higher than the average value is obtained in the focus detection pixel positions 14 to 46 corresponding to the background subject image 210 including the tree in FIG. [J] | is included. Therefore, the control device 3 does not perform the process of step S310, but in step S320, the absolute value | a [i] −b of the difference indicating a value equal to or greater than the average value over the entire section 300 in the horizontal direction of the selected area 200. If it is determined that [j] | exists, this processing may be advanced to step S400.

(Modification 5)
As shown in FIG. 1, not only the focus detection device 50 having the focus detection sensor 6 covered with the microlens array 9, but also reflected by the submirror 70 after passing through the half mirror 7 and passed through the re-imaging optical system 17. The present invention is also applicable to a focus detection device 50 having a focus detection sensor 16 that is a focus detection unit that receives a light beam, and a focus detection device 50 having an image sensor 2 including a focus detection sensor covered with a microlens array 19. Can do.

  FIG. 15 shows a focus detection device 50 having a focus detection sensor 16 in which a plurality of focus detection pixels that receive a light beam that has passed through the half mirror 7 and is further reflected by the sub-mirror 70 and passed through the re-imaging optical system 17 are arranged. FIG. FIG. 16 is a diagram illustrating a configuration of the imaging apparatus 100 including the focus detection apparatus 50 having the imaging element 2 including the focus detection sensor covered with the microlens array 19. That is, in the imaging device 2 covered with the microlens array 19, a plurality of focus detection pixels that generate a plurality of focus detection signals and a plurality of imaging pixels that generate a plurality of imaging signals are mixedly arranged. ing. In FIG. 15 and FIG. 16, portions denoted by the same reference numerals as those in FIG. 1 are the same as those of the imaging device 100 shown in FIG.

  In the imaging apparatus 100 illustrated in FIG. 16, the magnitude of ISO sensitivity at the time of imaging processing by the imaging element 2 may be used as the brightness determination index in step S <b> 310 of FIG. 7. When the ISO sensitivity is less than the predetermined value, the control device 3 determines that the brightness of the entire subject image is not darker than the predetermined brightness, that is, a negative determination is made in step S310.

  FIG. 17 is a front view showing a detailed configuration of the image sensor 2 of FIG. 16, and shows an enlarged vicinity of one of a plurality of focus detection areas on the image sensor 2. FIG. 17 shows a layout of the imaging pixel 310 and the focus detection pixel 311. In FIG. 17, the imaging pixels 310 and the focus detection pixels 311 are densely arranged in a two-dimensional square lattice. The focus detection pixels 311 are continuously arranged in two horizontal pixel rows, and form two focus detection pixel columns L1 and L2 adjacent to each other.

  As shown in FIG. 17, the focus detection pixel rows L1 and L2 are formed by disposing the focus detection pixels 311 in a part of the two-dimensional array of the image pickup pixels 310 in place of the image pickup pixels 310. . By adding the output data of the pair of photoelectric conversion units 213 and 214 included in the focus detection pixel 311, data equivalent to the output data of the photoelectric conversion unit 11 of the imaging pixel 310 can be obtained, as shown in FIG. All the pixels of the image sensor 2 can be used as the focus detection pixels 311. FIG. 18 shows an arrangement of the focus detection pixels 311 when a part of the image sensor 2 is enlarged. A Bayer array color filter is arranged in each focus detection pixel 311.

  The focus detection pixel 311 has been described as including a pair of photoelectric conversion units 213 and 214. However, as illustrated in FIG. 19, the focus detection pixel rows L1 and L2 include a focus detection pixel 313 having only one photoelectric conversion unit 213 of the pair of photoelectric conversion units 213 and 214, and a pair of photoelectric conversion units 213. , 214, the focus detection pixels 314 having only the other photoelectric conversion unit 214 may be alternately arranged.

  Note that although two focus detection pixel columns L1 and L2 are provided, only one focus detection pixel column or three or more focus detection pixel columns may be provided.

  Note that the imaging apparatus including the focus detection apparatus according to the present embodiment is not limited to the imaging apparatus 100 as described above. For example, the present embodiment can also be applied to a focus detection device included in a lens-integrated digital still camera, film still camera, or video camera. Furthermore, the present embodiment is also applied to a focus detection device included in a small camera module built in an electronic device such as a mobile phone, a smart phone, or a tablet PC, a visual recognition device for a surveillance camera or a robot, or an in-vehicle camera. it can. In particular, when the present embodiment is applied to a small camera module, it is preferable to use the image sensor 2 including the focus detection sensor described above in order to reduce the number of components.

  You may combine embodiment and the modification which were mentioned above. The present invention is not limited to the above-described embodiments and modifications as long as the characteristics of the present invention are not impaired, and other forms conceivable within the scope of the technical idea of the present invention are also within the scope of the present invention. included.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element, 2 ... Imaging device, 3 ... Control apparatus, 4 ... Imaging optical system, 5 ... Lens drive part, 6 ... Focus detection sensor, 7 ... Half mirror, 8 ... Focus adjustment apparatus, 9 ... Micro lens array DESCRIPTION OF SYMBOLS 10 ... Optical axis, 15 ... Memory | storage device, 16 ... Focus detection sensor, 17 ... Re-imaging optical system, 19 ... Micro lens array, 50 ... Focus detection apparatus, 70 ... Submirror

Claims (17)

A plurality of light receiving units that receive light beams that have passed through different pupil regions of the optical system, respectively, with a plurality of pixels;
A detection unit that detects a focus state of the optical system based on a shift of an image of the different pupil region received by the light receiving unit;
Have
The focus detection device that detects a focus state of the optical system based on a shift of an image of the different pupil region received by the light receiving unit other than the light receiving unit that has received a plurality of images having different shifts. The focus detection apparatus according to claim 1,
The focus detection apparatus, wherein the detection unit uses the light receiving unit that has received a plurality of images having different deviations by a predetermined value or more as the light receiving unit that has received a plurality of images having different deviations. The focus detection apparatus according to claim 1 or 2,
The said detection part is a focus detection apparatus which light-receives the several image from which the said shift | offset | difference is received by receiving the light beam from the several subject from which the distance from the said optical system differs. The focus detection apparatus according to claim 3,
The focus detection apparatus, wherein the detection unit uses a light receiving unit that receives light beams from a plurality of subjects whose difference in distance from the optical system differs by a predetermined value or more as the light receiving unit that receives a plurality of images having different displacements. In the focus detection apparatus according to any one of claims 1 to 4,
A focus detection unit having the light receiving unit;
The focus detection device, wherein the plurality of pixels of the light receiving unit are a plurality of focus detection pixels provided in the focus detection unit. In the focus detection apparatus according to any one of claims 1 to 4,
A focus detection apparatus in which the light receiving unit is provided in an image sensor that outputs image data upon incidence of a light beam that has passed through the optical system. The focus detection apparatus according to claim 6,
The imaging element has a plurality of imaging pixels and a plurality of focus detection pixels,
The focus detection device, wherein the plurality of pixels of the light receiving unit are the plurality of focus detection pixels included in the image sensor. The focus detection apparatus according to claim 6,
The image sensor has a plurality of focus detection pixels having a pair of photoelectric conversion units,
The focus detection device, wherein the plurality of pixels of the light receiving unit are the plurality of focus detection pixels included in the image sensor. In the focus detection apparatus according to any one of claims 1 to 8,
The focus detection apparatus, wherein the detection unit detects a shift of an image for each pupil region based on signals output from a plurality of pixels that receive light beams that have passed through the different pupil regions. The focus detection apparatus according to claim 9, wherein
The detection unit divides the plurality of pixels of the light receiving unit based on image shifts for the different pupil regions, and calculates the focal point of the optical system obtained by a signal output for each of the collected pixels. The focus detection apparatus which detects whether the said light-receiving part received the several image from which the said shift | offset | difference differs from the state. The focus detection apparatus according to claim 9 or 10,
The detection unit receives a plurality of images having different deviations based on a correlation amount and a signal intensity of signals output from a plurality of pixels that receive the respective light beams that have passed through the different pupil regions. Focus detection device that detects whether or not In the focus detection apparatus according to any one of claims 1 to 11,
A focus detection apparatus comprising: a signal generation unit that generates a signal for adjusting a focus of the optical system based on a focus state of the optical system detected by the detection unit. The focus detection apparatus according to claim 12,
When the signal generating unit receives a plurality of images with different deviations, at least one of the plurality of light receiving units receives a light beam received by the light receiving unit from a distance from the optical system. However, the focal point for generating a signal for adjusting the focal point of the optical system based on the deviation of the images of the different pupil regions received by the light receiving unit shorter than the light receiving unit receiving the plurality of images having different deviations. Detection device. The focus detection apparatus according to claim 12,
The signal generation unit detects whether or not a plurality of images having different deviations are received for each of a predetermined number of light receiving units of the plurality of light receiving units, and of the predetermined number of light receiving units The focus detection apparatus which produces | generates the signal which adjusts the focus of the said optical system based on the shift | offset | difference of the image of the said different pupil area | region of the said light-receiving parts other than the said light-receiving part which received the several image from which the said difference | shift differs. The focus detection apparatus according to claim 12,
For each of the light receiving units for detecting an image of each pupil region of a main subject imaged by the optical system among the plurality of light receiving units, it is detected whether or not a plurality of images having different deviations are received.
The signal generation unit generates a signal for adjusting the focal point of the optical system based on a shift of the images of the different pupil regions received by a light receiving unit that does not receive a plurality of images having different shifts;
A focus detection apparatus that changes the light receiving unit that detects an image of each pupil region of the main subject in accordance with the movement of the main subject when the main subject moves.   An imaging apparatus comprising the focus detection device according to claim 12, wherein the focus of the optical system is adjusted by a signal generated by a signal generation unit of the focus detection device.   An electronic apparatus comprising the focus detection device according to any one of claims 12 to 15, wherein the focus of the optical system is adjusted by a signal generated by a signal generation unit of the focus detection device.

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