JP2020073971A - Imaging device - Google Patents

Abstract

To solve a problem that, in a technology for adjusting a focus by using a region of a part of an AF sensor when images of a plurality of subjects different in distances from a camera are included in images of subjects which are detected by a phase-difference AF type AF sensor, a focus is not adjusted to a desired position.SOLUTION: A focus detection device has a plurality of light receiving parts for receiving light fluxes passing pupil areas different in optical systems by a plurality of pixels, respectively, and a detection part for detecting focus states of the optical systems on the basis of the displacement of images of the different pupil areas which are light-received by the light receiving parts. The detection part detects the focus states of the optical systems on the basis of the displacement of the images of the different pupil areas which are light-received by the light receiving parts other than the light receiving parts which have light-received the plurality of images different in the displacement.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an imaging device.

  When the images of the subject detected by the phase-difference AF-type AF sensor include images of a plurality of subjects at different distances from the camera (referred to as perspective competition), focus adjustment is performed using a part of the AF sensor. Technology is known (for example, Patent Document 1).

JP, 2013-29803, A

  The conventional technique has a problem that the focus may not be adjusted to a desired position.

  According to the first aspect of the present invention, an image pickup device picks up an image of a subject formed by an optical system and outputs a signal, and a plurality of regions preset in a range picked up by the image pickup device. And a calculation unit that calculates a deviation value between the image and an imaging surface that captures the image for each area, and a plurality of images having different deviation values in the area for each area. Based on a value relating to the deviation calculated in the area other than the area determined to have a plurality of images with different deviation values in the determination section And a control unit that gives an instruction to move the optical system so that the image of the optical system is focused on the imaging surface.

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 overlaps and shows an imaging screen and several focus detection areas. It is a figure which shows a microlens 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 flow chart of focus adjustment processing performed by a control device. It is a figure showing an example in which two subject images are contained in a focus detection area. It is a flowchart of a near-far conflict determination process performed by the control device. 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 sequences relatively by the specific shift amount which gives the minimum value of the amount of correlation of a pair of focus detection signal sequences. It is a figure for demonstrating the division process of a pair of focus detection signal sequence. It is a flow chart of focus adjustment processing performed by a control device. It is a flow chart of focus adjustment processing performed by a control device. It is a flow chart of first time tracking processing performed by a control device. It is a flow chart of tracking calculation processing performed by a control device. 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 sensor. It is a front view which shows the detailed structure of an image sensor. It is a front view which shows the detailed structure of an image sensor.

(First embodiment)
FIG. 1 is a diagram showing a configuration of an image pickup apparatus 100 according to the first embodiment. The image pickup apparatus 100 includes a focus detection device 50, a liquid crystal display element 1, an image pickup element 2, an image pickup 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, which is a focus detection unit, a microlens array 9, and a control device 3.

  The imaging optical system 4 forms a subject 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 of 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 flux 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 rest of the incident light flux that has not been reflected. The reflected light flux reflected by the half mirror 7 passes through the microlens array 9 and enters the focus detection sensor 6. The transmitted light flux 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 arranged on the image plane of the imaging optical system 4. The position of the microlens array 9 is optically equivalent to the position of the image pickup surface of the image pickup 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 according to the received light flux. 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, read control of a plurality of focus detection signals, and / or amplification control of a plurality of read focus detection signals. The pair of focus detection signal strings 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 the shift amount (phase difference amount) of the pair of focus detection signal sequences. The control device 3 calculates the defocus amount from the detected shift amount. The control device 3 calculates the lens drive 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 drive amount to the focus adjustment device 8. The focus adjusting device 8 drives the focus adjusting lens of the imaging optical system 4 by the received lens driving amount via the lens driving unit 5.

  During the image capturing process, the half mirror 7 jumps up so as to cover the focus detection sensor 6 and retracts from the optical path. After retracting the half mirror 7, all the incident light flux that has passed through the image pickup optical system 4 enters the image pickup element 2. A subject image is formed on the light receiving surface of the image sensor 2. In the image pickup element 2, a plurality of image pickup pixels are arranged two-dimensionally. Each of the plurality of imaging pixels receives the incident light flux and performs photoelectric conversion. The plurality of image pickup pixels generate a plurality of electrical image pickup signals corresponding to the subject image formed by the image pickup optical system 4. The image pickup device 2 outputs the generated plurality of image pickup signals to the control device 3.

  The control device 3 generates image data of a subject image based on the plurality of image pickup signals output by the image pickup element 2. The control device 3 causes the liquid crystal display element 1 to display an image based on the generated image data as a through image. The control device 3 records the generated image data in the storage device 15 at the time of the image capturing process executed according to the image capturing instruction from the user.

  FIG. 2 is a schematic diagram illustrating an image pickup screen 400 and a plurality of focus detection areas 410 in an overlapping manner. The image pickup screen 400 is provided with 25 focus detection areas 410 in total, 5 in length × 5 in width, in advance. In FIG. 2, the focus detection areas 410 are independent of 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 units of the focus detection sensor 6 can generate, for each of the plurality of focus detection areas 410, a pair of focus detection signal sequences corresponding to the partial subject image in the focus detection area 410. In the following description, the pair of focus detection signal sequences corresponding to the partial subject image in the specific focus detection area 410 will be simply referred to as the 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 covering the focus detection sensor 6. FIG. 3A shows an enlarged view of the focus detection sensor 6 and the microlens array 9 near 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 shown as a spherical shape, it may be a hexagonal shape 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 of the microlens array 9 are overlapped when viewed from directly above the microlens array 9. In the example of FIG. 3B, a plurality of focus detection pixels 60 each including 5 pixels in the vertical direction and 5 pixels in the horizontal direction correspond to each microlens 90. The light flux reflected by the half mirror 7 (FIG. 1) passes through the microlens array 9 and enters the focus detection sensor 6. The light flux that has passed through each microlens 90 is received by a plurality of focus detection pixels 60 corresponding to each microlens 90, which has a total of 25 pixels of 5 pixels in the vertical direction × 5 pixels in the horizontal direction. The plurality of focus detection pixels 60 convert incident light into electrical focus detection signals 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 showing a correspondence relationship between the plurality of focus detection pixels 60 and the microlens 90. 4A and 4B are plan views of the plurality of focus detection pixels 60 and the microlens 90. In the example shown in FIGS. 4A and 4B, the plurality of focus detection pixels 60 corresponding to each microlens 90 are 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 consisting of 25 pixels. The control device 3 defines a pair of focus detection pixel groups for each of the 25 focus detection pixels 60. The pair of focus detection pixel groups receives a pair of light fluxes of the light fluxes incident on the focus detection sensor 6 via the microlens array 9. The pair of focus detection pixel groups photoelectrically converts the pair of received light fluxes to generate a pair of electrical focus detection signal sequences corresponding to the subject image. In the example of the focus detection pixel 60 having a total of 25 pixels of 5 pixels in the vertical direction × 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 shown by hatching. ing. The pair of focus detection pixel groups 610a and 610b includes three focus detection pixels at the center among the five focus detection pixels included in each of the two vertical focus detection pixel rows located at both ends in the horizontal direction. It is a pixel.

  In the example of the focus detection pixel 60 having a total of 25 pixels of 5 pixels in the vertical direction × 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 shown by hatching. ing. The pair of focus detection pixel groups 620a includes five focus detection pixel rows, each of which is located at the left end of the horizontal plane of the drawing and a vertical focus detection pixel row adjacent to the vertical focus detection pixel row. Of the detection pixels, there are three central focus detection pixels. The pair of focus detection pixel groups 620b includes five focus points included in each of a vertical focus detection pixel row located at the right end in the horizontal plane and a vertical focus detection pixel row adjacent to the vertical focus detection pixel row. Of the detection pixels, there are three central focus detection pixels. As shown in FIG. 4B, in each of the pair of focus detection pixel groups 620a and 620b, three focus detection pixels arranged in the vertical direction are arranged adjacent to each other in two rows in the horizontal direction, so that a total of six focus points are formed. Includes detection pixels.

  FIGS. 4C and 4D show a total of 25 focus detection pixels 60 and microlenses 90 of 5 pixels in the vertical direction × 5 pixels in the horizontal direction shown in FIGS. 4A and 4B, respectively. FIG. 6 is a cross-sectional view of the plan view taken along dashed-dotted lines S1 and S2 that extend in the horizontal direction through a focus detection pixel located at the center of 25 focus detection pixels 60. In FIG. 4C, the pair of focus detection pixel groups 610 a and 610 b receives the pair of light fluxes 11 and 12 passing through the pair of pupil areas, which are different pupil areas of the imaging optical system 4, and the microlens 90, and photoelectrically converts them. The conversion generates a pair of electrical focus detection signals. FIG. 4A illustrates five combinations of 25 focus detection pixels 60 and microlenses 90. Therefore, there are 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. The two focus detection signal sequences thus obtained form a pair of focus detection signal sequences. Similarly, in FIG. 4D, the pair of focus detection pixel groups 620a and 620b receives the pair of light fluxes 13 and 14 passing through the pair of pupil regions of the imaging optical system 4 and the microlens 90, and is subjected to photoelectric conversion. An electric pair of focus detection signals are generated. In FIG. 4B, five combinations of the focus detection pixels 60 of 25 pixels and the microlenses 90 are illustrated, but the number of combinations is not limited to five, and 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 form 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 thus obtained or the defocus amount calculated based on the shift amount (phase difference). .. 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. 4D. Therefore, the size of the opening angle formed by the pair of light fluxes 11 and 12 shown in FIG. 4C is larger than the size of the opening angle formed by the pair of light fluxes 13 and 14 shown in FIG. 4D. In any case, the present embodiment has the operational effect described later, but the larger the opening angle, the more easily the difference in change in the focus detection signal value due to the perspective competition described later is detected. More preferably, a configuration having a large opening angle as shown in FIG. 4 (c) is adopted.

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

  Prior to the focus adjustment processing, the user designates one focus detection area 410 to be the target of focus adjustment 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 target for focus adjustment. In the following description, the focus detection area 410 designated by the user as the focus adjustment target is referred to as a selection area. When the user performs a predetermined focus adjustment operation using an operation member (not shown), the control device 3 starts execution of the focus adjustment processing shown in FIG. For example, the operation member (not shown) is a shutter release button, and the focus adjustment operation is a half-press operation of the shutter release button.

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

  In the following description, like the selection area 200 shown in FIG. 6, a focus detection area 410 that includes 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 near-far conflict state. ..

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

  In step S120, the control device 3 calculates the defocus amount for each of the pair of focus detection signal sequences acquired in step S110. For example, let a pair of focus detection signal sequences be {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]} (relatively shifting the phase 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 identifies the minimum value C (k) _min of the correlation amount C (k). The control device 3 acquires the 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 the defocus amount as the focus detection amount parameter based on the shift amount X0.

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

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

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

  In step S160, the control device 3 determines whether the defocus amount calculated in the selection area 200 is within the predetermined range. The predetermined range is, for example, a range in which the subject can move back and forth in the imaging device 100 during a focus detection cycle (for example, 1/60 second). That is, the determination in step S160 is a determination to confirm whether the subject that was the focus adjustment target is out of the selected area 200 when the focus detection is repeatedly performed. It should be noted that this determination is always a positive determination when the focus is detected for the first time. When this determination is a positive determination, this processing proceeds to step S170. In step S170, the control device 3 sets the selection area 200 as the target area. Then, the process proceeds to step S200. When a negative determination is made 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 during the previous focus adjustment is calculated, it is considered that the subject that was the focus adjustment target has deviated from the selection area 200, and the process proceeds to step S180. move on.

  In step S200, the control device 3 determines whether or not the target area is selected. When the determination is affirmative, the process proceeds to step S210. In step S210, the control device 3 calculates the lens drive 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 drive amount calculated in step S210 to the focus adjustment device 8. The control device 3 controls the focus adjusting device 8 so that the focus adjusting device 8 drives the lens of the imaging optical system 4 via the lens driving unit 5. When the process of step S220 is completed, this process ends. When a negative determination is made in step S200, the process proceeds to step S230. In step S230, the control device 3 performs a scan operation. When the process of step S230 is completed, this process ends.

  FIG. 7 is a flowchart showing details of the near-far conflict determination process performed by the control device 3 in step S130 of FIG. This process is a process of determining whether or not the selection area 200 is in the perspective conflict state. In step S300, the control device 3 determines whether the minimum value C (k) _min of the correlation amount C (k) specified during the calculation of the defocus amount is smaller than the predetermined threshold value 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 near-far conflict state, and ends this processing. When a negative determination is made in step S300, the process proceeds to step S310.

  As shown in FIG. 6, when the selected 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) Change the interval between the pair of focus detection signal sequences {a [i]} and {b [j]} by a specific shift amount (X0) that gives the minimum value C (k) _min of (shift relative phase) Even if it is made, the pair of focus detection signal strings {a [i]} and {b [j]} do not match in the entire focus detection area, and a partially non-matching interval occurs (see FIG. 8). Use later). Therefore, the minimum value C (k) _min of the correlation amount C (k) deviates from 0. On the contrary, in the focus detection area 200, when a background subject image including a tree located at a distance and a subject image of a person located nearby are not mixed, or a background object including a tree located at a distance is present. When the difference between the image and the image of the subject of a person located nearby is small from the image capturing apparatus 100, the minimum value C (k) _min of the correlation amount C (k) is the background including trees located far away. Compared with the case where the difference in distance from the image capturing apparatus 100 between the subject image of 1 and the subject image of a person located nearby is large, the value approaches 0. 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 the perspective conflict state.

  In step S310, the control device 3 determines whether or not the brightness of the subject image including the background subject image 210 including trees and the subject image including the person 220 is darker than a predetermined brightness in the selection area 200. .. If the determination is affirmative, that is, if the brightness of the subject image is darker than the predetermined brightness, amplification control may be performed with a large amplification degree for the focus detection signal in step S100 of FIG. When the amplification control is performed with a large amplification degree, the 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) does not become smaller than the predetermined threshold value C (k) _th is that noise is amplified, not because of the near-far conflict condition. Is considered to be. Therefore, the control device 3 advances the process to step S400. When 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 lower than the predetermined brightness, that is, a negative determination is made in step S310.

  In step S320, the control device 3 compares the pair of focus detection signal sequences {a [i]} and {b [j]} corresponding to the selected area 200 acquired in step S110 by a specific shift amount X0. A plurality of differences by sequentially calculating the absolute value | a [i] −b [j] | of the differences between the focus detection signals. That is, the control device 3 sets the absolute value of the difference between the focus detection signals | a [i] for the pair of focus detection signal sequences {a [i]} and {b [j]} that are shifted to have the highest correlation. -B [j] | is calculated. In step S330, the control device 3 calculates the average absolute value of the differences between the focus detection signals calculated in step S320.

  In step S340, the control device 3 compares the pair of focus detection signal sequences {a [i]} and {b [j]} corresponding to the selected area 200 acquired in step S110 by a specific shift amount X0. In a state of being shifted, a pair of partial signal sequences corresponding to a distant subject image (a background subject image 210 including a tree) and a pair of partial signal sequences corresponding to a near subject image (a human subject image 220). Is divided into two pairs of partial signal sequences. For example, the control device 3 calculates each of the plurality of differences obtained by sequentially calculating the absolute value of the difference | a [i] −b [j] | in step S320 and the average value calculated in step S330. The division process in step S340 is performed based on whether or not the above is true. Details will be described later with reference to FIG.

  In step S350, the control device 3 calculates the maximum value of the brightness 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 luminance value of the distant subject image (background subject image 210 including a tree) and the maximum luminance value of the near subject image (human subject image 220). In step S360, the control device 3 determines whether or not the difference between the maximum brightness values calculated in step S350 is equal to or more than a predetermined amount. In the affirmative determination, the process proceeds to step S390. In step S390, the control device 3 determines that the selected area 200 is in the near-far conflict state, and ends this processing. The affirmative determination made in step S360 means that the selected area 200 is considered to be in the near-far conflict state from the minimum value C (k) _min of the correlation amount C (k) and the brightness value. Is. In other words, both the correlation amount and the luminance value indicate that the selected area 200 is in the perspective conflict state. Therefore, the control device 3 determines that the selected area 200 is in the perspective conflict state. When a negative determination is made in step S360, the process proceeds to step S370.

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

  In step S380, the control device 3 determines whether the difference between the two defocus amounts D1 and D2 calculated in step S370 is equal to or more than a predetermined amount. In other words, in step S380, it is determined whether or not the two pairs of partial signal sequences respectively correspond to subjects that are separated by a certain amount or more. When the determination is affirmative, the process proceeds to step S390, and the control device 3 determines that the selection area 200 is in the perspective conflict state. When a negative determination is made in step S380, the process proceeds to step S370, and the control device 3 determines that the selected area 200 is not in the near-far conflict state.

  The negative determination in step S360 means that the selected area 200 is in the near-far conflict state from the minimum value C (k) _min of the correlation amount C (k), but is selected from the brightness value. That is, it is considered that the area 200 is not in the near-far conflict state. In other words, the correlation amount indicates that the selected area 200 is in the near-far 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 to more precisely determine whether or not the selected area 200 is in the perspective conflict state. When the defocus amounts D1 and D2 actually calculated have a difference of a predetermined amount or more, the control device 3 finally determines that the selected area 200 is in the near-far conflict state, and the defocus amounts D1 and D2 are close values. If so, it is determined that the selection area 200 is not in the near-far conflict state.

  FIG. 8 corresponds to the example of the image pickup screen 250 shown in FIG. 6, and a pair of focus detection signal strings {a [i] with respect to 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 graphs showing 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 the focus detection pixel positions 1 to 13 in the horizontal direction in the focus detection area 200 corresponds to the subject image 220 of the person located near the image pickup apparatus 100 shown in FIG. 6, and in this section, One focus detection signal train 655a of the pair of focus detection signal trains 655a and 655b is displaced to the left with respect to the other focus detection signal train 655b. In FIG. 8, the section 320 of the focus detection pixel positions 14 to 46 in the horizontal direction 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. 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 side with respect to the other focus detection signal sequence 655b.

  In FIG. 8, in a section corresponding to the subject image 220 of a person located at a position close to the image capturing apparatus 100, the focus detection signal sequence 655a is displaced to the left side with respect to the focus detection signal sequence 655b, and is located far from the image capturing apparatus 100. In the section corresponding to the background subject image 210 including a 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 difference between the focus detection signal sequences is that the distance of the person from the image capturing apparatus 100 and the distance of the background including the tree from the image capturing apparatus 100 are different. This is because there is a difference between the image shift of the different pupil regions due to the subject image of the person received in step S6 and the image shift of the different pupil regions due to the subject image of the background including the tree received by the light receiving portion of the focus detection sensor 6. ..

  In FIG. 8, as the image received by the light receiving unit of the focus detection sensor 6, a subject image of a person and a background subject image including a tree are taken as an example. However, the image received by the light receiving unit of the focus detection sensor 6 is a predetermined image. Any luminance may be used as long as it is based on a specific subject that has a luminance of 4 and a focus detection signal having a luminance change of a predetermined value or more as shown in FIG. The person shown in FIG. 8, animals other than trees, natural objects such as plants, and artificial objects such as cars, trains, and buildings may be used. Further, the number of specific subjects is not limited to one person in FIG. 8, and may be a plurality of person masses or a plurality of object masses such as a plurality of tree masses.

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

  In FIG. 8, when the correlation amount C (k) exhibits 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 trains 660a and 660b that are a pair of focus detection signal trains {a [i]} and {b [j]} are illustrated in FIG.

  FIG. 9 is a diagram relatively showing 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 8 focus detection signal sequences {a [i]} and {b [j]}. Since the contrast is higher in the section 320 corresponding to the background subject image 210 including trees than the section 310 corresponding to the person subject image 220 illustrated in FIG. 8, the correlation between the pair of focus detection signal sequences 655a and 655b is high. But higher. In that case, the specific shift amount X0 may be greatly affected by the subject image 210 of the background including the trees. Therefore, the specific shift amount X0 is relatively increased by the specific shift amount X0. ] 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 trees are detected. In the section 320, the pair of focus detection signal trains 660a and 660b may be close to a matched state. As shown in FIG. 9, in the section 310 of the focus detection pixel positions 1 to 13 in the horizontal direction in the focus detection area 200 corresponding to the human subject image 220, there is a gap between the pair of focus detection signal rows 660a and 660b. (Phase difference) has occurred. The entire horizontal section 300 of the focus detection area 200 is divided into a section 310 corresponding to the above-described subject image 220 of a person and a background subject image 210 including a tree between the focus detection pixel positions 13 and 14. A method of identifying the boundary 350 that divides the corresponding section 320 will be described with reference to FIG.

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

  In the entire horizontal section 300 of the focus detection area 200, in the section 320 corresponding to the subject image 210 of the background including the trees described above, the change of the horizontal focus detection pixel position in the focus detection area 200. The variation of the absolute value of the difference | a [i] -b [j] | In the section 310 corresponding to the human subject image 220 described above, the absolute value of the difference | a [i] -b [j] is increased each time the horizontal focus detection pixel position in the focus detection area 200 is increased by one pixel. | Has increased or decreased sharply. When the average value of the plurality of differences 671 over the entire section 300 in the horizontal direction of the focus detection area 200 is obtained, in the section 320 corresponding to the subject image 210 of the background including trees, the absolute value of the difference that is equal to or larger 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 of the difference | a [i] -b [j] indicating a value equal to or higher than the average value. There are many | Therefore, in FIG. 10, with respect to the change of the focus detection pixel position in the horizontal direction within the focus detection area 200, a section in which each of the plurality of differences 671 changes below the average value of the plurality of differences 671, that is, the focus The section between 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, which is the section on the opposite side of the section 320 across the boundary 350, can be specified as the section 310. Based on this result, in step S340 of FIG. 7, a pair of focus detection signal sequences 655a and 655b showing the current focus state are displayed in the range of focus detection pixel positions 1 to 13 corresponding to the human subject image 220. It can be divided into a pair of partial signal trains 310 and a pair of partial signal trains in the section 320 of the focus detection pixel positions 14 to 46 corresponding to the background subject image 210 including trees.

According to the above-described embodiment, the following operational effects can be obtained.
(1) The focus detection sensor 6 receives a pair of light fluxes 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 the selected area 200 among the plurality of focus detection areas 410 is based on a pair of focus detection signal sequences corresponding to the selection area 200, and the selection area 200 is in a near-far conflict state. It functions as a perspective conflict detection unit that detects that 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 when the selection area 200 is in the perspective conflict state. Since this is done, it is possible to provide a focus adjustment device in which focus adjustment is not performed on a subject not intended by the user.

(2) When the selection area 200 is not in the near-far conflict state, the control device 3 performs focus adjustment based on the pair of focus detection signal sequences corresponding to the selection area 200. Since this is done, it is possible to perform accurate focus adjustment for the subject desired by the user.

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

(4) The control device 3 estimates that the pair of focus detection signal sequences corresponding to the selection area 200 corresponds to the first pair of partial signal sequences estimated to correspond to the first subject and the second subject. Functioning 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 result of comparing 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 based on. Since it did in this way, a near-far race condition 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 the difference between the corresponding focus detection signals in the pair of focus detection signal sequences when the pair of focus detection signal sequences is relatively shifted by the shift amount (phase difference amount). Function as a department. The control device 3 divides the pair of focus detection signal sequences corresponding to the selected area 200 into two pairs of partial signal sequences based on the plurality of differences. When the first subject and the second subject are present in the selection area 200, the difference between the focus detection signals greatly differs between the subjects. It is possible to accurately divide into a pair of two 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 regarded from the correlation amount that it is apparently not in the perspective conflict state, the calculation amount can be suppressed low.

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

(8) When the selection area 200 is in the near-far conflict state, the control device 3 outputs a pair of focus detection signal strings indicating that the focus is ahead of the selection area 200 in the other focus detection areas 410. Focus adjustment is performed based on a pair of focus detection signal strings corresponding to the focus detection area 410. Since this is done, it is possible to precisely adjust the focus on the subject desired by the user.

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

  FIG. 11 is a flowchart of focus adjustment processing 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 execution of the focus adjustment processing shown in FIG. For example, the operation member (not shown) is a shutter release button, and the 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 the 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, read control of a plurality of focus detection signals, and / or read a plurality of read signals. Amplification control of the focus detection signal is performed.

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

  In step S120, the control device 3 calculates the defocus amount for each of the pair of focus detection signal sequences acquired in step S110. For example, let a pair of focus detection signal sequences be {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]} (relatively shifting the phase 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 identifies the minimum value C (k) _min of the correlation amount C (k). The control device 3 acquires the 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 the defocus amount as the focus detection amount parameter based on the shift amount X0.

  In step S500, the control device 3 executes the perspective competition determination process of FIG. The content of the processing is the same as that of the first embodiment, but the control device 3 of the present embodiment executes the perspective conflict determination processing for all the focus detection areas 410. Through this process, it is determined whether or not all the focus detection areas 410 are in the perspective competition state. The perspective conflict determination processing 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. When 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 areas 410 determined not to be in the perspective conflict state. For example, the focus detection area 410 with 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. If it is determined that the calculated defocus amount is low in reliability and focus detection is not possible in all the focus detection areas 410 determined not to be in the perspective conflict state, the target area is not selected. Then, the process proceeds to step S200. If a negative determination is made 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. Then, the process proceeds to step S200.

  In step S200, the control device 3 determines whether or not the target area is selected. When the determination is affirmative, the process proceeds to step S210. In step S210, the control device 3 calculates the lens drive 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 drive amount calculated in step S210 to the focus adjustment device 8. The control device 3 controls the focus adjusting device 8 so that the focus adjusting device 8 drives the lens of the imaging optical system 4 via the lens driving unit 5. When the process of step S220 is completed, this process ends. When a negative determination is made in step S200, the process proceeds to step S230. In step S230, the control device 3 performs a scan operation. When the process of step S230 is completed, this process ends.

According to the above-described embodiment, the following operation and effect can be obtained in addition to the operation and effect of the first embodiment.
(9) For each of the predetermined number of focus detection areas 410 among the plurality of focus detection areas 410, the control device 3 detects that the focus detection area 410 is in the perspective conflict state. The control device 3 performs focus adjustment based on a pair of focus detection signal sequences corresponding to the focus detection areas 410 out of the predetermined number of focus detection areas 410 that are not in the near-far conflict state. Since this is done, it is possible to precisely adjust the focus 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 there is a near-far conflict state or not when subject tracking is performed using a technique such as template matching. Hereinafter, differences from the image pickup apparatus according to the first embodiment will be mainly described. In the following description, the same parts as those in the first embodiment will be designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

  FIG. 12 is a flowchart of focus adjustment processing performed by the control device 3 according to the third embodiment. Prior to the focus adjustment processing, the user specifies one focus detection area 410 to be the focus adjustment target. The control device 3 sets a 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 focused. When the user performs a predetermined focus adjustment operation with an operation member (not shown), the control device 3 repeatedly executes the focus adjustment processing shown in FIG. For example, the operation member (not shown) is a shutter release button, and the 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 S100, 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 sequences based on the plurality of focus detection signals read in step S100. The control device 3 acquires a pair of corresponding focus detection signal trains not only for the selection area 200 but also for all the focus detection areas 410.

  In step S120, the control device 3 calculates the defocus amount for each of the pair of focus detection signal sequences acquired in step S110. For example, let a pair of focus detection signal sequences be {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]} (relatively shifting the phase 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 identifies the minimum value C (k) _min of the correlation amount C (k). The control device 3 acquires the 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 the defocus amount as the focus detection amount parameter based on the shift amount X0.

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

  In step S600, the control device 3 determines whether the tracking operation has been started. A negative determination is made when the focus adjustment process is first executed, and an affirmative determination is made when the focus adjustment process is executed a second time or later. In the case of negative determination, the process proceeds to step S610. In step S610, the control device 3 executes the initial tracking process of FIG. 13 described later. By the first tracking process, the tracking area and the search area are defined in the imaging screen. The tracking area is an area showing a part of the subject image specified for tracking the subject. The search area is an area indicating a range in which the subject image is searched when the tracking area is updated. After that, the process proceeds to step S630. In the case of positive determination in step S600, the process proceeds to step S620. In step S620, the control device 3 executes the tracking calculation process of FIG. 14 described later. The tracking calculation process updates the tracking region and the search region. Then, the process proceeds to step S630.

  In step S630, the control device 3 has succeeded in focus detection in at least one focus detection area 410 of the focus detection areas 410 at least partially overlapping with the tracking area, that is, calculates a highly reliable defocus amount. It is determined whether it has been done. In the case of negative determination, the process proceeds to step S660. In step S660, the control device 3 selects the previous target area as a new target area. It should be noted that the target area is not selected when it is determined that the calculated defocus amount is low in reliability in the previously selected area and focus detection is not possible. Then, the process proceeds to step S200. In the case of positive determination in step S630, the process proceeds to step S640.

  In step S640, the control device 3 determines whether 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 area. judge. The predetermined range is, for example, a range in which the subject can move back and forth in the imaging device 100 during a focus detection cycle (for example, 1/60 second). That is, the determination in step S640 is a determination to confirm whether or not the subject targeted for focus adjustment is out of the tracking area when the focus detection is repeatedly performed. It should be noted that this determination is always a positive determination when the focus is detected for the first time. If this determination is affirmative, the process proceeds to step S650. In step S650, the control device 3 selects a target area from the focus detection areas 410 in which the calculated defocus amount is within a predetermined range among the focus detection areas 410 that at least partially overlap with the tracking area. .. Then, the process proceeds to step S200. In the case of a negative determination in step S640, the process proceeds to step S660.

  In step S200, the control device 3 determines whether or not the target area is selected. When the determination is affirmative, the process proceeds to step S210. In step S210, the control device 3 calculates the lens drive 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 drive amount calculated in step S210 to the focus adjustment device 8. The control device 3 controls the focus adjusting device 8 so that the focus adjusting device 8 drives the lens of the imaging optical system 4 via the lens driving unit 5. When the process of step S220 is completed, this process ends. When a negative determination is made in step S200, the process proceeds to step S230. In step S230, the control device 3 performs a scan 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 S700, the control device 3 selects, from 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. Memorize the color information of the subject. 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 by the user as the target of focus adjustment. 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 area in the sensor output (image output) from the focus detection sensor 6 as a template image used in the subsequent tracking processing. In step S740, control device 3 determines a region obtained by enlarging the tracking region vertically and horizontally by a predetermined amount as a search region.

  FIG. 14 is a flowchart of the tracking calculation process called from step S620 of FIG. In step S800, the control device 3 executes so-called template difference calculation. That is, an area of 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 obtained. Is calculated. In step S810, the control device 3 searches for an area having the smallest color information difference and determines the 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 a region obtained by expanding the new tracking region vertically and horizontally by a predetermined amount as a search region.

  Note that the subject tracking processing 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 above-described embodiment, the following operation and effect can be obtained in addition to the operation and effect of the first embodiment.
(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 that each of the focus detection areas 410 located in the tracking area among the plurality of focus detection areas 410 is in the perspective conflict state. The control device 3 performs focus adjustment based on a pair of focus detection signal sequences corresponding to the focus detection areas 410 that are not in the perspective conflict state among the focus detection areas 410 located in the tracking area. Since this is done, focus adjustment can be performed at a position closer to the center position (center of gravity position) of the tracking target object.

  The following modifications are also within the scope of the present invention, and it is possible to combine one or more modifications with the above-described embodiment.

(Modification 1)
The perspective competition 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, when the difference between the maximum brightness values is not equal to or more than the predetermined amount, that is, when the negative determination is made in step S360, the process of step S370 and step S380 is not executed and the process immediately proceeds to step S400. Good.

(Modification 2)
In the above-described embodiment, an example in which the focus detection area 410 includes two subject images as illustrated in FIG. 6 has been described, but the focus detection area 410 may include three or more subject images. 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 partial signal sequences and handled.

(Modification 3)
The method of dividing the pair of focus detection signal sequences may be different from that of the above-described embodiment. For example, the control device 3 calculates the differential value of the plurality of differences 671. The differential value is calculated by calculating a difference between absolute values | a [i] -b [j] | of two adjacent focus detection pixel positions in the horizontal direction in the selected area 200. It is obtained by carrying out over the entire 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, in the section 320 corresponding to the background subject image 210 including the trees described above, in the selection area 200. The variation of the absolute value of the difference | a [i] -b [j] | with respect to the change of the focus detection pixel position in the horizontal direction is substantially 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 subject image 220 of the person described above, the absolute value of the difference | a [i] -b [j] | is increased each time the horizontal focus detection pixel position in the selection area 200 is increased by one pixel. Is increasing and decreasing sharply. Therefore, the magnitude of the differential value in this section 310 is not less than the above-mentioned predetermined value. That is, in step S340 of FIG. 7, the control device 3 has the differential value that is the difference between absolute values | a [i] −b [j] | of the differences 671 that are adjacent to each other in the plurality of differences 671 obtained in step S320. On the basis of whether or not the size is smaller than a predetermined value, a pair of focus detection signal trains 655a and 655b is set to a pair of partial signal trains corresponding to a subject image 220 of a person located near the imaging device 100, and It may be divided into a pair of partial signal sequences corresponding to a 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 a tree and the subject image 220 of a person is lower than a predetermined brightness. To determine. As described above, when the brightness of the entire subject image is darker than the predetermined brightness, noise superimposed on the focus detection signal is also amplified, and thus the process of step S310 is not performed and a plurality of steps of step S320 are performed. When the difference is obtained, the absolute value of the difference | a [i] −b indicating a value equal to or larger than the average value is obtained in the section of the focus detection pixel positions 14 to 46 corresponding to the background subject image 210 including the tree in FIG. [J] | will be included. Therefore, the control device 3 does not perform the process of step S310, but in step S320, the absolute value of the difference | a [i] -b indicating a value equal to or higher than the average value over the entire section 300 in the horizontal direction of the selected area 200. When it is determined that [j] | exists, the process may proceed to step S400.

(Modification 5)
Not only the focus detection device 50 having the focus detection sensor 6 covered with the microlens array 9 shown in FIG. 1, but also after being transmitted through the half mirror 7, it is further reflected by the sub-mirror 70 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 which is a focus detection unit that receives a light flux, and a focus detection device 50 having an image sensor 2 including the focus detection sensor covered with the microlens array 19. You can

  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 been transmitted through the half mirror 7 and then reflected by the sub-mirror 70 and passed through the re-imaging optical system 17 is arranged. It is a figure which shows the structure of the imaging device 100 which has. FIG. 16 is a diagram showing a configuration of an image pickup apparatus 100 having a focus detection apparatus 50 having the image pickup element 2 including the focus detection sensor covered with the microlens array 19. That is, in the image pickup device 2 covered by the microlens array 19, a plurality of focus detection pixels that generate a plurality of focus detection signals and a plurality of image pickup pixels that generate a plurality of image pickup signals are arranged in a mixed manner. ing. In FIGS. 15 and 16, the parts denoted by the same reference numerals as those in FIG. 1 are the same as those in the image pickup apparatus 100 shown in FIG.

  In the image pickup apparatus 100 shown in FIG. 16, the magnitude of ISO sensitivity at the time of image pickup processing by the image pickup element 2 may be used as the brightness determination index in step S310 of FIG. 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 lower 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 is an enlarged view of one of the plurality of focus detection areas on the image sensor 2 in the vicinity thereof. FIG. 17 shows a layout of the image pickup 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 shape. The focus detection pixels 311 are continuously arranged in two pixel rows in the horizontal direction, and form two focus detection pixel columns L1 and L2 adjacent to each other.

  As illustrated in FIG. 17, the focus detection pixels 311 are arranged in a part of the two-dimensional array of the imaging pixels 310 by being replaced with the imaging pixels 310, thereby forming the focus detection pixel rows L1 and L2. .. By adding the output data of the pair of photoelectric conversion units 213 and 214 included in the focus detection pixel 311, it is possible to obtain the same data as the output data of the photoelectric conversion unit 11 of the imaging pixel 310, and as shown in FIG. It is also possible to use all the pixels of the image sensor 2 as the focus detection pixels 311. FIG. 18 shows the arrangement of the focus detection pixels 311 when a part of the image sensor 2 is enlarged, and each of the focus detection pixels 311 is provided with a Bayer array color filter.

  The focus detection pixel 311 has been described as having the pair of photoelectric conversion units 213 and 214. However, as shown 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.

  Although the two focus detection pixel rows L1 and L2 are described, the number of focus detection pixel rows may be only one or may be three or more.

  The image pickup apparatus including the focus detection apparatus according to this embodiment is not limited to the above-described image pickup apparatus 100. For example, the present embodiment can be applied to a focus detection device included in a lens-integrated digital still camera, a film still camera, or a video camera. Further, the present embodiment is also applied to a small camera module built in an electronic device such as a mobile phone, a smart phone, and a tablet PC, a visual recognition device for a surveillance camera or a robot, and a focus detection device included in an in-vehicle camera. it can. Particularly 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 parts.

  The above-described embodiments and modifications may be combined. 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 considered 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 element, 3 ... Control device, 4 ... Imaging optical system, 5 ... Lens drive part, 6 ... Focus detection sensor, 7 ... Half mirror, 8 ... Focus adjustment device, 9 ... Micro lens array 10 ... Optical axis, 15 ... Storage device, 16 ... Focus detection sensor, 17 ... Reimaging optical system, 19 ... Microlens array, 50 ... Focus detection device, 70 ... Submirror

Claims (6)

An image sensor that captures an image of a subject formed by an optical system and outputs a signal,
A plurality of regions set in advance in a range captured by the image sensor,
A calculation unit that calculates a value of a shift between the image and an imaging surface that captures the image, for each region;
For each of the areas, a determination unit that determines whether or not there are a plurality of images having different values of the shift in the area,
The image of the optical system is captured based on a value relating to the deviation calculated in the area other than the area in which the plurality of images having different deviation values are present in the area in the determination unit. A control unit for instructing to move the optical system so as to focus on a surface,
An imaging device having a. The imaging device according to claim 1,
When tracking the selected subject selected from the subjects, the control unit performs the determination by the determination unit for each of the plurality of regions existing in the range of the image of the selected subject, and the deviation value is Except for the region determined to have different images in the region, based on the values regarding the deviation calculated in the plurality of regions existing in the range of the image of the selected subject, the optical system Instructing to move the optical system so as to focus an image on the imaging surface,
Imaging device. The imaging device according to claim 1,
An operation unit for selecting a selected area from the plurality of areas,
When the control unit determines that a plurality of images having different shift values are present in the selected area, among the shift values calculated in the areas other than the selected area, the subject that is closest to the target is present. An instruction to move the optical system based on the shift value corresponding to
Imaging device. The imaging device according to any one of claims 1 to 3, wherein the determination unit is formed by light that has passed through different regions of the optical system in one of the regions on the imaging surface. Based on the value indicating the degree of coincidence of the shape of the image, it is determined whether or not there are a plurality of images with different shift values in the region,
Imaging device. The imaging device according to claim 4,
The determination unit determines whether or not there are a plurality of images with different shift values in the region, based on the brightness value of the image in the region of the imaging surface,
Imaging device. The imaging device according to claim 4 or 5,
The determination unit divides a signal output based on the image in the region of the imaging surface into a plurality of signals, and based on a difference in maximum value of each of the divided signals, the shift value within the region. Determines whether there are multiple images with different
Imaging device.

Images