JP5836761B2 - Focus adjustment apparatus and control method thereof - Google Patents

Description

  The present invention relates to a focus adjustment apparatus, and more particularly to a focus adjustment apparatus suitable for a camera having a subject tracking function and a control method thereof.

  2. Description of the Related Art Conventionally, a focus adjustment device using a phase difference detection method has been known that includes a plurality of focus detection positions. In this type of focus adjustment apparatus, a region of a subject to be tracked is set as a template image from an image output from a photometric sensor, and a position of an image similar to the template image is detected for each image captured continuously, There is one that selects a focus detection position corresponding to this (so-called subject tracking function).

  In the focus adjustment having such a subject tracking function, when the tracking subject is erroneously recognized or when focus detection becomes impossible at the focus detection position corresponding to the position of the tracking subject, the focus state is detected at the position of the tracking subject. You may not be able to. On the other hand, for example, Patent Document 1 proposes a method for detecting a focus state at a larger number of focus detection positions if all focus detection is impossible as a result of detection of focus states at a plurality of focus detection positions. .

JP 2009-265239 A

  However, the above-mentioned patent document 1 expands the focus detection position in a stepwise manner within the focus detection area where the focus state can be detected, and is optimal when the position of the tracking subject is detected outside the focus detection area. The focus detection position is not selected.

  The object of the present invention is to improve tracking performance by enabling the selection of the optimum focus detection position based on the position of the tracking subject even when the subject moves greatly or the subject moves out of the focus detection area due to camera shake or the like. Is to provide a focused focusing device.

In order to achieve the above object, the first invention of the present application includes a plurality of focus detection areas, and detects a focus state based on a relative positional shift amount in a division direction of a light beam from a subject that has passed through an imaging optical system. A focus detection unit, a photometric unit that divides a subject image formed by the imaging optical system into a plurality of photometric regions, and outputs photometric information for each of the photometric regions, and a photometric region corresponding to a specified tracking subject A photometric information similar to the photometric information of the extraction area held by the setting means, from a setting means for holding the photometric information of the extraction area and the photometric information subsequently output by the photometric means. Subject tracking means that sequentially detects the photometric area as a tracking subject position, and the focus detection means detects the tracking subject position detected by the subject tracking means as the focus detection area. If the tracking subject position detected by the subject tracking means is outside the focus detection region, focus detection is performed using the focus detection region corresponding to the tracking subject position. the have line focus detection using the focus detection area, after a predetermined time elapses, if lower than the reliability of the tracking threshold by the subject tracking unit, the setting means, and characterized by reconfiguring the extracted region Focusing device.

A second invention of the present application includes a focus detection step that includes a plurality of focus detection areas and detects a focus state based on a relative positional shift amount in a split direction of a light beam from a subject that has passed through the imaging optical system; The subject image formed by the system is divided into a plurality of photometric areas, and the photometric step for outputting the photometric information for each photometric area, and the photometric area corresponding to the specified tracking subject are set as the extraction areas, A photometric area having photometric information similar to the photometric information of the extraction area held in the setting step is set as a tracking subject position from the setting step of holding photometric information of the extraction area and the photometry information continuously output by the photometric step. Subject tracking step that sequentially detects, and in the focus detection step, the tracking subject position detected in the subject tracking step is If it is within the focus detection area, focus detection is performed using the focus detection area corresponding to the tracking subject position, and the tracking subject position detected in the subject tracking step is outside the focus detection area, There line focus detection using the focus detection area in the vicinity of the tracked object position, after a predetermined time has elapsed, if lower than the reliability threshold tracking by the object tracking step, in said setting step, resetting the extraction region A control method for a focus adjusting apparatus.

  According to the present invention, the tracking performance is improved by making it possible to select the optimum focus detection position based on the position of the tracking subject even when the subject moves greatly or the subject moves out of the focus detection area due to camera shake or the like. A focused focusing device can be provided.

It is a block diagram of the focus detection apparatus concerning this embodiment. It is a schematic diagram of a structure of the focus detection apparatus concerning this embodiment. It is a schematic diagram of the focus detection sensor and photometry sensor of the focus detection apparatus according to the present embodiment. It is a figure explaining the operation | movement flow of the focus detection apparatus in connection with this embodiment. It is a figure explaining the flow of the subject tracking process of the focus detection apparatus concerning this embodiment. It is a figure explaining the subject tracking process of the focus detection apparatus concerning this embodiment. It is a figure explaining the subject tracking process of the focus detection apparatus concerning this embodiment. It is a figure explaining the flow of the setting of the focus detection position of the focus detection apparatus concerning this embodiment. It is a figure explaining the flow of the setting of the extraction area | region in connection with this embodiment. It is a figure explaining the setting of the focus detection position of the focus detection apparatus concerning this embodiment, and the setting of an extraction area | region. It is a figure explaining the setting of the focus detection position of the focus detection apparatus concerning this embodiment, and the setting of an extraction area | region.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a block diagram of a camera 100 (focus detection apparatus) according to an embodiment of the present invention.

  In FIG. 1, an image sensor 107 is a CCD, a CMOS sensor, or the like that forms a subject optical image that has passed through the imaging optical system 101. The image sensor 107 includes a plurality of pixels, photoelectrically converts a subject image formed by the imaging optical system 101, and outputs an imaging signal. The aperture shutter 110 adjusts the amount of light incident on the camera 100 main body. The shutter 111 adjusts the exposure time of the image sensor 107.

  FIG. 1 shows a state where the main mirror 102 is inserted in the imaging light beam (mirror down). The main mirror 102 having the semi-transmissive portion is retracted out of the photographing light beam at the time of photographing, and is obliquely installed in the photographing light beam (in the optical path) at the time of detecting the focus. The main mirror 102 is a finder optical system that includes a focus plate 103, a pentaprism 104, and an eyepiece lens 105 for a part of the light beam that has passed through the imaging optical system 101 while being inclined in the photographing light beam. Lead to. The luminous flux enters the photometric optical system 109, and the luminance signal and color difference signal of the subject optical image that has passed through the imaging optical system 101 are detected.

  The sub mirror 106 is configured to be foldable and unfoldable with respect to the main mirror 102 in synchronization with the operation of the main mirror 102. A part of the light beam that has passed through the semi-transmissive portion of the main mirror 102 is reflected downward by the sub-mirror 106 and enters the phase difference type distance measuring optical system 108, and the focus state of the imaging optical system 101 is detected.

  Next, functions of the camera 100 according to the embodiment of the present invention will be described with reference to the schematic diagrams of FIGS. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals. In FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals.

  The system control unit 201 includes a CPU that controls the entire camera 100, a RAM that is a storage device, and the like, and appropriately controls the operation of each unit described later such as the AF control unit 202. The AF control unit 202 is connected to the system control unit 201 and drives the focus detection sensor 203 provided in the distance measuring optical system 108. The focus detection sensor 203 includes a pair of line sensors 302 corresponding to the arrangement of the 61 focus detection positions 301 shown in FIG. The AF control unit 202 converts the light flux from the subject incident through the sub mirror 106 into an electric signal, and the focus detection position corresponding to each line sensor based on the shift amount of the pair of image signals in the division direction of the light flux. Calculate the defocus amount.

  The AE control unit 204 is connected to the system control unit 201 and drives a photometric sensor 205 provided in the photometric optical system 109. The photometric sensor 205 is divided into a plurality of photometric areas shown in FIG. 3B, and is composed of a plurality of pixels that detect RGB components in each photometric area 303. The AE control unit 204 converts the light beam of the subject optical image that has passed through the imaging optical system 101 into an electrical signal, reads photometric image data, performs automatic exposure calculation based on this data, and outputs the result to the system control unit 201. To do. The system control unit 201 controls the aperture of the aperture shutter 110 based on the result of the automatic exposure calculation output from the AE control unit 204, and adjusts the amount of light that enters the camera body. Further, the AE control unit 204 controls the shutter 111 at the time of release to adjust the exposure time of the image sensor 107.

  The AE control unit 204 performs subject tracking using photometric image data read from the photometric sensor 205 and outputs subject position data to the system control unit 201. The system control unit 201 outputs the tracking subject position data output from the AE control unit 204 to the AF control unit 202. The AF control unit 202 calculates the defocus amount of the tracking target position output from the system control unit 201 and a focus detection position in the vicinity thereof, and selects an optimum focus detection position.

  The lens control unit 206 is connected to the system control unit 201 and drives the imaging optical system 101. The mirror control unit 207 is connected to the system control unit 201 and drives the main mirror 102 out of the imaging light beam. The image sensor control unit 208 is connected to the system control unit 201, drives the image sensor 107, photoelectrically converts the subject image formed by the imaging optical system 101, and outputs an image signal to the system control unit 201. The digital signal processing unit 209 is connected to the system control unit 201 and performs image processing such as shading correction and gamma correction on the image signal read from the image sensor 107 via the image sensor control unit 208.

  The operation unit 210 is connected to the system control unit 201 and is provided with operation members for operating the camera 100 (imaging device) such as a power switch and a release button for turning on / off the power of the camera 100 (imaging device). It has been. When these switches and buttons are operated, a signal corresponding to the operation is input to the system control unit 201. The release button includes a release switch SW1 that is turned on by a first stroke operation (half-pressing operation) of the release button operated by a photographer, and a release switch that is turned on by a second stroke operation (full-pressing operation) of the release button. SW2 is connected.

  Here, the focus detection area of the focus detection sensor 203 and the photometry area of the photometry sensor 205 of this embodiment will be described with reference to FIGS. In FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals. The focus detection area of the focus detection sensor 203 is composed of 61 focus detection positions shown in FIG. 3A and a line sensor 302 arranged corresponding thereto. In FIG. 3B, the photometric sensor 205 is divided into a plurality of photometric areas 303.

  Subsequently, an operation flow of the camera 100 according to the present embodiment will be described with reference to FIG. In FIG. 4, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  FIG. 4 shows that the three control units of the system control unit 201, the AF control unit 202, and the AE control unit 204 operate in parallel. In step 401, the system control unit 201 receives an input from the release switch SW1 or SW2 from the release button of the operation unit 210, and starts processing of the AF control unit 202 and the AE control unit 204 in AE / AF of step 402. Thereafter, the system control unit 201 drives the main mirror 102 out of the imaging light beam via the mirror control unit 207 in the mirror-up operation in step 403. Further, the system control unit 201 drives the image sensor 107 via the image sensor control unit 208 in the imaging at step 404. Further, the system control unit 201 drives the main mirror 102 into the photographing light beam via the mirror control unit 207 in the mirror down operation in step 405.

  The AF control unit 202 starts the operation in response to the AF start data D01 from the system control unit 201 that has received the input of the release switch SW1 or SW2.

  In step 406, the AF control unit 202 performs accumulation in the focus detection sensor 203. In step 407, the AF control unit 202 reads an image signal from the focus detection sensor 203. In step 408, the AF control unit 202 performs a focus detection calculation based on the read image signal, calculates a defocus amount at each focus detection position, and selects one optimum focus detection position. Here, the system control unit 201 waits for notification of data D04 described later.

  The AE control unit 204 receives the AE start data D02 from the system control unit 201 that has received the input of the release switch SW1 or SW2, and starts its operation.

  In step 411, the AE control unit 204 accumulates charges in the photometric sensor 205. In step 412, the AE control unit 204 reads out image data having a luminance signal and a color difference signal from the photometric sensor 205. In step 413, the AE control unit 204 performs subject tracking. In subject tracking, a template image generated in a tracking template generation step 417 described later is set as a tracking target, and template matching is performed with the image data read out in step 412. Thereby, the position of the tracking subject is detected, and the reliability of tracking is obtained based on the result of template matching. Detailed processing will be described later.

  The AE control unit 204 notifies the system control unit 201 of the tracking subject position and tracking reliability data detected in step 413 as D03. Upon receiving the tracking subject position and tracking reliability data D03 from the AE control unit 204, the system control unit 201 notifies the AF control unit 202 of the tracking subject position and tracking reliability data D03 as D04. To do.

  When notified of the tracking subject position and tracking reliability data D04, the AF control unit 202 sets a focus detection position corresponding to the tracking subject position in step 409. In step 410, the AF control unit 202 calculates the defocus amount of the focus detection position, compares it with the one focus detection position previously selected in step 408, and selects the optimum focus detection position. The AF control unit 202 notifies the system control unit 201 of information on the selected focus detection position as data D05. Detailed description of the setting of the focus detection position in step 409 will be described later. In step 414, the AE control unit 204 performs an exposure calculation based on the image data read in step 412, and notifies the result to the system control unit 201 as data D06.

  In step 415, face detection is performed based on the image data read in step 412. Many methods have already been proposed for face detection, and a detailed description thereof will be omitted. For example, Japanese Patent Laid-Open No. 8-63597 proposes a method of determining a face candidate area corresponding to the shape of a human face and determining the face area from the feature amount of the face candidate area. In addition, a method for detecting a face candidate area by extracting the outline of a human face from an image and a correlation value with a plurality of templates having various shapes of the face are calculated, and the face candidate area is calculated based on the correlation value. A method has been proposed.

  In step 416, the AE control unit 204 generates a template from the image data read in step 412 based on the data D07 including the face area detected in step 415, the AF selected focus detection position information, and the template generation request flag. The area to be extracted is determined. In determining the area, branch processing is performed depending on whether or not face detection is established in step 415. First, if face detection is established in step 415, the AE control unit 204 sets a certain area centered on the detected face area as the template extraction area. On the other hand, if face detection is not established in step 415, the AE control unit 204 sets a certain region centered on the tracking target position detected in the immediately preceding subject tracking processing step 413 as the template extraction region.

  The above is a process for preferentially tracking the face area. However, depending on the result of the subject tracking process, even if face detection is established, the tracking target position detected in the immediately preceding subject tracking process step 413 is used as the center. A certain area to be set may be set as the template extraction area.

  In step 417, the AE control unit 204 calculates the color distribution in the template extraction region set in step 416, and detects the characteristic color to be tracked. The feature color is detected as follows. First, the color signal of each pixel in the template extraction region is converted into RGB color data, and an RGB histogram is created based on the strength of each of the R signal, G signal, and B signal. This is performed for all the pixels in the template extraction area, and the color with the highest frequency is set as the characteristic color to be tracked.

  Next, the subject tracking process in step 413 will be described with reference to FIGS. FIG. 5 is a flowchart of the subject tracking process, and the AE control unit 204 performs the process. In FIG. 6A, 61 focus detection positions are shown as in FIG. Based on the focus detection position 601 selected by the photographer, a template extraction region 603a is set from the input image 602 in FIG. 6B in step 416, and a template image 603b in FIG. 6C is generated.

  In step 501, the AE control unit 204 performs color conversion processing on the color image data read from the photometric sensor 205, and generates a color converted image 606 in FIG. Specifically, the characteristic color (the shaded portion in FIG. 6C) extracted in the tracking template generation step 417 of the previous frame is converted to high luminance, and the other colors are converted to low luminance. This is because the calculation load of template matching is reduced by generating a luminance image in a state where the characteristic color to be tracked is emphasized.

  In step 502, template matching is performed using the template image 603b created in the tracking template generation step 417 of the previous frame, and a region having the highest correlation (similar) with the template image is detected in the color conversion image 606. The AE control unit 204 notifies the system control unit 201 of the tracking reliability obtained based on the tracking subject position 607 and the correlation amount as data D03 for the region having the highest correlation. The system control unit 201 notifies the AF control unit 202 of the tracking subject position 607 and tracking reliability as data D04.

  As a template matching method, a cross-correlation function, a residual sequential test method, or the like may be used. Further, in order to obtain the tracking reliability, it is determined that the tracking reliability is high if the correlation amount is higher than the set threshold value, and that the tracking reliability is low if the correlation amount is lower than the threshold value. The method for obtaining the reliability of template matching and tracking is not limited to these methods, and various modifications and changes can be made within the scope of the gist.

  Subsequently, the focus detection position reselection in step 410 will be described with reference to FIG.

  In step 410, the AF control unit 202 sets the focus detection position 604 in FIG. 7 corresponding to the position 607 of the tracking subject notified as data D04 from the system control unit 201. The AF control unit 202 calculates the defocus amounts of the set focus detection position 604 and the surrounding focus detection positions 605a to 605d, and selects one optimum focus detection position.

  Here, the defocus amounts of the surrounding focus detection positions 605a to 605d are calculated because the tracking subject position 607 may exist between the focus detection position and the focus detection position. When the tracking subject position 607 and the focus detection position 604 coincide with each other, the defocus amounts of the surrounding focus detection positions 605a to 605d may not be calculated. Further, depending on the reliability of tracking, if the reliability is high, the defocus amounts of the surrounding focus detection positions 605a to 605d may not be calculated.

  Hereinafter, the setting of the focus detection position in step 409 according to the embodiment of the present invention will be described with reference to FIG.

  In step 701, the AF control unit 202 determines whether or not the tracking has been established in accordance with the tracking reliability notified from the system control unit 201 to the AF control unit 202 as data D04. If the tracking reliability is high, it is determined that tracking has been established, and the process proceeds to step 702. On the other hand, if the tracking reliability is low, the focus detection position is not set, and the information on the focus detection position previously selected in step 408 is notified to the system control unit 201 as D05.

  In step 702, it is determined whether the position of the tracking subject notified from the system control unit 201 to the AF control unit 202 as data D04 is within or outside the focus detection area of the focus detection sensor 203. If the position of the tracking subject is within the focus detection area, the process proceeds to step 703, and if it is outside the focus detection area, the process proceeds to step 704.

  In step 703, the AF control unit 202 sets a focus detection position corresponding to the position of the tracking subject.

  In step 704, the AF control unit 202 determines whether or not the position of the tracking subject is outside the focus detection area for the first time. If it is the first time, the process proceeds to step 705, and if not, the process proceeds to step 706.

  In step 705, the AF control unit 202 stores the current time. This is the out-of-area timer.

  In step 706, the AF control unit 202 measures the elapsed time from the time stored in step 705, and determines whether the set time has elapsed. If the set time has not elapsed, the process proceeds to step 707, and if it has elapsed, the process proceeds to step 708.

  In step 707, the AF control unit 202 selects and sets a focus detection position near the position of the tracking subject.

  In step 708, according to the tracking reliability notified from the system control unit 201 to the AF control unit 202 as data D04, the process proceeds to step 707 if the reliability is high, and to step 709 if the reliability is low.

  In step 709, the AF control unit 202 sets a template generation request flag in order to update the template at the position of the focus detection position selected by the AE control unit 204. The template generation request flag is notified to the system control unit 201 as data D05 together with the focus detection position selected in step 707, and is notified to the AE control unit 204 as data D07 via the system control unit 201.

  Subsequently, the setting of the extraction region in step 416 according to the embodiment of the present invention will be described with reference to FIG.

  In step 711, the AE control unit 204 determines whether the subject tracking process is the first time or the second time or later. If it is the first time, the process proceeds to step 712.

  In step 712, the AE control unit 204 determines whether face detection is established in step 415. If face detection is not established, the process proceeds to step 713, and if it is established, the process proceeds to step 714.

  In step 713, the AE control unit 204 sets a photometric area of the photometric sensor 205 corresponding to the user-selected focus detection position.

  In step 714, the AE control unit 204 sets the face area closest to the user-selected focus detection position.

  In step 715, the AE control unit 204 determines whether or not the template generation request flag of the data D07 notified from the system control unit 201 is set. If the template generation request flag is set, the process proceeds to step 716. If not set, the extraction area setting process is terminated.

  In step 716, the AE control unit 204 sets a photometric area corresponding to the selected focus detection position included in the data D 07 notified from the system control unit 201.

  As described above, according to the embodiments of the present invention described above, even if the subject has moved greatly or the tracking subject is removed from the focus detection area due to camera shake or the like, it is possible to keep following the subject as the tracking target. .

  In FIG. 10A, it is assumed that the photographer selects the focus detection position 801 and aims at the subject A. In FIG. 10B, the AE control unit 204 detects the face area 804 and 805 by performing the face detection in step 415 because the tracking number is the first in the determination of the tracking number in step 711 in FIG. It is shown that. In this case, the face detection is established in the determination of the establishment / non-establishment of the face detection in step 712 in FIG. 9. Therefore, in step 714, the face region 804 closest to the focus detection position 801 selected by the user is used as a template. Set the area to be extracted. Then, the characteristic color to be tracked is set from the template extraction area 804 set in step 417, and tracking is started.

  In the setting of the focus detection position in step 409 in FIG. 4, the AF control unit 202 determines that the position 804 of the tracking subject is within the focus detection area in step 702 in FIG. 8, and corresponds to the position of the tracking subject in step 703. The focus detection position 802 to be set is set. In the focus detection position reselection in step 410, the AF control unit 202 calculates the defocus amounts of the focus detection positions of the focus detection position 802 and the surrounding focus detection positions 803a to 803c, and obtains one optimum focus detection position. Select.

  Next, FIG. 11A shows a case where the subject has moved greatly after the start of tracking, or the tracking subject A has been removed from the focus detection area due to camera shake or the like. At this time, the AE control unit 204 proceeds to step 715 because the number of tracking is the second or later in the determination of the number of tracking in step 711 of FIG. In the determination of whether or not the template generation request flag is set in step 715, since the template generation request flag is not set, the extraction area setting is ended. That is, the characteristic color of the tracking target extracted previously is continuously tracked.

  In the setting of the focus detection position in step 409 in FIG. 4, the AF control unit 202 proceeds to step 702 because tracking is established in the determination of establishment of tracking in step 701 in FIG. 8. In step 702, the tracking subject position 808 is determined to be outside the focus detection area, and the process proceeds to step 704. In step 704, since it is outside the first focus detection area, the process proceeds to step 705, where the time is stored, and in step 707, a focus detection position 802 in the vicinity of the tracking subject position 804 is set. In the focus detection position reselection in step 410, the defocus amounts of the focus detection positions of the focus detection position 806 and the surrounding focus detection positions 807a to 807c are calculated, and one optimum focus detection position is selected.

  If the out-of-region timer is within the set time in the determination of the out-of-region timer set time in step 706, the AF control unit 202 determines the focus detection position in the vicinity of the position of the subject tracked by the AE control unit 204 in step 707. Set. As a result, the focus state can be detected in a part of the tracking subject region, and when the tracking subject returns to the focus detection region again, the focus detection position is not changed greatly and the focus detection position corresponding to the tracking subject position is detected. The focus state can be detected.

  On the other hand, if the out-of-region timer has passed the set time in the determination of the out-of-region timer set time elapse in step 706, the AF control unit 202 determines in step 708 whether the tracking reliability is high. If it is determined in step 708 that the tracking reliability is high, the tracking subject may return to the focus detection area again, and the focus detection position near the subject position is set continuously. On the other hand, if it is determined that the tracking reliability is low, the tracking subject is unlikely to return to the focus detection area again, and the currently selected focus detection position may be a part of the tracking subject area. In step 709, the template generation request flag is set. When the template generation request flag is set, the AE control unit 204 determines whether or not the template generation request flag in step 715 in FIG. 9 is set in the extraction area setting in step 416 in FIG. Proceed to 716. In step 716, the AE control unit 204 sets a photometric area corresponding to the currently selected focus detection position, which is likely to be a part of the area of the tracking subject, as a template extraction area. In step 417 in FIG. 4, the AE control unit 204 updates the characteristic color to be tracked. Thus, according to the present embodiment, it is possible to continuously detect the focus state at the focus detection position in a part of the tracked subject area.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 100 Camera 101 Imaging optical system 108 Distance measuring optical system 109 Photometric optical system 201 System control part 202 AF control part 203 Focus detection sensor 204 AE control part 205 Photometric sensor

Claims (4)

A focus detection unit that includes a plurality of focus detection regions and detects a focus state based on a relative positional shift amount in a split direction of a light beam from a subject that has passed through the imaging optical system;
A photometric unit that divides a subject image formed by the imaging optical system into a plurality of photometric areas and performs photometry, and outputs photometric information for each photometric area;
Setting means for setting a photometric area corresponding to the specified tracking subject as an extraction area, and holding photometric information of the extraction area;
Subject tracking means for sequentially detecting as a tracking subject position a photometric area having photometric information similar to the photometric information of the extraction area held by the setting means from the photometric information continuously output by the photometric means;
The focus detection means performs focus detection using the focus detection area corresponding to the tracking subject position when the tracking subject position detected by the subject tracking means is within the focus detection area, and the subject tracking means If in the detected tracking subject position is outside the focus detection area, have rows focus detection using the focus detection area in the vicinity of the tracked object position, after a predetermined time, reliability of tracking by the object tracking means The focus adjustment device is characterized in that the setting means resets the extraction region if the characteristic is lower than a threshold value . When the tracking subject position detected by the subject tracking means is outside the focus detection area, the focus detection means does not reset the extraction area by the setting means until the predetermined time elapses. The focus adjustment apparatus according to claim 1, wherein focus detection is performed using the focus detection region in the vicinity of the tracking subject position. A designation means for the user to designate a focus detection position;
It further has subject detection means for detecting a specific subject,
When the specific object is detected by the object detection means, the setting means sets the area of the specific object that is present nearest to the position specified by the specifying means as the extraction area, and detects the object 3. The focus adjustment apparatus according to claim 1, wherein when a specific subject is not detected by the means, an area corresponding to the position designated by the designation means is set as the extraction area. A focus detection step that includes a plurality of focus detection areas and detects a focus state based on a relative positional shift amount in a split direction of a light beam from a subject that has passed through the imaging optical system;
A photometric step of dividing a subject image formed by the imaging optical system into a plurality of photometric areas and performing photometry, and outputting photometric information for each photometric area; and
Setting a photometric area corresponding to the specified tracking subject as an extraction area, and holding photometric information of the extraction area;
A subject tracking step for sequentially detecting, as a tracking subject position, a photometric area having photometric information similar to the photometric information of the extraction area held in the setting step from the photometric information continuously output by the photometric step;
In the focus detection step, when the tracking subject position detected in the subject tracking step is within the focus detection region, focus detection is performed using the focus detection region corresponding to the tracking subject position, and the subject tracking step If in the detected tracking subject position is outside the focus detection area, have rows focus detection using the focus detection area in the vicinity of the tracked object position, after a predetermined time, reliability of tracking by the object tracking step If the characteristic is lower than a threshold value, the extraction region is reset in the setting step .

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