Control device, imaging apparatus, control method, and program

Abstract

To provide a technique for selecting a subject desired by a user as a main subject, even when a plurality of subjects is in an approximately focused state.SOLUTION: A control device includes; focus detection means which is focus detection means for detecting a focus state in a screen and acquires first focus information decided on the basis of a range regarded as first focusing and second focus information decided on the basis of the range regarded as second focusing; extraction means which extracts a subject area on the basis of the first focus information; area setting means which sets a main subject area on the basis of the second focus information from among the subject areas extracted by the extraction means; and focus adjustment means which controls focus adjustment so as to keep focusing on a subject corresponding to the main subject area set by the area setting means, when performing switching from manual focusing for controlling a position of a focus lens according to an operation of a user to autofocusing for automatically controlling the position of the focus lens.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a focus control technique. [Background technology]

[0002] Patent Document 1 describes a method in which, after a user completes a manual focus operation, the area closest to being in focus is determined to be the main subject area, and autofocus (AF) control is continuously performed on the main subject area. Patent Document 1 also describes a method in which, if a detected subject such as a person is present at the in-focus position, AF control is performed on the person. If there are multiple people, AF control is performed on the person selected according to priority. If no person is detected, AF control is performed based on a range of the same color within the in-focus position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5474528 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, when a user switches the main subject by manual focus operation, the camera determines that the subject in a nearly in-focus state is the main subject selected by the user and performs AF control. However, when there are multiple subjects at nearly the same distance, the multiple subjects are in a nearly in-focus state, which may prevent the user from selecting the desired subject as the main subject.

[0005] The present invention has been made in view of the above-mentioned problems, and its object is to realize a technique for selecting a subject desired by a user as a main subject even when multiple subjects are substantially in focus. [Means for solving the problem]

[0006] A control device according to one aspect of the present invention is characterized by having a focus detection means for detecting a focus state within a screen, the focus detection means acquiring first focus information determined based on a first range considered to be in focus and second focus information determined based on a second range considered to be in focus, an extraction means for extracting a subject area based on the first focus information, an area setting means for setting a main subject area from the subject area extracted by the extraction means based on the second focus information, and a focus adjustment means for controlling focus adjustment so as to maintain focus on a subject corresponding to the main subject area set by the area setting means when switching from manual focus, which controls the position of the focus lens in response to user operation, to autofocus, which automatically controls the position of the focus lens. [Effects of the Invention]

[0007] According to the present invention, even when a plurality of subjects are substantially in focus, a subject desired by the user can be selected as the main subject. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram illustrating the configuration of an imaging apparatus according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams illustrating a method for setting a ranging area on an imaging screen according to the present embodiment. [Figure 3] 10 is a flowchart illustrating a focus control process according to the present embodiment. [Figure 4] 10A and 10B are diagrams illustrating an example of a setting menu for an AF control mode when a focus operation is completed in this embodiment. [Figure 5] 10 is a flowchart illustrating a focus mode determination process according to the present embodiment. [Figure 6] 10 is a flowchart illustrating an example of an AF frame determination process when a subject is detected according to the present embodiment. [Figure 7] 10 is a flowchart illustrating an example of an AF frame determination process when a subject is not detected according to the present embodiment. [Figure 8]10 is a flowchart illustrating a focus threshold setting process when a subject is not detected according to the present embodiment. [Figure 9] 10 is a flowchart illustrating an example of an AF frame display process when a subject is detected according to the present embodiment. [Figure 10] 10 is a flowchart illustrating an example of an AF frame display process when a subject is not detected according to the present embodiment. [Figure 11] 10A to 10C are diagrams illustrating a subject extraction method when a subject is not detected according to the present embodiment. [Figure 12] 10A and 10B are diagrams illustrating a method for setting a focus threshold when no subject is detected according to the present embodiment. [Figure 13] 10A to 10C are diagrams illustrating a method of displaying an AF frame when a subject is detected according to the present embodiment. [Figure 14] 10A to 10C are diagrams illustrating a method of displaying an AF frame when a subject is not detected according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] Below, an example in which the imaging device of the present invention is applied to a digital video camera will be described, but it may also be applied to other imaging devices such as a digital still camera.

[0011] <Device configuration> First, the hardware configuration of the imaging device of this embodiment will be described with reference to FIG.

[0012] FIG. 1 is a block diagram illustrating the hardware configuration of an imaging apparatus according to this embodiment.

[0013] The imaging device 100 includes an imaging optical system 150 for forming a subject image, which is light from a subject. The imaging optical system 150 includes a fixed first lens group 101, a variable magnification lens 102, an aperture 103, a fixed second lens group 104, and a focus compensator lens 105. A camera controller (hereinafter referred to as a camera microcomputer) 115 includes a focus position detection unit 119, a focus determination unit 120, a focus control unit 121, and a zoom control unit 122.

[0014] The variable magnification lens 102 moves in the optical axis direction to perform a variable magnification operation. The focus compensator lens (hereinafter referred to as the focus lens) 105 has a function of correcting movement of the focal plane accompanying a variable magnification operation and a function of adjusting the focus state. The imaging optical system 150 also has a focus lens operation unit 124 (hereinafter referred to as the focus ring). The focus ring 124 is an operation member that can be rotated around the optical axis of the imaging optical system 150 and can be operated by the user. When the user operates the focus ring 124 in the shooting mode, the focus lens 105 is moved in the optical axis direction by the focus lens driving unit 112 in accordance with the amount of operation of the focus ring 124. Note that operation information of the focus ring 124, such as the amount of drive, drive speed, and drive direction of the focus lens 105 corresponding to the amount and direction of rotation of the focus ring 124, is output to the camera microcomputer 115. The imaging optical system 150 also has a control ring operation unit (hereinafter referred to as the control ring) 125. The control ring 125 is an operating member that can be rotated around the optical axis of the imaging optical system 150 and can be operated by the user. When the user operates the control ring 125, the detected subject is switched and the shooting settings (ISO / aperture / gain, etc.) are changed according to the operation information of the control ring 125. Note that the operation information of the control ring 125, such as the amount and direction of rotation of the control ring 125, is output to the camera microcomputer 115.

[0015] The imaging unit 106 includes an image sensor having a photoelectric conversion element such as a CCD or CMOS and peripheral circuits for driving the photoelectric conversion element and reading out signals, and photoelectrically converts an object image formed on the imaging surface by light passing through the imaging optical system 150, and outputs the image as an electrical signal. The image sensor has a microlens that performs pupil division of the exit pupil of the imaging optical system 150. The imaging device 100 then performs autofocus (AF) control using an imaging surface phase difference method based on a pair of image signals obtained from light beams that have passed through different pupil regions.

[0016] The CSD / AGC circuit 107 has a CDS circuit that performs correlated double sampling to remove reset noise (low frequency) contained in the imaging signal output from the imaging unit 106. The CSD / AGC circuit 107 also has an AGC circuit that amplifies the imaging signal output from the imaging unit 106 and controls the magnitude of the signal to a constant level.

[0017] The image signal processing unit 108 performs image processing on the imaging signal output from the CDS / AGC circuit 107 to generate image data.

[0018] The display unit 109 is equipped with a display device such as a liquid crystal panel or organic EL, and displays image data output from the image signal processing unit 108, as well as setting information at the time of shooting and an AF frame indicating the focus detection area at the start of AF control, which will be described later.

[0019] The recording unit 110 encodes the image data output from the image signal processing unit 108 using a video compression format such as MP4 and records the encoded video file on a recording medium, or decodes the video file read from the recording medium. The recording medium may be a magnetic tape, an optical disk, a semiconductor memory, or the like. Note that the imaging device 100 of this embodiment can generate not only video data, but also still image data and video data combined with audio data.

[0020] The zoom lens driver 111 includes an actuator such as a stepping motor, a DC motor, a vibration motor, or a voice coil motor for moving the variable magnification lens 102 in the optical axis direction. The focus lens driver 112 includes an actuator such as a stepping motor, a DC motor, a vibration motor, or a voice coil motor for moving the focus lens 105 in the optical axis direction.

[0021] The phase-difference AF gate 113 passes first and second focus detection signals from pixels in a ranging area set by a ranging area setting unit 118 for phase-difference AF (described later) that correspond to a focus detection area within an AF frame detected by the image-sensing-plane phase-difference AF method. Here, the ranging area is also referred to as a focus detection area. While this embodiment describes image-sensing-plane phase-difference AF, other focus detection methods may be used as long as they provide information about the subject distance. For example, a ToF (Time of Flight) method may be used, in which light (infrared light or laser) is emitted, hits the subject, reflects, and returns to calculate the distance. Another possible method involves attaching an RFID (Radio Frequency Identification) tag or a UWB (Ultra-Wideband) tag to the subject, receiving a signal from the tag via an antenna, and identifying the subject's location.

[0022] The phase difference AF signal processing unit 114 performs correlation calculations based on the two focus detection signals that have passed through the phase difference AF gate 113, calculates the amount of image shift for each focus detection area, and outputs the amount of image shift to the focus position detection unit 119 of the camera microcomputer 115.

[0023] The camera microcomputer 115 includes a processor (CPU) that performs arithmetic processing and control processing of the image capture device 100. It also includes a nonvolatile memory (ROM) that stores programs executed by the processor, and a work memory (RAM) into which programs read from the nonvolatile memory and constants and variables for executing the programs are loaded. The camera microcomputer 115 controls each component of the image capture device 100 by loading the programs stored in the ROM into the RAM and executing them.

[0024] The memory 123 is an external flash memory that is attached to the camera microcomputer 115 to expand its memory area.

[0025] The focus position detection unit 119 calculates a defocus amount, which is the amount of deviation between the current focus position and the in-focus position on the imaging plane of the imaging unit 106, from the image shift amount calculated by the phase difference AF signal processing unit 114, using an imaging plane phase difference AF method. Then, the focus position detection unit 119 outputs the defocus amount as a focus detection result to the focus control unit 121. The focus position detection unit 119 also converts the defocus amount into a drive amount of the focus lens 105 and outputs it to the focus determination unit 120.

[0026] The focus determination unit 120 calculates control information for driving the focus lens 105 based on the drive amount of the focus lens 105 received from the focus position detection unit 119 , and outputs the control information to the focus control unit 121 .

[0027] The focus control unit 121 controls the focus lens driving unit 112 to drive the focus lens 105 based on the control information for the focus lens 105 received from the in-focus determination unit 120, thereby performing AF control.

[0028] The zoom control unit 122 controls the zoom lens driving unit 111 based on the driving amount and driving speed of the variable magnification lens 102 according to the zoom operation by the user to drive the variable magnification lens 102, thereby performing zoom control.

[0029] The AF method of this embodiment is not limited to the image plane phase difference AF method, and other AF methods may be applied.

[0030] The TV-AF gate 116 and the TV-AF signal processing unit 117 in FIG. 1 are components for realizing a TV-AF method other than the imaging surface phase difference AF method.

[0031] The TV-AF gate 116 outputs to a TV-AF signal processor 117 only the image pickup signal of the focus detection area for focus detection by the TV-AF method out of the image pickup signals of all pixels output from the CDS / AGC circuit 107 .

[0032] The TV-AF signal processing unit 117 applies a known method, such as extracting specific frequency components using a filter, to the image pickup signal of the TV-AF focus detection area (AF frame in this embodiment) output from the TV-AF gate 116. Then, it generates a TV-AF evaluation value that maximizes the sharpness (contrast) of the image at the in-focus position.

[0033] The TV-AF evaluation value is output to a focus determination unit 120. The TV-AF evaluation value is also output to a focus control unit 121. The focus control unit 121 controls a focus lens driving unit 112 based on the TV-AF evaluation value to drive the focus lens 105, thereby performing AF control using the TV-AF method.

[0034] The ranging area setting unit 118 for phase difference AF sets a pixel group from among all pixels of the imaging unit 106 that reads out the first and second focus detection signals that are input to the phase difference AF gate 113. The ranging area setting unit 118 can variably set the focus detection area that reads out the focus detection signals for focus detection using the phase difference AF method in accordance with the subject detection state.

[0035] The subject area detection unit 126 performs a known subject detection process on the imaging signal output from the CDS / AGC circuit 107 to detect a subject present within an imaging screen corresponding to the image data generated by the image signal processing unit 108. The subject detection process of this embodiment is face detection processing in which the detection target is a human face area. For example, the face area detection process may involve extracting a skin-color area from the gradation colors of each pixel represented by the image data and detecting a face based on the degree of match with a pre-prepared face outline plate. Other methods include face detection by extracting facial feature points such as the eyes, nose, and mouth using known pattern recognition technology. This embodiment is not limited to a specific subject detection process, and any method may be used. Furthermore, the subject to be detected is not limited to a person or a face, but may also be a non-human or non-face animal, insect, vehicle, or the like.

[0036] The imaging device 100 of this embodiment can be switched between multiple focus modes, including AF mode, MF mode, and MF / AF switching mode. AF mode is a mode in which a target subject (main subject) is automatically adjusted to a focused state through AF control. MF mode is a mode in which a user manually operates the focus ring 124 to adjust a desired subject (main subject) to a focused state. MF / AF switching mode is a mode in which the mode automatically switches to AF mode after operation in MF mode is completed, and AF control continues to be performed on the subject that has been brought into a focused state through manual focus operation as the main subject.

[0037] <How to set the focusing area> Next, a method for setting a ranging area by the ranging area setting unit 118 of this embodiment will be described with reference to FIG.

[0038] 2(a) to 2(c) show examples of ranging areas set by the ranging area setting unit 118. FIG.

[0039] 2(a) illustrates an example of a ranging area 201 set in an imaging screen 200 corresponding to image data generated by the image signal processing unit 108. The ranging area 201 is configured by a plurality of rectangular areas arranged two-dimensionally. Note that FIG. 2(a) illustrates an example of the ranging area in a state where no subject is detected in the imaging screen 200, and the ranging area 201 is arranged as shown in FIG. 2(a) regardless of whether the focus mode of the imaging device 100 is AF mode, MF mode, or MF / AF switching mode.

[0040] FIG. 2(b) illustrates ranging areas 202-204 when a subject is detected. For each of detected subjects 205-207, multiple two-dimensional ranging areas are set according to the center and size of the face. Note that FIG. 2(b) illustrates ranging areas when a subject is detected, and is arranged when the focus mode of the imaging device 100 is AF mode or MF / AF switching mode. The ranging areas are arranged as shown in FIG. 2(b) in order to reduce out-of-focus during AF control for each detected subject.

[0041] FIG. 2(c) illustrates an example of a ranging area 208 when a subject is detected. In the example of FIG. 2(c), multiple two-dimensional ranging areas are set for all detected subjects 209 to 211. Note that FIG. 2(c) illustrates an example of ranging areas when a subject is detected, and is arranged when the focus mode of the image capture device 100 is MF mode. The ranging areas are arranged as in FIG. 2(c) so that the image capture device 100 can efficiently identify the subject that the user has targeted by performing a manual focus operation, and the arrangement is similar to that in the state of FIG. 2(a).

[0042] In this way, by changing the distance measurement range depending on the subject detection status and focus mode, it becomes possible to identify a subject that matches the user's intentions and maintain a focused state on the targeted subject during AF control.

[0043] The focus control unit 121 executes AF control based on at least one or more of the plurality of focus detection results obtained from the distance measurement regions 201 to 204 illustrated in FIGS. 2(a) to 2(c).

[0044] <AF control mode> Next, the AF control mode will be described.

[0045] The imaging device 100 of the present embodiment can execute the following plurality of AF control modes. Further, the imaging device 100 of the present embodiment can be changed to the following first AF control mode, second AF control mode, or third AF control mode by a user operation. · First AF control mode: Center-closest priority AF · Second AF control mode: Face AF · Third AF control mode: Tracking AF

[0046] In the "First AF control mode: Center-closest priority AF", AF control is performed with priority given to the subject located at the center and closest to the camera on the imaging screen. The focus control unit 121 determines the presence or absence of a subject located at the center-closest position, which is the closest to the center of the imaging screen and the closest in the optical axis direction, based on the subject detection result detected by the subject region detection unit 126 and the like. When the focus detection result of the subject located at the center-closest position can be obtained, AF control is performed according to the focus detection result of the center-closest subject. As a result, the subject appearing near the center of the imaging screen is successively focused, resulting in highly versatile AF control that enables AF in various scenes.

[0047] In the "Second AF control mode: Face AF," the position and size of a person's face area are determined as the main subject based on the subject detection results detected by the subject area detection unit 126. AF control is then performed while tracking the main subject so that the focus detection results for the face area are always in focus. Furthermore, if there are multiple faces within the image capture screen, the face that is prioritized is, for example, the face that is closest to the center of the image capture screen and is the largest in size. This allows the image capture device 100 to automatically determine the priority of subjects and perform AF control according to the subject detection results within the image capture screen, which is effective when a detected subject such as a face is present.

[0048] In addition, "First AF control mode: Center closest focus priority AF" and "Second AF control mode: Face AF" are controlled exclusively, and if the detected subject disappears in "Second AF control mode: Face AF," the mode will switch to "First AF control mode: Center closest focus priority AF."

[0049] In the "Third AF Control Mode: Tracking AF," AF control is performed while tracking a main subject selected by the user from among multiple detected subjects within the imaging screen so that the subject remains in focus. For example, the user may specify a position on the imaging screen, and the position and size of the subject may be determined from color information and focus detection results for the specified position, or the position and size of a face may be determined from the detection results for a face selected by the user. This allows tracking AF to be performed on the main subject so that the focus detection results for the area corresponding to the position specified by the user are always in focus. This allows AF control to be maintained only on the subject targeted by the user, and imaging device 100 does not change the subject, resulting in highly specialized AF control.

[0050] In addition, "First AF control mode: Center closest subject priority AF" and "Third AF control mode: Tracking AF" are mutually exclusive controls, and if the detected subject no longer exists in "Third AF control mode: Tracking AF", the mode will switch to "First AF control mode: Center closest subject priority AF".

[0051] Since AF control is well known, a detailed description thereof will be omitted.

[0052] <Menu Settings> Next, the menu setting items of this embodiment will be described with reference to FIG.

[0053] The menu of this embodiment includes a menu name 301. The menu name 301 is "AF control at the end of MF operation," and AF control after the end of manual focus operation can be selected.

[0054] In this embodiment, the menu 301 includes three options 302, 303, and 304. The first option 302 is a setting for "No tracking AF." When the first option 302 is selected, tracking AF does not start after manual focus operation ends. Specifically, if the AF mode is set to "First AF control mode: Center closest focus priority AF" or "Second AF control mode: Face AF," the same AF control is maintained even after manual focus operation ends. Alternatively, operation of the focus ring 124 is restricted.

[0055] The second option 303 is a setting for "Perform tracking AF (do not display tracking candidate frames)." When the second option 303 is selected, tracking AF starts after manual focus operation is completed. In more detail, if the AF mode is set to "First AF control mode: Center closest subject priority AF" or "Second AF control mode: Face AF," it switches to "Third AF control mode: Tracking AF" after manual focus operation is completed.

[0056] In the second option 303, when the user operates the focus ring 124 to change to one of multiple detected subjects at different distances from the imaging optical system 150, tracking AF is started for the targeted subject after the manual focus operation is completed. This eliminates the need for the user to change the AF control mode.

[0057] The third option 304 is a setting for "Perform tracking AF (display tracking candidate frame)." The third option 304 switches the AF control mode after a manual focus operation is completed in the same way as the second option 303. During and after a manual focus operation, a tracking candidate frame is displayed on the main subject to be tracked, selected by the user using the focus ring 124. As will be described later with reference to FIG. 14 , the tracking candidate frame is displayed in a different display format from the tracking frame indicating that tracking AF will be performed on the selected main subject after a manual focus operation is completed. The third option 304 allows the user to confirm whether the intended subject is substantially in focus while operating the focus ring 124. In this way, by presenting the user with a subject to be tracked after a manual focus operation is completed in advance during a manual focus operation, it is possible to reduce the number of failed photographs.

[0058] The first option 302, the second option 303, and the third option 304 will be described in detail later with reference to FIG.

[0059] <Method for determining the main subject from multiple detected subjects> In this embodiment, it is possible to determine a main subject to be the target of tracking AF from among multiple subjects detected by the subject area detection unit 126 using the following first subject determination method A or second subject determination method B. First subject determination method A: Changing subject priority Second subject determination method B: Changing the subject's focus state "A: Method of changing the priority of subjects" is a method in which priorities are assigned to multiple detected subjects according to the position and size of each subject, and the user determines the main subject by changing the priority. The user can change the priority of subjects and determine the main subject by selecting a detected subject using a touch operation (not shown), a cross key operation, or operation of the control ring 125. "B: Method of changing the focus state of the subject" is a method of changing the focus state of the subject using the focus ring 124, and determining an approximately focused subject from a plurality of detected subjects as the main subject.

[0060] The imaging device 100 of this embodiment can be operated for the first subject determination method A or the second subject determination method B using the following different operating members. First subject determination method A: Control ring 125 Second subject determination method B: Focus ring 124

[0061] <Focus ring 124 and control ring 125> As shown in FIG. 1, the imaging device 100 of this embodiment includes an imaging optical system 150 that includes a focus ring 124 and a control ring 125.

[0062] When switching the main subject using focus ring 124, image capture device 100 of this embodiment determines that the subject in a nearly in-focus state is the subject targeted by the user and performs tracking AF. However, if there are multiple detected subjects at approximately the same distance from image capture optical system 150, the multiple subjects will be in a nearly in-focus state, making it difficult for the user to determine the subject targeted by the user.

[0063] Therefore, in this embodiment, when there are multiple detected subjects at approximately the same distance, the main subject can be switched by operating the control ring 125 instead of the focus ring 124. This makes it possible to move the AF frame to the subject to the right or left of the subject on which the current AF frame is displayed, depending on the direction of rotation of the control ring 125, just like with other operating members (cross key, touch operation).

[0064] In this embodiment, it is recommended to operate the focus ring 124 when switching between multiple detected subjects with different distances, and to operate the control ring 125 when switching between subjects with no difference in distance.

[0065] This has two benefits.

[0066] The first advantage is that the user can select the target subject (subject with or without distance difference) using only the left hand. Conventionally, when there are multiple detected subjects at approximately the same distance, the user has had to operate a cross key or the like with the right hand to select the subject. In this embodiment, the imaging optical system 150 has two operating members: the focus ring 124 and the control ring 125. This allows the user to select the target subject (subject with or without distance difference) simply by operating the operating members of the imaging optical system 150 held in the left hand.

[0067] The second benefit is that the quality of the video is improved because the user can control the speed of focus shift when switching subjects by operating the focus ring 124, which is recommended when selecting subjects with a difference in distance. On the other hand, when selecting subjects with no difference in distance, focus shift quality is not necessary, so simply switching subjects by operating the control ring 125 does not affect the quality of the video.

[0068] <Focus control processing> Next, the focus control process of this embodiment will be described with reference to FIGS.

[0069] The focus control process of this embodiment is realized by the camera microcomputer 115 loading a program stored in the ROM into the RAM and executing it, and controlling each component as the focus control unit 121.

[0070] First, the main flow of the focus control process of this embodiment will be described with reference to FIG.

[0071] The process of FIG. 4 is repeatedly executed in accordance with a predetermined cycle, for example, a cycle at which an image signal is read from the image capturing unit 106.

[0072] In step S400, the focus control unit 121 acquires lens information of the imaging optical system 150, and proceeds to step S401. The lens information (optical information) includes focal length information, subject distance information, aperture information, operation information of the focus ring 124, operation information of the control ring 125, and the like.

[0073] In step S401, the focus control unit 121 acquires information about "AF control at the end of focus operation" set by the user on the menu screen described with reference to FIG. 5, and the process proceeds to step S402.

[0074] In step S402, the focus control unit 121 sets the distance measurement area described with reference to FIG. 2, and the process proceeds to step S403.

[0075] In step S403, the focus control unit 121 acquires the focus detection result from the in-focus position detection unit 119, and proceeds to step S404. In this embodiment, it is assumed that the results of all the ranging areas set in FIG. 2 are acquired.

[0076] In step S404, the focus control unit 121 determines whether the setting of “AF control after MF operation ends” acquired in step S401 is “tracking.” If it is “not tracking,” the process proceeds to step S405, and if it is “tracking,” the process proceeds to step S408.

[0077] In step S405, the focus control unit 121 performs processing to determine an AF frame, and proceeds to step S406. If a face is detected, the focus control unit 121 performs face AF, setting the ranging area for the face as the AF frame. If a face is not detected, and if a focus detection result close to the center of the imaging screen can be obtained, the focus control unit 121 sets the ranging area close to the center as the AF frame; otherwise, it predicts the position of the subject from the current focus detection result and sets that ranging area as the AF frame.

[0078] In step S406, the focus control unit 121 performs processing to display an AF frame, and proceeds to step S407. If a face is detected, the focus control unit 121 displays an AF frame around the face, and if not, the focus control unit 121 performs center-closest priority AF and does not display an AF frame.

[0079] In step S407, the focus control unit 121 performs AF control processing, and returns the processing to step S400 to repeat the processing. The focus control unit 121 outputs control information for driving the focus lens 105 to the focus lens driving unit 112 in accordance with the focus detection result of the AF frame determined in step S405.

[0080] In step S408, the focus control unit 121 determines whether the focus mode is "AF mode," "MF mode," or "MF / AF switching mode," and proceeds to step S409. Details of the process will be described later with reference to FIG.

[0081] In step S409, the focus control unit 121 determines whether the focus mode is the "AF mode," and if it is the AF mode, the process proceeds to step S410; otherwise, the process proceeds to step S415.

[0082] In step S410, the focus control unit 121 determines whether an instruction to change the main subject has been received from the control ring 125, and if an operation has been received, the process proceeds to step S411; otherwise, the process proceeds to step S412.

[0083] In step S411, focus control unit 121 performs processing to change the subject, and proceeds to step S412. The user can issue a subject change instruction to camera microcomputer 115 by rotating control ring 125. When multiple subjects are detected by subject area detection unit 126, and a subject change instruction is received from control ring 125, focus control unit 121 changes the main subject in accordance with the instruction.

[0084] 2(b), when control ring 125 is rotated to the right, if the face for which the AF frame is currently displayed is detected subject 207, the AF frame moves to detected subject 206 located to the right. When control ring 125 is rotated to the left, if the face for which the AF frame is currently displayed is detected subject 207, the AF frame moves to detected subject 205 located to the left of the face for which the AF frame is displayed.

[0085] In step S412, the focus control unit 121 performs processing to determine an AF frame, and proceeds to step S413. When tracking AF is being performed, the focus control unit 121 sets the ranging area of ​​the tracking target as the AF frame. When tracking AF is not being performed, if focus detection results can be obtained in the center of the imaging screen, the focus control unit 121 sets the ranging area in the center of the imaging screen as the AF frame; otherwise, the focus control unit 121 predicts the position of the subject from the current focus detection results and sets the ranging area in the center of the imaging screen as the AF frame.

[0086] In step S413, the focus control unit 121 performs processing to display an AF frame, and proceeds to step S414. If tracking AF is being performed, the focus control unit 121 displays an AF frame in the ranging area of ​​the tracking target, and if not, center-closest-priority AF is being performed and no AF frame is displayed.

[0087] In step S414, the focus control unit 121 performs AF control processing, and returns the processing to step S400 to repeat the processing. The focus control unit 121 outputs control information for driving the focus lens to the focus lens driving unit 112 in accordance with the focus detection result of the AF frame determined in step S412.

[0088] In step S415, the focus control unit 121 determines whether or not a detected subject is present in the approximately in-focus range, and if a detected subject is present, the process proceeds to step S416; otherwise, the process proceeds to step S419.

[0089] In step S416, the focus control unit 121 performs an AF frame determination process when a subject is detected, and the process proceeds to step S417. Details of the process will be described later with reference to FIG.

[0090] In step S417, the focus control unit 121 performs an AF frame display process when a subject is detected, and the process proceeds to step S418. Details of the process will be described later with reference to FIGS.

[0091] In step S418, focus control unit 121 performs manual focus control processing, returns the processing to step S400, and repeats the processing. Focus control unit 121 outputs control information for driving the focus lens to focus lens driving unit 112 based on the amount of operation of focus ring 124 or the amount of focus operation by a remote control (not shown).

[0092] In step S419, the focus control unit 121 performs an AF frame determination process when a subject is not detected, and the process proceeds to step S420. Details of the process will be described later with reference to FIGS.

[0093] In step S420, the focus control unit 121 performs an AF frame display process when a subject is not detected, and the process proceeds to step S418. Details of the process will be described later with reference to FIGS.

[0094] <Focus mode determination process> Next, the focus mode determination process in step S408 in FIG. 3 will be described with reference to FIG.

[0095] In step S501, focus control unit 121 determines whether a manual focus operation is being performed using focus ring 124, or whether a manual focus operation is being performed using a remote control (not shown) to drive focus lens 105. If a manual focus operation is being performed, focus control unit 121 proceeds to step S502; otherwise, focus control unit 121 proceeds to step S503.

[0096] In step S502, the focus control unit 121 sets the focus mode to the "MF mode" and ends the process.

[0097] In step S503, the focus control unit 121 determines whether a predetermined time has elapsed since the manual focus operation ended. If the predetermined time has elapsed, the process proceeds to step S504; otherwise, the process proceeds to step S505. In this embodiment, the predetermined time is set to, for example, 0.6 seconds.

[0098] In step S504, the focus control unit 121 determines that the manual focus operation has ended, sets the focus mode to the "AF mode", and ends the process.

[0099] In step S505, the focus control unit 121 determines that the manual focus operation is in progress, sets the focus mode to the "MF / AF switching mode" as preparation for switching from the MF mode to the AF mode, and ends the process.

[0100] Regarding the change of the focus mode, there is also a method of switching the AF and MF switches before the manual focus operation. However, in this embodiment, in order to perform AF and MF seamlessly, the change to the AF mode is performed based on whether the manual focus operation has ended.

[0101] <AF frame determination process> Next, referring to FIG. 6, the AF frame determination process at the time of subject detection in step S416 of FIG. 3 will be described.

[0102] In step S601, the focus control unit 121 determines whether multiple detected subjects are present in the approximate focus range. If multiple detected subjects are not present in the approximate focus range, the focus control unit 121 proceeds to step S603, where it sets an AF frame for one detected subject in the approximate focus range. If multiple detected subjects are present in the approximate focus range, the focus control unit 121 proceeds to step S602, where it sets an AF frame for a detected subject that is closest to the center of the imaging screen. Note that the method for determining the AF frame is not limited to the example in FIG. 6, and if multiple detected subjects are present in the approximate focus range, it may set an AF frame for a detected subject that is closest to the in-focus state or a detected subject that is closest to a predetermined area (for example, the center of the screen).

[0103] Next, the AF frame determination process when no subject is detected in step S419 in FIG. 3 will be described with reference to FIG.

[0104] In step S700, the focus control unit 121 performs processing to set a first focus threshold and a second focus threshold, and then proceeds to step S701. The first focus threshold is a threshold of focus information for extracting a subject area from the focus detection result acquired in step S403 of FIG. 4. The second focus threshold is a threshold of focus information for setting a representative area from the main subject area extracted based on the first focus threshold. The representative area is an area set when the user changes the in-focus subject using the focus ring 124, and is set, for example, as an AF frame for performing AF control after completing a manual focus operation. During a manual focus operation, the representative area is set as a tracking candidate frame at the start of AF in step S420 of FIG. 4. Details of how to set the first focus threshold and the second focus threshold will be described later with reference to FIG. 8.

[0105] In step S701, the focus control unit 121 extracts a subject area based on the first focus threshold set in step S700, and then proceeds to step S702. Here, with reference to FIG. 11A, a method for extracting a subject area when a subject is not detected according to this embodiment will be described. In the example of FIG. 11A, subjects 1100 to 1104 are objects and the ground. Furthermore, objects 1100 and 1101 are located at approximately the same distance from the imaging optical system 150, objects 1102 and 1103 are located close to the center of the screen as viewed from object 1100, and ground 1104 is located at approximately the same distance. First focus information 1105 is first focus information determined based on the first focus threshold set in step S700 in the focus detection result acquired in step S403 of FIG. 4. Subject area 1106 is the extracted subject area. For example, when each focus information 1105 is adjacent, the object area is extracted as a single subject area. Other extraction methods may also be methods for extracting subject regions based on color, brightness, etc. When multiple objects exist within the range of the first focus threshold, such as object 1100 and object 1101, and the focus information 1105 is not adjacent, such as object region 1106 and object region 1107, they can be extracted as separate subject regions.

[0106] In step S702, the focus control unit 121 determines whether or not a non-subject area exists in the subject area extracted in step S701. If it is determined that a non-subject area exists, the process proceeds to step S703; otherwise, the process proceeds to step S704. Here, with reference to FIG. 11(b), a method for determining a non-subject area according to this embodiment will be described. FIG. 11(b) illustrates an example of a state in which, from the focus state of FIG. 11(a), the user operates the focus ring 124 toward the center of the screen, and the object 1102, the object 1103, and the ground 1104 are in focus. An area 1108 is a collection area of ​​the first focus information when the focus ring 124 is operated, and the object 1102, the object 1103, and the ground 1104 are extracted as a single subject area. In this way, for example, when the subject areas of different objects are connected with a ground area interposed therebetween, they are extracted as a single subject area. In order to extract this single subject area 1108 as a separate subject area, if the ground area portion of the subject area is larger than a predetermined ratio to the captured image, as in area 1109, it is determined to be a non-subject area and removed. This non-subject area is, for example, a ground area that is continuous with the subject area, but it may also be a wall or ceiling.

[0107] In step S703, the focus control unit 121 performs processing to remove the non-subject region, and the process proceeds to step S704. Here, with reference to FIG. 11(c), a method for removing the non-subject region of this embodiment will be described. FIG. 11(c) illustrates an example of a state in which the non-subject region 1109 determined in step S702 has been removed from the subject region 1108 of FIG. 11(b). By removing the non-subject region 1109 from the subject region 1108, the previously adjacent subject region 1108 is divided into non-adjacent subject regions 1110 and 1111, and these can be extracted as separate subject regions. In this way, removing the non-subject region improves the accuracy of extracting the subject region, and the non-subject region is no longer selected in the AF frame determination process.

[0108] In step S704, the focus control unit 121 performs processing to set a reference point from the subject area after the non-subject area has been removed in step S703, and then proceeds to step S705. Here, with reference to FIG. 11C, a method of setting a reference point from the subject area after the non-subject area has been removed according to this embodiment will be described. First, a main subject area is determined from the subject area 1110 and the subject area 1111 remaining after the non-subject area has been removed in step S703. When multiple subject areas are extracted, the main subject area may be determined, for example, by determining the largest subject area as the main subject area, or by determining the subject area at the center of the screen as the main subject area. When only one subject area is extracted, that subject area is determined as the main subject area. When no subject area is extracted, no main subject area is determined. Next, after the main subject area is determined, a reference point 1112 is set from the main subject area. The reference point 1112 may be set, for example, at the center of gravity of the main subject area, or at a position close to the center of the screen.

[0109] In step S705, the focus control unit 121 sets a representative area based on the reference point of the subject determined in step S704 and the second focus threshold set in step S700, and then proceeds to step S706. Here, with reference to FIG. 11(d), a method for setting a representative area in this embodiment will be described. Area 1113 is second focus information determined based on the second focus threshold set in step S700. Area 1114 is a representative area. First, since the representative area 1114 is selected from the second focus information 1113, which is the focus range, when the representative area 1114 is set as an AF frame in step S707, AF control can be started from a focus position within the focus range. This eliminates the need to consider the transition between the user's operation speed of the focus ring 124 and the AF control speed when starting AF control after completing manual focus operation. Furthermore, the amount of change in the focus position is small, so the quality of the video does not deteriorate. Next, a method for selecting the representative area 1114 from the second focus information 1113 will be described. The second focus information may be, for example, a region including a lot of background around the object 1102, as in focus information 1113, or a region included in the object 1103, as in focus information 1116. Therefore, when selecting the representative region 1114 from the second focus information, there is a possibility that a region outside the region of the object 1102, which is the main subject region set in step S704, will be selected. To avoid this, when selecting the representative region 1114 from the second focus information 1113, the region is set as the region that is the shortest distance on the xy plane to the reference point set in step S704. In this way, by setting the region that is the shortest distance to the reference point and that is included in the second focal depth as the representative region, it is possible to prevent a region different from the main subject region from being set as the representative region.

[0110] In step S706, the focus control unit 121 determines whether the representative area acquired in step S705 exists, and if it exists, the process proceeds to step S707, and if not, the process proceeds to step S709.

[0111] In step S707, the focus control unit 121 sets the representative area as the AF frame, and the process proceeds to step S708.

[0112] In step S709, the focus control unit 121 sets an AF frame when no representative area exists in step S706, and proceeds to step S710. If a face is detected, the focus control unit 121 sets the ranging area for the face as the AF frame and performs face AF. If a face is not detected and there is a closest focus detection result in the center of the imaging screen, the focus control unit 121 sets that ranging area as the AF frame; otherwise, the focus control unit 121 predicts the position of the subject from the current focus detection result and sets that ranging area as the AF frame.

[0113] In step S708, the focus control unit 121 sets the AF control mode to "tracking AF," and the process proceeds to step S420 in FIG.

[0114] In step S710, the focus control unit 121 sets the AF control mode to "face AF / center-closest-focus-priority AF control," and the process proceeds to step S420 in FIG.

[0115] <Processing for Setting the First and Second Focus Thresholds> Next, the process of setting the first and second focus thresholds in step S700 of FIG. 7 will be described with reference to FIG.

[0116] In step S800, the focus control unit 121 performs processing to set the upper and lower limits of the width of the first focus threshold (the range considered to be the first in-focus state) based on the lens information acquired in step S400 of FIG. 4, and then proceeds to step S801. Here, with reference to FIG. 12, a method for setting the width of the first focus threshold according to this embodiment will be described. In FIG. 12, the vertical axis indicates the depth of field, with 0 representing the in-focus position and larger numbers representing greater distances from the in-focus position. FΔ is a unit of focus, and in this embodiment, the depth of field ranges from -1FΔ to 1FΔ. The in-focus range represents the range of the depth of field in which an object appears to be in focus, and is the range obtained by adding the front focus distance (close side) and the rear focus distance (infinity side) to the in-focus position (0F).

[0117] Region 1200 indicates the range of the first focus threshold, and regions 1201 and 1202 indicate areas outside the first focus threshold range. Regions 1203 to 1205 indicate objects, with objects 1203 and 1204 indicating objects within the range of the first focus threshold, and object 1205 indicating an object outside the range of the first focus threshold. In this embodiment, the first focus threshold is set to a range of -1FΔ to 3FΔ, and is set to include not only the in-focus range (-1FΔ to 1FΔ) but also the out-of-focus range (1FΔ to 3FΔ). Note that in this embodiment, the first focus threshold is the depth of field, but it may also be a value based on the subject distance. By setting the first focus threshold to include the out-of-focus range in this way, for example, an object such as object 1203, which is slightly out of the in-focus range but has a large presence, can be extracted as a large subject region in step S701 of FIG. 7. Extracting a large subject area increases the likelihood that the object will be selected when determining the main subject in step S704 of FIG. 7 . On the other hand, because an object extracted by enlarging the subject area is selected as the main subject area, it is possible to prevent an object like object 1204, which is within the focus range but is not desired to be selected as the main subject (e.g., a small object such as a stone), from being selected. Furthermore, by setting the first focus threshold to include an area outside the focus range, it is possible to extract the targeted object as a large subject area even if the focus position slightly deviates from the focus range when the user focuses on the targeted object using focus ring 124. In contrast, if the first focus threshold is set within the focus range (−1FΔ to 1FΔ) and the subject area is extracted, the size of the extracted subject area becomes small. Therefore, even if the focus position deviates slightly from the targeted object when the user finishes operating focus ring 124, the size relationship between the sizes of the subject areas of the targeted object changes. This may result in the ground area or another small subject area at approximately the same distance being selected as the main subject area.

[0118] In step S801, the focus control unit 121 determines the operation direction of the focus ring 124. If the focus ring 124 is operated toward the infinity side in the optical axis direction, the focus control unit 121 proceeds to step S802, and if the focus ring 124 is operated toward the close side in the optical axis direction, the focus control unit 121 proceeds to step S805.

[0119] In step S802, the focus control unit 121 sets a first focus threshold based on the operation direction (toward infinity) of the focus ring 124 in step S801 and the width of the first focus threshold set in step S800. Here, with reference to FIG. 12, a method for setting the first focus threshold of this embodiment will be described. An arrow 1206 indicates the operation direction of the focus ring 124. A region 1200 indicates the range of the first focus threshold. In the example of FIG. 12, the first focus threshold range 1200 is divided into a range on the closest side and a range on the infinity side, with the in-focus position (0F) as the boundary, and is set so that the ratio of the threshold on the infinity side, which is the operation direction 1206 of the focus ring 124, is larger than the threshold on the closest side. In this way, by increasing the ratio of the range of the first focus threshold for the operation direction 1206 of the focus ring 124, it is possible to exclude objects on the closest side from options for the focus position when the user finishes operating the focus ring 124. On the other hand, if AF control is performed on the main subject without excluding objects on the closest side, there is a possibility that the focus position will shift in the opposite direction to the operation direction 1206 of the focus ring 124. Therefore, by increasing the ratio of the first focus threshold to the operation direction 1206 of the focus ring 124, it is possible to extract a large subject area without the focus position shifting in the opposite direction to the operation direction 1206 of the focus ring 124.

[0120] In step S805, the focus control unit 121 sets the first focus threshold value based on the operation direction (close side) of the focus ring 124 in step S801 and the width of the first focus threshold value set in step S800. In this case, since the operation direction of the focus ring 124 is the close side, the range of the first focus threshold value is set so that the ratio of the close side is greater than the infinity side.

[0121] In step S803, focus control unit 121 determines whether the operation of focus ring 124 has ended, and if it determines that the operation of focus ring 124 has ended, proceeds to step S804, otherwise proceeds to step S806. Focus control unit 121 determines that the operation of focus ring 124 has ended if the operation speed of focus ring 124 is decelerating, and determines that the focus ring is being operated if the operation speed of focus ring 124 is accelerating or constant.

[0122] In step S804, if it is determined in step S803 that the operation of the focus ring 124 has ended, the focus control unit 121 performs processing to set a second focus threshold (a range considered to be a second in-focus state), and proceeds to step S701 in FIG. 7. In this case, the second focus threshold is set to a width smaller than the first focus threshold set in step S800, for example. This is because, when the user ends the operation of the focus ring 124, the user performs an operation to focus on the intended subject, and it is expected that the focus position will not fluctuate after the operation of the focus ring 124 is ended. Therefore, by setting the representative area set in step S705 in FIG. 7 within the in-focus range, the amount of fluctuation in the focus position after the operation of the focus ring 124 is ended is small, and AF control can be performed on the main subject without degrading the quality of the video.

[0123] In step S806, when the focus control unit 121 determines that the focus ring 124 is being operated in step S803, it performs a process of setting a second focus threshold value and advances the process to step S701 in FIG. 7. In this case, the second focus threshold value is set to the same value as the first focus threshold value set in step S800. During the operation of the focus ring 124, there is no need to set a representative area from within the in-focus range, and the reference point set in step S704 is set as the representative area. Thereby, for example, when the reference point is the center of gravity of the subject area, it becomes possible to display the tracking candidate frame at the start of AF at the center of gravity position of the subject area in step S420 of FIG. 4. If the position of the tracking candidate frame at the start of AF displayed in step S420 of FIG. 4 is, for example, the center of gravity position of the subject area, etc., the user can easily grasp the AF start position after the operation of the focus ring 124 is completed.

[0124] <AF Frame Display Process> Next, referring to FIG. 9, the AF frame display process at the time of subject detection in step S417 of FIG. 4 will be described.

[0125] In step S901, the focus control unit 121 determines the focus mode. If it is the "MF / AF Switching Mode", the process advances to step S902; otherwise, the process advances to step S903.

[0126] In step S902, when the focus control unit 121 determines that the user has finished operating the focus ring 124, for the detected subject for which the AF frame was set in step S416 of FIG. 4, it displays a tracking face frame illustrated in FIG. 13(a). In the example of FIG. 13(a), a tracking frame 1302 indicating that tracking AF is to be executed for the detected subject 1301 for which the AF frame was set in step S416 of FIG. 4 is displayed.

[0127] In step S903, the focus control unit 121 determines whether the tracking candidate frame display setting is valid. If it is valid, the process advances to step S904; if it is invalid, the process advances to step S905.

[0128] In step S904, the focus control unit 121 displays a face frame 1304 and a tracking candidate frame 1305, as illustrated in Fig. 13(b), for a detected subject for which an AF frame was set in step S416 of Fig. 4 while the user is operating the focus ring 124. In the example of Fig. 13(b), a face frame 1304 indicating that the detected subject 1303 for which an AF frame was set in step S416 of Fig. 4 is in an approximately in-focus range is displayed. In addition, a tracking candidate frame 1305 indicating that the detected subject is a tracking candidate is displayed for a main subject specified by the user by operating the control ring 125 among the multiple detected subjects 1303 in the approximately in-focus range.

[0129] In step S905, the focus control unit 121 displays a face frame 1304, as illustrated in Fig. 13(c), for the detected subject for which an AF frame was set in step S416 in Fig. 4. In the example of Fig. 13(c), a face frame 1304 indicating that the detected subject is in the approximate in-focus range is displayed for the detected subject 1303 for which an AF frame was set in step S416 in Fig. 4. Furthermore, because the tracking candidate frame display setting is not enabled, the tracking candidate frame 1305 is not displayed for the main subject that the user specified by operating the control ring 125 among the multiple detected subjects 1303.

[0130] The tracking frame, face frame, and tracking candidate frame are displayed in different forms so that they can be distinguished by the user.

[0131] 6, if there are multiple detected subjects in the approximate-focus range, icon 1306 is displayed as shown in FIGS. 13(b) and 13(c). This prompts the user to operate the control ring 125, and notifies the user that the main subject cannot be changed using the focus ring 124. Note that instead of notification using icon 1306, notification may be made by continuing to display a tracking candidate frame at the AF frame position determined in step S602 of FIG. 6, and restricting switching of subjects.

[0132] Next, the AF frame display process when no subject is detected in step S420 of FIG. 4 will be described with reference to FIG.

[0133] In step S1001, the focus control unit 121 determines the focus mode, and if it is the "MF / AF switching mode", the process proceeds to step S1002, and if not, the process proceeds to step S1005.

[0134] In step S1002, the focus control unit 121 determines whether the AF control mode is "tracking AF," and if it is "tracking AF," proceeds to step S1003; otherwise, proceeds to step S1004.

[0135] In step S1003, when the user has finished operating the focus ring 124, focus control unit 121 displays a tracking frame on the main subject designated by the user through manual focus operation in step S418 of FIG.

[0136] In step S1004, the focus control unit 121 does not display the tracking frame.

[0137] In step S1005, the focus control unit 121 determines whether the tracking candidate frame display setting is enabled, and if it is enabled, the process proceeds to step S1006, and if it is disabled, the process proceeds to step S1008.

[0138] In step S1006, the focus control unit 121 determines whether the AF control mode is "tracking AF," and if it is "tracking AF," proceeds to step S1007; otherwise, proceeds to step S1008.

[0139] In step S1007, the focus control unit 121 displays a tracking candidate frame indicating that the subject for which the AF frame was set in step S419 in FIG. 4 is a tracking target while the user is operating the focus ring 124.

[0140] In step S1008, the focus control unit 121 does not display the tracking frame.

[0141] FIG. 14 is a diagram illustrating a method for displaying an AF frame when no subject is detected in this embodiment.

[0142] 14(a) to 14(d) show examples of transitions in the display state of the AF frame from before, during, and after operation of the focus ring 124. Subjects 1401 to 1403 shown in Fig. 14 respectively indicate subjects not detected by the subject area detection unit 126, with subject 1401 being on the infinity side, subject 1402 being closer than subject 1401, and subject 1403 being closer than subject 1402.

[0143] Fig. 14(a) shows an example of the imaging screen before operation of the focus ring 124. In the example of Fig. 14(a), no subject has been detected and the camera is in AF mode, so the AF frame is not displayed as described in Fig. 2(a).

[0144] Fig. 14(b) shows an example of an imaging screen during operation of the focus ring 124. In the example of Fig. 14(b), an AF frame is set around the subject 1402 by the AF frame determination process in step S419 in Fig. 4, and a tracking candidate frame 1404 indicating that the subject 1402 is a candidate for a tracking target is displayed superimposed on the subject 1402 at the start of tracking.

[0145] Fig. 14(c) shows an example of an imaging screen during operation of the focus ring 124 when manual focus operation is performed to an even closer position than in Fig. 14(b). In Fig. 14(c), as in Fig. 14(b), an AF frame is set around the subject 1403 by the AF frame determination process in step S419 in Fig. 4, and a tracking candidate frame 1404 is displayed superimposed on the subject 1403.

[0146] In addition, when the subject in Figures 14(a) to 14(c) is not detected, icon 1306 may be displayed as shown in Figures 13(b) and 13(c) to notify the user that the main subject can be changed using focus ring 124.

[0147] Fig. 14(d) shows an example of the imaging screen after completion of operation of the focus ring 124. In the example of Fig. 14(d), the focus mode is set to "MF / AF switching mode," and the AF control after completion of MF operation is set to "tracking AF." Therefore, a tracking frame 1405 is displayed superimposed, indicating that tracking AF will be performed on the subject 1403 that was a tracking candidate in Fig. 14(c).

[0148] Note that, in this embodiment, an example has been shown in which the tracking candidate frame 1404 is a rectangular frame with dashed lines, and the tracking frame 1405 is a rectangular frame with solid lines, but this is not limiting, and the shape, color, size, etc. of the frame may be changed. For example, the tracking candidate frame 1404 may be an orange double lock frame displayed with a fixed size, and the tracking frame 1405 may be a white double rectangular frame with a variable size according to the size of the subject.

[0149] According to this embodiment, by superimposing a tracking frame or a tracking candidate frame on the AF frame position set by manual focus operation when a subject is not detected, the user can easily grasp the subject to be tracked during manual focus operation and after the manual focus operation is completed.

[0150] [Other embodiments] This embodiment can also be realized by supplying a program that realizes one or more of the functions of the above-described embodiment to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more of the functions.

[0151] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0152] The disclosure of this specification includes the following control device, imaging device, control method, and program.

[0153] [Configuration 1] a focus detection means for detecting a focus state within a screen, the focus detection means acquiring first focus information determined based on a first range regarded as being in focus and second focus information determined based on a second range regarded as being in focus; extraction means for extracting a subject area based on the first focus information; an area setting means for setting a main object area from the object area extracted by the extraction means based on the second focus information; and a focus adjustment means for controlling focus adjustment so as to keep the focus on a subject corresponding to a main subject area set by the area setting means when switching from manual focus, which controls the position of a focus lens in response to a user's operation, to autofocus, which automatically controls the position of the focus lens.

[0154] [Configuration 2] 2. The control device according to configuration 1, wherein the first range regarded as in focus and the second range regarded as in focus are determined based on optical information of an optical system including the focus lens.

[0155] [Configuration 3] 3. The control device according to configuration 2, wherein the optical information includes at least one of focal length information, aperture information, and subject distance information.

[0156] [Configuration 4] The control device described in configuration 1, characterized in that the range considered to be the second focus is the same as the range considered to be the first focus, or the range considered to be the second focus is smaller than the range considered to be the first focus.

[0157] [Configuration 5] The control device according to configuration 1, wherein the range regarded as the second in-focus state is changed based on the operation information of the user.

[0158] [Configuration 6] 6. The control device according to configuration 5, wherein when the operation information indicates an end of operation, the range regarded as the second focus is made smaller than when the operation information indicates an operation in progress.

[0159] [Configuration 7] the first in-focus range and the second in-focus range are set on the infinity side and the close-up side of the current focus position, The control device described in configuration 5, characterized in that when the operation information is an operation to drive the focus lens toward the infinity side, at least one of the range considered to be the first in-focus range and the range considered to be the second in-focus range is larger on the infinity side than on the close-up side.

[0160] [Configuration 8] the first in-focus range and the second in-focus range are set on the infinity side and the close-up side of the current focus position, The control device described in configuration 5, characterized in that when the operation information is an operation to drive the focus lens toward the close-up side, at least one of the range considered to be the first in-focus range and the range considered to be the second in-focus range is larger on the close-up side than on the infinity side.

[0161] [Configuration 9] further comprising a detection means for detecting a non-subject region; 2. The control device according to configuration 1, wherein the extraction means excludes the non-subject region from the subject region.

[0162] [Configuration 10] 10. The control device according to configuration 9, wherein the non-subject area is an area including the ground and the sky.

[0163] [Configuration 11] The control device according to configuration 1, characterized in that when the manual focus is switched to the autofocus and the subject area does not exist, a predetermined area is set as the area to be focused on.

[0164] [Configuration 12] 12. The control device according to configuration 11, wherein the predetermined area is the center of the screen. [Configuration 13] 12. The control device according to configuration 11, wherein the predetermined area is an area where the focus detection result by the focus detection means is the closest.

[0165] [Configuration 14] A control device according to any one of configurations 1 to 13; and imaging means for capturing an object image formed by an optical system including the focus lens.

[0166] [Configuration 15] the imaging device is switchable between a plurality of focus modes, The imaging device according to configuration 14, wherein the plurality of focus modes include an AF mode that performs the autofocus, an MF mode that performs the manual focus, and an MF / AF switching mode that switches to the autofocus after the manual focus is completed.

[0167] [Method 1] a focus detection step of detecting a focus state within a screen and acquiring first focus information determined based on a first range regarded as being in focus and second focus information determined based on a second range regarded as being in focus; an extraction step of extracting a subject area based on the first focus information; a region setting step of setting a main subject region from the subject region extracted by the extraction step based on the second focus information; a focus adjustment step of controlling focus adjustment so as to keep the subject in focus corresponding to the main subject area set by the area setting step when switching from manual focus, which controls the position of the focus lens in response to a user's operation, to autofocus, which automatically controls the position of the focus lens.

[0168] [Program 1] A program for causing a computer to function as the control device according to any one of claims 1 to 13. [Explanation of symbols]

[0169] 100 Imaging device 106 Imaging unit 109 Display section 121 Focus control section 124 Control ring operation section 125 Focus ring operation section 126 Object area detection unit 150 Imaging optical system

Claims

1. a focus detection means for detecting a focus state within a screen, the focus detection means acquiring first focus information determined based on a first range regarded as being in focus and second focus information determined based on a second range regarded as being in focus; an extraction means for extracting a subject area based on the first focus information; an area setting means for setting a main object area from the object area extracted by the extraction means based on the second focus information; and a focus adjustment means for controlling focus adjustment so as to keep the focus on a subject corresponding to a main subject area set by the area setting means when switching from manual focus, which controls the position of a focus lens in response to a user's operation, to autofocus, which automatically controls the position of the focus lens.

2. 2. The control device according to claim 1, wherein the first in-focus range and the second in-focus range are determined based on optical information of an optical system including the focus lens.

3. 3. The control device according to claim 2, wherein the optical information includes at least one of a focal length, an aperture information, and a subject distance.

4. 2. The control device according to claim 1, wherein the second range regarded as being in focus is the same as the first range regarded as being in focus, or the second range regarded as being in focus is smaller than the first range regarded as being in focus.

5. 2. The control device according to claim 1, wherein the range regarded as the second in-focus state is changed based on operation information from the user.

6. 6. The control device according to claim 5, wherein when the operation information indicates an end of operation, the range regarded as the second focus is made smaller than when the operation information indicates an operation in progress.

7. the first in-focus range and the second in-focus range are set on the infinity side and the close-up side of the current focus position, The control device according to claim 5, characterized in that when the operation information is an operation to drive the focus lens toward the infinity side, at least one of the range considered to be the first in-focus range and the range considered to be the second in-focus range is larger on the infinity side than on the close-up side.

8. the first in-focus range and the second in-focus range are set on the infinity side and the close-up side of the current focus position, The control device according to claim 5, characterized in that when the operation information is an operation to drive the focus lens toward the close-up side, at least one of the range considered to be the first in-focus range and the range considered to be the second in-focus range is larger on the close-up side than on the infinity side.

9. further comprising a detection means for detecting a non-subject region; 2. The control device according to claim 1, wherein the extraction means excludes the non-subject region from the subject region.

10. The control device according to claim 9 , wherein the non-subject area is an area including the ground and the sky.

11. 2. The control device according to claim 1, wherein when the manual focus is switched to the autofocus, if the subject area does not exist, a predetermined area is set as the area to be focused on.

12. 12. The control device according to claim 11, wherein the predetermined area is the center of the screen.

13. 12. The control device according to claim 11, wherein the predetermined area is an area where the focus detection result by the focus detection means is the closest.

14. A control device according to any one of claims 1 to 13; and imaging means for capturing an object image formed by an optical system including the focus lens.

15. the imaging device is switchable between a plurality of focus modes, 15. The imaging device according to claim 14, wherein the plurality of focus modes include an AF mode in which the autofocus is performed, an MF mode in which the manual focus is performed, and an MF / AF switching mode in which the autofocus is performed after the manual focus is completed.

16. a focus detection step of detecting a focus state within a screen and acquiring first focus information determined based on a first range regarded as being in focus and second focus information determined based on a second range regarded as being in focus; an extraction step of extracting a subject area based on the first focus information; a region setting step of setting a main subject region from the subject region extracted by the extraction step based on the second focus information; a focus adjustment step of controlling focus adjustment so as to keep the subject in focus corresponding to the main subject area set by the area setting step when switching from manual focus, which controls the position of the focus lens in response to a user's operation, to autofocus, which automatically controls the position of the focus lens.

17. A program for causing a computer to function as the control device according to any one of claims 1 to 13.

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