Imaging device, control method, and program

Abstract

To achieve a technique that can photograph a subject targeted by a user and reduces flickering of exposure.SOLUTION: An imaging apparatus has imaging means, photometric means, subject detection means, setting means that sets the degree of weighting in performing photometry, and control means that controls exposure based on a result of photometry. When a subject detected by the subject detection means is included in a predetermined first range in an image, the setting means increases the weighting on a first subject included in the first range compared with the other subjects, and when the first subject exceeds a second range wider than the first range, if the subject does not exceed a third range wider than the second range, continues a state in which the weighting on the first subject is increased for a predetermined time and subsequently updates a photometry target subject on which weighting is increased, and in response to the first subject exceeding the third range, updates a target subject on which weighting is increased.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for determining a subject to be photographed. [Background technology]

[0002] Conventionally, a first method (FIG. 3(a)) is known in which a preset distance measurement frame (fixed frame) is displayed on a screen that displays an image captured by a live view or the like, and the user aligns the subject with the fixed frame to perform shooting (AF processing or AE processing), and a second method (FIG. 3(b)) is known in which the frame is automatically aligned with a main subject (such as a face) in the screen to perform shooting. When shooting with the first method, the user can easily align a stationary subject with the fixed frame, but if the subject moves quickly, it becomes difficult to align the subject with the fixed frame. In contrast, when shooting a fast-moving subject, a tracking function that automatically aligns a frame (tracking frame) with the main subject by the second method is effective, but depending on the condition of the subject, the tracking frame may not be aligned with the desired subject. For example, when multiple subjects are present in the screen, even if the user wants to shoot a subject near the center of the screen, if the entire screen is set as the detection target, the subject at the edge of the screen may be selected as the main subject.

[0003] To address this issue, Patent Document 1 describes a method in which a first area and a second area are set within a screen, centered on a reference point of a captured image, and even if the main subject moves outside the first area, if it is within the second area it is maintained as a tracking target, and if a predetermined time has passed since the main subject moved outside the second area, a new tracking target is selected from the subjects included in the first area. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-7272 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the size of the second area is variable, but depending on the manner and speed of the subject's movement, the main subject being tracked may move outside the second area, which may prevent the user from capturing the intended subject, or may cause exposure fluctuations (flickering) as the tracking target is changed.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to realize a technology that enables a user to capture a desired subject and reduces exposure flicker by appropriately weighting a detected subject for which exposure is performed according to the condition of the subject at the time of shooting. [Means for solving the problem]

[0007] In order to solve the above problems and achieve the object, an image pickup apparatus of the present invention comprises an image pickup means for picking up an optical image of a subject formed through an image pickup optical system and outputting the image, a photometry means for measuring the photometry of the target subject, a subject detection means for detecting a subject included in the image output from the image pickup means, and a photometry means for detecting a photometry of the subject included in the image output from the image pickup means. Area within the image A setting means for setting a determination means for determining whether a photometric value of the object measured by the photometric means is valid; and a control means for controlling exposure based on a photometry result of the photometry means, wherein when the subject detected by the subject detection means is included in a predetermined first range in the image, the setting means sets a value for a first subject included in the first range. The photometric value More effective than other subjects It was determined to be effective When the first object exceeds a second range wider than the first range, if the first object does not exceed a third range wider than the second range, the first object is held in a constant state for a predetermined time. The photometric value for is valid. After continuing the state Photometric values ​​are valid The subject Newly Determined and the first object exceeds the third range. The photometry value is valid when The subject Newly Determined do. Effect of the Invention

[0008] According to the present invention, by appropriately weighting the subject to be detected for exposure depending on the condition of the subject at the time of shooting, etc., it is possible for the user to shoot the subject he or she is aiming at and exposure flicker can be reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing an apparatus configuration according to an embodiment of the present invention. [Diagram 2] 4 is a flowchart showing the operation during shooting in this embodiment. [Diagram 3] 1A and 1B are diagrams for explaining the positional relationship between a distance measurement frame and a subject according to the related art. [Figure 4] 4A and 4B are diagrams for explaining the positional relationship between a distance measurement frame and a subject in the embodiment; [Diagram 5] 5A to 5C are diagrams for explaining a method of acquiring photometric values ​​of a subject area and a distance measuring area according to the present embodiment. [Figure 6] 6A to 6C are diagrams for explaining a validity determination process based on the positional relationship between a fixed frame, a margin range, and a tracking frame according to the present embodiment. [Figure 7] 6A and 6B are diagrams for explaining reasons for changing the validity determination conditions in the present embodiment. [Figure 8] 6A to 6C are diagrams illustrating an example of changing the validity determination condition depending on the lens focal length in the present embodiment. [Figure 9] 5 is a diagram illustrating an example of the relationship between the lens focal length and the validity determination condition according to the embodiment. [Figure 10] 6A to 6C are diagrams for explaining an example of changing the validity determination condition depending on the subject speed in the present embodiment. [Figure 11] 5 is a diagram illustrating an example of the relationship between subject speed and validity determination conditions in the present embodiment. [Figure 12] 6A to 6C are diagrams for explaining an example in which the validity determination conditions are changed depending on the type of subject in the present embodiment. [Figure 13] 5A and 5B are diagrams illustrating examples of the relationship between the type of subject and the validity determination conditions according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] [Summary] First, an overview of this embodiment will be described with reference to FIG.

[0012] In this embodiment, as shown in Fig. 4(a), a subject frame (tracking frame) 401 showing a main subject and a preset distance measurement frame (fixed frame) 402 can be simultaneously displayed on a screen displaying a captured image. Then, as shown in Figs. 4(b) to (d), a predetermined margin range 403 is set in the fixed frame 402, and depending on the positional relationship between the main subject to be tracked (tracking frame 401) and the fixed frame 402 and the predetermined margin range 403, it is determined whether to detect the main subject to which the tracking frame 401 is attached or to detect a subject existing within the fixed frame 402, thereby enabling the user to capture a subject that he or she is aiming at and reducing exposure flicker.

[0013] Fig. 4(a) shows an example of a screen displaying a live view visible to the user, with 401 being a tracking frame and 402 being a fixed frame. When the tracking frame 401 and the fixed frame 402 are displayed simultaneously as in Fig. 4(a), if a subject is not detected, a subject inside the fixed frame 402 is validated as a detection target for photographing (AF processing or AE processing).

[0014] 4(b) to (d), a predetermined margin range 403 is set by enlarging the fixed frame 402 as a reference, and the size of the predetermined margin range 403 is appropriately set according to the type of lens, the movement or type of the subject, the shooting mode, etc. The tracking frame 401, the fixed frame 402, and the margin range 403 are displayed in a manner that makes them identifiable on the image by making the types of lines or colors different from one another.

[0015] In this way, even if the main subject (tracking frame 401) moves outside the fixed frame 402 as shown in FIG. 4(c), if the center of the subject is inside the predetermined margin range 403, the main subject is maintained (enabled) as a detection target, and the fixed frame 402 is disabled. Also, if the center of the subject moves outside the predetermined margin range 403 as shown in FIG. 4(b), the subject is disabled as a detection target, and the fixed frame 402 is enabled. As a result, even if the movement of the subject targeted by the user in the fixed frame 402 is large and the center of the subject is slightly deviated from the fixed frame 402, the subject targeted by the user is not disabled as a detection target. Also, even if there are multiple subjects in an image as shown in FIG. 4(d), by setting a predetermined margin range 403 based on the fixed frame 402, the subject targeted by the user can be photographed as the main subject, and exposure flicker can be reduced.

[0016] [Embodiment 1] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an image pickup apparatus according to the present invention is applied to a digital camera will be described in detail below with reference to the accompanying drawings.

[0017] The imaging device of the present invention is not limited to a digital camera, but can be applied to any device equipped with an AE (automatic exposure) function, an AF (automatic focusing) function, and a subject detection function (tracking function), such as a smartphone (a type of mobile phone) or a tablet device.

[0018] <Device Configuration> With reference to FIG. 1, the configuration and functions of a digital camera (hereinafter, camera) according to this embodiment will be described.

[0019] FIG. 1 is a block diagram showing the configuration of a camera 100 according to this embodiment.

[0020] The control unit 101 is an arithmetic processing unit such as a CPU or an MPU that controls the entire camera 100. The control unit 101 executes a program loaded in the memory unit 102 to realize the processing of a flowchart that will be described later.

[0021] The memory unit 102 includes a volatile memory such as a RAM, and is used as a work memory for storing image data output from the image processing unit 108 described later, and for expanding constants, variables, programs, etc. for the operation of the control unit 101.

[0022] The operation unit 103 includes switches, buttons, dials, etc. that accept user operations such as power on / off, shooting preparation instructions, shooting instructions, menu screen display, operation mode change, etc. The operation unit 103 also includes a touch sensor 104 that can detect touch operations on a display unit 109, which will be described later. The operation mode of the camera 100 can be switched to, for example, a still image shooting mode, a video recording mode, or a playback mode.

[0023] The imaging unit 106 has an image sensor composed of photoelectric conversion elements such as CCD and CMOS that converts an optical image of a subject formed by an imaging optical system 105 including a lens, an aperture, a shutter, and mechanisms for driving them into an electrical signal. The imaging unit 106 captures the optical image of the subject and outputs the generated analog image signal to the A / D conversion unit 107.

[0024] The A / D conversion unit 107 converts an analog image signal output from the imaging unit 106 into a digital signal. In this embodiment, the exposure time of the imaging unit 106 is adjusted by a shutter, but the present invention is not limited to this. For example, the imaging unit 106 may have an electronic shutter function and adjust the exposure time by a control signal.

[0025] The image processing unit 108 performs predetermined pixel interpolation, resizing such as reduction, and color conversion processing on the data output from the A / D conversion unit 107. The image processing unit 108 also performs predetermined calculation processing using captured image data, and the control unit 101 performs AF (autofocus) processing, AE (auto exposure) processing, EF (flash pre-flash) processing, and AWB (auto white balance) processing based on the calculation results.

[0026] Display unit 109 includes an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display, and displays the shooting state of camera 100, captured images, various settings, operation modes, etc. Display unit 109 is provided with touch sensor 104. Touch sensor 104 is capable of detecting contact (touch operation) with the display surface of display unit 109 (the touch operation surface of touch sensor 104).

[0027] The connection unit 110 is an interface connector that connects an external device such as an external monitor or external storage to the camera body and transmits and receives images and audio. By connecting the camera body to an external monitor via the connection unit 110, it becomes possible to display the screen of the display unit 109 on the external monitor. In addition, by connecting the camera body to an external storage via the connection unit 110, it becomes possible to store image data captured by the camera in the external storage. The connection unit 110 is, for example, an analog output terminal such as a composite terminal, an S video terminal, a D terminal, a component terminal, or an analog RGB terminal, or a digital output terminal such as a DVI terminal or an HDMI (registered trademark) terminal.

[0028] The compression / expansion unit 111 compresses and encodes the image data output from the image processing unit 108 and stored in the memory unit 102 in a predetermined format (such as JPEG) and stores it in the memory unit 112, and reads the encoded image file from the memory unit 112 and decodes the image signal.

[0029] The storage unit 112 is a non-volatile memory such as a ROM, or a memory card, a hard disk, etc. The storage unit 112 stores image files, constants for the operation of the control unit 101, programs, etc.

[0030] The AF processing unit 113 performs AF processing to adjust the focus by displacing the position of the focus lens of the imaging optical system 105 based on the AF calculation processing result (phase difference and contrast) performed by the control unit 101 using the image data generated by the image processing unit 108. Note that in this embodiment, depending on the result of the validity determination processing described later, there are cases where AF processing is performed on a subject at an arbitrary position (fixed frame) such as the center of an image, and cases where AF processing is performed on a subject to be tracked (tracking frame) such as a person's face or an animal.

[0031] The AE processing unit 114 performs AE processing to adjust the brightness to an appropriate level by changing the aperture diameter of the imaging optical system 105 based on the photometry result (difference from appropriate brightness) from the AE calculation processing performed by the control unit 101 using image data generated by the image processing unit 108. Note that the AE processing in this embodiment performs AE calculation processing using photometry information obtained by the control unit 101 from the entire image and photometry information obtained by the AF processing unit 113 from a main subject (fixed frame or tracking frame) on which AF processing is performed.

[0032] The AE calculation processing result ΔBV is calculated by the following formula.

[0033] ΔBV = photometric value of entire image + photometric value of main subject + various correction values The EF processor 115 performs EF (pre-flash) processing to emit a strobe 116 to irradiate the subject with supplementary light when the brightness during shooting is not appropriate.

[0034] The subject detection unit 121 performs subject detection processing to detect the type, part, or state (type) of the subject, and the position and size (area) of the subject, using image data generated by the image processing unit 108. The subject detection unit 121 also has a subject tracking function that displays a tracking frame around a main subject determined automatically or by a user operation from one or more subjects detected in an image as a tracking target.

[0035] The judgment condition setting unit 122 sets a fixed frame and valid judgment conditions (margin range) that are displayed together with a tracking frame on the screen of the display unit 109 during live view, in which an image captured by the imaging unit 106 (live view image) is displayed in real time. The fixed frame is displayed fixedly in the center of the screen of the display unit 109, but its position and size can be set by a user operation. A subject within the fixed frame or within a margin range that satisfies the valid judgment conditions, which will be described later, becomes a target for AE processing.

[0036] Validity determination section 123 performs a validity determination process, which will be described later, based on the tracking frame of the main subject determined by subject detection section 121, and the fixed frame and validity determination conditions (margin ranges) set by determination condition setting section 122.

[0037] <Photographing Operation> Next, the photographing operation of the camera 100 of this embodiment will be described.

[0038] First, when a user turns on the power supply included in the operation unit 103 of the camera 100, the operation unit 103 notifies the control unit 101 of the power-on operation, and the control unit 101 supplies the necessary power to each component of the camera 100.

[0039] When power is supplied to each component of the camera 100, a shutter included in the imaging optical system is opened, and subject image light incident through the imaging optical system 105 is formed on the imaging surface of the imaging unit 106. The imaging unit 106 reads out the electric charges accumulated in the image sensor, and outputs them to the A / D conversion unit 107 as an analog image signal.

[0040] The A / D conversion unit 107 performs sampling and gain adjustment on the analog image signal output from the imaging unit 106, converts it into a digital image signal, and outputs it to the image processing unit 108.

[0041] The image processing unit 108 performs various image processing on the digital image signal output from the A / D conversion unit 107 to generate image data, stores the image data in the memory unit 102, and outputs the image data to the control unit 101, the subject detection unit 121, the judgment condition setting unit 122, and the validity judgment unit 123.

[0042] The subject detection unit 121 performs subject detection processing using image data generated by the image processing unit 108, and acquires information on the main subject. In this embodiment, the information on the main subject is, for example, information on a face area occupying an image that is obtained from the center coordinates and size of a person's face. Note that, instead of the face area information, information obtained by human body / torso detection, animal detection, or the like may be used as long as the information is capable of identifying the subject area.

[0043] In the AE processing and AF processing of this embodiment, a subject within a fixed frame previously set by the user or a subject within a margin range that satisfies the validity determination condition set by the determination condition setting unit 122 is detected.

[0044] The control unit 101 performs AF processing by the AF processing unit 113 and AE processing by the AE processing unit 114, using information on the subject region obtained by the subject detection unit 121 and information on the fixed frame and validity determination conditions obtained by the determination condition setting unit 122. The validity determination conditions will be described later.

[0045] When a shutter button included in the operation unit 103 of the camera 100 is half-pressed, a shooting preparation instruction (shutter switch signal SW1 ON) is input from the operation unit 103 to the control unit 101. The control unit 101 performs AF processing and AE processing using image data at the time of receiving the shooting preparation instruction, and obtains optimal focus and exposure conditions for shooting.

[0046] When a shutter button included in the operation unit 103 of the camera 100 is fully pressed, a shooting instruction (shutter switch signal SW2 ON) is input to the control unit 101 from the operation unit 103. When the control unit 101 receives the shooting instruction, it starts a series of shooting processes (main shooting process) from reading out a signal from the imaging unit 106 to writing the captured image as an image file in the storage unit 112. In the main shooting process, the control unit 101 detects a current luminance value using image data output from the image processing unit 108, and when it determines that the luminance value is darker than a predetermined threshold, it causes the EF processing unit 115 to emit light from the strobe 116.

[0047] <Processing Flow> Next, the operation of the camera 100 of this embodiment during shooting will be described with reference to FIG.

[0048] 2 is a flowchart showing the operation of the camera 100 of this embodiment when photographing. The process of FIG. 2 is realized by the control unit 101 expanding a program stored in the storage unit 112 into the memory unit 102, executing the program, and controlling each component of the camera 100.

[0049] In step S201, the control unit 101 supplies power to each component of the camera 100 in response to the power being turned on.

[0050] In step S202, the control unit 101 acquires a live view image captured by the imaging unit .

[0051] In step S203, the control unit 101 acquires information on the position and size of the fixed frame and the margin range displayed on the live view image. Note that in this embodiment, the fixed frame is a single frame that is arbitrarily set by a user operation.

[0052] In step S204, the control unit 101 acquires a subject area using the live view image acquired in step S202 by the subject detection unit 121. In this embodiment, face detection is used, but body detection, animal detection, etc. may also be used.

[0053] In step S205, the control unit 101 acquires the photometric values ​​of the object and each area of ​​the fixed frame obtained in steps S203 and S204. The photometric values ​​are calculated by dividing the entire image into a number of blocks as shown in FIG. 5(a) and using the Y value calculated and averaged for each block. The photometric value of the ranging area (fixed frame) 502 is the average luminance of the shaded area shown in FIG. 5(b). The luminance of the object area (tracking frame) 501 is calculated by the average luminance of the area (shaded area in FIG. 5(c)) where the object area obtained by object detection corresponds to the block integration area.

[0054] In steps S206 and S207, the control unit 101 sets parameters for the validity determination conditions in the validity determination process, and executes the validity determination process. The details of the validity determination process will be described later.

[0055] In step S208, the control unit 101 acquires a photometric value calculated from the subject that has been validated by the validation determination process.

[0056] In step S209, the control unit 101 executes AE processing by the AE processing unit 114 using the photometric value obtained in step S208, and acquires a live view image captured by the imaging unit .

[0057] In step S210, the control unit 101 determines whether or not the shutter switch signal SW1 is turned on. If the control unit 101 determines that the shutter switch signal SW1 is not turned on, the process returns to step S202, that is, the process of steps S202 to S209 is repeated until the shutter switch signal SW1 is turned on. If the control unit 101 determines that the shutter switch signal SW1 is turned on, the process proceeds to step S211.

[0058] In step S211, the control unit 101 obtains the photometric value obtained in step S208 as the final photometric value.

[0059] In step S212, the control unit 101 determines whether the shutter switch signal SW2 is turned on. If the control unit 101 determines that the shutter switch signal SW2 is not turned on, the process returns to step S210. If the control unit 101 determines that the shutter switch signal SW2 is turned on, the process proceeds to step S213.

[0060] In step S213, the control unit 101 performs a series of image capturing processes (main image capturing processes) from reading out a signal from the image capturing unit 106 to writing the captured image in the storage unit 112 as an image file.

[0061] <Validity Determination Process> Next, the validity determination process in step S207 in FIG. 2 will be described with reference to FIGS.

[0062] The validity determination process of this embodiment is a process for determining which frame contains a subject that is to be determined as a valid target for photometric value detection (photometric target) when a fixed frame and a tracking frame are displayed simultaneously on a screen displaying an captured image.

[0063] 6(a) to (e) show examples of a fixed frame, a margin range, and a subject (tracking frame) displayed on a screen displaying a captured image in the validity determination process of this embodiment.

[0064] 6(a) to 6(e), region 601 indicates a tracking frame for a main subject, and region 602 indicates a fixed frame. The position and size of tracking frame 601 are set and displayed according to the position and size of the main subject (a person's face). The position and size of fixed frame 602 are set according to a user operation (step S206 in FIG. 2).

[0065] Rectangular areas 603 to 605 are set based on fixed frame 602 according to parameters of validity determination conditions (step S206 in FIG. 2), and are margin ranges used in the validity determination process (step S207 in FIG. 2). The size of area 603 is smaller than the size of area 604, which is smaller than the size of area 605 (area 603<area 604<area 605), and can be calculated using the following formula:

[0066] Size of area 603 = size of fixed frame x p + size of tracking frame x q + size of screen x r Size of area 604 = size of fixed frame x s + size of tracking frame x t + size of screen x u Size of area 605 = size of fixed frame x v + size of tracking frame x w + size of screen x x The above formula is an example, and other calculation formulas may be used. The parameters p, q, r, s, t, u, v, w, and x in the above formula are validity determination conditions for setting the weighting degree of the subject as a detection target for performing photometry in AE processing, and are, for example, the following values. p=0.3, q=0.3, r=0 s=0.3, t=0.3, u=0.05 v=0.3, w=0.3, x=0.1 The tracking frame 601, the fixed frame 602, and the areas 603 to 605 are displayed in a manner that makes them identifiable on the screen that displays the captured image, for example, by making the types of lines or colors different from one another.

[0067] In the validity determination process of this embodiment, if the subject center is located closer to the center of the fixed frame 602 than the boundary line of the area 603, the main subject (tracking frame) is validated as a detection target for photometry, and the fixed frame is invalidated. In addition, the area 604 is a margin range for determining whether the subject once validated in the area 603 is valid or invalid, and is invalidated when the subject center validated in the area 603 exceeds the rectangular boundary line of the area 604. The area 605 is a margin range that continues to be validated for a predetermined time, and even if the subject center once validated in the area 603 exceeds the area 604, it continues to be validated for a predetermined time if it does not exceed the boundary line of the area 605, and is invalidated after the predetermined time has elapsed in that state. In addition, if the subject center once validated in the area 603 exceeds the area 604 and also exceeds the area 605, it is invalidated without waiting for a predetermined time.

[0068] Figures 6(a) to (e) illustrate the transition of a tracking frame 601 relative to a fixed frame 602 and margin ranges 603 to 605 on a screen displaying a captured image, and illustrate the state change from when a main subject (a person's face) indicated by the tracking frame 601 enters area 604 from outside area 605 and is activated, until it moves out of area 605 and is deactivated.

[0069] In FIG. 6(a), since the tracking frame (subject center) 601 is outside the area 605, the tracking target subject is invalidated, and the fixed frame 602 is valid. In FIG. 6(b), since the tracking frame (subject center) 601 is inside the boundary line of the area 603, the tracking target subject is validated, and the fixed frame 602 is invalidated. In FIG. 6(c), after the tracking target subject is validated in FIG. 6(b), the tracking frame (subject center) 601 goes outside the boundary line of the area 603 but is inside the boundary line of the area 604, so the validity continues, and the invalidation of the fixed frame 602 also continues. In FIG. 6(d), since the tracking target subject goes outside the boundary line of the area 604 but is inside the boundary line of the area 605, the validity continues for a predetermined time (the fixed frame 602 is invalidated), and after the predetermined time has elapsed, the tracking target subject is invalidated, and the fixed frame 602 is valid. In FIG. 6(e), the subject to be tracked is outside the boundary line of the area 605, so it is invalidated and the fixed frame 602b is validated.

[0070] In the above-mentioned validity determination process, each of the regions 603 to 605 is set based on the size of the fixed frame 602 that is set in advance, but for example, when a moving subject as shown in Fig. 7 is photographed with a margin range that is optimally set for photographing a static subject, the subject may move outside the margin range and be easily invalidated, and the user may not be able to photograph the intended subject as the main subject. To prepare for such a case, in this embodiment, the parameters of the validity determination conditions are changed according to various situations, as described below.

[0071] (Conditions change according to lens type) In a lens-interchangeable camera or a camera with a zoom function, the focal length of the lens varies greatly when shooting, so if the amount of hand shake by the user increases when shooting at a high magnification, the subject the user aimed at is likely to be invalidated. To deal with such a case, the parameters of the validity determination conditions for areas 603 to 605 are increased as the focal length of the lens increases, as shown in Figs. 8 and 9.

[0072] It is possible to increase the parameters of the validity determination conditions for areas 603 to 605 as the degree of correction by the image stabilization function increases, and to increase the parameters of the validity determination conditions for areas 603 to 605 when the image stabilization function is not operating compared to when the image stabilization function is operating.

[0073] (Conditions change depending on subject movement) Focusing on the movement of the subject, if the subject moves slowly (e.g., walking), the possibility of invalidating the subject targeted by the user is low, but if the subject moves quickly, such as in sports photography, the possibility of invalidating the subject targeted by the user increases. To deal with such cases, as shown in Figs. 10 and 11, the parameters of the validity determination conditions of the regions 603 to 605 are increased as the speed of the subject (e.g., the number of pixels moving during one frame in a VGA image) increases. However, if there are multiple subjects in an image, there is a possibility that a subject other than the desired subject will become the tracking target, so the parameters of the validity determination conditions of the regions 603 and 604 are not changed, and the parameters of the validity determination conditions of the region 605 are increased.

[0074] (Change conditions according to subject type) For example, when at least one of a person, an animal, and a vehicle is detected as the type of the subject, the ease with which the user can capture the subject varies greatly depending on the type of the subject. For example, if the subject is a person or a vehicle, the movement can be predicted to some extent, but if the subject is an animal or a bird, it is difficult to predict, and if the subject suddenly moves, the subject targeted by the user is likely to be invalidated. To deal with such cases, as shown in Figs. 12 and 13, the parameters of the validity determination conditions of the regions 603 to 605 are changed depending on the type of the subject. For example, if the subject is a dog, a cat, a bird, etc., the parameters of the validity determination conditions of the regions 603 to 605 are relatively larger than those of the subject being a person or a vehicle. Furthermore, if it is determined that the subject is flying or running based on the shape of the subject, the parameters of the validity determination conditions of the regions 603 to 605 are further increased.

[0075] Furthermore, parameters of the validity determination conditions of the regions 603 to 605 may be changed according to the direction in which the subject is moving. For example, the regions 603 to 605 may be made larger in the direction in which the subject is moving than in the direction in which the subject is not moving.

[0076] (Conditions change depending on the shooting mode) The ease of capturing a subject also differs depending on whether a still image or a video is shot. When shooting a still image, it is easy to fit the subject in the vicinity of the fixed frame 602, but when shooting a video, the angle of view may be fixed, which increases the movement of the subject around the fixed frame 602 and increases the possibility that the subject targeted by the user will be invalidated. To deal with such cases, the parameters of the validity determination conditions for the areas 603 to 605 are made larger when shooting a video than when shooting a still image. For example, the parameters of the validity determination conditions for the areas 603 to 605 are uniformly set to 1.2 times when shooting a video compared to when shooting a still image.

[0077] (Conditions change according to the size of the fixed frame) In this embodiment, the position and size of the fixed frame 602 can be changed, so the parameters of the validity determination conditions of the areas 603 to 605 are also changed in conjunction with the position and size of the fixed frame 602. However, when the positions or sizes of the areas 603 to 605 reach the ends of the angle of view, the ends of the angle of view are set as the upper limit for enlargement.

[0078] (Changes conditions depending on whether tracking frame is displayed or not) In this embodiment, it is assumed that the tracking frame 601 is displayed, but there are cases where the tracking frame 601 can be set to be hidden (that is, the tracking function is turned off). In the case of a setting to display the tracking frame 601, the user can easily recognize whether the subject corresponding to the tracking frame 601 or the fixed frame 602 is enabled or disabled as a detection target, so the parameters of the validity determination conditions are increased in the direction of enlarging the areas 603 to 605. However, in the case of a setting to hide the tracking frame 601, it is expected that the user will feel uncomfortable when taking a picture depending on the positional relationship between the subject and the fixed frame 602, so when the tracking frame 601 is hidden, the parameters of the validity determination conditions of the areas 603 to 605 are made smaller than when the tracking frame 601 is displayed. For example, when the tracking frame is hidden, the parameters of the validity determination conditions of the areas 603 to 605 are set to 0.8 times that when the tracking frame is displayed.

[0079] In addition to the above examples, the parameters of the validity determination conditions of the areas 603 to 605 may be varied according to the AF mode (one-point AF, area expansion AF, zone AF, whole area AF, etc.) and the metering mode (evaluative metering, average metering, spot metering, etc.).

[0080] According to this embodiment, even if the subject (tracking frame) 601 targeted by the user is outside the range of the fixed frame 602, if it is included in a first margin range 603 expanded from the fixed frame 602, it is enabled as a detection target for photographing (AF processing and AE processing) (the fixed frame 602 is disabled). Also, if the subject (tracking frame) 601 targeted by the user exceeds a predetermined second margin range 604 larger than the first margin range 603, but does not exceed a third margin range 605 larger than the second margin range 604, it continues to be enabled as a detection target for photographing (AF processing and AE processing) for a predetermined time (the fixed frame 602 is disabled). Furthermore, if the subject (tracking frame) 601 targeted by the user exceeds the third margin range 605, it is disabled as a detection target for photographing (AF processing and AE processing), and a subject to be enabled as a detection target for photographing (AF processing and AE processing) from among the subjects present inside the first margin range 603 is determined and updated. In this way, by setting an appropriate margin range according to the function at the time of shooting and the condition of the subject, the subject targeted by the user is not invalidated as a detection target for shooting (AF processing and AE processing), and exposure flicker can also be reduced.

[0081] In this embodiment, an example in which a tracking frame and a fixed frame are simultaneously displayed on a screen that displays a captured image has been described, but the present invention is also applicable to cameras that do not have a subject tracking function or cameras that can turn on / off the tracking function. In cameras that do not have a subject tracking function or cameras that can turn on / off the tracking function, the tracking frame is not displayed, but in this case, it is sufficient to determine whether the subject in the image is valid or invalid as a detection target.

[0082] [Other embodiments] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0083] The invention is not limited to the above-described embodiments, and various modifications and variations are possible 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. [Explanation of symbols]

[0084] 101...control section, 105...imaging optical system, 106...imaging section, 108...image processing section, 109...display section, 113...AF processing section, 114...AE processing section, 121...subject detection section, 122...determination condition setting section, 123...validity determination section

Claims

1. an imaging means for capturing an optical image of a subject formed via an imaging optical system and outputting the image; A photometry means for measuring the photometry of a target object; a subject detection means for detecting a subject included in an image output from the imaging means; a setting means for setting a range within the image when the photometry means performs photometry; a determination means for determining whether a photometric value of the object measured by the photometric means is valid; a control means for controlling exposure based on a photometry result of the photometry means, the determination means determines, when the subject detected by the subject detection means is included in a predetermined first range within the image, that the photometric value for the first subject included in the first range is more valid than that for other subjects; when the first subject exceeds a second range wider than the first range, but does not exceed a third range wider than the second range, the photometric value for the first subject continues to be valid for a predetermined period of time, and then determines a new subject for which the photometric value is valid; and when the first subject exceeds the third range, determines a new subject for which the photometric value is valid.

2. A first frame indicating an area of ​​a subject in the image and a second frame set in a fixed area in the image can be simultaneously displayed on the image, 2. The imaging device according to claim 1, wherein the second frame can be set by a user operation, and the first range, the second range and the third range are areas enlarged at a predetermined magnification based on the second frame.

3. 3. The imaging device according to claim 2, wherein the first range, the second range and the third range have different sizes depending on whether the first frame is displayed or not.

4. 3. The imaging device according to claim 2, wherein the first range, the second range, and the third range have different sizes depending on whether a still image is captured or a moving image is captured.

5. 2. The imaging apparatus according to claim 1, wherein the setting unit increases the first range, the second range and the third range as a degree of correction by a camera shake correction function increases.

6. 2. The imaging device according to claim 1, wherein the setting means sets the first range, the second range and the third range to be larger when the image stabilization function is not operating than when the image stabilization function is operating.

7. 2. The imaging apparatus according to claim 1, wherein the setting means changes the sizes of the first range, the second range and the third range depending on the type of the subject to be detected by the subject detection means.

8. 8. The imaging apparatus according to claim 7, wherein the subject detection means detects at least one of a person, an animal, and a vehicle as the type of the subject.

9. the first range, the second range, and the third range are changeable in accordance with a movement of the subject; 2. The imaging apparatus according to claim 1, wherein the setting means sets the first range, the second range and the third range to be larger when the subject is moving than when the subject is stationary.

10. the first range, the second range, and the third range are changeable depending on a direction in which the subject is moving; 2. The imaging apparatus according to claim 1, wherein the setting means sets the first range, the second range and the third range in a direction in which the subject is moving to be larger than those in a direction in which the subject is not moving.

11. 2. The imaging device according to claim 1, wherein the setting unit increases the first range, the second range and the third range as the focal length of a lens included in the imaging optical system increases.

12. A control method for an imaging device, comprising: The imaging device includes: an imaging means for capturing an optical image of a subject formed via an imaging optical system and outputting the image; A photometry means for measuring the photometry of a target object; a subject detection means for detecting a subject included in an image output from the imaging means, The control method includes: a setting step of setting a range within the image when the photometry is performed by the photometry means; a determination step for determining whether a photometric value of the object measured by the photometric means is valid; a control step of controlling exposure based on a photometry result of the photometry means, a control method for an imaging device, characterized in that in the determination step, when the subject detected by the subject detection means is included in a predetermined first range within the image, it is determined that the photometric value for the first subject included in the first range is more valid than that for other subjects; when the first subject exceeds a second range wider than the first range, but does not exceed a third range wider than the second range, the photometric value for the first subject continues to be valid for a predetermined period of time, and then a new subject for which the photometric value is valid is determined; and when the first subject exceeds the third range, a new subject for which the photometric value is valid is determined.

13. A computer-readable program for causing a computer to execute the method for controlling an image pickup apparatus according to claim 12.

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