APPARATUS HAVING EXPOSURE CONTROL, IMAGING APPARATUS, CONTROL METHOD, AND STORAGE MEDIUM

An apparatus includes an acquisition unit configured to acquire an image, a detection unit configured to detect an object from the image, a photometry unit configured to perform photometry on the image in accordance with a set photometry mode, wherein the photometry mode includes a first photometry mode in which an exposure is determined by weighting a region having a relatively high luminance value in comparison with a region having a relatively low luminance value at least in a photometry region, and wherein, in a case where the detection unit detects the object in the image in a state where the first photometry mode is selected, the photometry unit performs photometry in the first photometry mode by using a region of the object as the photometry region.

BACKGROUND

Technical Field

The aspect of the embodiments relates to an apparatus, an imaging apparatus, a control method, and a storage medium.

Description of the Related Art

Conventional digital cameras perform image capturing through automatic exposure control using an Auto Exposure (AE) function. In the automatic exposure control, setting an exposure of the entire screen to a proper exposure is a typical practice. However, such an automatic exposure control has an issue in a situation where an entire screen is dark but has partially bright regions. More specifically, if such a screen is subjected to photometry to set an exposure of the entire screen to a proper exposure, the bright regions are to be overexposed. Among methods for addressing this issue is a method called highlight photometry in which photometry is mainly performed on a high-luminance region in a screen. The highlight photometry generally uses the maximum output photometry value in the entire screen to set the exposure setting with which overexposure in a high-luminance region is prevented. However, if an extremely high-luminance region exists in a screen during the highlight photometry, the exposure setting may be set such that regions other than the extremely high-luminance region unnecessarily become dark to prevent overexposure of the extremely high-luminance region. Japanese Patent Application Laid-Open No. 2015-166767 discusses a technique for determining an extremely high-luminance region based on an average luminance of an entire screen and excluding the extremely high-luminance region from a photometry operation, to prevent or reduce the influence of the extremely high luminance region.

However, the technique discussed in Japanese Patent Application Laid-Open No. 2015-166767 is able to exclude only the extremely high luminance region. For example, in a case where an imaging object is the face of a person wearing a white cloth, photometry is mainly performed on the cloth, which is a high-luminance region, which lead to image capturing with the face unnecessarily darkened.

SUMMARY

According to an aspect of the embodiments, an apparatus includes at least one processor; and at least one memory coupled to the at least one processor storing instructions that, when executed by the at least one processor, cause the at least one processor to function as an acquisition unit configured to acquire an image, a detection unit configured to detect an object from the image, a calculation unit configured to calculate luminance values of the image, and a photometry unit configured to perform photometry on the image in accordance with a set photometry mode, wherein the photometry mode includes a first photometry mode in which an exposure is determined by weighting a region having a relatively high luminance value in comparison with a region having a relatively low luminance value at least in a photometry region, and wherein, in a case where the detection unit detects the object in the image in a state where the first photometry mode is selected, the photometry unit performs photometry in the first photometry mode by using a region of the object as the photometry region.

DESCRIPTION OF THE EMBODIMENTS

Preferable exemplary embodiments of the disclosure will be described in detail below with reference to the accompanying drawings. The following exemplary embodiments do not limit the disclosure within the scope of the appended claims. Although a plurality of features is described in the exemplary embodiments, not all of the plurality of features is indispensable to the disclosure, and the plurality of features may be combined in an arbitrary way. In the accompanying drawings, identical or similar components are assigned the same reference numerals, and the redundant descriptions will be omitted.

Differences between a photometry method in which the entire screen (entire image and entire area) is subjected to photometry to set an exposure of the entire screen to a proper exposure and highlight photometry will be briefly described below with reference toFIGS.1A,1B, and2.

FIG.1Ais a diagram illustrating an image of a person captured using the photometry method in which the entire screen is subjected to photometry to set an exposure of the entire screen to a proper exposure when only the person is illuminated in a dark place. InFIG.1A, a background region11occupying most of the screen is dark and a human region12is bright. In the photometry method in which the entire screen is subjected to photometry to set an exposure of the entire screen to a proper exposure, the exposure value is set to high to cause an exposure of the background region11occupying most of the screen to be close to the proper exposure. As a result of the setting, in the captured image, the human region12is bright and highly likely overexposed.

FIG.1Bis a diagram illustrating an image captured with the highlight photometry under the similar imaging condition.

Similar to the case illustrated inFIG.1A, inFIG.1B, a background region13is dark and a human region14is bright. Since the highlight photometry generally performs photometry based on the maximum output photometry value in the entire screen, image capturing is able to be performed with an exposure lower than that inFIG.1Aso that the human region14having the largest photometry value is not overexposed. Thus, using the highlight photometry enables image capturing without overexposure even in a case of a screen including an object which is highly likely to be overexposed if the photometry method for setting an exposure of the entire screen to a proper exposure is used.

FIG.2is a diagram illustrating an image captured using the highlight photometry when a high-luminance object, such as an illumination, is included in a screen under conditions similar to that inFIGS.1A and1B. The screen illustrated inFIG.2includes an illumination region22as a high-luminance object. In the highlight photometry, photometry is performed based on the maximum output photometry value in the entire screen, to perform the exposure setting in such a manner that overexposure of the illumination region22is reduced or prevented. Consequently, in a captured image, a human region21having a luminance value lower than the luminance value of the illumination region22becomes darker than the human region14illustrated inFIG.1B. This means that, in a case where the user's target object is the human region21, the human region21becomes unnecessarily dark in the captured image.

In the first exemplary embodiment, photometry is performed in a region of a detected object in the highlight photometry mode, to avoid the object being affected by high-luminance regions outside the object region.

FIG.3is a block diagram illustrating a configuration of a camera as an example of an imaging apparatus according to a first exemplary embodiment of the disclosure. The camera according to the present exemplary embodiment includes a camera body1000, and a lens unit2000attachable to and detachable from the camera body1000. The lens unit2000includes an optical system that supports the camera body1000. The camera body1000and the lens unit2000may be integrally configured as one unit. A camera configuration where the lens unit2000is attached to the camera body1000will be described below with reference toFIG.3.

A camera system control unit1001is a control unit for entirely controlling various units in the camera body1000. A memory1002includes a Random Access Memory (RAM) and a Read Only Memory (ROM) connected to the camera system control unit1001. An image sensor1003is a charge storage type image sensor, such as a complementary metal oxide semiconductor (CMOS) sensor. The image sensor1003photoelectrically converts an object image focused on the image sensor1003via the lens unit2000serving as an optical system and outputs analog image data. A shutter1004is controlled and driven by signals from the camera system control unit1001. The shutter1004operates in two states: a light-shielding state in which the image sensor1003is shielded from a light flux incident through the lens unit2000and a retracted state in which an object optical image incident through the lens unit2000is guided to the image sensor1003.

An analog-to-digital (A/D) conversion unit1005converts the analog image data output from the image sensor1003into digital image data, and the digital image data is recorded in the memory1002.

An image processing unit1006performs various processing, such as pixel interpolation processing and color conversion processing, on the data from the A/D conversion unit1005or data from a memory control unit1007. The image processing unit1006also performs other processing, such as resize processing, conversion processing, and correction processing for image signals of saturated pixels and underexposure pixels, on the data. Image data obtained by these pieces of processing is stored in the memory1002again via the memory control unit1007.

A digital-to-analog (D/A) conversion unit1008converts the digital image data recorded in the memory1002into an analog image signal for display. A display unit1009includes a thin film transistor-driven liquid crystal display (TFT-driven LCD) to display images based on the analog image signal for display. The display unit1009also displays a live view by successively displaying image data, acquired through image capturing, via the D/A conversion unit1008. The display unit1009also displays various information in addition to the acquired image data. The display of the image data and various information to be displayed on the display unit1009is able to be controlled by the camera system control unit1001.

A timing generator (hereinafter abbreviated to a TG)1010transmits an exposure timing and a frame rate change of the image sensor1003, a shielding timing of the shutter1004, and timings of other camera operations to various units of the camera.

A release button1011and an operation unit1012are operation units via which the user inputs various operation instructions to the camera system control unit1001. The release button1011is an instruction unit for issuing an instruction for starting an imaging preparation operation and an imaging operation. When the user changes the release button1011to an SW1state (for example, half press state), the release button1011issues an instruction for starting the imaging preparation operation to start distance measurement operation processing and photometry calculation processing. When the user changes the release button1011to an SW2state (for example, full press state), the release button1011issues an instruction for starting the imaging operation to start a series of processing from image capturing of an object to image acquisition.

The operation unit1012includes switches, buttons, dials, and other operation members (the power switch, menu buttons, and direction buttons) that are used by the user to issue various instructions and make various settings on the camera body1000. The display unit1009as a capacitive-type touch panel may be configured to receive an information input operation similar to that performed on the operation unit1012via a User Interface (UI) displayed on the display unit1009.

A detection unit1013performs detection processing to detect a specific object by using image data obtained from the image processing unit1006. Known techniques may be used for the detection processing performed by the detection unit1013. Examples of usable techniques include a convolutional neural network (CNN) that completed machine learning, and a learned model generated through machine learning using, for example, a support vector machine and decision tree. Any object detection technique not using machine learning can also be used.

A photometry unit1014performs photometry operations by using image data obtained from the image processing unit1006. The photometry operations will be described in detail below. The photometry unit1014calculates luminance values (photometry values) in a predetermined region (photometry frame) in a screen in accordance with a set photometry method to determine exposure control values. Examples of selectable photometry methods, in addition to the above-described highlight photometry, include spot photometry for performing photometry at a specific set position, evaluation photometry in which the camera automatically determines a photometry frame position according to a scene, and center-weighted average photometry for averagely performing photometry for an entire screen centering on the central part of the screen.

A distance measurement unit1015performs distance measurement operations by using image data obtained from the image processing unit1006. Examples of known distance measurement operation methods include an image plane phase difference method. In the present exemplary embodiment, the camera system control unit1001calculates the amount of deviation of an object image acquired by the image sensor1003by using the image data obtained from the image processing unit1006. A lens system control unit2001(described below) controls the lens unit2000based on the calculated amount of deviation of the object image to focus on the object, whereby the distance measurement (focusing processing) is completed. The distance measurement operation method is not limited to the above-described method, but existing methods can also be used.

The distance measurement unit1015and the photometry unit1014may be integrally configured with the camera system control unit1001. In this case, the camera system control unit1001performs the above-described various processing.

The lens system control unit2001controls entire operations of the lens unit2000. In a state where the lens unit2000is attached to the camera body1000, the lens system control unit2001and the camera system control unit1001are able to communicate with each other via an interface (not illustrated). For example, in response to an instruction from the camera system control unit1001, information about the lens unit2000attached to the camera body1000is output to the camera system control unit1001. An imaging lens group2002includes a plurality of lenses, such as an optical axis shift lens, a zoom lens, and a focusing lens. A diaphragm2003is a light quantity adjustment member for adjusting the light quantity of a light flux having transmitted through the imaging lens group2002. The diaphragm2003is driven and controlled by the lens system control unit2001. In a configuration in which the lens unit2000does not include the lens system control unit2001, operations of the imaging lens group2002and the diaphragm2003are controlled based on instructions from the camera system control unit1001.

A recording medium3000is a memory card or a hard disk capable of recording image data recorded in the memory1002. The recording medium3000is not limited to a memory card insertable into and removable from the camera body1000. Examples of recording media include an optical disk such, as a digital versatile disc rewritable (DVD-RW) disc, and a magnetic disk, such as a hard disk. Further, the recording medium3000may be not removable but built in the camera body1000.

The above descriptions are of the basic configuration of the camera according to the present exemplary embodiment.

The highlight photometry method and an average photometry method as an example of a photometry method other than the highlight photometry method will be describes below with reference toFIGS.4A and4B. The photometry unit1014calculates evaluation values by using image data obtained from the image sensor1003.

FIGS.4A and4Bare diagrams illustrating a method that is performed by the photometry unit1014to obtain evaluation values in the screen illustrating inFIG.2. The photometry unit1014calculates, as an evaluation value, the average of luminance values of pixels included in each division region having a certain size, as illustrated inFIG.4A. While, in the example illustrated inFIG.4A, the image is divided into 10×10 regions, the number of divisions and the division method are not limited thereto. InFIG.4B, a region41is an evaluation value region for the entire screen, and a region42is one of division evaluation value regions including the illumination region22. In this example, the evaluation value of the region42is the brightest among the division regions in the screen and has the largest evaluation value.

Then, the photometry unit1014uses the obtained evaluation values to calculate photometry values in each photometry method. In the highlight photometry method, the photometry unit1014performs photometry operations based on the largest evaluation value in the screen, i.e., the evaluation value of the region42inFIG.4B, to set the exposure setting in such a manner that an exposure of the region42having the largest evaluation value is set to the proper exposure. In the average photometry method, the photometry unit1014performs photometry operations based on the average of evaluation values of the entire screen, i.e., evaluation values of the region41, to set the exposure setting in such a manner that an average luminance of the entire screen is to be at the proper level.

Processing procedure of regular live view static image capturing will be described below with reference toFIG.5.FIG.5is a flowchart illustrating the distance measurement and photometry for regular live view static image capturing. The procedure of the flowchart starts in a state where the user has preset the photometry method with the camera main body1000activated. Each process of the flowchart is executed by the camera system control unit1001or various units in the camera main body1000based on instructions issued from the camera system control unit1001.

In step S501, the camera system control unit1001determines the photometry method preset by the user. The photometry method may be set by the user via the operation unit1012. The camera system control unit1001may control the display of the display unit1009to display the set photometry method so that the user is able to check the set photometry method via the display unit1009. In a case where the camera system control unit1001determines that the average photometry has been set (AVERAGE PHOTOMETRY in step S501), the processing proceeds to step S502. In step S502, the photometry unit1014performs photometry based on an average luminance of the entire screen. On the other hand, in a case where the camera system control unit1001determines that the highlight photometry is preset (HIGHLIGHT PHOTOMETRY in step S501), the processing proceeds to step S503. In step S503, the photometry unit1014performs photometry based on the largest luminance of the entire screen (highlight photometry). While, in the present exemplary embodiment, photometry is performed based on the largest luminance, the disclosure is not limited thereto. The issue addressed by the disclosure is to be resolved to a certain extent if the photometry is performed based on a relatively high luminance value in the screen. Therefore, the photometry may be performed based on a relatively high luminance value (for example, the average luminance value of top 5% of luminance values when a luminance histogram is generated) in the screen.

While, in the present exemplary embodiment, the description is given using a case in which the average photometry is performed using luminance values of the entire screen, as a photometry method other than the highlight photometry, the photometry method is not limited thereto. Examples of applicable photometry include object priority photometry for performing control to preferentially set the exposure of a particular detected object to the proper exposure. In the object priority photometry, the photometry unit1014performs photometry by weighing luminance of a detected object region in comparison with luminance of other regions. More specifically, the photometry unit1014calculates the average luminance value of the detected object region and the average luminance value of the entire screen, calculates a weighted average of the two average luminance values by weighting the average luminance value of the object region with a larger weight, and performs photometry based on the calculated luminance values.

Processes of step S504and subsequent steps in the flowchart are a processing procedure from distance measurement to image capturing. The loop of processes from step S501to step S504is repeated at predetermined intervals to repetitively perform the photometry processing described in steps S502and S503. In a case where the release button1011enters the SW1state (YES in step S504), the processing proceeds to step S505. In step S505, the distance measurement unit1015starts the distance measurement (focus detection).

In step S506, the distance measurement unit1015performs determination of a result of the distance measurement in step S505. In a case where the distance measurement unit1015fails to focus on an object detected by the detection unit1013or an object closest to the camera within a focus detectable range (NO in step S506), the processing returns to S504. In step S504, the photometry unit1014repeats the photometry processing until the release button1011enters the SW1state again. In a case where the distance measurement unit1015focuses on the object (YES in step S506), the processing proceeds to step S507. In a case where the release button1011enters the SW2state (YES in step S507), the processing proceeds to step S508. In step S508, the camera performs image capturing processing. This completes the processing procedure of regular live view static image capturing.

Processing and a method of the highlight photometry according to the first exemplary embodiment of the disclosure will be described below with reference toFIG.6.FIG.6is a flowchart illustrating a processing procedure of the highlight photometry according to the first exemplary embodiment, which is executed in the processing in step S503inFIG.5. In a case where the camera system control unit1001determines that the highlight photometry has been set as the photometry method (HIGHLIGHT PHOTOMETRY in step S501inFIG.5), the processing enters the flowchart illustrated inFIG.6corresponding to step S503.

In step S601, the detection unit1013determines whether any object(s) is detected. The object(s) indicates one or a plurality of objects among objects detectable by the detection unit1013. Examples of the detectable objects include a human head, a human body, a vehicle, and the sky, but the aspect of the embodiments is not limited thereto.

In a case where the detection unit1013determines that an object is detected (YES in step S601), the processing proceeds to step S602. In step S602, the photometry unit1014performs the highlight photometry by using only luminance values in a region corresponding to the detected object (object detection region).

The highlight photometry that is performed on the object detection region will be described below with reference toFIGS.7A and7B.

FIG.7Ais a diagram illustrating a state in which the detection unit1013detects a human head as a detected object in a screen similar to the screen illustrated inFIG.2, which includes an object detection region71.FIG.7Bis a diagram illustrating evaluation values in the state illustrated inFIG.7A. In the highlight photometry that is performed in the object detection region in step S602, the photometry unit1014performs photometry operations using only evaluation values within a division range72among evaluation values including evaluation values of the object detection region. In a case where the largest evaluation value in the division range72is of a region73, the photometry unit1014performs photometry operations based on the evaluation value of the region73, to set the exposure setting in such a manner that an exposure of the region73is set to the proper exposure.

In a case where the detection unit1013determines that no object is detected (NO in step S601), the processing proceeds to step S603. In step S603, the photometry unit1014performs the highlight photometry in the entire screen. In step S603, the photometry unit1014performs photometry operations based on the largest evaluation value region in the range of the region41which is the entire screen, as described above with reference toFIG.4B.

This completes the processing procedure of the highlight photometry using the method according to the first exemplary embodiment. In the conventional highlight photometry, the highlight photometry is not performed in the object detection region as illustrated inFIG.6but is performed based on the largest evaluation value in the entire screen. Consequently, even in a case where the user performs image capturing to capture the human region21as an object in the screen inFIG.2, the exposure is performed to adjust brightness of the illumination region22, but not the object, to be a proper brightness. Thus, the human region21is dark in the captured image. In contrast, in a case where the highlight photometry is performed in the object detection region as illustrated inFIG.6, the exposure is set in such a manner that brightness is adjusted to be proper brightness with respect to the largest evaluation value in the human region21.

As described above, according to the first exemplary embodiment, photometry is performed in the detected object region in the highlight photometry mode, whereby underexposure of the detected object region due to high-luminance regions outside the detected object region is able to be prevented.

The first exemplary embodiment still has an issue that depending on the detected object, a significant exposure change may occur due to an unstable result of the highlight photometry. Thus, in a second exemplary embodiment, the photometric processing is changed in accordance with a type of the detected object in a case where the highlight photometry is performed in the object detection region. Elements in the present exemplary embodiment denoted by the same reference numerals as those in the first exemplary embodiment perform operations and processing similar to the first exemplary embodiment, and the redundant descriptions will be omitted.

Processing procedure of static image capturing according to the present exemplary embodiment of the disclosure will be described below with reference to the flowcharts illustrated inFIGS.5and6and the images inFIGS.8A,8B, and8C. Each processing of the flowcharts is executed by the camera system control unit1001or various units in the camera body1000according to instructions issued from the camera system control unit1001.

Processing procedure of live view static image capturing according to the present exemplary embodiment is similar to the processing in the flowchart inFIG.5and the processing according to the first exemplary embodiment. In a case where the camera system control unit1001determines that the photometry method is the highlight photometry (HIGHLIGHT PHOTOMETRY in step S501), the processing enters the processing procedure of the flowchart illustrated inFIG.6. This processing is also similar to the processing in the first exemplary embodiment, and the redundant descriptions will be omitted.

According to the present exemplary embodiment, when performing the highlight photometry in the object detection region in step S602of the flowchart inFIG.6, the photometry unit1014changes the photometry processing in accordance with a type of the detected object.

As a first example, a case where the detection unit1013has detected a vehicle as an object will be described below. In a case where the object is a vehicle, the object may move in a high speed.FIGS.8A,8B, and8Care diagrams illustrating images of a case where a vehicle moves in a right direction, and a high-luminance object exists in front of the vehicle. The images illustrated inFIGS.8A,8B, and8Care captured in this time order.

InFIG.8A, a vehicle81moves in the right direction, and an object detection region82is detected as a region indicating the vehicle81as an object. A high-luminance object83, such as a white object or an electric lamp, exists in front of the vehicle81(on a side with the user of the camera). InFIG.8B, the vehicle81captured in the image illustrated inFIG.8Amoves in the right direction and reaches the position of a vehicle84. In this state, a high-luminance object86is included in an object detection region85. InFIG.8C, the vehicle84captured in the image illustrated inFIG.8Bfurther moves in the right direction and reaches the position of a vehicle87. In this case, a high-luminance object89is not included in an object detection region88.

FIGS.9A,9B, and9Care diagrams illustrating changes in evaluation values calculated by the photometry unit1014when a screen composition changes with the movement of the vehicle in the above described way.FIGS.9A,9B, and9Ccorrespond toFIGS.8A,8B, and8C, respectively. More specifically, object detection regions91,92, and93indicate the object detection regions82,85, and88inFIGS.8A,8B, and8C, respectively. InFIGS.9A and9C, evaluation values of the object detection regions91and93correspond to regions of the vehicles81and87inFIGS.8A and8C, respectively. InFIG.9B, evaluation values of the object detection region92include evaluation values corresponding to regions of the high-luminance object86in addition to the vehicle84.

FIG.10Ais a diagram illustrating variations of the largest evaluation value in the object detection region in the evaluation values inFIGS.9A,9B, and9C. InFIG.10A, the vertical axis represents the largest evaluation value in the object detection region, and the horizontal axis represents time. Times (a), (b), and (c) on the horizontal axis correspond to the times when the images illustrated inFIGS.8A,8B, and8Care acquired, respectively. In a case where the largest evaluation value largely changes between the time (a) and (b) inFIG.10A, the exposure rapidly changes based on the highlight photometry. As a result, brightness of the acquired image significantly changes, which causes flickering in displayed images.

With respect to the flickering, in a case where an object is a vehicle, a method for decreasing an exposure tracking speed may be used to prevent a significant exposure change. As a specific example of calculations of the largest evaluation value, the largest evaluation value of n-time past imaging operations is stored, and an average of the stored values is used as a current largest evaluation value. The following formula is used:

where Maverageis the largest evaluation value obtained by the calculation and Miis the largest evaluation value in the i-time past imaging operations.

FIG.10Bis a diagram illustrating variations of averaged largest evaluation values corresponding to the largest evaluation values inFIG.10A. A dotted line101inFIG.10Bindicates the same chart as that inFIG.10A, and a solid line102indicates the averaged largest evaluation values. Averaging the largest evaluation values decreases variations of the largest evaluation values. This results in prevention of variation in the amount of exposure and prevention of a significant exposure change, whereby flickering due to variations in brightness of displayed images is prevented.

In a state where the vehicle84as an object is behind the high-luminance object86, as illustrated inFIG.8B, the detection unit1013may fail to detect the object. More specifically, inFIGS.8A,8B, and8C, the detection unit1013detects the vehicle81inFIG.8A, fails to detect the vehicle84inFIG.8B, and detects the vehicle87again inFIG.8C. In such a case, inFIG.8B, the photometry unit1014performs the highlight photometry for the entire screen since the vehicle84is not detected, which results in performing an exposure setting that has been set based on evaluation values of the high-luminance object86. This means that the largest evaluation value changes as illustrated inFIG.10A, which may cause a significant exposure change. In a case of such an object detection failure, the object detection may be immediately recovered in some cases as described above. However, there is also a case in which the object moves out of the angle of field, and the object originally detected is not detected again. Thus, in a case where the object detection fails, the photometry unit1014performs the highlight photometry for the entire screen with the limited amount of exposure reduction. For example, the amount of exposure reduction is limited to one lower level, which enables prevention of screen flickering in consideration of a case where the object is immediately detected again while performing the highlight photometry for the entire screen in consideration of a case where the object has been moved out of the angle of field and does not return. While, in the present exemplary embodiment, the object is a vehicle (automobile), a similar situation may arise even in a case where the object is a moving animal or bird.

As a second example, a case where the detection object is the Sky.FIG.11Ais a diagram illustrating an image including the sky at the upper portion and a mountain at the lower portion. A region111inFIG.11Aindicates the object detection region of the sky.FIG.11Bis a diagram illustrating evaluation values corresponding toFIG.11A. In a region112inFIG.11B, evaluation values are calculated for the object detection region of the sky. A division evaluation value region in the region112having the largest evaluation value is an evaluation value region113corresponding to a position of the sun. In a case where the highlight photometry is performed in the object detection region, the exposure setting is set in such a manner that an exposure of the evaluation value region113having the largest evaluation value is adjusted to the proper exposure. However, since the sun is a strong light source, the exposure of the evaluation value region113may not be adjusted to the proper exposure even if the exposure is lowered. Consequently, if the exposure setting is set based on the evaluation value region113having the largest evaluation value as in the regular highlight photometry, in a captured image as illustrated inFIG.11C, regions other than the evaluation value region113is dark and the region of the sun is overexposed. In order to prevent this, in a case where the detected object is the sky, the amount of exposure reduction is limited. Limiting the amount of exposure reduction may be performed by a method in which exposure reduction is limited to three lower levels or less from the average photometry value obtained from the entire screen. Limiting the amount of exposure reduction in this way prevents regions other than the region having the largest evaluation value from becoming extremely dark in a captured image in which the largest evaluation value in the region of the detected object is factored.

As described above, according to the second exemplary embodiment, photometry processing is changed in accordance with a type of a detected object, a region of which is subjected to a highlight photometry, whereby an issue arising in accordance with a type of a detected object is prevented.

In a third exemplary embodiment, in view of an issue that the exposure control is not to be appropriately performed when a detected object is not an object intended by the user, the user selects an object which is to be a target of when the highlight photometry is performed in the object detection region. Elements denoted by the same reference numerals as those of the first exemplary embodiment perform operations and processing similar to the first exemplary embodiment, and the redundant descriptions will be omitted.

In the third exemplary embodiment, the user selects an object which is to be a target of when the highlight photometry is performed in the object detection region. While an object is selectable via a menu setting screen displayed on the display unit1009of the camera, the selection method is not limited thereto.FIG.12is a diagram illustrating a display of selection that is performed via the menu setting screen. InFIG.12, a list of objects including “Human Head”, “Human Body”, “Vehicle”, and “Sky” are displayed. The number of selection options is not limited to the example illustrated inFIG.12. Preferably, the menu setting screen displays objects detectable by the detection unit1013. Check boxes121inFIG.12each indicate a state where a corresponding object is selected by the user. More specifically, an item of a checked box is selected. InFIG.12, a human head and a vehicle are selected. A plurality of the objects is selectable as illustrated inFIG.12, or none of the objects may also be selected. If none of the objects is selected, the photometry unit1014performs the highlight photometry in the entire screen. The flowchart in this case will be described below.

Processing procedure of live view static image capturing according to the present exemplary embodiment is similar to the processing procedure of the flowchart illustrated inFIG.5and the processing according to the first exemplary embodiment. Thus, the redundant descriptions will be omitted. According to the present exemplary embodiment, in a case where the camera system control unit1001determines that the highlight photometry has been set as the photometry method (YES in step S501inFIG.5), the processing enters the flowchart illustrated inFIG.13.FIG.13is a diagram illustrating processing procedure of the highlight photometry in the present exemplary embodiment. Each processing of this flowchart is executed by the camera system control unit1001or various units of the camera body1000based on instructions issued from the camera system control unit1001.

In step S1301, the camera system control unit1001determines whether the user has selected (set) an object in advance. In a case where the camera system control unit1001determines that an object has been selected (YES in step S1301), the processing proceeds to step S1302. In a case where the camera system control unit1001determines that no object has been selected (NO in step S1301), the processing proceeds to step S1304. In step S1304, the photometry unit1014performs the highlight photometry in the entire screen.

In step S1302, the detection unit1013determines whether the object selected by the user has been detected. In a case where the detection unit1013determines that the object selected by the user has been detected (YES in step S1302), the processing proceeds to step S1303. In step S1303, the photometry unit1014performs the highlight photometry by only using evaluation values in the object detection region. On the other hand, in a case where the detection unit1013determines that the object selected by the user has not been detected (NO in step S1302), the processing proceeds to step S1304. In step S1304, the photometry unit1014performs the highlight photometry in the entire screen.

The highlight photometry in the detection region in step S1303inFIG.13will be described below with reference toFIGS.14A and14B.FIG.14Ais a diagram illustrating an image of the highlight photometry corresponding to the example of menu selection on the display illustrated inFIG.12. InFIG.14A, a detection region141is of the human head, and a detection area142is of the vehicle.FIG.14Bis a diagram illustrating evaluation values corresponding to the image inFIG.14A. InFIG.14B, regions143and144represent evaluation values corresponding to the detection regions141and142of the human head and the vehicle, respectively. In this case, the camera system control unit1001knows that the user has selected “Human Head” and “Vehicle” by the processing in step S1301. In the highlight photometry in the detection region in step S1303, the photometry unit1014performs the highlight photometry based on evaluation values corresponding to the objects selected by the user and the largest evaluation value in a region combining the regions143and144.

As described above, according to the third exemplary embodiment, photometry is performed in the region of the object(s) specified by the user in the highlight photometry mode in which exposure is determined based on the maximum output photometry value in the photometry region. Thus, exposure control to prevent overexposure of the object specified by the user is performed, whereby exposure control intended by the user is performed.

A fourth exemplary embodiment is to address an issue that the exposure control may be not to be appropriately performed if a detected object is not an object intended by the user. According to the present exemplary embodiment, in a case where a detection object has been selected by other functions when the user selects a type of an object, the region of which is to be set as a highlight photometry region, the default value of object selection for the highlight photometry is adjusted to the object type selected by other functions.

Processing procedure of the static image capturing according to the present exemplary embodiment of the disclosure will be described below with reference to the flowcharts inFIGS.5and13and displays illustrated inFIGS.15A and15B. Each processing of the flowchart is executed by the camera system control unit1001or various units of the camera body1000based on instructions issued from the camera system control unit1001.

Processing procedure of the live view static image capturing according to the present exemplary embodiment is similar to the flowchart inFIG.5. In a case where the camera system control unit1001determines that the highlight photometry has been set as the photometry method (HIGHLIGHT PHOTOMETRY in step S501inFIG.5), the processing enters the flowchart illustrated inFIG.13. This processing is similar to the processing in the third exemplary embodiment, and the redundant descriptions will be omitted. While, in the present exemplary embodiment, the user selects an object which is to be a target of when the highlight photometry is performed in the object detection region, this processing is similar to that in the third exemplary embodiment, and the redundant descriptions will be omitted.

In the fourth exemplary embodiment, in a case where a detection object has been selected by other functions when the user selects a type of an object, the region of which is to be set as a highlight photometry region, a default value of object selection for the highlight photometry is adjusted to the object type selected by other functions. For example,FIG.15Ais a diagram illustrating an image of the menu selection screen of a case in which, in the Auto Focus (AF) function with which the camera automatically performs focusing, the object to be focused is selectable (settable) by the user in advance and when a human head has been selected by the AF function.

In a case where the user has selected a human head as an AF target object as illustrated inFIG.15A, it can be considered that the user intends to capture an image of a human head.FIG.15Bis a diagram illustrating a default setting of an object selection menu screen for the highlight photometry in the above-described case. As illustrated inFIG.15B, when a human head has been selected as an AF target object, a human head is also selected as the default setting of object selection for the highlight photometry. As described above, in the present exemplary embodiment, the default setting of object selection for the highlight photometry is adjusted to a type of a detection object selected by other functions, to coincide the object for the highlight photometry with the object that the user intends to capture.

The object selection for the highlight photometry may be changed from the default setting by the user. More specifically, the user may possibly select (set) an object different from the one selected (set) by other functions, such as AF.FIG.16is a diagram illustrating an image of detection frame display displayed when a human head has been set as an AF detection target object and the sky has been selected as a detected object for the highlight photometry. A frame161inFIG.16indicates a detection frame of the AF function, and a frame162indicates a detection frame of the highlight photometry. In a case where a detection object selected by other functions and a detection object in the highlight photometry are different from each other, as illustrated inFIG.16, both of the detection frames may be displayed together. In this case, the frames161and162may be displayed in different colors. This allows the user to check that the object selected by other functions, such as AF, and the object selected for the highlight photometry are different from each other.

As described above, according to the present exemplary embodiment, in the highlight photometry mode in which exposure is determined based on the maximum output photometry value in the photometry region, the default setting of object selection for the highlight photometry is adjusted to the type of a detection object which has been selected by other functions, such as AF. This makes it easier to make object setting that conforms to the user's intention.

Other Embodiments

This application claims the benefit of Japanese Patent Application No. 2022-188973, filed Nov. 28, 2022, which is hereby incorporated by reference herein in its entirety.