JP2007318563A - Camera, image discrimination method, exposure control method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera, an image discrimination method, an exposure control method, a program, and a recording medium. <P>SOLUTION: The camera photographs a scene wherein a bright scenery and people under a backlight are intermingled with a high speed shutter and a strobe. The bright scene part is shown in a curve in I2a in Fig. 4 by an exposure at the high speed shutter at very nearly a saturation level. The scenery part receives no effect by the strobe. The backlight people part is shown in a proper luminance level I2b in Fig.4(A) by strobe lighting. Further, gamma correction is applied to the bright scenery part to decrease the luminance from I2a to I3b. The curve I3b indicates a proper luminance level as shown in Fig.4(B). Both the bright scenery and the people under the backlight respectively reach the proper luminance level. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera, and more particularly to a camera that supports shooting of a backlight scene.

  Backlit scenes are difficult to shoot. This is conspicuous in digital cameras that use an image sensor having a narrow dynamic range as compared with a silver salt film. In particular, when a person is the main subject, the photograph often fails when the face becomes dark. Therefore, in such a backlight scene where a person is a subject, the person is appropriately exposed by normal flash photography. The flash photography is executed by an operation such as the photographer selecting the flash mode or selecting the scene mode of the camera as a backlight scene.

  Proposals for this strobe shooting include a function that allows an ND (neutral density) filter to be inserted and removed between the image sensor and the photographic lens in order to increase the dynamic range of brightness that can be handled, and the strobe light is weakened to reduce the strobe light. There is one that exhibits the effect of irradiation (Patent Document 1).

On the other hand, since face detection technology has recently been developed (for example, Patent Document 2), it is expected that it can be determined whether a person is a subject by applying this face detection technology.
JP 2000-122128 (Fuji) JP 07-073298 (Sharp)

  In order for the face detection to be performed with high accuracy, it is premised that the contour of the target subject is expressed sufficiently clearly. Under the backlight conditions, the image of the subject is crushed, so it cannot be expected that the person can be easily determined by the face detection technique.

  Also, when shooting in a situation where both bright and dark parts are mixed, as represented by the above-mentioned backlight scene, the conventional simple method of simply expanding the brightness range of the image by strobe illumination It is becoming unsatisfactory with simple control. In other words, there is a need for a camera that beautifully depicts scenes where brightness, which has been a weak point until now, changes greatly, taking into account the characteristics of an image sensor such as a CCD.

  In view of the above, the present invention provides a camera, an image determination method, an exposure control method, a program, and a recording medium that can be beautifully depicted even in a scene where the brightness changes greatly, such as a backlight scene.

  In order to achieve the above object, a camera according to a first invention has an exposure control unit for controlling exposure of a subject image to an image sensor, and a function of inserting and removing an ND filter between an imaging lens and an optical path of the image sensor. The camera includes a scene determination unit that determines a scene that needs to supplement a person's subject by determining a shooting situation, and the exposure control unit is determined to be a scene that needs to supplement light by the scene determination unit. In some cases, the ND filter is controlled to be removed from the optical path.

  According to a second aspect of the present invention, there is provided a display unit that displays an image obtained from an image sensor as a monitor image, and a face detection that detects whether a person is present on the screen using the image obtained from the image sensor as a face detection image. And an exposure control unit that switches exposure to the image sensor depending on whether an image obtained from the image sensor is used as the monitor image or the face detection image.

    An exposure control method according to a third aspect of the invention is an exposure control method for a camera including a face detection unit that detects whether a person is present in a screen using an image obtained from an image sensor as a face detection image. The exposure to the image sensor is switched depending on whether the obtained image is used as a monitor image displayed on the display unit or as the face detection image.

  According to the present invention, it is possible to provide a camera, an image determination method, an exposure control method, a program, and a recording medium that can be beautifully depicted even in a scene where brightness changes greatly, such as a backlight scene.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is an overall block diagram of a camera 1 to which the present invention is applied. The camera 1 includes a lens unit 2, an ND (neutral density) filter 3, a shutter 4, an image sensor 5, an analog front end (hereinafter abbreviated as AFE) unit 6, an image processing unit 7, a recording / reproducing control unit 8, and a recording medium 9. Is provided. The lens unit 2 forms an image of the incident subject 20 on the image sensor 5. The ND filter 3 is an optical filter that attenuates a certain amount of light incident from the lens unit 2 and adjusts the exposure amount. The ND filter 3 is detachably provided in the optical path of the lens unit 2. The shutter 4 selectively blocks the light that has passed through the ND filter 3 from entering the image sensor 5 and adjusts the exposure amount.

  The image sensor 5 is composed of a CMOS or a CCD, and converts the formed subject image into an image signal. The AFE unit 6 converts an analog electrical signal output from the image sensor 5 into digital image data and outputs the digital image data. The AFE unit 6 is provided with a cutout unit 6a. The cutout unit 6a can select only a limited pixel signal from all the light receiving surfaces by selecting signals output from the image sensor 5. In addition, pixels can be extracted from the image sensor 5 by thinning out.

  The image processing unit 7 corrects gamma (gradation correction), color, gradation, and sharpness for the image data output from the AFE unit 6. The image processing unit 7 has a compression / expansion unit for still images such as a JPEG (Joint Photographic Coding Experts Group) core unit (not shown) in the image processing unit. Compress. The image processing unit 7 is provided with a resizing unit 7a that changes the image size to a display size.

  The recording / playback control unit 8 records the image data compressed by the image processing unit 7 in a recording medium 9 as a recording medium at the time of shooting. The recording medium 9 is a recording medium for storing and recording images. The recording / playback control unit 8 reads image data from the recording medium 9 during playback.

  The camera 1 is provided with a display control unit 11 and a display unit 12. The display unit 12 includes, for example, a liquid crystal or an organic EL, and displays a monitor image at the time of shooting, and displays a recorded image that has been subjected to expansion processing at the time of reproduction. At the time of shooting, the user determines the composition and timing while performing the shooting operation while viewing the image displayed on the display unit 12. The image is processed by the resizing unit 7 a so that the image signal from the image sensor 5 can be displayed almost in real time, and is controlled by the display control unit 11 and displayed on the display unit 12. At the time of reproduction, the compressed data recorded on the recording medium 9 is read by the recording / reproduction control unit 8, reproduced by the image processing unit 7, resized and displayed on the display unit 12.

  In addition, the camera 1 is provided with an MPU 10, a ROM 19, and an operation unit 16. An MPU (microcontroller) 10 is a control unit that controls the entire camera 1 such as shooting and reproduction according to a program. The ROM 19 is a non-volatile and recordable memory, for example, a flash ROM, and stores a control program for performing control processing of the camera 1. The operation unit 16 notifies the MPU 10 of the photographer's instruction. As a representative example of the operation unit 16, switches 16a, 16b, and 16c are provided. The switch 16a is a release switch. Reference numerals 16b and 16c denote switches for switching, for example, shooting / playback mode switching and shooting mode switching. The MPU 10 detects user instructions such as shooting and display with the switches 16a, 16b, and 16c.

  Further, the camera 1 is provided with an AF control unit 13, an ND filter control unit 14, a shutter control unit 15, a strobe unit 17, an exposure control unit 10a, a scene determination unit 10b, and a face detection unit 18. The AF control unit 13 controls the focus position of the lens unit 2. The focus position is controlled by the image processing unit 7 detecting the contrast of the image data output from the image sensor 5 and outputting it to the MPU 10, and the MPU 10 outputting a control signal to the AF control unit 13 accordingly. . The MPU 10 outputs a control signal to the AF control unit 13 so that the contrast signal of the image data is maximized.

  The ND filter control unit 14 controls insertion / removal of the ND filter 3 between the lens unit 2 and the image sensor 5. Unlike a conventional photographic film, the image sensor 5 such as a CCD has a narrow dynamic range and is difficult to control exposure. Therefore, the ND filter control unit 14 inserts the ND filter 3 in a bright scene to attenuate the light amount to the image sensor 5 so that an appropriate light amount enters the image sensor 5. However, since the ND filter attenuates the strobe light when the strobe emits light, more than the effect of attenuating the brightness of the subject, it is preferable that the ND filter is not in the optical path when the strobe is used. Therefore, as will be described later, the ND filter control unit 14 controls not only to be out of the optical path when it is dark, but also out of the optical path depending on the situation.

  The shutter control unit 15 controls the opening / closing of the shutter 4. The shutter control unit 15 performs exposure control that closes the shutter 4 in a short time when it is bright and closes the shutter 4 in a long time when it is dark so as to keep the amount of light incident on the image sensor 5 at a predetermined amount. .

  The strobe unit 17 is auxiliary light irradiation means for assisting exposure. When the subject is relatively dark or absolutely dark, the strobe unit 17 that projects strong light is used as auxiliary light.

  Further, in the MPU 10, an exposure control unit 10a and a scene determination unit 10b are provided as one of the processing functions of the MPU 10. Based on the image data from the AFE unit 4, the exposure control unit 10a controls the gamma correction functions of the ND filter control unit 14, the shutter control unit 15, the strobe unit 17, and the image processing unit 7 so that the image exposure is appropriate. To.

  The exposure control unit 10a controls the exposure so that the state of the subject on the entire screen can be confirmed, particularly when the monitor image is displayed during shooting. Specifically, this is controlled by data reading control of the image sensor 5.

  The scene determination unit 10b determines the brightness of the entire screen from the monitor image and determines whether it is a dark scene or a backlight scene. The scene determination unit 10b uses image data from a wide range of the image sensor for determination. The scene determination unit 10b also uses the result of the face detection unit 18 for scene determination. Then, the exposure control unit 10a switches the amount of light incident on the image sensor 5 according to the scene determination result.

  The face detection unit 18 detects whether or not a human face exists in the subject using information at the time of shooting. The face detection unit 18 detects a face based on the image data output from the image processing unit 7 by extracting information on focusing and extracting feature points of the monitor image described above. Then, the face detection unit 18 outputs the size and position of the face in the screen to the MPU 10. However, as will be described later, when the main subject is in a dark part of the screen, the image is crushed and the difference between light and dark cannot be recognized, and the face detection unit 18 cannot be detected. Therefore, the exposure control unit 10a determines the situation of a dark place for face detection and switches to exposure control different from the monitor display.

  FIG. 2 is a diagram showing a general example of a backlight photographing scene. FIG. 2A shows a scene to be photographed beautifully with this camera. In other words, it is a desirable shooting although both the bright outdoor scenery 30a and the dark person 30b are beautifully depicted. However, in general, depending on the dynamic range of the image sensor and the dynamic range of the display system, an image that emphasizes a bright part (landscape) (see FIG. 2B) or an emphasis on a dark part (person) Only one of the images (see FIG. 2C) can be obtained. That is, in the image of FIG. 2B, the person 30b is crushed in black, and in the image of FIG. 2C, the landscape 30a is flying out in white.

  The camera of the present embodiment is a beautiful depiction of a bright outdoor landscape 30a and a dark room person 30b. FIG. 3 shows the same shooting scene as FIG. The line 30c is a transverse line set at an appropriate location on the screen in order to explain the luminance distribution of the screen.

  4A and 4B are graphs showing the luminance distribution along the line 30c in FIG. The horizontal axis represents the position in the horizontal direction X of the screen, and the vertical axis represents the brightness (luminance value). The brightness is dark in the downward direction and bright in the upward direction. The noise level of the image sensor 5 is indicated by L1, and the saturation level is indicated by L2.

  A brightness curve (solid line) I1 in FIG. 4A is a brightness distribution when exposure control is performed so that the landscape 30a has an appropriate luminance level. I1 is divided into I1a and I1b, I1a corresponds to the region portion of the landscape 30a, and I1b corresponds to the region portion of the person 30b. In this state, I1b, which is the portion of the person 30b, can only obtain a brightness equal to or lower than the noise level L1, and is crushed in black (see FIG. 2B).

  Therefore, in the first embodiment, the ND filter 3 is removed and strobe light is emitted at the exposure stage, and gamma correction is performed at the image processing stage. 4A shows the change in brightness distribution at the exposure stage, and FIG. 4B shows the change in brightness distribution at the image processing stage.

  The ND filter 3 is removed from the optical path, and the shutter speed is set so that I1a, which is the part of the landscape 30a, is just below the saturation level L1. It is desirable to increase the shutter speed. As a result, the brightness of 30a increases from l1a to l2a (broken line). Note that the flash emission does not affect. This is because the strobe light does not reach the landscape 30a at a long distance. The reason why the ND filter 3 is removed is to fully exhibit the effect of strobe light on a person.

  FIG. 5 is a timing chart showing the timing of shutter and strobe light emission at the time of shooting in FIG. Since the flash light has a short emission time, the shutter time is also shortened in accordance with the flash emission. That is, in the above photographing, it is desirable to control the shutter so as to increase the speed. This is because if the shutter opening (L active) time is shortened, the contribution ratio of the strobe light to the exposure becomes relatively large.

  Next, regarding the portion of the person 30b, the brightness is slightly changed from l1b to l2b (broken line) by removing the ND filter 3 first, but is assumed to be below the noise level L1. Then, by strobe light emission, it rises from l2b (broken line) to l3b (thick solid line), rises above the noise level L1, and becomes an appropriate luminance level. This is because the light quantity of the person 30b is supplemented by the light emission of the strobe.

  FIG. 4B is a diagram showing the brightness distribution of the landscape 30a further corrected by gamma correction. Only the I2a of the landscape 30a is digitally corrected (gamma correction) and dropped to the level of I3a. I3a is an appropriate luminance level. As a result, both I3a of the landscape 30a and I3b of the person 30b are exposed at appropriate levels. A photograph as shown in FIG. 2A can be obtained by using the I3a image for the landscape 30a thus obtained and the I3b image for the person 30b.

  Next, an example will be described in which the above exposure control is performed only when there is a backlit person. For example, it is not necessary to perform exposure control as described above in a scene such as FIG. 6 where there is no person, that is, a photograph in which the landscape is raised. This is because if the flash is emitted in an unnecessary scene, not only is the energy of the light emission wasted, but there is also a possibility of failure when raising the exposure of the landscape to the limit of the saturation level. Therefore, the exposure control is performed only in a scene where a person is detected in a dark place.

  FIG. 7 is a diagram illustrating an example of determining whether there is a person on the screen by face detection. There are various means for determining the presence of a person. Here, an example of a method for detecting whether there is a face pattern in the screen will be described. FIG. 7A is a diagram showing a face similarity pattern as a reference. (A-1), (A-2), and (A-3) are face similarity patterns having different face sizes. The face similarity patterns (A-1), (A-2), and (A-3) are stored in the ROM 19.

  The scene of FIG. 7B is the same scene as FIG. If the face detection unit 18 scans the screen with reference face similarity patterns (A-1), (A-2), and (A-3) in the scene of (B), and there is a matching part. For example, it is determined that there is a person on the shooting screen. Here, it is a case where the face similarity pattern of A-1 is matched.

  FIG. 8 is a flowchart for explaining the procedure of the photographing control process including face detection. This photographing control process is mainly executed by the MPU 10 according to the program, the image processing unit 7, the exposure control unit 10a, the scene determination unit 10b, and the face detection unit 18. First, the mode of the camera 1 is set to the monitor image mode (step S11). The monitor image mode is a mode in which the output of the image sensor is displayed as a monitor image at the time of shooting. The image sensor 5 and the system are driven and controlled so as to display the image as soon as possible. The exposure controller 10a controls the focus and exposure of the lens unit 2 based on the image data obtained here (step S12).

  Next, prior to shooting (NO in step S13), face detection and backlight determination are performed (step S14). The face detection unit 18 performs face detection, and the scene determination unit 10b performs backlight determination. Then, it is determined whether face detection has been performed (step S15). When face detection is possible, the fact is displayed on the display unit 12 (step S16). Then, the reference face similarity pattern as shown in FIG. 7A is switched to a new face similarity pattern (close to the shape of the face detected earlier) (step S17). As a result, the second and subsequent detection speeds can be increased. In other words, since the pattern (reference face similarity pattern) that was used as a reference is detected by switching to a new face similarity pattern, face determination can be performed quickly in scenes where the face does not move, and the face position and angle change. Even when this is done, the effect of tracking the face portion can be obtained by preferentially detecting the vicinity of the previous detection position in the screen. Then, focus control and exposure control are performed with emphasis on the face portion. The process returns to step S12 and waits for a user's shooting instruction.

  On the other hand, when the face cannot be detected (NO in step S15), it is determined whether the exposure control unit 10a performs exposure control dedicated to face detection (step S18). For example, in the case of an image as shown in FIG. 2B, since the face is too dark, it is determined that exposure switching is to be performed (YES in step S18). The exposure control unit 10a switches to an exposure dedicated to face detection (step S19). Control is performed to increase the exposure time or to remove the ND filter 3 as described in FIG. Further, depending on the case, it may be switched to a control that facilitates face detection by irradiating a strobe or an LED light source (not shown) to compensate for exposure. As a result, an image as shown in FIG. 2C, which is an image in which the background is skipped and the dark place is emphasized, is obtained. This makes it possible to obtain a clear face image that could not be obtained with the image as shown in FIG. 2B, thereby facilitating face detection.

  The face detection image obtained here may be displayed on the screen of the display unit 12 as the auxiliary image 32 (step S20). FIG. 9 is a diagram illustrating a screen on which a main image 31 and an auxiliary image 32 that are images that are normally displayed are simultaneously displayed. With such a device, the user can shoot while confirming the background and the facial expression of the person at the same time. In order to display as shown in FIG. 9, control is performed so that the main image and the auxiliary image are alternately read from the image sensor 5. However, the ratio of the number of times of reading two images is not necessarily 1: 1. The exposure control unit 10a controls exposure switching in accordance with the read image.

  On the other hand, when the auxiliary image as shown in FIG. 9 is not displayed, the exposure control unit 10a does not display the image as shown in FIG. Switch the shutter etc. so that it can be obtained once every four times. This is to prevent the monitor display from being affected. That is, if the image acquisition by the face detection exposure is frequently performed, the display image is affected. This is because, for example, the subject's movement becomes unnatural. Although not shown because the flowchart is complicated, once the face is determined in this mode, it is likely that it will not be found even if it is searched with the same detection method at different exposures. It is also possible to devise such that an exposure change image is appropriately captured and face detection is performed on the change image within a range where no problem occurs. If it is determined that exposure switching is unnecessary (NO in step S18), the process proceeds to step S12 and waits for a user's shooting instruction.

  When there is a user's shooting instruction (YES in step S13), shooting is performed. Here, the exposure control is changed according to the condition (step S21, step S23, step S24) of "dark", "backlight", or "has a face". The determination of “backlight” or “has a face” uses the result of the face detection backlight determination in step S14.

  First, it is determined whether the entire subject is dark (step S21). The scene determination unit 10b determines. When it is determined that the image is dark (YES in step S21), shooting is performed by exposure control with strobe light emission (step S22). At this time, the ND filter 3 is used in combination with a close subject. On the other hand, when it is not dark and not backlit (step S21 NO, step S23 NO), photographing is performed by exposure control with the ND filter 3 inserted (step S25). Also, when the image is not dark and backlit and there is no face (NO in step S21, YES in step S23, NO in step S24), photographing is performed by exposure control with the ND filter 3 inserted (step S25). This is the case of the scene as shown in FIG.

  Then, when it is not dark and backlit and there is a face (step S21 NO, step S23 YES, step S24 YES), the ND filter 3 is removed from the optical path, and shooting is performed by the exposure control as described with reference to FIG. S26). This is the case of the scene as shown in FIG.

  After shooting in step S22, step S25, and step S26, all the pixel data of the image sensor is read, and the obtained image is subjected to image processing and compression by the image processing unit 7 (step S27). Recording is performed (step S28).

  In this way, it is possible to detect a person under backlight correctly and use ND filters and strobes effectively to support shooting from a bright scene to a dark scene. Even when shooting under strong sunlight, the facial expression and face color of the person You can shoot beautifully. This avoids the risk that the background is exposed at the saturation level, and allows a photograph taken on the same screen even in a scene with a large luminance difference.

  Even under backlit conditions, it is possible to detect the face of the subject by means of fine exposure control switching during monitor image display. A person can be determined as a main subject, and their facial expressions and skin color can be accurately reproduced.

(Second embodiment)
A second embodiment will be described with reference to FIG. In the first embodiment, in a scene where a bright part and a dark part are mixed, the main image and the auxiliary image are displayed on the monitor at the same time when shooting with both the bright part and the dark part balanced. . In the second embodiment, if one of the displayed images is liked, it can be acquired as it is. A block diagram of a camera to which the present invention is applied is the same as FIG.

  FIG. 10 is a flowchart illustrating the procedure of the imaging process according to the second embodiment. The operation unit 16 is provided with a first switch 16d for setting the shooting of the main image 31 shown in FIG. 9 and a second switch 16e for setting the shooting of the auxiliary image 32. If the release operation is performed with the first switch 16d being operated (step S31 YES), the background-oriented shooting is performed without the flash emission (step S33). A background-oriented photograph such as the main image 31 of FIG. 9 is taken.

If a release operation is performed with the second switch 16e being operated (YES in step S32), a person-focused shooting is performed with a strobe light emission or with exposure control focused on the person (step S34). A person-oriented photograph as shown in the auxiliary image 32 of FIG. 9 is taken. If the release operation is performed in a state where neither the first switch 16d nor the second switch 16e is operated (step S31NO, step S32NO), shooting is performed with exposure suitable for both the background and the person. A photograph in which both are emphasized as shown in FIG. 2A is taken (step S35).
As described above, it is possible to shoot according to the user's wish as to which part of the subject is important.

(Third embodiment)
A third embodiment will be described with reference to FIG. The third embodiment is an example in which an image composed of a landscape 30a and a person 30b having a large luminance difference is created by image synthesis in addition to the shooting of the first embodiment. Furthermore, this is an example of measures against backlight scenes that make full use of digital image technology. A block diagram of a camera to which the present invention is applied is the same as FIG.

  FIG. 11 is a flowchart for explaining the procedure of the imaging control process. This photographing control process is mainly executed by the MPU 10 according to the program, the image processing unit 7, the exposure control unit 10a, the scene determination unit 10b, and the face detection unit 18. Since this flowchart has a lot of common parts with the flowchart of FIG. 8, common steps are given the same step numbers, and descriptions thereof are omitted.

  The difference from the flowchart of FIG. 8 is when the face is not dark and is backlit (step S21 NO, step S23 YES, step S24 YES). Here, first, the ND filter 3 is removed from the optical path, the strobe 17 is emitted, and a person is photographed by the exposure control described with reference to FIG. 4 (step S51). Further, a landscape is photographed by exposure control with the ND filter 3 inserted (step S52). A portrait image and a landscape image are combined (step S53). As described above, it is possible to obtain an image in which the landscape and the person are clearly depicted.

  In each of the above embodiments, part or all of the MPU 10 processing, the exposure control unit 10a, and the scene determination unit 10b described in the above embodiments may be configured by hardware. Conversely, hardware such as the face detection unit 18 may be configured by software. The specific configuration is a design matter. Each control process by the MPU 10 is realized by a software program stored in the ROM 19 being supplied to the MPU and operating according to the supplied program. Therefore, the software program itself realizes the functions of the MPU 10, and the program itself constitutes the present invention. A recording medium for storing the program also constitutes the present invention. As a recording medium, besides a flash memory, an optical recording medium such as a CD-ROM or DVD, a magnetic recording medium such as an MD, a tape medium, a semiconductor memory such as an IC card, or the like can be used. Moreover, although each embodiment demonstrated the example which applied this invention to the digital camera, you may apply not only to this but the camera part of a mobile telephone, for example.

  Furthermore, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is an overall block diagram of a camera 1 to which the present invention is applied in a first embodiment. The figure which shows the general example of a backlight imaging scene in 1st Embodiment. The figure which shows the same imaging | photography scene as FIG. 2 in 1st Embodiment. FIG. 4 is a graph showing a luminance distribution along a line 30c in FIG. 3 in the first embodiment. 6 is a timing chart illustrating the timing of shutter and strobe light emission during shooting in the first embodiment. The figure which shows the scenery without a person in 1st Embodiment. The figure which shows the example which determines whether a person is on a screen by face detection in 1st Embodiment. 5 is a flowchart for explaining a procedure of imaging control processing in the first embodiment. The figure which shows the screen on which the main image 31 and the auxiliary image 32 were simultaneously displayed in 1st Embodiment. 9 is a flowchart for explaining a procedure of imaging control processing in the second embodiment. 9 is a flowchart for explaining a procedure of a synthesis process in the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Camera, 2 ... Lens part, 3 ... ND filter, 4 ... Shutter, 5 ... Image pick-up element, 6 ... Analog front end part, 6a ... Cutting-out part, 7 ... Image processing part, 7a ... Resizing part,
8 ... Recording / playback control unit, 9 ... Recording medium, 10 ... MPU, 10a ... Exposure control unit, 10b ... Scene determination unit,
DESCRIPTION OF SYMBOLS 11 ... Display control part, 12 ... Display part, 13 ... AF part, 14 ... ND control part, 15 ... Shutter control part,
16 ... operation unit, 16a ... release switch, 16b, 16c ... changeover switch, 16d ... first switch, 16e ... second switch,
17 ... Strobe part, 18 ... Face detection part, 19 ... ROM, 20 ... Subject,
30a ... Landscape, 30b ... Person, 30c ... Line, 31 ... Main image, 32 ... Auxiliary images I1, I2, I3 ... Brightness curve, L1 ... Noise level, L2 ... Saturation level

Claims (11)

In an exposure control unit that controls exposure of a subject image to an image sensor, and a camera having a function of inserting and removing an ND filter between an imaging lens and the optical path of the image sensor,
A scene determination unit that determines a scene that needs to be supplemented with light on a person's subject by determining the shooting situation,
The exposure control unit controls the ND filter to be removed from the optical path when the scene determination unit determines that the scene needs to be supplemented with light. A display unit for displaying the output of the image sensor to monitor the shooting situation;
The camera according to claim 1, wherein the scene determination unit performs the scene determination using the image sensor signal taken out for the monitor. The exposure control unit changes the exposure for the image sensor in the monitor,
The camera according to claim 1, wherein the scene determination unit performs the scene determination based on whether or not the image sensor signal whose exposure has been changed includes a face portion of a human subject. In a camera image determination method for displaying an output of an image sensor on a display unit in order to check a subject at a timing prior to shooting,
At the display timing, exposure control to the image sensor is switched to control different from that for display on the display unit, and it is determined whether an image corresponding to a human face is included in the output of the image sensor. A camera image determination method comprising: steps. In the camera that displays the output of the image sensor on the display unit in order to check the subject at the timing prior to shooting,
A camera comprising an exposure control unit that switches between exposure control for face detection and exposure control for screen display at the display timing. A display unit for displaying an image obtained from the image sensor as a monitor image;
A face detection unit that detects whether a person exists in the screen as an image obtained from the image sensor as a face detection image;
An exposure control unit that switches exposure to an image sensor depending on whether an image obtained from the image sensor is used as the monitor image or the face detection image. The camera according to claim 6, wherein the exposure control unit alternately switches the exposure for the monitor image and the exposure for the face image in order to acquire the face detection image while the monitor image is displayed. The camera according to claim 7, wherein the exposure control unit switches exposure so that a ratio of acquiring the monitor image is higher than a ratio of acquiring the face detection image. In an exposure control method in a camera including a face detection unit that detects whether a person exists in the screen as an image obtained from an image sensor as a face detection image,
An exposure control method, wherein exposure to an image sensor is switched depending on whether an image obtained from the image sensor is used as a monitor image displayed on a display unit or as the face detection image. In a program for causing a computer to execute an exposure control method in a camera including a face detection unit that detects whether a person is present in a screen as an image obtained from an image sensor as a face detection image,
The program according to claim 1, wherein the exposure control method switches the exposure to the image sensor depending on whether an image obtained from the image sensor is used as a monitor image displayed on a display unit or as the face detection image. In a computer-readable recording medium storing a program for causing a computer to execute an exposure control method in a camera including a face detection unit that detects whether a person is present in a screen using a face detection image as an image obtained from an image sensor,
A recording medium characterized in that the exposure control method switches exposure to an image sensor depending on whether an image obtained from the image sensor is used as a monitor image displayed on a display unit or as the face detection image.

Images