JP2009058837A - Imaging apparatus, imaging method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To photograph a subject with an appropriate exposure amount using an imaging apparatus that emits stroboscopic light. <P>SOLUTION: A main control unit 10 includes: a scene determination part 41 for determining a scene in the circumference of the subject; a face detection part 42 for detecting a face of the subject; a stationary determination part 43 for determining a stationary state of a case on the basis of blurring information received from a blurring detection part; an LV value detection part 46 for detecting an LV value indicating brightness of the subject; an exposure condition assumption part 45 for comparing the LV value detected by the LV value detection part 46 with a predetermined threshold and assuming exposure conditions; an exposure decision part 44 for deciding whether the assumed exposure conditions are proper, based on the scene determined by the scene determination part 41, the face of the subject detected by the face detection part 42 and the stationary state determined by the stationary determination part 43; and an exposure condition determination part 48 for determining the exposure conditions changed into a program chart 47 corresponding to the exposure conditions determined on the basis of the LV value detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, an imaging method, and a program suitable for application to, for example, a digital still camera that records an image file generated by imaging a subject on a recording medium.

Conventionally, when a subject is imaged with a digital still camera in a low illuminance or backlight environment, a strobe is emitted, and the subject is illuminated with the light, whereby a darkly sinking subject can be imaged brightly. Appropriate exposure during strobe emission is defined by the strobe guide number (GNo), aperture (FNo), and distance (m) to the subject. When a digital still camera capable of obtaining a sensitivity equivalent to ISO (International Organization for Standardization) 100 is used, proper exposure is defined by the following equation.
GNo = FNo × (distance to subject)

  For example, when shooting an object 2 m away using a GNo. 5 strobe, if the aperture is set to F2.5, proper exposure can be obtained.

  In general, when shooting a dark scene such as a night view or indoors, the shutter speed is slow, so that camera shake is likely to occur and the probability of mistakes in shooting increases. In general, it is said that, as a measure for preventing camera shake, a shooting error caused by camera shake is less likely to occur when the shutter speed is faster than 1 second corresponding to the focal length of the taking lens. For this reason, a technique is known in which the rising shutter speed in the program diagram of the exposure mode is set to one second of the focal length of the photographing lens.

Japanese Patent Application Laid-Open No. 2004-228688 describes a technique for approximating with a bit operation when calculating with respect to the focal length f at the rising shutter speed Tv = log2f.
JP-A-1-271732

  By the way, there were the following problems during flash photography. For example, when shooting in a dark background such as a night view, if you take a strobe shot at a relatively high shutter speed that can prevent camera shake, the main subject will be kept at a proper exposure with strobe light, but the background will be It becomes dark due to underexposure, resulting in a photograph that is different from the photographer's appearance. In order to solve this problem, a technique called slow sync, which makes the background exposure appropriate by reducing the shutter speed, is used.

  However, when performing strobe shooting in an environment where the background such as a night view is dark, the shutter speed becomes low, so it is necessary to prevent camera shake using a tripod or the like. However, carrying a tripod is cumbersome for a user who uses a camera with a compact and excellent portability.

  Further, when a night scene and a person image are simultaneously photographed, the photographed image is too bright or too dark unless the person image as the main subject is located at an appropriate distance of the strobe light. Also, the night view as the background also becomes a dark image because an appropriate exposure amount cannot be obtained. Even if the photographer sets strobe light emission, unnecessary power is consumed due to wasteful strobe light emission when shooting a night scene or the like where strobe illumination does not make sense.

  Also, if you just increase the shutter speed, camera shake is unlikely to occur, but the background cannot be captured beautifully in dark scenes such as night views. Recently, a technique that can shoot the background by increasing the amplification gain (hereinafter referred to as gain) of AGC (Automatic Gain Control) processing and performing high-sensitivity imaging has become mainstream. However, when the gain is increased, noise increases, so that there is a problem that it cannot cope with all dark scenes such as night scenes.

  The present invention has been made in view of such a situation, and an object thereof is to photograph a subject with an appropriate exposure amount.

  The present invention picks up image light imaged through an optical system and outputs it as an image signal, illuminates the subject side obtained as image light, and based on the image signal capture timing, the exposure light amount of the image light , And outputs blur information that detects the blur that occurs in the casing of the apparatus. In this case, when the amount of light around the subject is insufficient, the subject's periphery is determined as a dark scene, the subject's face is detected, and the state where the housing is stationary is determined as the stationary state based on the blur information. Judging and detecting a value indicating the brightness of the subject, comparing the value indicating the brightness of the subject with a predetermined threshold, assuming an exposure condition, and determining the determined dark scene and the detected face of the subject And whether or not the assumed exposure condition is appropriate based on the resting state, and based on the value indicating the brightness of the subject, change to a program diagram corresponding to the determined exposure condition, The exposure conditions are determined.

  This makes it possible to determine the exposure condition based on the scene around the subject, the face of the subject, and the stationary state of the housing of the apparatus.

  According to the present invention, the exposure condition can be determined based on the scene around the subject, the face, and the stationary state of the housing of the apparatus. For this reason, when a user performs imaging, exposure is performed under appropriate exposure conditions even in a dark scene where the light quantity is insufficient such as a night view or a room by making a still determination of the imaging device without performing complicated settings. There is an effect that it is possible to perform photographing by controlling the amount of light.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The present embodiment is an example applied to a digital still camera that records (stores) photographed image data in a built-in recording medium or a removable external recording medium.

  First, an internal configuration example of the digital still camera of this example will be described. FIG. 1 is a block diagram showing an example of the internal configuration of the digital still camera 100 of this example. The digital still camera 100 includes a lens unit 1 including optical system parts such as a plurality of lenses, and forms image light incident through the lens unit 1 on an imaging surface of a CCD (Charge Coupled Device) imaging device 4. This is a configuration to be made. The capture timing of the imaging signal output from the CCD imaging device 4 is instructed by a shutter operation unit 20 as an imaging instruction unit.

  The lens unit 1 includes an iris mechanism 2 that controls the aperture amount and a shutter mechanism 3 that performs shutter control. The iris mechanism 2 controls the size of an aperture through which light incident through the lens unit 1 is transmitted by a control signal supplied from a main control unit 10 that controls each unit. The shutter mechanism 3 is driven by a control signal supplied from the main control unit 10 in response to a pressing operation of the shutter operation unit 20, thereby allowing light incident through the lens unit 1 to pass through (exposure time). It has a function as an exposure light quantity control unit for controlling the above. Thus, the iris mechanism 2 and the shutter mechanism 3 control the amount of exposure light. The CCD image sensor 4 can obtain an imaging output signal corresponding to the subject image formed on the imaging surface.

  The lens unit 1 includes a zoom control mechanism unit (not shown), a focus control mechanism unit, and a camera shake control mechanism unit. A control signal from the main control unit 10 is supplied to the zoom control mechanism unit and the focus control mechanism unit of the lens unit 1 via the lens control unit 8 to drive and control zoom and focus. The digital still camera 100 of this example receives a supply from a power supply unit (not shown) and always performs loop control while the power is on. When the brightness changes, the iris mechanism 2 and the shutter mechanism 3 are changed to achieve proper exposure.

  In addition, a shake detection unit 13 that detects camera shake that occurs when the photographer holds the digital still camera 100, supplies the main control unit 10 with shake information related to camera shake. The blur information includes a voltage value representing an angular velocity generated in the pitch (pitch) and yaw (yaw) directions with respect to the casing of the digital still camera 100. A voltage value included in the shake information is converted into a corresponding numerical value by a camera shake correction calculation unit (not shown) included in the main control unit 10. Then, the main control unit 10 determines the position where the correction optical system should move based on the blur amount of the digital still camera 100 converted from the blur information and the current position information of the correction optical system. The correction optical system is a system including a camera shake correction mechanism that corrects camera shake of the lens unit 1 so as to cancel camera shake. The lens control unit 8 can correct and control camera shake occurring in the digital still camera 100 by driving and controlling the camera shake correction mechanism.

  The analog signal processing circuit 5 that performs analog processing performs processing such as sampling processing (S / H) and amplification processing (AGC), and performs predetermined analog processing on the imaging output signal supplied from the CCD imaging device 4 to generate an image. Output a signal. The image signal output from the analog signal processing circuit 5 is supplied to the analog / digital conversion circuit 6. The analog / digital conversion circuit 6 samples the analog image signal supplied from the analog signal processing circuit 5 at a predetermined sampling rate and converts it into a digital image signal. The digital image signal output from the analog / digital conversion circuit 6 is supplied to a digital signal processing circuit 7 that performs digital processing.

  The digital signal processing circuit 7 generates various signals necessary for framing, still image capturing, autofocus, photometry, and the like from the digital image signal supplied from the analog / digital conversion circuit 6. For example, at the time of framing, a display image signal is generated from the input image signal and supplied to the display unit 15 that displays an image. The display unit 15 displays predetermined guidance messages and icons in addition to images.

  At the time of capturing a still image, the digital signal processing circuit 7 generates one still image signal from the input image signal, performs a process such as compression on the still image, and stores it in the removable recording medium 16. The recording medium 16 may be a memory card, an HDD (Hard Disk Drive) built in the digital still camera 100, a flash memory, or the like.

  At the time of autofocus, the digital signal processing circuit 7 detects a high frequency component in a predetermined area in the screen from the input image signal, generates a parameter indicating the level of the high frequency component, and supplies the parameter to the main control unit 10. Further, at the time of photometry, a light amount component (referred to as an AE (Auto Exposure) signal) in a predetermined area in the screen is detected from the input image signal, a parameter indicating the light amount level is generated, and supplied to the main control unit 10.

  The shutter operation unit 20, which is a momentary type push switch operated by the photographer, has a function of switching by distinguishing a plurality of pressed states. For example, the shutter operation unit 20 switches between three states: a state where the switch is not pressed at all (off), a state where the switch is fully pressed (deep press), and a state where the switch is pressed halfway (half press). To do. The deeply pressed state is a state for instructing shutter timing (imaging timing) for capturing an image, and the half-pressed state is a state for instructing preparation for capturing an image. The main control unit 10 determines the three pressed states (off, half-pressed, and deep-pressed) of the shutter operation unit 20.

  A timing signal generation circuit 9 that generates a predetermined timing signal generates various drive pulses that the CCD image sensor 4 needs to store and read image signals for each screen. Various pulses generated from the timing signal generation circuit 9 are supplied to the CCD image sensor 4 and used as timing signals for image signal imaging processing and output processing.

  A main control unit 10 that controls each unit in the digital still camera 100 includes a microcomputer, a CPU (Central Processing Unit), a program ROM (Read Only Memory), a work area RAM (Random Access Memory), and various I's (not shown). / O port and interface. The main control unit 10 performs various processes such as exposure amount calculation, lens zoom control, strobe light emission control, capture image storage, and image processing such as resizing. The main control unit 10 is connected to a lens control unit 8 that drives and controls the zoom mechanism and the focus mechanism of the lens unit 1.

  Further, the main control unit 10 is charged until a necessary strobe light amount is obtained, and a light emitting unit that illuminates strobe light on a subject side obtained as image light through a charging / light emission circuit control unit 11 that performs light emission control. 12 is connected. In addition, the main control unit 10 includes an operation input unit 14 including menu keys and operation cursors for a user to perform various operation inputs, a display unit 15 including, for example, an LCD (Liquid Crystal Display) panel, and a recording. An external interface 17 having an input / output terminal compliant with, for example, a USB (Universal Serial Bus) standard, an electrically rewritable EEPROM (Electrically Erasable and Programmable Read Only Memory) 18, generated data, etc. Is connected to a RAM (Random Access Memory) 19.

  The light emitting unit 12 is attached to, for example, the front surface or upper part of the housing, and is provided so as to irradiate a subject to be imaged with strobe light. That is, the light emitting unit 12 is provided so as to irradiate light in the direction of the optical axis of the lens and in the direction from the lens toward the front. The light emitting unit 12 is a discharge device such as a xenon lamp, and can emit strong light for a moment and irradiate the subject with strong flash light. The light emitting unit 12 is driven by the charge / light emission control unit 11 that controls charging and light emission of the light emitting unit 12, and the light emission timing is controlled by the main control unit 10.

  FIG. 2 shows an example of the configuration of functional blocks related to the determination of exposure conditions, among the functional blocks realized by the main control unit 10 executing the program recorded in the EEPROM 18. However, the functional blocks shown in FIG. 2 may be configured by hardware.

  The main control unit 10 determines a scene determination unit 41 that determines a scene such as a night view or the outdoors, a face detection unit 42 that detects the face of the subject, and a still state in which the digital still camera 100 is determined to be stationary. A determination unit 43, and each unit is independently controlled. Further, the main control unit 10 detects an LV value as a value indicating the brightness of the subject and the surroundings of the subject, and an exposure assuming an exposure condition based on the LV value detected by the LV value detection unit 46. A condition assumption unit 45; an exposure determination unit 44 that determines whether or not the assumed exposure condition is appropriate; a program diagram 47 that includes a plurality of types of program diagrams; and an appropriate program diagram. And an exposure condition determining unit 48 for determining.

The scene determination unit 41 is a control unit that determines a scene such as a night view or outdoors based on, for example, EV (Exposure Value) information, luminance information, color information, a histogram, distance information, and the like. The scene determination unit 41 determines the subject periphery as a dark scene when the amount of light around the subject is insufficient (for example, when the EV information is 6 EV or less).
The face detection unit 42 detects the face of the subject, for example, by performing matching processing using a face matching pattern within the angle of view.

The stillness determination unit 43 compares the output from the shake detection unit 13 included in the shake information with the output at the time of stillness, and determines the still state of the digital still camera 100 based on the deviation amount and time.
The LV value detection unit 46 detects an LV value indicating the brightness of the subject based on the AE signal received from the digital signal processing circuit 7.

  The exposure condition assumption unit 45 compares the LV value received from the LV value detection with a predetermined threshold, and assumes an exposure condition according to the difference. For example, when the detected LV value is smaller than a predetermined threshold value, the exposure is insufficient, so the exposure is performed so as to reduce the shutter speed, reduce the aperture amount, or increase the gain of AGC processing. Assume the conditions. On the other hand, if the detected LV value is equal to or greater than a predetermined threshold value, the exposure is excessive, so that the exposure is performed to increase the shutter speed, increase the aperture amount, or decrease the gain of AGC processing. Assume the conditions. Of the assumed exposure conditions, let the aperture amount be the reference aperture amount Ie, the shutter speed be the reference shutter speed Te, and the gain be the reference gain Ge.

  Based on the dark part scene determined by the scene determination unit 41, the face of the subject detected by the face detection unit 42, and the still state determined by the still determination unit 43, the exposure determination unit 44 It is determined whether the reference aperture amount Ie, the reference shutter speed Te, and the reference gain Ge assumed as exposure conditions are appropriate.

  The exposure condition determination unit 48 changes the program diagram 47 corresponding to the shooting mode specified by the user to a program diagram corresponding to the exposure condition determined by the exposure determination unit 44, and performs exposure based on the detected LV value. Determine the conditions. A program diagram 47 corresponding to each settable photographing mode is held in, for example, the EEPROM 18.

Next, an example of the shooting mode change process performed by the main control unit 10 will be described with reference to the flowchart of FIG.
First, the scene determination unit 41 determines whether or not it is a dark scene (step S1). If it is determined that the scene is not a dark part scene, the process is terminated. On the other hand, when it is determined that the scene is a dark part scene, the following control is performed.

  Next, the face detection unit 42 performs processing for detecting the face of the subject in the dark part scene (step S2). When the face detection unit 42 determines that “the face is present” within the angle of view, the face detection unit 42 changes to a flash emission mode capable of emitting a flash (step S3). On the other hand, when the face detection unit 42 determines that “there is no face” within the angle of view, the face detection unit 42 changes to a strobe light emission prohibiting mode that prohibits strobe light emission (step S7).

  When the scene determination unit 41 determines that the scene is a dark part scene, and when the face detection unit 42 determines that “there is a face” within the angle of view, the stillness determination unit 43 determines whether the digital still camera 100 is stationary. It is determined whether or not (step S4). At this time, the stationary determination unit 43 determines the stationary state based on information from a camera shake correction mechanism that performs camera shake correction based on the camera shake information obtained from the camera shake detection unit 13. Normally, when the digital still camera 100 is placed in a stable place and is stationary, the camera shake correction mechanism is turned off. Then, the stillness determination is performed based on the information that the camera shake correction mechanism is turned off and the shake information.

  Next, when it is determined that the digital still camera 100 is stationary, the stillness determination unit 43 shifts to the slow sync mode (step S5) and ends the process. At this time, the digital still camera 100 is fixed to a tripod or placed in a stable place.

  In the slow sync mode, in a dark scene, the subject (person) is clearly photographed by flashing light, and the shutter speed is slowed down to increase the amount of exposure of image light on the CCD image pickup device 4. It is a mode that can shoot dark scenes in the clear. Since the stillness determination unit 43 determines the still state of the digital still camera 100, the shutter speed can be reduced without performing the AGC process for raising the image signal. For this reason, the user can obtain a beautiful image without noise.

  On the other hand, if the face detection unit 42 determines that “there is a face” within the angle of view and the stillness determination unit 43 determines that the digital still camera 100 is not stationary in the process of step S4, the AGC process And an exposure mode (hereinafter referred to as a program diagram) in which camera shake can be prevented by increasing the shutter speed (step S6). At this time, the digital still camera 100 is in a state where the user is hand-held or placed in an unstable place. When the shutter speed is increased, the amount of exposure light of the image light at the CCD image sensor 4 is reduced.

  The high-sensitivity mode is a shooting mode in which a subject can be clearly photographed even at a normal shutter speed as well as strobe light emission by setting a state in which sensitivity is increased. In the high sensitivity mode, the camera shake correction mechanism is on and the camera shake correction is always performed. For example, when the standard setting is ISO 200 and the shutter speed is 1/10 second, the sensitivity can be increased in the order of ISO 800 and ISO 1600 by changing to the high sensitivity mode. Furthermore, the subject (person) can be clearly photographed by strobe light emission, and a dark scene in the background can be photographed by performing AGC processing. Therefore, by increasing the shutter speed to prevent camera shake, the user can obtain an image that does not fail even if it is held by hand.

  In the process of step S2, the face detection unit 42 determines that there is no face within the angle of view, and after changing to the strobe light emission prohibition mode in the process of step S7, the stillness determination unit 43 performs a digital still camera. It is determined whether 100 is stationary (step S8). If it is determined that the digital still camera 100 is still, the stillness determination unit 43 shifts to a program diagram specialized for night view shooting, changes to the night view mode (step S9), and ends the process.

  The night view mode is a mode suitable for shooting a night view in the absence of a person. In this case, since there is no person within the angle of view, the flash is prohibited from emitting light and slow shutter photography is performed. For this reason, the user can obtain a beautiful image without noise.

  On the other hand, when the face detection unit 42 determines that there is no face within the angle of view and the stillness determination unit 43 determines that the digital still camera 100 is not stationary, the mode is switched to the high sensitivity mode described above (step S10), the process is terminated. In this case, since there is no person, the AGC process is performed with the strobe disabled. In this way, since a dark scene in the background can also be photographed, the shutter speed that can prevent camera shake is increased. For this reason, the user can obtain a clear image without hand failure.

  Incidentally, the digital still camera 100 has various scene modes, but the program diagram may differ depending on each scene mode. Each scene mode includes, for example, an auto mode, a high sensitivity mode, a landscape mode, a night view mode, and a portrait mode. Setting to the program diagram of the scene mode to be set is referred to as “transition to program diagram”.

  Next, an example of stillness determination processing performed by the stillness determination unit 43 will be described with reference to the flowchart of FIG. This stillness determination process is performed in common in both directions of pitch (Pitch: vertical fluctuation) and yaw (Yaw: horizontal fluctuation) based on the shake information output by the shake detection unit 13.

  First, the stillness determination unit 43 compares the output signal from the blur detection unit 13 with the output signal at the time of stillness, obtains a deviation, and determines whether or not it is equal to or less than a predetermined threshold (step S11). If this deviation is less than or equal to the threshold value, it is assumed that the digital still camera 100 is stationary, and a stillness determination counter that counts the stationary period is incremented (step S12). The deviation from the stationary output signal may be obtained by applying a high-pass filter (HPF) to the output from the shake detector 13.

  Then, when a certain time or more has elapsed, the stillness determination unit 43 determines whether or not the stillness determination counter is greater than a predetermined time threshold (step S13). When it is determined that the stillness determination counter is greater than the predetermined time threshold, the stillness determination unit 43 determines that the digital still camera 100 is still. Then, the stationary determination flag indicating the stationary state in the pitch or yaw direction is set to “TRUE” (step S14), and the process ends. The stillness determination flag is replaced with “1” as “TRUE” when not stationary, and “0” as “FALSE” when not stationary, in the final stationary determination process (see FIG. 5) described later. Used.

On the other hand, if the deviation is larger than the threshold value as a result of the determination in step S11, the digital still camera 100 is regarded as not stationary and the stationary determination counter is reset to zero (step S15).
If the deviation is larger than the threshold value as a result of the determination in step S11, or the determination result in step 13 is that the stillness determination counter is equal to or smaller than the predetermined time threshold value, the stillness determination flag is set to “FALSE” ( Step S16), the process is terminated.

  In this manner, it is possible to detect a stationary state in at least one of the pitch direction and the yaw direction regardless of whether the camera shake correction function is on or off.

  Next, an example of the final stillness determination process performed by the stillness determination unit 43 will be described with reference to the flowchart of FIG. The final stillness determination process is a process in which the stillness determination unit 43 finally determines whether or not the digital still camera 100 is still. Basically, when both the pitch direction and yaw direction stationary determination flags are “TRUE”, the final stationary determination is “TRUE”.

First, the stillness determination unit 43 determines whether or not the stillness determination flag in the pitch direction is “TRUE” (step S21). If it is determined that the stillness determination flag in the pitch direction is “TRUE”, it is determined whether the stillness determination flag in the yaw direction is “TRUE” (step S22).
If it is determined that both the pitch direction and yaw direction stationary determination flags are “TRUE”, the final stationary determination flag is set to “TRUE” (step S23), and the process ends.

  On the other hand, if it is determined that the stillness determination flag in any one of the pitch direction and the yaw direction is not “TRUE”, the final stillness determination flag is set to “FALSE”, and the process is terminated (step S24).

  In this way, the stationary determination unit 43 can detect the stationary state by combining the pitch direction and the yaw direction.

Next, display examples of guidance messages that notify the user that the shooting mode has been automatically changed will be described with reference to FIGS. The guidance message is displayed on the display unit 15 together with the image icon.
FIG. 6 shows an example of guidance display when the mode is changed to the slow sync mode.
On the right side of the display unit 15, an icon 15a representing the slow sync mode is displayed. A guidance message 15 b is displayed at the center of the display unit 15. A person frame 15 c serving as a photographing guide for the subject is displayed below the center of the display unit 15.

FIG. 7 is an example of guidance display when the flash light emission mode and the high sensitivity mode are changed.
On the right side of the display unit 15, an icon 15d representing the strobe light emission mode and an icon 15e representing the high sensitivity mode are displayed. A guidance message 15 f is displayed at the center of the display unit 15. A person frame 15 c is displayed below the center of the display unit 15.

FIG. 8 is an example of guidance display when the mode is changed to the night view mode.
On the right side of the display unit 15, an icon 15g representing the night view mode and an icon 15h representing the strobe light emission prohibiting mode are displayed. A guidance message 15 i is displayed at the center of the display unit 15.

FIG. 9 shows an example of guidance display when the strobe emission prohibition mode is changed to the high sensitivity mode.
On the right side of the display unit 15, an icon 15h representing a strobe light emission prohibiting mode and an icon 15e representing a high sensitivity mode are displayed. A guidance message 15 j is displayed at the center of the display unit 15.

  In this way, appropriate exposure control is performed according to the subject and the scene around the subject, so that it is possible to support photographing appropriate for the user.

  According to the digital still camera 100 according to the present embodiment described above, based on the information obtained from the scene determination unit 41, the face detection unit 42, and the stillness determination unit 43, and the LV value detected by the LV value detection unit 46. Based on the exposure condition assumed by the exposure condition assumption unit 45, it is determined whether or not the exposure condition is optimal, and the exposure condition determination unit 48 uses the program diagram corresponding to every pattern in the dark scene to expose the exposure condition. Can be determined. For this reason, there is an effect that a good image can be obtained by the automatically changed shooting mode without a complicated operation by the user.

  In addition, the main control unit 10, as a shooting mode, has a slow sync mode with a strobe flash mode, a high sensitivity mode with a strobe flash mode, a night view mode with a strobe flash prohibit mode, and a high sensitivity with a strobe flash prohibit mode. Any one of the modes can be selected and switched. For this reason, appropriate exposure control is performed on the subject, and when the shooting mode is switched, a guidance function that supports each of the strobe light emission prohibition mode and the strobe light emission mode is provided, so that appropriate shooting for the user can be supported. It became so.

  In addition, by determining whether the digital still camera 100 is still in a dark scene such as a night view or a room, a user can easily obtain a good image without using various settings and shooting techniques. For example, when it is fixed to a tripod instead of being held by hand, there is an effect that a beautiful image can be obtained without noise. On the other hand, if it is handheld, there is an effect that an image without camera shake can be obtained.

  In addition, by using the scene determination unit 41, the face determination unit 42, and the stillness determination unit 43, a natural image can be obtained because the strobe light emission of the light emitting unit 12 only needs to be used. Furthermore, it is possible to reduce the power consumption of the digital still camera 100, and there is an effect that the user can extend the usage time of the digital still camera 100.

  In addition, when a strobe light emission mode is used during still image shooting under an environment such as a night scene with a dark background, it is possible to automatically determine whether or not the main subject is at the position where the strobe light reaches. For this reason, even when the strobe light does not reach the subject, the image light of the main subject captured by appropriate processing of the shutter speed and AGC does not become dark. As a result, there is an effect of reducing the possibility that the user will fail in photographing.

  In the above-described embodiment, the exposure control technique applied when shooting a night scene and a person at the same time has been described. However, the exposure control technique is not limited to a shooting scene such as a night scene with a dark background, but is used in this example in any scene. An exposure control technique can be applied. For example, even when shooting in backlit conditions, the strobe emission, shutter speed, and gain can be set appropriately, so that an image intended by the user can be easily obtained.

  It should be noted that the exposure control when using the flash emission mode may be manually switched on / off by the operation input unit 14. Further, the auto mode on / off may be configured to include a control for manually turning on / off by the operation input unit 14. Further, the guidance mode may be always turned on without determining the guidance mode, or the guidance mode may be manually turned off by the operation input unit 14.

  In addition, the stillness determination unit 43 can determine whether or not the digital still camera 100 is still in order to determine the still state in the pitch direction and the yaw direction. For this reason, there is an effect that shooting can be performed by switching to an appropriate shooting mode. Even in a stable place fixed by a tripod, the stationary determination flag may become “FALSE” when the user touches the shutter in the pitch direction. For this reason, the final stillness determination may be performed only in the yaw direction. Alternatively, the final stillness determination may be performed only in the pitch direction.

  Further, the stationary determination criterion (steps S4 and S8 in FIG. 3) may have a determination criterion different from the determination criterion for hand-shake-off by the shake detection unit 13. This is because the judgment criterion for changing the exposure condition by judging the dark part scene can be optimized by being different from the stationary judgment criterion for hand shake off. As a guide for preventing camera shake, it is said that a shooting error caused by camera shake is less likely to occur when the shutter speed is faster than 1 second corresponding to the focal length of the taking lens. For this reason, the shutter speed may be faster than 1 second corresponding to the focal length of the photographing lens.

  Further, the imaging device according to the above-described embodiment is not limited to the digital still camera 100. For example, it is obvious that the present invention can be applied to a camera having another structure such as an interchangeable lens camera or a film camera. Further, the imaging device may be configured not to include the shutter mechanism 3. Even in this case, the main control unit 10 controls the capture speed of the image signal output from the CCD image sensor, and therefore can capture images at an appropriate shutter speed.

  Further, each of the scene determination unit 41, the face detection unit 42, and the stillness determination unit 43 may include a control unit that is manually turned off by the operation input unit 14. As for the guidance function control, the same functions and effects can be obtained even if various notification functions such as a vibration function and an alarm function are used together to prompt the user to switch the strobe light emission control.

Further, if the image pickup apparatus has a self-timer, when the self-timer is on, the digital still camera 100 is likely to be placed at a place where a tripod is fixed or fixed. For this reason, if the self-timer is on, the scene determination unit 41, the face detection unit 42, and the stillness determination unit 43 may be controlled to operate. Further, a configuration in which strobe light emission is not prohibited regardless of face detection on / off may be employed. In this case, the mode can be automatically changed by providing the main control unit 10 with a self-timer that instructs the shutter 3 to capture the imaging signal output from the CCD 4 after a predetermined time has elapsed since the main control unit 10 was turned on. It is.
Here, an example of processing when the main control unit 10 includes a self-timer will be described with reference to the flowchart of FIG.

First, the scene determination unit 41 determines whether it is a dark part scene (step S31). If it is determined that the scene is not a dark part scene, the process is terminated. On the other hand, if it is determined that the scene is a dark scene, it is determined whether or not the self-timer is on (step S32).
If the self-timer is off, it is unclear whether it is hand-held or placed in a stable location, so this process is terminated and the process proceeds to the shooting mode change process shown in FIG. On the other hand, when the self-timer is on, the face detection unit 42 performs face detection with the face detection unit 42 in the dark part scene (step S33). If it is determined that “there is a face” within the angle of view, the face detection unit 42 changes to the slow sync mode (step S34) and ends the process. On the other hand, when it is determined that “there is no face” within the angle of view, the face detection unit 42 changes to the night view mode (step S35).

  In this way, when the self-timer is on, control that operates the scene determination unit 41 and the face detection unit 42 can reduce power consumption and extend the usage time used by the user. effective. Even when the strobe flash mode is used for still image shooting in dark scenes such as night scenes, the proper shutter speed minimizes camera shake and balances the main subject with the background for proper exposure. There is an effect that an image can be obtained.

It is the block diagram which showed the internal structural example of the digital still camera in one embodiment of this invention. It is the block diagram which showed the example of an internal structure of the main control part in one embodiment of this invention. It is the flowchart which showed the example of the imaging | photography mode switching process in one embodiment of this invention. It is the flowchart which showed the example of the stillness determination process in one embodiment of this invention. It is the flowchart which showed the example of the last still determination process in one embodiment of this invention. It is explanatory drawing which showed the example of a display of the guidance function (slow sync mode) in one embodiment of this invention. It is explanatory drawing which showed the example of a display of the guidance function (strobe light emission mode and high sensitivity mode) in one embodiment of this invention. It is explanatory drawing which showed the example of a display of the guidance function (night view mode) in one embodiment of this invention. It is explanatory drawing which showed the example of a display of the guidance function (strobe light emission prohibition mode and high sensitivity mode) in one embodiment of this invention. It is the flowchart which showed the example of the imaging | photography mode switching process in other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens part, 2 ... Iris mechanism, 3 ... Shutter mechanism, 4 ... CCD image sensor, 5 ... Analog signal processing circuit, 6 ... Analog / digital conversion circuit, 7 ... Digital signal processing circuit, 8 ... Lens control part, 9 DESCRIPTION OF SYMBOLS ... Timing signal generation circuit, 10 ... Main control part, 11 ... Charge and light emission control part, 12 ... Light emission part, 13 ... Shake detection part, 14 ... Operation input part, 15 ... Display part, 15a-15g ... Guidance menu, icon 16 ... recording medium, 17 ... external interface, 18 ... EEPROM, 19 ... RAM, 20 ... shutter operation unit, 41 ... scene determination unit, 42 ... face detection unit, 43 ... stationary determination unit, 44 ... exposure determination unit, 45 ... exposure condition assumption unit, 46 ... LV value detection unit, 47 ... program diagram, 48 ... exposure condition determination unit, 100 ... digital still camera

Claims (9)

An imaging unit that outputs image light imaged through an optical system as an imaging signal;
A light emitting unit that illuminates the subject side obtained as the image light;
An imaging instruction unit for instructing capturing timing of an imaging signal output by the imaging unit;
An exposure light amount control unit that controls the exposure light amount of the image light in the imaging unit based on the capturing timing of the imaging signal instructed by the imaging instruction unit;
A blur detection unit that detects blur generated in the housing of the apparatus and outputs it as blur information;
A control unit that receives the blur information from the blur detection unit,
The controller is
A scene determination unit that determines the periphery of the subject as a dark scene when the amount of light around the subject is insufficient;
A face detection unit for detecting the face of the subject;
Based on the shake information received from the shake detection unit, a stationary determination unit that determines that the housing is stationary as a stationary state;
A subject brightness detector for detecting a value indicating the brightness of the subject;
An exposure condition assumption unit that assumes an exposure condition by comparing a value indicating the brightness of the subject detected by the subject brightness detection unit with a predetermined threshold;
The exposure condition assumed by the exposure condition assumption unit is based on the dark scene determined by the scene determination unit, the face of the subject detected by the face detection unit, and the still state determined by the still determination unit. An exposure determination unit for determining whether it is appropriate;
Based on a value indicating the brightness of the subject detected by the subject brightness detection unit, the exposure condition is determined by changing to a program diagram corresponding to the exposure condition determined by the exposure determination unit. And an imaging device. The imaging device according to claim 1,
The controller is
When the scene determination unit determines that the scene is a dark part scene, the face detection unit detects the face of the subject, and the still determination unit determines that it is in a stationary state, the light emission unit emits light and the exposure light quantity The first mode to increase
When the scene determination unit determines that the scene is a dark part scene, the face detection unit detects the face of the subject, and the still determination unit determines that it is not in a stationary state, the light emitting unit emits light, and the imaging unit The second mode to increase the gain of the imaging signal output by
When the scene determination unit determines that the scene is a dark scene, the face detection unit does not detect the face of the subject, and the still determination unit determines that it is in a stationary state, prohibits light emission of the light emitting unit, A third mode for increasing the amount of exposure light,
When the scene determination unit determines that the scene is a dark part scene, the face detection unit does not detect the face of the subject, and the still determination unit determines that it is not in a stationary state, and prohibits light emission of the light emitting unit, An imaging apparatus, characterized in that a fourth mode for increasing the gain of an imaging signal output from the imaging unit is provided. The imaging apparatus according to claim 2, wherein
The blur information includes blur information in at least one of a pitch direction and a yaw direction with respect to a housing of the device. The imaging device according to claim 3.
An imaging apparatus comprising: a display unit that displays a predetermined guidance message for the first to fourth modes. The imaging apparatus according to claim 4.
The image pickup apparatus, wherein the control unit includes a self-timer that instructs the exposure light amount control unit to take in an image pickup signal output from the image pickup unit after a predetermined time has elapsed after being turned on. The imaging device according to claim 5.
When the self-timer is turned on, the scene determination unit determines that the scene is a dark scene, and when the face detection unit detects the face of the subject, the light emission unit emits light and the amount of exposure light is increased. An imaging device characterized by being increased. The imaging device according to claim 5.
When the self-timer is turned on, the scene determination unit determines the dark scene, and when the face detection unit does not detect the face of the subject, the light emission unit prohibits light emission, An image pickup apparatus that increases the gain of an image pickup signal output from the image pickup unit. The image light imaged through the optical system is imaged and output as an imaging signal, the subject side obtained as the image light is illuminated, and the exposure light amount of the image light is determined based on the capturing timing of the imaging signal. An imaging method to control,
When the amount of light around the subject is insufficient, determine the periphery of the subject as a dark scene,
Detecting the face of the subject,
Based on the shake information that detects the shake that occurs in the housing of the device, the state where the housing is stationary is determined as a stationary state,
Detecting a value indicating the brightness of the subject;
Comparing a value indicating the brightness of the subject with a predetermined threshold, assuming an exposure condition,
Based on the determined dark area scene, the detected face of the subject, and the determined still state, it is determined whether or not the assumed exposure condition is appropriate,
The imaging method, wherein the exposure condition is determined by changing to a program diagram corresponding to the determined exposure condition based on a value indicating the brightness of the subject. The image light imaged through the optical system is imaged and output as an imaging signal, the subject side obtained as the image light is illuminated, and the exposure light amount of the image light is determined based on the capturing timing of the imaging signal. A program for controlling imaging,
A process of determining the periphery of the subject as a dark scene when the amount of light around the subject is insufficient;
Detecting the face of the subject;
A process of determining the stationary state of the casing as a stationary state based on the blur information detected in the casing of the device;
Processing for detecting a value indicating the brightness of the subject;
A process of comparing the value indicating the brightness of the subject with a predetermined threshold and assuming an exposure condition;
A process of determining whether or not the assumed exposure condition is appropriate based on the determined dark part scene, the detected face of the subject, and the determined stationary state;
A program that changes to a program diagram corresponding to the determined exposure condition based on a value indicating the brightness of the subject and performs the process of determining the exposure condition.

Images