JP6017225B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus capable of displaying an image in the middle of exposure by repeatedly reading out an image signal from an image sensor during an exposure operation and adding the read image signals.

  In general, when shooting a subject such as a starry sky, fireworks, or a night view, bulb shooting is often used. In this bulb photography, an appropriate exposure time, that is, a time from opening the shutter to closing the shutter differs depending on the photographing object and surrounding conditions, and the exposure time must be determined by the photographer himself / herself. For this reason, if the determination is made incorrectly, the photo will be underexposed or overexposed.

  Therefore, it is convenient to determine the exposure time if the exposure level can be observed in real time during bulb photography or the like. For example, Patent Document 1 discloses an imaging apparatus that takes out pixel signals from an imaging element at a predetermined time interval (for example, 1/10 second) during an imaging operation and displays sequentially added images on a liquid crystal monitor. Yes. According to this imaging apparatus, the exposure level can be confirmed almost in real time even during bulb photography or long-time photography, and a major failure can be prevented even in bulb photography.

  According to the imaging apparatus described in Patent Document 1, it is convenient to observe a subject image during exposure during bulb photography. However, it may be difficult to confirm the progress of exposure on the display unit of the imaging apparatus. In view of this, the imaging apparatus disclosed in Patent Document 2 discloses an imaging apparatus capable of displaying an exposure state by displaying a luminance level of a subject and a histogram.

JP 2005-117395 A JP 2009-141599 A

  According to the imaging apparatus disclosed in Patent Document 2 described above, it is possible to check the progress of exposure in long-time exposure. However, depending on the subject image, it may be desired to partially promote or suppress exposure. For example, when shooting fireworks with bulb photography, the fireworks can be photographed sufficiently brightly, but the surrounding subject becomes dark. For this reason, it may be difficult to shoot for a long time as the image intended by the photographer.

  In addition, when performing long exposure, it is difficult to set shooting conditions such as aperture / ISO sensitivity and image quality setting before shooting due to the following conditions (1) and (2). (1) In long-time shooting, the subject is often very dark, and it is difficult to set shooting conditions. (2) Experience and intuition are required to predict the movement and brightness of main subjects such as fireworks, stars, fireflies, and car headlights in advance. Is difficult. Therefore, if the shooting conditions can be changed after the start of shooting, shooting at the long time intended by the photographer can be performed.

  The present invention has been made in view of such circumstances, and when shooting at a long time, it is possible to partially promote or suppress exposure on the subject image, and the long time at which the photographer intends. An object of the present invention is to provide an imaging apparatus capable of acquiring an image. It is another object of the present invention to provide an imaging apparatus that can change imaging conditions after the start of imaging.

  In order to achieve the above object, an image pickup apparatus according to a first invention includes an image sensor that converts an optical image into an image signal and outputs the image signal, and image data based on the image signal read from the image sensor. An image composition unit that sequentially performs cumulative addition, a display unit that displays the cumulative addition image synthesized by the image synthesis unit, and a level of image data of a specific area of the cumulative addition image displayed on the display unit. A level changing unit to be changed.

In the imaging device according to a second aspect of the present invention, in the first aspect, the display unit has a touch panel, and the specific area is set based on a detection output from the touch panel.
In the imaging apparatus according to a third aspect, in the first aspect, the level changing unit imparts an exposure promoting effect or suppressing effect by performing image processing on the image data belonging to the specific region. Then, the level of the image data belonging to the specific area is changed.
According to a fourth aspect of the present invention, in the image pickup apparatus according to the first aspect, the level of the image data is changed by performing image processing so as to move the peak of the histogram of the cumulative addition image.

An imaging device according to a fifth aspect of the present invention is an image sensor that converts an image into an image signal and outputs the image sensor, an image composition unit that sequentially accumulates image data based on the image signal read from the image sensor, An output detection unit that detects the intermediate composite image data added by the image composition unit or each pixel data level constituting the intermediate composite image data, and an exposure that is appropriate exposure based on the detection result of the output detection unit An exposure time calculation unit that calculates time, a display unit that sequentially displays the display of the intermediate composite image data, the result of the output detection unit, and the result of the exposure time calculation unit during shooting, and the display unit An operation input unit that specifies a range in which the output detection unit detects the level of image data from an image display output, and an exposure setting operation unit that variably controls exposure settings during shooting. The display unit, the exposure setting operation unit, during shooting, when changing the exposure settings, sequentially, based on calculated exposure time again, and displays by changing the appropriate exposure time.

In the imaging device according to a sixth aspect based on the fifth aspect, the variable exposure setting control by the exposure setting operation unit varies the photoelectric conversion sensitivity of the image sensor based on the variable exposure setting.
An image pickup apparatus according to a seventh invention varies the aperture mechanism in the fifth invention based on the variable exposure setting of the exposure setting operation unit.

According to an eighth aspect of the present invention, in the fifth aspect of the present invention, based on the variable exposure setting of the exposure setting operation section, the imaging device switches the operation of arranging or not arranging the dimming element on the optical axis.
An imaging device according to a ninth invention is the imaging device according to the fifth invention, wherein the first region specified by the operation input unit is a region different from the first region and the second region specified. , And exposure is performed by designating an exposure difference in the exposure setting conditions of the designated first area and second area.

  According to the present invention, it is possible to provide an imaging device capable of partially promoting or suppressing exposure of a subject image during long-time shooting and acquiring a long-time image intended by the photographer. Can do. In addition, it is possible to provide an imaging apparatus that can change the shooting conditions after the start of shooting.

1 is a block diagram mainly showing an electrical configuration of a camera according to an embodiment of the present invention. It is a flowchart which shows the operation | movement in the valve | bulb photography mode of the camera which concerns on one Embodiment of this invention. It is a flowchart which shows the operation | movement in the valve | bulb photography mode of the camera which concerns on one Embodiment of this invention. In the camera which concerns on one Embodiment of this invention, the suitable exposure time during live valve | bulb imaging | photography is calculated and it is a figure which shows the display screen of this calculated estimated exposure time. In the camera which concerns on one Embodiment of this invention, it is a figure which shows the display screen for changing imaging conditions during live valve | bulb imaging. In the camera which concerns on one Embodiment of this invention, it is a figure which shows a mode that imaging conditions are changed on a display screen during live valve | bulb imaging | photography. In the camera which concerns on one Embodiment of this invention, it is a figure which shows the calculation of appropriate exposure time during live valve | bulb photography, estimation of remaining time, and variable adjustment of exposure time. In the camera which concerns on one Embodiment of this invention, it is a figure which shows the example which accelerates or suppresses exposure about a part of to-be-photographed image during live valve | bulb photography. FIG. 6 is a diagram illustrating an example in which contrast adjustment is performed on a part of a subject image during live bulb shooting in the camera according to the embodiment of the present invention.

  Hereinafter, a preferred embodiment in which an imaging apparatus according to the present invention is applied to a camera will be described with reference to the drawings. A camera according to a preferred embodiment of the present invention is a digital camera that converts a captured optical image into a video signal and obtains image data based on the video signal. The digital camera has an image pickup unit as a main configuration, and converts the subject image into image data by the image pickup unit, and based on the converted image data, the display unit arranges the subject image on the back of the main body. Display live view. The photographer determines the composition and the photo opportunity by observing the live view image displayed on the display unit before the release operation for instructing photographing. When the photographer performs a release operation, the image data obtained from the imaging unit is recorded on the recording medium. The image data recorded on the recording medium can be read and displayed on the display unit by reading the image data from the recording medium when the photographer operates the operation unit of the camera and selects the playback mode.

  In addition, this camera can perform so-called bulb photography in which the exposure start and exposure end timings are taken based on the intention of the photographer. At the time of bulb shooting, when a photographer selects and sets a shooting progress display mode (also referred to as a live bulb mode), the camera reads out image data every preset time from the imaging unit during bulb shooting, and this read image A cumulative addition image of data is generated, and the cumulative addition image is displayed on the display unit. In displaying the cumulative addition image, the remaining time until the appropriate exposure time is reached is calculated based on the luminance information of the cumulative addition image, and is displayed together with the display unit. Further, in the cumulative addition image displayed on the display unit, it is possible to take an image as if dodging has been performed by giving an instruction to promote or suppress exposure in an area designated by the photographer.

  FIG. 1 is a block diagram mainly showing an electrical configuration of a camera 100 according to an embodiment of the present invention. The imaging unit 10 includes a lens 1, a variable ND filter 3, a diaphragm 5, a mechanical shutter 5, and an image sensor 9. The lens 1 includes a plurality of optical lenses for forming an optical image (subject image) of a subject, and is a single focus lens or a zoom lens. Focusing is performed by moving a focus lens constituting the lens 1 along the optical axis by a lens driving mechanism (not shown).

  The variable ND filter 3 is an example of a light reducing element, and is an optical element that reduces the transmittance of incident light. The variable ND filter 3 is arranged behind the lens 1, and the amount of decrease in the subject light transmitted through the lens 1 can be varied by switching the arrangement / non-arrangement in the subject light transmitted through the lens 1. In addition to changing the amount of light reduction by putting in and out the optical element for dimming on the optical axis of the lens 1 as described above, two polarization transmitting elements such as a polarizing filter are arranged on the optical axis. Then, the transmittance may be made variable by driving the two polarization transmission elements to rotate the deflection angle about the optical axis center with respect to the incident surface light as the rotation center. Further, the dimming element may be an optical element having an electro-optic effect, such as a liquid crystal element whose transmittance changes according to the applied voltage.

  The diaphragm 5 is disposed behind the variable ND filter 3 and reduces the amount of subject light transmitted through the lens 1 by making the aperture diameter variable. The mechanical shutter 7 is disposed behind the diaphragm 5 and performs an opening / closing operation of the subject light transmitted through the lens 1. The mechanical shutter 7 performs exposure and shading to the image sensor 9 by this opening / closing operation, and controls the shutter speed.

  In FIG. 1, the lens 1, the variable ND filter 3, the diaphragm 5, and the mechanical shutter 7 are arranged in this order. However, the arrangement is not limited thereto, and of course, these members may be arranged in the optical system of the lens 1. It doesn't matter. In addition, the lens 1, the variable ND filter 3, the diaphragm 5, and the like may be arranged in the interchangeable lens barrel so that they can be mounted on the camera body. In that case, an exposure control command may be transmitted from the camera body via the communication unit to perform exposure control.

  An image sensor 9 is disposed on the optical axis of the lens 1 and in the vicinity where the subject image is formed. The image sensor 9 converts the optical image formed by the lens 1 into an image signal and outputs it. In the image sensor 9, the photodiodes constituting each pixel are two-dimensionally arranged in a matrix, and each photodiode generates a photoelectric conversion current corresponding to the amount of received light. Charges are accumulated by a capacitor connected to.

  The image sensor 9 sequentially reads out the electrical signals accumulated in the two-dimensionally arranged pixels at a predetermined cycle, thereby converting the subject image into an analog output image signal. Further, the image sensor 9 is provided with color filters that transmit the three primary colors of R, G, and B with respect to the light incident on each pixel, and R, R, Analog image signals of G and B color components are output. The analog image signal acquired by such an action is output to the AD conversion unit 11.

  The image sensor 9 includes a CCD image sensor that sequentially transfers the accumulated charge amount of each pixel to obtain an image signal, and a charge amplifier circuit that converts the accumulated charge into a voltage for each pixel, and sequentially transfers the voltage signal. A solid-state imaging device such as a MOS image sensor. In addition, not only a destructive readout type imaging device such as a CCD image sensor or a MOS image sensor, but also various imagen sensors such as a non-destructive readout type imaging device such as a CMD (Charge Modulation Device) can be adopted. .

  The AD conversion unit 11 receives an analog output image signal output from the image sensor 9 and converts it into digital image data. The digital image data is composed of digitized luminance data of R, G, and B color components, respectively. The digital image data converted by the AD conversion unit 11 is output to the gain processing unit 21 and the development processing unit 29 in the image processing unit 20.

  The image processing unit 20 includes a gain processing unit 21, an image synthesis unit 23, an output detection unit 25, a gain coefficient calculation unit 27, a local gain processing unit 28, and a development processing unit 29. These units are connected to the system control unit 31 via the bus line 33. Thereby, each unit inputs / outputs various data such as image data, and inputs / outputs a control command to / from the system control unit 31. The bus line 33 for transmitting data input / output and control commands between these units is not limited to an electric signal transmission line, and may be an optical transmission line.

  The gain processing unit 21 performs arithmetic processing by weighting a uniform gain coefficient to the luminance data of each pixel included in the image data output from the AD conversion unit 11. With this uniform gain processing, it is possible to perform image processing that brightens the entire screen or conversely darkens it.

  The image composition unit 23 performs image addition composition at the time of multiple composition photography. Here, for example, when the shooting progress display mode is set as the shooting operation, if the release button as one of the operation instruction units 19 is fully pressed, the image sensor 9 and the AD conversion unit 11 are switched. Then, every time an image signal is acquired, the cumulative added image is processed. The image data of the cumulative addition image is temporarily stored in the internal memory 13, and the image data of the cumulative addition image temporarily stored in the internal memory 13 is updated every time the cumulative addition image is processed, so that the latest cumulative addition image is always updated. Is temporarily stored.

  The output detection unit 25 detects the luminance level of the image data of the cumulative addition image synthesized by the image synthesis unit 23, temporal conversion of the luminance level, luminance distribution (histogram) of the imaging region, and the like. This luminance level is obtained by calculating a monochrome component from the luminance values of the three primary colors R, G, and B of each image output obtained from the image sensor 9. In the exposure adjustment operation in the AE operation by the system control unit 31 described later, the average luminance value of the entire subject image or the luminance value in a specific area specified by the photographer on the display unit (for example, the maximum luminance value or the specific area) Average luminance value). The output detection unit 25 functions as an output detection unit that detects intermediate composite image data (corresponding to image data of a cumulative addition image) added by the image synthesis unit or each pixel data level constituting the intermediate image data. The pixel data level is luminance data corresponding to each pixel of the image sensor 9.

  The gain coefficient calculation unit 27 divides an area with respect to the image data of the cumulative addition image synthesized by the image synthesis unit 23 and determines a gain coefficient. As will be described later, in the area division, the photographer touches the display surface of the display unit 17 or designates it with an operation member such as a cross button that is one of the operation instruction units 19, or the photographer designates as described above. An exposure correction amount for accelerating or suppressing the exposure with respect to the appropriate exposure condition is also designated for the selected area. Therefore, the gain coefficient calculation unit 27 determines the gain of the area of the image data corresponding to the designated area according to the designated amount.

  The local gain processing unit 28 further multiplies the cumulative addition image synthesized by the image synthesis unit 23 by a gain coefficient to give an exposure correction difference to the area determined by the gain coefficient calculation unit 27. . It should be noted that for areas not designated, exposure correction is not instructed in order to shoot with appropriate exposure, the gain coefficient is set to “1”, and the data of the cumulative added image synthesized by the image synthesis unit 23 is exposed. The data is output as it is without correction processing.

  As will be described later, the display unit 17 is provided with a touch operation unit 17a, and the photographer performs a touch operation on the touch operation unit 17a or a cross button and an OK button which are one of the operation instruction units 19. Can be used to set a specific area to be specified to the local gain processing unit 28. The above-described gain coefficient calculation unit 27 and local gain processing unit 28 function as a level changing unit that changes the level of image data in a specific region of the cumulative addition image for the set specific region.

  The level changing unit performs image processing on image data belonging to a specific area, thereby providing an exposure promoting effect (an effect of increasing the exposure amount) or a suppression effect (an effect of reducing the exposure amount), and the specific region. The level of image data belonging to can be changed. This level change will be described later with reference to S31 of FIG. 2, FIG. 6, and FIG.

  In addition, the level changing unit can change the level of the image data by performing image processing so as to move the peak of the histogram of the cumulative addition image. This level change will be described later with reference to S31 of FIG. 2, FIG. 5, and FIG.

  The development processing unit 29 performs development processing on the image data weighted by the local gain coefficient processing unit 28 or the image data digitized by the A / D conversion unit 11. The image data output from the A / D conversion unit 11 and the image data output from the local gain processing unit 28 are both raw image data before being subjected to development processing described later. As development processing in the development processing unit 29, processing such as synchronization processing (demosaicing), white balance adjustment, gamma correction, and image compression is performed.

  The internal memory 13 is configured by a non-volatile memory such as a flash memory, and temporarily stores various setting information necessary for camera operation and an intermediate image during image processing. Note that the image data of the cumulative addition image is also temporarily stored. The temporary storage memory may be a volatile memory.

  The external memory 15 is a non-volatile memory that can be built in or loaded in the camera 100, and records the image data developed by the development processing unit 29.

  The display unit 17 is configured by an electronic viewfinder (EVF) such as a TFT or an organic EL, and is disposed on the rear surface of the camera 100. The display unit 17 displays a live view display at the time of photographing, a reproduction display of photographed image data, a menu screen for setting photographing conditions, and the like. When the shooting progress display mode is set, a cumulative addition image during exposure is also displayed on the display unit 17.

  As will be described later, since the system control unit 31 functions as an exposure time calculation unit that calculates an exposure time for proper exposure, the display unit 17 displays intermediate composite image data (cumulative added image data) during shooting. (Image data) display, the result of the output detection unit, and the result of the exposure time calculation unit function as a display unit for sequentially displaying. In addition, when the exposure setting operation unit (corresponding to the cross button as one of the operation instruction units 19 and the operation unit 17a) changes the exposure setting during shooting, the display unit sequentially sets the exposure time again. Based on the calculation, an appropriate exposure time is acquired, and the remaining exposure time is changed and displayed.

  The display unit 17 is provided with a touch operation unit 17a that detects the touch position when the photographer touches the display screen as the position of the two-dimensional coordinates of the image output and outputs the detection result. The touch operation unit 17a has a touch panel and has a so-called touch panel interface function. As described above, during live bulb photography, the image being exposed is displayed on the display unit 17 as a cumulative addition image. At this time, when the photographer promotes or suppresses exposure to a specific area (area), the area can be specified by touching the display screen.

  The touch operation unit 17a functions as an operation input unit that designates a range in which the output detection unit detects the level of image data from the image display output of the display unit. The operation input unit may be a cross button or the like of the operation instruction unit 19. The touch operation unit 17a also functions as an exposure setting operation unit that variably controls the exposure setting during shooting.

  In the exposure setting variable control, the photoelectric conversion sensitivity of the image sensor 9 is variable according to the exposure setting variable operation. As the change of the photoelectric conversion sensitivity, the sensitivity of the image sensor 9 may be changed, and the gain processing unit 21 may change the gain for weighting the digitized image output. Further, the exposure setting variable control may be performed by changing a diaphragm mechanism (corresponding to the diaphragm 2), and a dimming element (variable ND filter 3) configured to switch an operation of disposition or non-arrangement on the optical axis of the lens 1. It is also possible to do this.

  Further, the first area designated by the operation input unit such as the touch operation unit 17a based on the operation of the photographer is an area different from the first area, and similarly, designated by the operation input unit. The second area is detected, and exposure is performed by designating an exposure difference in the exposure setting conditions of the first area and the second area. This exposure with the exposure difference designated will be described later with reference to FIG.

  The operation instruction unit 19 includes various operation members such as a release button, an OK button, a cross button, a power switch, a playback button (not shown), and the like, and is operated by the photographer. The release button can be detected in two steps of half-pressed and fully-pressed, and in the half-pressed state, the first switch is turned on to prepare for shooting, and when fully pressed, the second switch is turned on to perform shooting. The cross button is composed of four buttons, top, bottom, left, and right, and is used to change the cursor position when the photographer specifies an area at the time of operation input on the camera control screen or menu screen displayed on the display unit 17. The OK button determines the item selected by the cross button with respect to the item on the camera control screen or the menu screen displayed on the display unit 17 based on the pressing operation of the photographer.

  The system control unit 31 performs overall control of the camera 100 according to a program stored in the internal memory 13. The system control unit 31 functions as an exposure time calculation unit that calculates an exposure time for proper exposure based on the detection result of the output detection unit 25. The calculation of the exposure time will be described later in step S25 (see FIG. 2).

  Next, the outline of the photographing operation of the camera 100 shown in FIG. 1 will be described. First, based on the control of the system control unit 31, the focus position of the focus lens constituting the lens 1 is adjusted, and the subject image is focused. Next, the diaphragm 5 is set to a predetermined value, and the exposure amount at the time of photographing is adjusted. Subsequently, the mechanical shutter 7 is opened during the exposure time acquired based on the exposure condition, and an optical image from the subject enters the image sensor 9 and forms an image. An optical image is converted into an image signal by the image sensor 9, and analog image data read from the image sensor 9 is converted into digital image data by the A / D conversion unit 11. This digital image data is recorded in the external memory 15 as developed image data after desired image processing to be described later is performed by the image processing unit 20.

  The image data that has been subjected to predetermined image processing by the image processing unit 20 is resized according to the resolution and image size of the display unit 17 and then displayed on the display unit 17. The system control unit 31 receives an operation instruction from the photographer via the operation instruction unit 19 and performs timing control of the imaging unit 10 such as start of exposure of the image sensor 9 and reading of an image signal from the image sensor 9. Open / close timing control of the mechanical shutter 7, aperture control of the aperture 5, and autofocus control of the lens 1 are performed. In addition, the system control unit 31 receives image data from the image processing unit 20, and controls display of images on the display unit 17 and storage and recording of image data captured in the external memory 15.

  Next, the operation in the bulb photographing mode according to the embodiment of the present invention will be described using the flowcharts shown in FIGS. This flowchart is executed by the system control unit 31 in accordance with a program stored in the internal memory 13.

  In the present embodiment, on a menu screen or the like, a normal bulb shooting mode in which shooting progress display (displaying an image during shooting in the middle of bulb shooting) is not performed, and cumulative addition image display is performed by cumulatively adding image data. The live bulb photographing mode based on the photographing progress display mode for performing the selection can be selected. A photographer who is accustomed to bulb photography and dislikes image quality degradation caused by repeating image reading and addition processing from the image sensor 9 can select conventional bulb photography that does not display photographing progress. On the other hand, while observing the shooting progress display during bulb shooting, decide the timing of shooting stop, and image processing such as exposure correction for part or all of the subject image so that it becomes the image intended by the photographer If you want to perform, you can select live bulb shooting in the shooting progress display mode.

  Prior to bulb shooting, the photographer observes a live view display or an optical viewfinder (not shown) displayed on the display unit 7 of the camera 100, and adjusts the direction of the camera 100 and the focus of the lens according to the condition of the subject. The shooting composition is determined by adjusting the distance (zoom). If necessary, the photographer can select the shooting progress display mode, adjust the focus position of the focus lens of the lens 1, set the aperture value of the aperture 5, and image using the operation instruction unit 19 and the touch operation unit 17a. Shooting information such as ISO sensitivity of the sensor 9 is set.

  When the valve mode selection flow shown in FIG. 2 is entered based on the operation of the photographer, it is first determined whether or not the first release has been turned on (S1). Here, the system control unit 31 detects and determines whether or not the release button as one of the operation instruction units 19 is half-pressed and the 1st release switch is turned on. If the result of this determination is that it is not on, it enters a standby state (returning to the determination in step S1).

  If the result of determination in step S1 is that the first release is on, AF / AE operation is performed (S3). Here, the system control unit 31 performs autofocus (AF) and automatic exposure control (AE). As the AF operation, the system control unit 31 drives and controls the focus lens of the lens 1 so that the contrast, which is the evaluation value of the brightness contrast of the image data based on the image signal repeatedly read from the image sensor 9, becomes the maximum value. To focus. Further, as the AE operation, the system control unit 31 extracts luminance information from the image data, and calculates a shutter speed value, an aperture value, an ISO sensitivity value, and the like that are appropriate exposure at the time of photographing based on the luminance information. In addition, an electronic shutter speed value, an ISO sensitivity value, and the like for the live view display to achieve proper exposure are calculated.

  Once the AF / AE operation is performed in step S3, it is next determined whether or not the 2nd release is turned on by the photographer's operation (S5). Here, based on the operation of the photographer, the system control unit 31 determines whether or not the release button, which is one of the operation instruction units 19, is further pressed halfway down, and whether or not the 2nd release switch is turned on. It is determined by detecting whether or not. If the result of this determination is that it is not on, a shooting start standby state based on detection of the 2nd release is entered (the determination step of step S5 is repeated).

  If the 2nd release is turned on as a result of the determination in step S5, it is next determined whether or not the shooting progress display mode is set (S7). As described above, since the shooting progress display mode is set on the menu screen or the like, it is determined in this step whether or not the shooting progress display mode is set. As a result of the determination, if the shooting progress display mode is set (determination in step S7: Yes), live valve shooting in the shooting progress display mode is executed in step S9 and subsequent steps. On the other hand, when the shooting progress display mode is not set (determination in step S7: No), normal bulb shooting is executed in step S61 (see FIG. 3) and thereafter. In normal bulb photography, image signals are not read out from the image sensor 9 during bulb photography, and progress display is not performed using a cumulative addition image.

  First, if the result of determination in step S7 is that the shooting progress display mode has not been set, exposure is started (S61). In this step, the system control unit 31 instructs the image sensor 9 to start charge accumulation and starts exposure.

  Once exposure is started, it is next determined whether or not the 2nd release has been turned off based on the operation of the photographer (S63). When the photographer fully presses the release button and starts bulb photography, the photographer continues to fully push the release button while bulb photography continues. When the bulb photographing is finished, the full release of the release button is released (that is, the finger is released from the release button). In this step, it is determined whether or not the 2nd release switch is off. As a result of this determination, if the 2nd release is on (determination in step S63: No), bulb photographing is continued.

  As a result of the determination in step S63, when the 2nd release is turned off (determination in step S63: Yes), the image signal is read (S65). Here, the system control unit 31 instructs the image sensor 9 to read out the image signal, and the image signal is read out.

  If an analog image signal is read from the image sensor 9 in step S65, then A / D conversion is performed (S67). Here, the read image signal is output to the A / D converter 11, and the A / D converter 11 converts it into digital image data.

  Once A / D conversion has been performed in step S67, the digital image data acquired in step S67 is stored in the internal memory 13 (S69). Subsequently, development processing is performed (S71). Here, the development processing unit 29 performs development processing of image data in the RAW data format.

  Returning to step S7 (see FIG. 2), if the shooting progress display mode has been set as a result of the determination in this step (determination in step S7: Yes), the display unit 17 sets the time period for displaying the intermediate progress. The corresponding image readout time period T is set (S9). As described above, in the shooting progress display mode, image signals are repeatedly read from the image sensor 9 during bulb shooting. In this step, a time period T for reading the image is set. The image readout time period T is a preset initial setting value or a time set by the photographer via the operation instruction unit 19. Alternatively, it may be automatically set according to the subject luminance information of the live view image before the start of exposure.

  When the image reading cycle T is set, exposure is started (S11). Here, the system control unit 31 instructs the image sensor 9 to start charge accumulation and starts exposure.

  Once exposure is started, it is next determined whether or not the exposure time T has elapsed (S13). This exposure time is the exposure time T set in step S9. As a result of this determination, if the exposure time T has not elapsed (determination in step S13: No), the exposure continues until the exposure time T elapses.

  As a result of the determination in step S13, when the exposure time T has elapsed (determination in step S13: Yes), the image signal is read (S15). Here, the system control unit 31 instructs the image sensor 9 to read out an image signal, and an analog image signal is read out.

  Once the image signal is read, AD conversion is next performed (S17). Here, the read image signal is output to the A / D converter 11, and the A / D converter 11 converts it into digital image data. If A / D conversion is performed in step S17, then digital image data is stored in the internal memory 13 (S19).

  When digital image data is stored in the internal memory, next, image composition processing is performed (S21). Here, the cumulative addition image is synthesized by the image synthesis unit 23. That is, every time an image signal from the image sensor 9 is output, an addition calculation process of image data based on the image signal just read out is performed on the accumulated addition image stored in the internal memory 13, and this addition is performed. The accumulated addition image is stored in the internal memory 13 again. The cumulative added image is used as a display image on the display unit 17 in the shooting progress display mode.

  Once image composition processing has been carried out, next development processing is carried out (S23). Here, the development processing unit 29 performs development processing on the RAW digital image data of the cumulative addition image synthesized by the image synthesis unit 23.

  Once the development process is performed, the remaining exposure time is calculated (S25). Here, the system control unit 31 calculates the remaining exposure time until appropriate exposure is performed using an apex operation or the like based on the luminance information of the image data of the cumulative addition image generated in the image composition processing in step S21. . The calculation of the remaining exposure time will be described later.

  That is, when the shooting progress display mode is set, a cumulative addition image (shooting progress display image) is displayed on the display unit 17 during exposure, and when a photographer designates a specific area on the cumulative addition image, Apex calculation formula is used to calculate the luminance information of the designated area, the aperture value (Av value) of the aperture 3, the reduced light amount setting value of the variable ND filter 5, and the ISO sensitivity (Sv value) corresponding to the photoelectric conversion gain of the image sensor 9. Based on the above, the remaining exposure time for proper exposure is calculated.

  Further, as will be described later, an exposure correction operation display such as a slide operation unit 77 is displayed on the display unit 17, and a luminance distribution display of the cumulative added image is displayed on the histogram display unit 75 (see FIG. 5). When the photographer gives a correction instruction by a touch operation on the operation unit 77 or the display unit 75 to change the exposure setting, the remaining exposure time is calculated according to the change.

  If the remaining exposure time is calculated in step S25, the added image is then displayed (S27). Here, the cumulative addition image developed in step S23 is displayed on the display unit 17. Further, when displaying the cumulative addition image, the remaining exposure time calculated in step S25 is also displayed.

  Once the added image is displayed, it is next determined whether or not the exposure setting has been changed by the photographer (S29). It is determined whether or not the exposure setting has been changed by the photographer operating with the operation instructing unit 19 and performing the touch operation with the touch operating unit 17a during bulb photographing.

  If the result of determination in step S29 is that exposure setting has been changed (determination in step S29: Yes), exposure setting change is performed (S31). Here, the target appropriate exposure value is changed, and the exposure is promoted or suppressed for a part of the subject image. Details of the exposure setting changing process will be described later with reference to FIGS.

  If the exposure setting is changed in step S31, or if the photographer has not changed the exposure setting as a result of the determination in step S29, then exposure is started again (S33). Here, as in step S11, the system control unit 31 instructs the image sensor 9 to start charge accumulation and starts exposure. Further, the exposure time T is reset, and the timing operation for the exposure time T is restarted.

  When exposure is started in step S33, it is next detected whether or not the 2nd release is off (S35). As described above, the photographer releases the full press of the release button when completing the bulb photographing. In this step, it is determined whether or not the 2nd release switch is off. If the result of this determination is that the 2nd release is on, the flow returns to step S13 to continue bulb shooting in the shooting progress display mode.

  If the result of determination in step S35 is that the second release is off (determination in step S35: Yes), that is, if the release button has been fully pressed, then exposure is terminated (see FIG. 3). S41). Here, the system control unit 31 instructs the image sensor 9 to end the charge accumulation operation.

  When the exposure is completed, the image signal is read out (S43). Here, the system control unit 31 instructs the image sensor 9 to read out the image signal, and the image signal is read out. Once the image signal has been read, A / D conversion is performed (S45). Here, the read image signal is output to the A / D converter 11, and the A / D converter 11 converts it into digital image data.

  When A / D conversion is performed, the AD converted digital image data is stored in the internal memory 13 (S47). Subsequently, image composition processing is performed (S49). Here, the image data based on the image signal read in step S43 is added to the image data of the cumulative addition image stored in the internal memory 13, and the image data of the added cumulative addition image is again obtained. Store in the internal memory 13.

  When image composition is performed, development processing is performed (S51). Here, the development processing unit 29 performs development processing of digital image data in the RAW data format of the cumulative addition image synthesized in step S49.

  If development processing is performed in step S51 or step S71, it is then stored in an external memory (S53). Here, the image data (compressed) developed by the development processor 29 is recorded in the external memory 15.

  Subsequently, image display is performed (S55). Here, the image stored in the external memory 15 is displayed on the display unit 17 for a predetermined time. As a result, the photographer can check the image recorded in the external memory 15. When the image display is performed, the valve mode flow is terminated.

  Thus, in the valve mode flow in the present embodiment, image data based on the image signal read from the image sensor 9 is sequentially accumulated and added each time the image signal is read (S15) (S21). The synthesized cumulative added image is displayed (S27), and the exposure setting of the displayed cumulative added image can be changed (S31). For this reason, exposure according to the photographer's intention can be achieved during shooting in the bulb mode.

  Next, a method for calculating the remaining exposure time in step S25 will be described. The exposure amount for achieving proper exposure is calculated using the Apex calculation formula, and the remaining exposure time Tres for achieving proper exposure is also calculated using the Apeck calculation formula.

  In calculating the remaining exposure time Tres, first, the light flux amount Lv incident on the image sensor 9 is calculated using the SV value corresponding to the ISO sensitivity of the image sensor 9 and the BV value corresponding to the brightness of the subject (formula). 1). Next, the sum of the Av value (see Equation 2) corresponding to the aperture ratio (F number) of the imaging unit 10 and the Tv value (see Equation 3) corresponding to the exposure time is calculated to obtain the exposure value Ev (see Equation 4). ) Since the exposure value Ev for appropriate exposure is equal to the light value Lv described above, Expression 5 is obtained. In general, during bulb photographing, the Av value corresponding to the aperture ratio (F number) of the imaging unit 10 is known during photographing, and thus a Tv value based on the appropriate exposure time Tev is calculated (see Equation 6).

Lv = Sv + Bv (Formula 1)
Av = log ₂ (F ² ) (Formula 2)
Tv = log ₂ (1 / Tev) (Formula 3)
Ev = Av + Tv (Formula 4)
Lv = Ev = (Sv + Bv) = (Av + Tv) (Formula 5)
Tv = (Sv + Bv) −Av (Formula 6)

In Equation 6, assuming that the Bv value corresponding to the brightness of the subject is a constant value during shooting, the aperture value before the exposure setting change based on the apex calculation formula is Av1, and the Sv value corresponding to the ISO sensitivity is Sv1, the appropriate exposure The Tv value Tv1 corresponding to the exposure time for obtaining the above is calculated from the following (formula 7).
Tv1 = (Sv1 + Bv) −Av1 (Formula 7)

Also, assuming that the shooting cycle is T (sec) and the cumulative number of additions in the middle is m, the exposure value Ev1 in the middle is calculated as shown in the following (formula 8).
Ev1 = Av1 + Tv (m) (Tv (m) = log ₂ (1 / mT)) (Formula 8)

Next, calculation is performed for the case where the aperture value is changed during shooting to change the exposure amount. Here, when the aperture value before the exposure setting change based on the Apex equation is Av2, the Tv value based on the remaining exposure time Tres, Tv2, is expressed by the following (Equation 9).
TV2 = (SV1 + Bv) −Av2− (Av1 + Tv (m)) (Formula 9)

Further, when the Sv value based on the ISO sensitivity is changed from Sv1 to Sv2 during photographing, the Tv value based on the remaining exposure time Tres, Tv2, is expressed by the following (formula 10).
Tv2 = (Sv2 + Bv) −Av1− (Av1 + Tv (m)) (Formula 10)

Therefore, Tv2 is obtained from (Equation 9) when the aperture value is changed during shooting, and (ISO 10) is changed during ISO shooting, and the remaining exposure time Tres is calculated using this Tv2. The remaining exposure time Tres calculated from the following (11) is displayed in step S25 (see FIG. 2).
Tres = 2 ^(−Tv2) (Formula 11)

  Next, an image display in the shooting progress display mode and an operation for changing the exposure setting will be described with reference to FIGS.

  FIG. 4 shows the cumulative addition image 70 displayed on the display unit 17 when the shooting progress display mode is set. The exposure analysis area 71 indicates a two-dimensional area to be set in the cumulative addition image, and is an area set based on the coordinates touched on the display unit 17 by the photographer by a touch operation. The area specified by is detected. Note that this area need not have a one-to-one relationship with the area touched by the photographer, and may be a method of setting the area in a shape including a plurality of coordinate positions instructed by the photographer's touch operation. Good. Further, the shape of the exposure analysis region 71 shown in FIG. 4 is a quadrangle, but the shape of this region is not limited to this, and may be appropriately determined based on, for example, the touch operation position.

  The remaining exposure time display unit 73 is an area for displaying the remaining exposure time calculated by the system control unit 31 in step S25 (FIG. 2). As described above, the remaining exposure time is a time until appropriate exposure is performed using an apex calculation or the like based on the image data of the cumulative addition image. When the exposure analysis region 71 is set, this exposure time is set. It is calculated based on the image data of the cumulative addition image belonging to the analysis area 71.

  In addition to the remaining exposure time, the remaining exposure time display unit 73 may display the luminance value of the cumulative added image in the exposure analysis area 71. The display at this time is, for example, “+ ** EV” (where ** indicates a luminance value). Further, both the remaining exposure time and the luminance value may be displayed.

  The histogram display unit 75 displays a histogram indicating luminance distribution information in the exposure analysis area 71. Specifically, the horizontal axis of this histogram is the brightness of the exposure analysis region 71, and in FIG. 5, the brightness increases toward the right side of the paper, and the vertical axis indicates the frequency of occurrence with respect to the brightness, with the frequency increasing toward the top of the paper. Become. Since this histogram is detected by the output detection unit 25, it is superimposed on the display screen of the cumulative addition image when the cumulative addition image is displayed based on the detection result of the output detection unit 25.

  Note that the display positions and display forms of the exposure analysis region 71, the remaining exposure time display unit 73, and the histogram display unit 75 in FIG. 4 are examples, and other display positions and display forms may of course be used. For example, the display image or histogram display corresponding to the exposure analysis area 71 set by the photographer may be displayed in such a manner that the correspondence between the two can be uniquely determined by the photographer by blinking the display color. Good. In addition to the touch operation, the exposure analysis area 71 may be set by moving the cursor indicating the area using, for example, a cross button as one of the operation instruction units 19.

  FIG. 5 shows an operation method for variable adjustment of the exposure time. A slide operation unit 77 is displayed on the right side of the cumulative addition image 70 displayed on the display unit 17. The slide operation unit 77 may be always displayed when the shooting progress display mode is set, or may be displayed only when the operation instruction unit 19 such as an exposure correction button is operated. Good.

  In the example illustrated in FIG. 5, image processing for promoting exposure is performed when the photographer performs a sliding operation in the upward direction by touching the slide operation unit 77, and image processing for suppressing exposure is performed when performing a sliding operation in the downward direction. The When performing this image processing on the entire screen, the gain is adjusted by the gain processing unit 21. Further, when image processing for promoting / suppressing exposure is performed only in an area designated by the photographer, it is performed by the gain coefficient calculating unit 27 and the local gain processing unit 28.

  In the case where exposure is uniformly promoted or suppressed over the entire screen, the aperture amount of the diaphragm 5 may be increased or decreased rather than image processing, and the variable ND filter 3 is placed on the optical axis. A dimming effect may be provided by switching between arrangement and non-arrangement.

  As described with reference to FIG. 4, the histogram display unit 75 is displayed below the cumulative addition image 70 displayed on the display unit 17. In the captured image display of FIG. 5, the histogram peak 75 a in the histogram display section 75 indicates the luminance distribution of the area where the fireworks 79 are displayed, and the peak 75 b indicates the luminance distribution of the area where the buildings 78 are displayed. 75c shows the luminance distribution of the area where the night sky 80 as the background is displayed. When the photographer touches one of the peaks of the histogram display portion 75 and slides to the right side, the image processing is performed so that the exposure is promoted. On the other hand, when the photographer slides the left side, the image is displayed so that the exposure is suppressed. It is processed.

  When the photographer touches the peaks 75a to 75c of the histogram display unit 75 and further performs a slide operation on the right side, image processing is performed so that a relatively bright portion in the subject image is further brightened. When a slide operation is performed on the left side, image processing is performed so that a relatively bright portion in the subject image becomes dark. In other words, when the slide operation is performed on the right side, the cumulatively added image is set to have a bright overall brightness, and the image that is to be exposed every time period T is changed so that the exposure is increased by the slide operation. Based on the setting, cumulative addition processing is performed. Similarly, when the photographer slides the histogram to the left, the cumulatively added image is set so that the brightness is darkened as a whole, and the exposure of images that are exposed every time period T is also suppressed by the slide operation. The cumulative addition processing is performed on the basis of the exposure setting that has been changed. This image processing is performed by changing the gain coefficient so that it becomes brighter or darker with respect to the luminance data of the image data of the cumulative added image corresponding to the slide-operated peak. This process is performed by the gain coefficient calculation unit 27 and the local gain processing unit 28, and is executed in the exposure setting change in step S31 (see FIG. 2).

  In the example shown in FIG. 5, if the building 78 is desired to be brightened, the peak 75b may be slid to the right, and if the night sky 80 is desired to be further darkened, the peak 75c may be slid to the left. Of course, this sliding operation may be performed on a plurality of peaks. In this case, exposure can be performed by designating an exposure difference of a plurality of peaks.

  In addition to performing a slide operation on the slide operation unit 77 by a touch as shown in FIG. 5, for example, exposure correction is performed by an upward operation or a downward operation of the cross button. Also good. In the example shown in FIG. 5, the exposure analysis area 71 is not set. However, of course, it may be set. In this case, exposure is promoted with respect to the set exposure analysis area 71, or Image processing can be performed to suppress the image, and a desired difference is given to the exposure setting between the set exposure analysis region 71 and the non-set region, and the image looks as if dodging is performed. .

  FIG. 6 shows the difference between when the image processing is performed and when it is not performed based on the exposure analysis region designated by the photographer. FIG. 6A shows a case where image processing for promoting or suppressing exposure is not performed for a specified region. As in the case of fireworks photography, when the subject of the main subject, fireworks, changes with time and the timing of fireworks ignition is not known in advance, subjects other than the main subject, fireworks 79 (for example, building 78), It may be long exposure and brighten.

  On the other hand, when image processing that promotes or suppresses exposure is performed, the brightness balance of the main subject and the surrounding subjects can be kept moderate. In the example shown in FIG. 6B, a setting is made in advance so as to suppress exposure to subjects other than the main subject (in this case, the building 78). As a result, the brightness of subjects other than the main subject is suppressed to be dark, and the brightness balance with the fireworks 79 as the main subject becomes appropriate. These image processes are executed in the exposure setting change in step S31 (see FIG. 2).

  Next, an example of calculating the appropriate exposure time and adjusting the exposure time in the shooting progress display mode will be described with reference to FIG. FIG. 7 shows a transition of the shooting progress of the cumulative added image acquired every predetermined time from the start of exposure as a shot image sequence. The upper, middle and lower shot image sequences in FIG. From right to left, the cumulative addition image corresponding to the elapsed time from the start of exposure is shown in the horizontal direction. The photographed image sequence shown in the upper part of FIG. 7 is an example in which the exposure time is not adjusted, the middle part is a case where the process is changed to the process of promoting exposure at time 0, and the lower part is the process of suppressing exposure at time 0. When changed to.

  When the adjustment of the exposure time is not performed, as shown in the upper part of FIG. 7, at time 0, the remaining exposure time display unit 73 displays 200 seconds as the time until proper exposure. Thereafter, the cumulative added image gradually becomes brighter and reaches the target exposure in 200 seconds.

  As shown in the middle part of FIG. 7, when the slide operation unit 77 is operated at time 0 and the processing is changed to processing that promotes exposure so that the target exposure level is reached at time 100 sec, the gain processing unit 21 increases the gain. To do. In this case, the remaining exposure time display section 73 displays the remaining exposure time up to time 100 sec. In the case shown in the middle part of FIG. 7, the exposure time at the time of shooting is promoted compared to the case where the exposure time is not adjusted (see the upper part of FIG. 7). It is shortened. Note that the exposure promoting process may be performed by controlling the diaphragm 5 in addition to the image process when performed on the entire screen.

  Further, as shown in the lower part of FIG. 7, when the slide operation unit 77 is operated at time 0 and the processing is changed to suppress exposure so as to reach the target exposure level at time 300 sec, the gain processing unit 21 increases the gain. Adjust to decrease. In this case, the remaining exposure time display section 73 displays the remaining exposure time up to time 300 sec. In the case shown in the lower part of FIG. 7, since the exposure amount at the time of shooting is suppressed as compared with the case where the exposure time is not adjusted (see the upper part of FIG. 7), the time until the target exposure is obtained is extended. . In addition, as a process which suppresses exposure, when performing to the whole screen, you may carry out by control of the aperture time 5, the variable ND filter 3, the exposure time interval of an electronic shutter, etc. other than an image process.

  Next, an example in which the photographer designates an area in the shooting progress display mode and performs a process of promoting or suppressing exposure for the area will be described with reference to FIG. The upper part of FIG. 8 shows a case where bulb photography is performed without specifying an area, and the lower part designates a subject 78 (building) other than the main subject and touches the slide operation unit 78a when 100 seconds have elapsed after the start of photography. Thus, the slide operation is performed on the left side, that is, on the suppression side.

  By this sliding operation, the exposure of the building part is suppressed, while the exposure of the main subject, fireworks, is not suppressed, so that the brightness of the subject is balanced so that the main subject, fireworks, stands out. Bulb photography can be performed.

  In the processing for the subject 78 other than the main subject, image processing for suppressing exposure is performed by the gain coefficient calculation unit 27 and the local gain processing unit 28 for the region designated by the touch operation unit 17a.

  Next, an example in which the photographer designates the peak of the histogram and performs the process of adjusting the contrast in the photographing progress display mode will be described with reference to FIG. The upper part of FIG. 9 shows a case where bulb photographing is performed without specifying a peak of the histogram.

  In the lower part of FIG. 9, after the start of photographing, a slide operation is performed on the peak of the histogram display portion 75 to adjust the exposure. That is, when 100 seconds have elapsed since the start of shooting, the peaks 75b and 75c of the histogram display portion 75 are slid to the left, that is, to the suppression side so as to suppress exposure of the subject 78 (building) other than the main subject and the night sky. Yes. Further, the peak 75a is slid to the right side by touching, that is, to the promotion side so as to promote the exposure of the fireworks of the main subject 79.

  In the upper part of FIG. 9, since contrast adjustment is not performed, buildings and the like that are subjects other than the main subject become bright. On the other hand, in the lower part of FIG. 9, since the contrast is adjusted by adjusting the exposure difference between the peak 75a and the peak 75b (75c), the main subject fireworks are bright and the surrounding buildings are entirely This makes it possible to perform bulb photography with a well-balanced brightness.

  In this contrast adjustment, the gain coefficient is calculated so that the brightness data of the cumulative addition image corresponding to the peak that has been slid by the gain coefficient calculation unit 27 and the local gain processing unit 28 becomes brighter or darker. Change and do.

  As described above, in one embodiment of the present invention, a cumulative addition image is displayed on the display unit, and the level of image data in a specific area of the cumulative addition image displayed on the display unit is accelerated or suppressed. (See FIGS. 6 and 8). For this reason, at the time of long time shooting, it is possible to partially promote or suppress the exposure of the subject image, and it is possible to acquire the long time image intended by the photographer. For example, after the start of shooting, when the main subject or the background is dark or bright, it can be controlled to have an appropriate brightness. Further, according to the movement of the main subject and changes in brightness, exposure can be promoted, conversely suppressed, and the time until proper exposure can be controlled. In addition, it is possible to prevent the low-brightness portion from being blacked out or the high-brightness portion from being blown out during shooting.

  In addition, in the embodiment of the present invention, an exposure setting operation unit (which corresponds to the touch operation unit 17a) that variably controls the exposure setting during shooting is provided, and the exposure can be changed according to the exposure setting operation. Yes (S31 in FIG. 2). For this reason, it is possible to change the shooting conditions after the start of shooting.

  In one embodiment of the present invention, when the exposure setting operation unit changes the exposure setting during shooting, the appropriate exposure time is changed based on sequentially calculating the exposure time again. It is displayed on the display unit (see S25 in FIG. 2, FIG. 4). For this reason, when the exposure setting is changed, it is possible to easily check the remaining time until the proper exposure is achieved. Since the exposure can be changed to an appropriate exposure after the start of imaging, for example, when the remaining exposure time until the appropriate exposure is too long, or conversely too short, the remaining exposure time can be controlled as the photographer desires.

(Modification of one embodiment of the present invention)
In one embodiment of the present invention, when the shooting progress display mode at the time of bulb shooting is set, exposure is promoted or suppressed for the shooting area designated by the photographer. That is, a difference is given to the exposure amount of the photographed image for each designated area, and the brightness of the photographed image is changed. In this case, the specified region and the captured image outside the specified region have the same color temperature setting, and thus the ratios of the white balance gains of the R, G, and B components of the captured image data are the same. On the other hand, in the modification of the embodiment of the present invention, the color temperature is changed and the ratio of the white balance gain is changed for the designated area and the captured image outside the designated area.

  Specifically, in the exposure progress display of FIG. 4, the slide operation unit 77 shown in FIG. 5 is displayed, and from the color temperature setting amount, for example, 3000 K (Kelvin) corresponding to the slide operation of the slide operation unit 77. Set input to 7000K. If the designated area is set, the color temperature can be adjusted for each designated area, and the white balance gain setting ratio in the image processing unit 20 is changed based on the set color temperature.

  As an effect of the slide operation of the slide operation unit 77, when the color temperature set value is set to a low value, the white balance gain ratio is adjusted so that the color of the cumulative added image is bluish, and the color temperature set value is On the contrary, when the value is set to a high value, image processing for adjusting the ratio of the white balance gain is performed so that the color of the cumulative added image is reddish.

  For example, when a subject such as a night view as shown in FIG. 6 is bulb-photographed, the color of the night sky 80 as a background and the building 78 is illuminated by a street light, or the light of the indoor light of the building Various light source colors may be mixed, such as when leaking from a building window or being reflected by another building wall, etc. With a uniform white balance gain setting, the subject image may be photographed with different colors .

  Even in such a situation, in the modification of the embodiment of the present invention, the color temperature setting value can be changed for each designated region, so that the color of the subject image can be optimized. In other words, when shooting in the shooting progress display mode, in addition to the effects of adjusting and changing the exposure during shooting, the desired color temperature for each area specified by the photographer, such as the night sky and buildings, is also shown. It is possible to perform adjustment processing and adjust the display unit 17 so as to obtain an optimum color while confirming the color of the cumulative addition image.

  In the embodiment of the present invention, the case where the image sensor 9 uses a destructive sensor (a type in which accumulated charge is reset when an image signal is read) has been described. However, the present invention can also be applied to an imaging device that displays a progress in progress using a non-destructive sensor. In this case, it is possible to eliminate generation of an added image every time an image signal is read.

  In the present embodiment, the digital camera is used as the photographing device. However, the camera may be a digital single-lens reflex camera or a compact digital camera, and may be used for moving images such as video cameras and movie cameras. It may be a camera, or may be a camera built into a mobile phone, a smart phone, a personal digital assistant (PDA), a game machine, or the like. In any case, the present invention can be applied to any device capable of displaying a shooting progress during long exposure such as live bulb shooting.

  In addition, regarding the operation flow in the claims, the specification, and the drawings, even if it is described using words expressing the order such as “first”, “next”, etc. It does not mean that it is essential to implement in this order.

  The present invention is not limited to the above-described embodiments as they are, 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, you may delete some components of all the components shown by embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 ... Lens, 3 ... Variable ND filter, 5 ... Aperture, 7 ... Mechanical shutter, 9 ... Image sensor, 10 ... Imaging part, 11 ... A / D conversion part, DESCRIPTION OF SYMBOLS 13 ... Internal memory, 15 ... External memory, 17 ... Display part, 17a ... Touch operation part, 19 ... Operation instruction part, 20 ... Image processing part, 21 ... Gain Processing unit, 23 ... Image composition unit, 25 ... Output detection unit, 27 ... Gain coefficient calculation unit, 28 ... Local gain processing unit, 29 ... Development processing unit, 31 ... System Control part 33 ... Bus line 70 ... Accumulated addition image 71 ... Exposure analysis area 73 ... Remaining exposure time display part 75 ... Histogram display part 77 ... Slide operation , 77a ... slide operation part, 78 ... subject other than main subject , 79 ... the main subject, 100 ... camera

Claims (9)

An image sensor that converts an optical image into an image signal and outputs the image signal;
An image composition unit for sequentially accumulating image data based on the image signal read from the image sensor;
A display unit for displaying the cumulative addition image synthesized by the image synthesis unit;
A level changing unit that changes a level of image data of a specific area of the cumulative addition image displayed on the display unit;
An imaging apparatus comprising:   The imaging apparatus according to claim 1, wherein the display unit includes a touch panel, and the specific area is set based on a detection output from the touch panel.   The level changing unit performs image processing on the image data belonging to the specific area, thereby giving an exposure promoting effect or suppressing effect, and changing the level of the image data belonging to the specific area. The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized.   The imaging apparatus according to claim 1, wherein the level of the image data is changed by performing image processing so as to move a peak of a histogram of the cumulative addition image. An image sensor that converts an image into an image signal and outputs the image signal;
An image composition unit for sequentially accumulating image data based on the image signal read from the image sensor;
An output detection unit for detecting the intermediate combined image data added by the image combining unit or each pixel data level constituting the intermediate combined image data;
Based on the detection result of the output detection unit, an exposure time calculation unit that calculates an exposure time for proper exposure;
A display unit that sequentially displays the intermediate composite image data display, the output detection unit result, and the exposure time calculation unit result during shooting,
An operation input unit for designating a range in which the output detection unit detects the level of image data from the image display output of the display unit;
An exposure setting operation unit that variably controls the exposure setting during shooting,
Comprising
When the exposure setting operation unit changes the exposure setting during shooting, the display unit changes and displays the appropriate exposure time based on sequentially calculating the exposure time again. An imaging device.   6. The imaging apparatus according to claim 5, wherein the variable control of the exposure setting by the exposure setting operation unit varies the photoelectric conversion sensitivity of the image sensor based on the variable exposure setting.   The imaging apparatus according to claim 5, wherein the diaphragm mechanism is varied based on a variable exposure setting of the exposure setting operation unit.   The imaging apparatus according to claim 5, wherein an operation of arranging or not arranging the light reducing element on the optical axis is switched based on a variable exposure setting of the exposure setting operation unit.   Further, the first area designated by the operation input unit is different from the first area, and the designated second area is detected, and the designated first area and second area are detected. 6. The imaging apparatus according to claim 5, wherein exposure is performed by designating an exposure difference in the exposure setting condition.