JP5784316B2 - Valve imaging device and valve imaging method - Google Patents

Description

  The present invention relates to a bulb imaging device and a bulb imaging method capable of observing changes in a subject during bulb photography in a photography device such as a digital camera.

  In a conventional photographing apparatus such as a digital camera, an object image is observed using an optical viewfinder. However, recently, a digital camera with a live view display function for displaying an image acquired by an image sensor on a display device such as a liquid crystal monitor and observing the image is commercially available.

  In the case of a digital camera having an optical viewfinder, it is not possible to confirm the brightness of a photographed image during exposure in bulb photography. For this reason, an image that has already been shot is confirmed only after the shooting is completed. In view of this, a technique has been proposed in which image data is sequentially read out in a time-division manner, the sequentially read image data is added, and bulb photography is performed while the bulb photography images represented by the added image data are sequentially displayed on the monitor. (See Patent Document 1).

JP 2005-117395 A

  When image data is read and added in a time-division manner, various electrical noises are generated due to image reading, and the image quality deteriorates as the number of additions of image data increases. In order to guarantee a certain level of image quality, it is necessary to limit the number of additions of image data. However, in bulb shooting, for example, in the case of a sudden and moving subject such as fireworks, it is required to shorten the display time interval in order to observe the subject's movement, while fireworks are launched. Since the shooting is started from before, the entire exposure time becomes long. For this reason, the number of additions of image data increases, and the image quality of the finally obtained image data deteriorates. In order to solve this problem, if the entire exposure time is shortened, there is a possibility that the target subject is not captured in the finally obtained image due to the limitation of the exposure time. Thus, shortening the display time interval and increasing the total exposure time are in a trade-off relationship.

  The present invention has been made in view of such circumstances, and is capable of observing a photographed image in the middle of exposure in bulb photography and capable of obtaining high-quality image data and a bulb imaging method. The purpose is to provide.

In order to achieve the above object, a bulb imaging apparatus according to a first aspect of the present invention is a bulb imaging apparatus that captures images while displaying images captured during exposure in bulb photography, and continuously captures images in a time-division manner. An imaging unit that generates data, a detection unit that detects a temporal change amount of the image data captured by the imaging unit, and whether or not the temporal change amount of the image data detected by the detection unit is equal to or greater than a predetermined value A determination unit that determines whether the temporal change amount is equal to or greater than a predetermined value, and an image data addition unit that starts an operation of sequentially adding image data captured by the imaging unit When a display unit that chronologically display the image represented by the image data that has been added by the image data adding unit, the number of additions of the image data by the image data adding unit By detecting that it is now above order set predetermined value and a control unit that performs control for terminating the addition of the image data by the image data adding unit.

  According to a second aspect of the present invention, in the first aspect of the invention, when the number of times the image data is added by the image data adder is equal to or greater than a predetermined value, the photographer further takes image data from the image data adder An instruction unit for instructing to continue the addition of the image data, and when the photographer gives an instruction to continue the addition of the image data by the image data addition unit, the control unit performs imaging by the imaging unit. At the same time, the control is performed so as to continue the addition of the image data picked up by the image pickup unit.

A bulb imaging apparatus according to a third aspect of the invention is a bulb imaging apparatus that performs imaging while displaying an image captured during exposure in bulb imaging, and that performs imaging in a time-division manner and generates image data. A detection unit that detects a temporal change amount of the image data captured by the imaging unit, and a determination unit that determines whether or not the temporal change amount of the image data detected by the detection unit is greater than or equal to a predetermined value When the determination unit determines that the temporal change amount is greater than or equal to a predetermined value, the image data addition unit sequentially adds the image data captured by the imaging unit, and the image data addition unit adds the image data. A display unit that displays the image represented by the image data in time series, and after the addition of the image data by the image data addition unit is started, When change amount is determined to be equal to or less than a predetermined value, and a control unit that performs control for terminating the addition of the image data by the image data adding unit.

In the valve imaging device according to a fourth aspect of the present invention, in the third aspect, the image data adding unit is controlled by the imaging unit when the determination unit determines that the temporal change amount is equal to or greater than a predetermined value. The operation of sequentially adding the captured image data is started.
According to a fifth aspect of the present invention, there is provided the valve imaging device according to the third aspect, wherein when the number of times of imaging by the imaging unit exceeds a predetermined value before the start of the addition of the image data by the image data adding unit, The controller includes an instruction unit for instructing to continue the bulb photographing, and the control unit continues the imaging by the imaging unit when the photographer gives an instruction to continue the bulb photographing.

According to a sixth aspect of the present invention, there is provided the valve imaging device according to the third aspect, wherein when the number of additions of the image data by the image data addition unit is equal to or greater than a predetermined value, An instruction unit for instructing to continue the addition of the image data, and when the photographer gives an instruction to continue the addition of the image data by the image data addition unit, the control unit performs imaging by the imaging unit. At the same time, the control is performed so as to continue the addition of the image data picked up by the image pickup unit.
According to a seventh aspect of the present invention, in the valve imaging apparatus according to the third aspect, the control unit detects that the number of additions of the image data by the image data addition unit exceeds a predetermined value and adds the image data. Control for terminating the addition of image data by the unit is performed.

According to an eighth aspect of the present invention, there is provided a valve imaging method according to an eighth aspect of the present invention, in which a valve imaging method for performing imaging while displaying an image captured during exposure in bulb imaging. A step of generating, a step of detecting a temporal change amount of the image data captured by the imaging unit by the detection unit, and a temporal change amount of the image data detected by the detection unit by the determination unit being a predetermined value determining whether more, the image data adding unit, when the temporal variation amount by the determination unit is determined to be greater than a predetermined value, sequentially adds the image data captured by the imaging unit A step of starting an operation, and a step of displaying, in a time series, an image represented by the image data added by the image data adding unit. And flop, the control unit, the image data adding unit detects and controls for terminating the addition of the image data by the image data adding unit that adds the number of the image data becomes equal to or larger than a predetermined value set in advance by Performing the steps.

Valve imaging method according to a ninth aspect of the present invention, in the valve imaging method for imaging while displaying the image captured in the partially exposed in the valve photographing by the image pickup section performs an imaging time division manner continuously, the image data A step of generating, a step of detecting a temporal change amount of the image data captured by the imaging unit by the detection unit, and a temporal change amount of the image data detected by the detection unit by the determination unit. The step of determining whether or not the value is equal to or greater than a predetermined value and the image data adding unit sequentially determines the image data captured by the image capturing unit when the determination unit determines that the temporal change amount is equal to or greater than the predetermined value. a step of adding, by the display unit, the image chronologically display the represented by the image data are added by the image data adding unit step When, by the control unit, after the addition of the image data is started by the image data adding unit, when the amount of the temporal change is determined to be equal to or less than the predetermined value by the judging unit, according to the image data adding unit Ending the addition of image data.

  ADVANTAGE OF THE INVENTION According to this invention, the valve | bulb imaging device and valve | bulb imaging method which can observe the picked-up image in the middle of exposure in valve | bulb imaging | photography and can obtain high quality image data can be provided.

It is a block diagram which shows the electric circuit of the camera concerning one Embodiment of this invention. 6 is a flowchart showing an operation mainly during bulb photographing of a camera according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the control 1 of the camera concerning one Embodiment of this invention. It is a flowchart which shows operation | movement of the control 2 of the camera concerning one Embodiment of this invention. It is a figure which shows the reading and display of image data at the time of bulb | bulb photography in the conventional camera. FIG. 6 is a diagram illustrating reading and displaying of image data at the time of bulb shooting in an automatic mode in the camera according to the embodiment of the present invention. 6 is a graph showing temporal changes in the pattern change amount in the pattern change area during bulb photographing in the camera of one embodiment of the present invention.

  Hereinafter, a preferred embodiment will be described using a camera to which the present invention is applied according to the drawings. A camera according to a preferred embodiment of the present invention is a digital camera, includes an imaging unit, converts a subject image into image data by the imaging unit, and converts the subject image into a main body based on the converted image data. Live view is displayed on the display unit placed on the back of the camera. The photographer determines the composition and the photo opportunity by observing the live view display. During the release operation, image data is recorded on the recording medium. The image data recorded on the recording medium can be reproduced and displayed on the display unit when the reproduction mode is selected.

  In addition, when bulb shooting in the automatic mode is set, when the luminance change of the subject exceeds a predetermined value, time-division-captured image data is sequentially added to display the bulb photographed image being photographed on the display unit. . When it is detected that the luminance change of the subject has become a predetermined value or less, the bulb photographing is terminated.

  FIG. 1 is a block diagram showing a configuration of a camera 10 according to an embodiment of the present invention. A shutter 13 and an image sensor 15 are arranged on the optical axis of the lens 11. The lens 11 is composed of a plurality of lenses for forming a subject image. The lens 11 can be moved along the optical axis direction of the lens 11 by a driving source (not shown) in accordance with an instruction from the imaging condition setting unit 37 in the system control unit 31, and focus control and zoom control are performed. In addition, an aperture is provided in the lens 11, and the aperture value can be changed by this aperture, and the exposure amount can be adjusted.

  The shutter 13 is disposed between the lens 11 and the image sensor 15 and performs exposure and light shielding on the image sensor 15. The shutter is constituted by a lens shutter or a focal plane shutter. The shutter 13 adjusts the exposure time of the subject luminous flux that has passed through the lens 11 in accordance with an instruction from the shooting condition setting unit 37 during shooting. Note that the shutter 13 is in an open state during live view display or bulb photography.

  The image sensor 15 is configured by a solid-state imaging device such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and converts the subject image formed by the lens 11 into an image signal. Accumulation and reading of image signals of the image sensor 15 are controlled by the imaging condition setting unit 37 in the system control unit 31.

  The output of the image sensor 15 is connected to the image processing unit 17. The image processing unit 17 inputs image data from the image sensor 15 and performs various image processing such as white balance adjustment and noise reduction processing. The image processing unit 17 is connected to the internal memory 19. The image sensor 15 and the image processing unit 17 described above function as an imaging unit that captures images in a time-sharing manner and generates image data. The internal memory 19 is a rewritable memory such as SDRAM (Dynamic Random Access Memory), and temporarily stores the image data processed by the image processing unit 17.

  The internal memory 19 is connected to the image adding unit 21. The image adding unit 21 adds the image data temporarily stored in the internal memory 19. That is, the addition result is temporarily stored in the image addition unit 21, and the addition result temporarily stored in the image addition unit 21 and the image data temporarily stored in the internal memory 19 are added. Therefore, every time image data is read out from the image sensor 19 and image data is stored in the internal memory 19, the images are added, and a bulb photographed image at the time of bulb photography is generated. Each time image data is read from the image sensor 15, each image data may be temporarily stored in the internal memory 19, and the image adding unit 21 may add each image data every time.

  The display unit 23 has a monitor such as an LCD (Liquid Crystal) disposed on the back surface of the camera 10 and is connected to the outputs of the image processing unit 17 and the image addition unit 21. The display unit 23 performs live view display based on the live view display image data output from the image processing unit 17 and also reproduces and displays the captured image recorded in the external memory 25. The display unit 23 displays the bulb photographed image represented by the image data added by the image data adding unit 21 in time series.

  The external memory 25 is a rewritable nonvolatile memory such as a compact flash (registered trademark) or an SD card that can be loaded into the camera 10. The external memory 25 records a final image in normal shooting or bulb shooting.

  The instruction unit 39 is an operation member for various settings such as a power switch, a release button, a menu button, a shooting mode dial, and a touch panel provided in the camera 10 and has a user interface function. The instruction unit 39 is an operation for instructing the photographer to continue addition of image data by the image data addition unit when the number of additions of the image data by the image data addition unit exceeds a predetermined value. It has a member.

  In the system control unit 31, a CPU (Central Processing Unit) 33, an addition control unit 35, and an imaging condition setting unit 37 are provided. The CPU 33 controls the overall operation of the camera 10 based on a program stored in a nonvolatile memory (not shown). The CPU 33 functions as a detection unit that detects a temporal change amount of the image data captured by the imaging unit. That is, in the present embodiment, as will be described later, the temporal change amount of the image data is detected based on the difference processing between the two images before and after in the pattern change region (S57 in FIG. 3, FIG. 4 of S93).

  The CPU 33 also functions as a determination unit that determines whether the temporal change amount of the image data detected by the detection unit is equal to or greater than a predetermined value. That is, in the present embodiment, as will be described later, it is determined whether or not the temporal change amount of the image data obtained by the difference processing is larger than a predetermined value (S59 in FIG. 3, S95 in FIG. 4, etc.). ).

  Further, the CPU 33 also functions as a control unit that detects that the number of additions of the image data has reached a predetermined value or more and performs control to end the addition of the image data by the image data addition unit. That is, in this embodiment, as will be described later, in order to generate a bulb photographed image, if the number of additions of image data exceeds a predetermined value (S97 in FIG. 4), bulb photography is performed after warning is performed. Is terminated (see S99, S101).

  Further, the CPU 33 also functions as a control unit that performs control for ending the addition of the image data by the image data addition unit when the determination unit determines that the temporal change amount is equal to or less than a predetermined value. . That is, in this embodiment, as will be described later, when image addition (S81) is performed in order to generate a bulb photographed image, the temporal change amount of the image data calculated by the difference processing is a predetermined value. Bulb shooting is terminated when the following occurs (S95 → Pe <Te).

  The addition control unit 35 performs addition control in the image addition unit 21 in accordance with an instruction from the CPU 33. The image addition unit 21 and the addition control unit 35 start image data that sequentially adds the image data picked up by the image pickup unit when the temporal change amount of the image data is determined to be a predetermined value or more. Serves as an adder.

  The imaging condition setting unit 37 performs aperture value control, focus control, shutter speed control, image sensor 15 signal readout timing control, and the like based on an instruction from the CPU 33.

  Next, the operation in this embodiment will be described with reference to the flowchart shown in FIG. The flowcharts shown in FIGS. 2 to 4 are executed by the CPU 33 in accordance with a program stored in a nonvolatile manner (not shown). The flowchart shown in FIG. 2 starts when the power of the camera 10 is turned on, but FIG. 2 shows only processing related to the bulb photographing mode, and omits other processing.

  In the flow shown in FIG. 2, when the user operates the power switch to turn on the power, live view display is first performed (S11). Here, the image processing unit 17 processes the image signal output from the image sensor 15 for live view display, and displays the live view image on the display unit 23 based on the processed image data.

  Once the live view display is performed, the user next selects a bulb shooting mode (S13). The bulb shooting mode is selected by an operation of the instruction unit 19 on a menu screen or the like. In selecting this mode, there are a normal bulb photographing mode and an automatic photographing mode in which bulb photographing is automatically performed, and either one can be selected.

  Once the bulb mode has been selected, shooting conditions are set (S15). Here, settings necessary for normal bulb photography, such as the aperture value of the aperture in the lens 11, ISO sensitivity, and focal length, are performed by the user himself. The shooting condition setting unit 37 sets shooting conditions according to the shooting conditions set here.

  If the bulb exposure automatic mode is selected, the total exposure time is also set in step S15. During normal bulb photography, pressing the release button starts bulb photography, and releasing the release button depresses the bulb photography. In automatic mode, the release button The total exposure time from pressing down to release is set in advance. Here, based on the set total exposure time, the image data reading interval in the automatic mode is calculated. For example, if the set exposure time is 100 seconds and the upper limit of the allowable number of additions is 10, assuming that the reading interval is S, S = 100/10 [sec] = 10 seconds. Note that the upper limit value of the number of additions is set as a fixed value in advance from the experimental evaluation of the relationship between the number of additions and noise.

  Once the shooting conditions are set, it is next determined whether or not the automatic shooting mode is set (S17). Here, the determination is made according to the valve mode set in step S13.

  If the result of determination in step S17 is not automatic shooting mode, normal bulb shooting mode is executed in step S31 and thereafter. First, it is determined whether or not the release has been depressed. When the release has been depressed, normal bulb photography is started (S31). When shooting is started, the image sensor 15 accumulates an image signal corresponding to the subject image formed by the lens 11.

  After the shooting is started, the release pressing is ended, and the shooting is ended when the finger is released from the release button (S33). When shooting is completed, a control signal is output from the shooting condition setting unit 37 to the shutter 13 and the image sensor 15, the shutter 13 changes from the open state to the light-blocking state, and the image sensor 15 ends the accumulation of the image signal.

  When shooting is completed, image reading is performed (S35). Here, an image signal is read from the image sensor 15 in accordance with a control signal from the imaging condition setting unit 37. Subsequently, image processing is performed (S37). Here, based on the image data from the image sensor 15, the image processing unit 17 performs various image processing.

  Once image processing has been performed, the image is stored and the image is displayed (S39). Here, the image processed image data is recorded in the external memory 25, and the recorded image is displayed on the display unit 23 for a predetermined time. When the image display for the predetermined time is performed, the photographing is finished, and if the power is not turned off, the process returns to step S11 and the live view display is performed.

  As described above, in the normal bulb shooting mode, bulb photography starts when the release button is pressed, and bulb photography ends when the release button is released. During this time, the image sensor 15 only stores the image signal and does not read the image signal. Therefore, the image during the exposure is not displayed during bulb photographing.

  If the result of determination in step S17 is that automatic shooting mode has been selected, bulb shooting is automatically performed in step S21 and subsequent steps. First, the start of photographing is controlled by the control 1 (S21). In this control 1 subroutine, it is determined whether or not a change has occurred in the subject, and bulb photographing is started when the change has been detected. The detailed operation of the control 1 will be described later with reference to FIG.

  When shooting is started by the subroutine of control 1, the end of shooting is controlled by control 2 (S23). In this control 2 subroutine, bulb photographing is continued, and photographing is terminated when there is no change in the subject. That is, when the image data is read out, the image adding unit 21 adds the image data, generates a bulb photographed image, and displays the bulb photographed image on the display unit 23. Then, when there is no change in the subject, the bulb photographing is finished. Detailed operation of the control 2 will be described later with reference to FIG.

  When the bulb photographing is finished by the subroutine of control 2, the added image is stored and displayed (S25). Here, the final bulb photographed image generated by addition by the image adding unit 21 is recorded in the external memory 25, and the bulb photographed image is displayed on the display unit 23 for a predetermined time. When image display for a predetermined time is performed, shooting is terminated. If the power is not turned off, the process returns to step S11 to perform live view display.

  Next, operation | movement of the control 1 in step S21 is demonstrated using the flowchart shown in FIG. If the flow of control 1 is entered, first, a pattern change area is selected (S41). This pattern change area is selected on the live view screen. For example, if the area is a rectangle, the coordinates of the area are entered numerically, or the cursor on the screen is moved and the four corners of the rectangle are moved by the OK button or the like. Fix it. When the display unit 39 is provided with a touch panel function, an area may be selected by touching four points on the screen.

  Once the pattern change area has been selected, it is next determined whether or not the release button has been pressed. If the release button has not been pressed, the process waits for pressing (S43). When the photographer starts bulb shooting in the automatic shooting mode, the release button is pressed down. In this step, the operation state of the release button is determined, and the release pressing is awaited.

  When the release button is pressed, 1 is substituted for the number of shots N (S45). The number of shots N counts the number of shots taken before the start of the addition of captured images. That is, in the present embodiment, even if the release button is pressed and bulb shooting is started, if there is no change in the pattern of the subject, the addition processing for acquiring the bulb shot image is not executed. If the addition process cannot be started even after the predetermined number of times of imaging, a warning is given (see S61 described later). For this reason, the number N of shots indicates the number of imaging performed before the addition process is started. Counting.

  If 1 is substituted for the number of shots N, then image shooting (G) is performed (S47). Here, the subject image is photoelectrically converted by the image sensor 15 and image signals are accumulated. The charge accumulation time in the image sensor 15 is determined according to the readout interval calculated in step S15.

  When an image is taken and a predetermined readout interval elapses, the image (G) is temporarily stored in the internal memory 19 as an image (X) (S49). Here, an image signal is read from the image sensor 15 and subjected to image processing in the image processing unit 17, and then temporarily stored as an image (X) in the internal memory 19. Once the image is temporarily stored, 1 is added to the number of shots N (S51). Here, since the image is taken once in step S47, 1 is added to the number N of shots.

  If 1 is added to the number of shots N, then the image (G) is shot (S53). Here, the image sensor 15 performs photoelectric conversion of the subject image. The charge accumulation time of the image sensor 15 here is also determined according to the readout interval calculated in step S15.

  When an image is taken and a predetermined readout interval elapses, the images (X) and (G) are added, and this added image is set to A (S55). Here, the image (G) is read from the image sensor 15, and the image adding unit 21 adds the read image (G) and the image (X) temporarily stored in the internal memory 19. The image A is temporarily stored in the internal memory 19.

  Once the added image A is calculated, the difference processing of the image (X) from the added image A is performed, and the difference processing result is set to S (S57). Here, the difference between the previous image and the current image is obtained, and the difference between the images is a value corresponding to a change in the image. That is, when there is no change in the image, the difference between the images is a value close to 0, whereas when there is a change in the image, the difference between the images is a large value.

  Once the difference process is performed, the pattern change amount (Ps) is detected (S59). As the pattern change amount (Ps), the average luminance level Ys of the difference image obtained by the difference process in step S57 is used in the pattern change region selected in step S41 described above. A high average luminance level Ys indicates that the change between the previous and current images is large, while a low average luminance level Ys indicates that the change between the previous and current images is small.

  When the pattern change amount (Ps) is detected, it is next determined whether or not the pattern change amount Ps is smaller than the threshold value Ts. The threshold value Ts is a value obtained by adding a fixed value (for example, 1000 LSB) from the luminance level in the area set by the photographer in step S41 (see FIG. 7). The threshold value Ts may be input as a unique value.

  If the result of determination in step S59 is that Ps is smaller than Ts, it is next determined whether or not the number N of captured images is smaller than 5 (S61). This is to determine whether or not the subject remains unchanged. In the present embodiment, “5” is used as the determination value, but it may be a value that can be determined that the subject has not changed.

  If the result of determination in step S61 is that the number of shots N is less than 5, the process returns to step S49 and the above-described processing is executed. That is, the previously captured image (G) and the current captured image (X) are added (S55), and the difference process between the added image (G + X) and the previous image (G) is performed (S57). This process is repeated until the pattern change amount (Ps) reaches the threshold value Ts.

  If the result of determination in step S61 is that the number of shots N is 5, a warning is given (S63). If the pattern change amount (Ps) does not reach the threshold value for a certain time (in this embodiment, the number of shots is five), a warning is given. That is, the display unit 23 is warned that the subject has not changed after the release button has been pressed, and bulb photography has not been performed. In addition to visual warning display, warning display may be performed by voice.

  Once the warning is displayed, it is next determined whether or not to continue (S65). Here, it is determined whether or not the photographer intends to continue bulb shooting. As the detection of the intention to continue, for example, the operation of the operation member of the camera is detected. When the display unit 23 is provided with a touch panel function, a touch on an icon displayed on the display unit 23 may be detected.

  If the result of determination in step S65 is continuation, processing returns to step S41. When returning to step S41, the number of shots N is reset to 1 again and waits for the subject to change. On the other hand, if the result of determination in step S65 is not continuation, bulb photographing is terminated.

  If the pattern change amount (Ps) is larger than the threshold value Ts as a result of the determination in step S59, the control 1 subroutine is terminated, and after returning to the original flow, the process proceeds to the control 2 subroutine.

  Next, operation | movement of the control 2 in step S23 is demonstrated using the flowchart shown in FIG. The control here is executed when the pattern change amount (Ps) exceeds the threshold value in the control 1.

  If the flow of control 2 is entered, first, 1 is substituted into the added number Na (S71). The number Na of additions counts the number of times the addition image has been captured. That is, in this embodiment, after entering the control 2 and starting the addition process to acquire a bulb photographed image, if the added number Na becomes equal to or greater than a predetermined value (10 in this embodiment), a warning is given. Display is in progress. If the number of additions increases, readout noise may be superimposed and image quality may deteriorate. For this reason, an additional number Na is provided to count the number of times the addition process has been performed.

  If the added number Na is reset to 1, then the added image A is updated as the stored image X in the internal memory 19 (S73). Immediately after the transition from the control 1 subroutine to the control 2 subroutine, the temporarily stored image is updated as the stored image X in step S55. If the determination result in step S97 described later returns to step S73, the added image A calculated in step S81 is updated as the stored image X. This stored image X is an image that has been added as a bulb image.

  Once the stored image X is updated, the stored image is displayed (S75). Here, in step S73, the updated stored image X is displayed on the display unit 23. Once the stored image is displayed, the image (G) is photographed (S77). Here, as in steps S47 and S53, the image signal of the subject image is accumulated by the image sensor 15 for the time of the read interval calculated in step S15. When the reading interval time elapses, an image signal is read from the image sensor 15.

  If an image has been shot in step S77, then 1 is added to the added number Na (S79). Subsequently, the image (G) acquired in step S77 is added to the stored image X updated in step S73 to calculate an added image A (S81).

  Once the images are added, difference processing is next performed (S93). Here, the stored image X updated in step S73 is subtracted from the added image A calculated in step S81. Similar to the difference process in step S57, also in this step, a difference image between the previous and current images can be obtained by performing this difference process.

  Once the difference processing is performed, the pattern change amount (Pe) is detected, and the detection result (Pe) is compared with a threshold value (S95). The pattern change amount (Pe) is similar to the pattern change amount (Ps), and is the average luminance level Ye of the difference image obtained by the difference process in step S93 in the pattern change region selected in step S41. A high average luminance level Ye indicates a large change between the previous and current images, while a low average luminance level Ye indicates a small change between the previous and current images. The threshold value Te is a value obtained by adding a fixed value (for example, 1000 LSB) from the luminance level in the area set by the photographer in step S41 (see FIG. 7). The threshold value Te may be input as a unique value.

  If the result of comparison between the pattern change amount (Pe) and the threshold value Te in step S95 is Pe> Te, next, the added number Na is confirmed (S97). Here, the added number Na is compared with a predetermined value (10 in the embodiment). As described above, when an image signal is read from the image sensor 15 and addition is repeated in the image adding unit 21 in order to obtain a bulb photographed image, readout noise and addition noise gradually increase and the image deteriorates. In the embodiment, the number of added sheets is confirmed. Note that, as described above, the upper limit value of the added number of sheets is set as a fixed value in advance by experimentally evaluating the relationship between the added number of sheets and noise.

  As a result of the determination in step S97, if the added number Na is less than 10, the process returns to step S73, images are taken at a predetermined reading interval, and image addition of the read images is repeated.

  On the other hand, if the result of determination in step S97 is that the added number Na is 10 or more, a warning is displayed (S99). Here, the display unit 23 is warned that the addition processing for obtaining a bulb-captured image has exceeded the upper limit value after bulb photography has been started. In addition to visual warning display, warning display may be performed by voice.

  Once the warning is displayed, it is next determined whether or not to continue (S101). Here, as in the case of step S65, it is determined whether or not the photographer has made an intention to continue bulb shooting in response to the warning display. As the intention to continue, for example, when an operation member of a camera is operated, or when a touch panel function is provided, touching an icon displayed on the display unit 23 may be used.

  If the result of determination in step S <b> 101 is to continue, processing returns to step S <b> 73, reading is performed at a predetermined time interval, and bulb read images are acquired by performing addition processing of the read images.

  If the result of determination in step S101 is not to continue, or if the result of determination in step S95 is that the pattern change amount (Pe) is smaller than the threshold value Te, that is, if Pe <Te, the control 2 subroutine is terminated. Return to the original flow.

  Thus, in bulb shooting in the automatic shooting mode, even if bulb shooting is started by pressing the release button, image data addition processing is not performed until a change occurs in the subject. When a change occurs in the subject, image data addition processing is started and a bulb photographed image is generated. The generated bulb image is sequentially displayed on the display unit 23. When the subject is no longer changed after the image data addition process is started, the image data addition process is terminated, and the final bulb shot image is recorded in the external memory 25 and displayed on the display unit 23.

  Next, bulb photographing performed in accordance with the flowcharts of FIGS. 2 to 4 will be described with reference to FIG. 6. For easy understanding, FIG. 5 illustrates conventional bulb photographing described with reference to Patent Document 1 and the like. It explains using.

  In FIG. 5, the upper row shows the subject after the start of bulb photography. In the example shown in FIG. 5, bulb photographing is started at time T01 (see P1), there is no change at time T02 (see P2), and fireworks are raised at time T03 (see P3). Then, fireworks open at time T04 (see P4), fireworks smoke remains at time T05 (see P5), and there is no change at times T06 and T07 (see P6 and P7). Note that the times T01 to T07 are predetermined reading time intervals.

  The lower part of FIG. 5 shows changes in the bulb photographed image read and added at each time. That is, at times T01 to T02 and T06 to T07, there is no change in the subject, but an image signal is read from the image sensor at this timing and addition processing is performed. For this reason, readout noise and addition noise are also superimposed at these timings, and the image quality is deteriorated.

  FIG. 6 shows bulb photography performed in accordance with the flowcharts of FIGS. The top row in FIG. 6 shows the subject after the start of bulb photography, as in the top row in FIG. That is, the change of the subject from time T01 to T06 is the same as in the case of FIG. Note that the white frame at the approximate center of the screen indicates the area selected in step S41. Further, a predetermined reading time interval is set from time T01 to T07.

  The second row from the top in FIG. 6 shows the added image A calculated in steps S55 and S81. The added image A2 corresponds to an image obtained by adding the subjects P1 and P2. The addition image A3 includes the subjects P2 and P3, the addition image A4 includes the images of the addition image A3 and the subject P4, the addition image A5 includes the images of the addition image A4 and the subject P5, and the addition image A6 includes the addition image A5 and the subject P6. These images correspond to the added images.

  The third row from the top in FIG. 6 shows an image obtained by the difference processing in steps S57 and S93. The difference image D1 is an image showing a pattern change between times T01 and T02, and is obtained by the difference between the image of the subject P1 and the added image A2. The difference image D2 is an image showing a pattern change between the times T02 and T03, and is obtained by the difference between the addition image A2 and the addition image A3. Similarly, the difference images D3 and D4 can be obtained by difference processing between the previous and next added images.

  It can be seen from the difference image D1 that there is no change between the two images before and after. For this reason, at time T01 and T02, addition processing for the bulb photographed image is not performed, and “moving object detection” is displayed on the display unit 23 (see B2). Further, it can be seen from the difference image D2 that there is a change between the two images before and after. Therefore, at time T03, an addition process for the bulb photographed image is performed, and the addition image A3 is displayed on the display unit 23 as the bulb photographed image B3.

  Similarly, in the difference images D3 and D4, since there is a change between the previous and subsequent images, the bulb photographed images B4 and B5 are displayed on the display unit 23 at times T04 and T05, respectively. Next, it can be seen from the difference image D5 that there is no change between the two images before and after. For this reason, at time T06, the addition process for the bulb photographed image is terminated, and the display unit 23 displays an image obtained by superimposing “photographing end” on the bulb photographed image B5 at time T05 (see B6). ).

  FIG. 7 is a graph showing changes in the pattern change amount in the pattern change area. The release button is depressed to perform bulb shooting at time T01, but the pattern change amount is smaller than the threshold Ts until time T02. However, since the fireworks change from time T03 to time T05, the pattern change amount changes greatly. Then, after the time T05, the fireworks disappear, and only the smoke accompanying the fireworks becomes, so the pattern change amount decreases. As described above, the threshold values Ts and Te are set as values obtained by adding a fixed value (for example, 1000 LSB) from the luminance level in the area set by the photographer in step S41.

  As described above, in one embodiment of the present invention, the temporal change amount of the image data captured by the imaging unit is detected, and the addition processing of the image data is controlled according to the temporal change amount. I am doing so. For this reason, it is possible to observe a photographed image in the middle of exposure in bulb photographing and obtain high-quality image data.

  In one embodiment of the present invention, the difference between the previous and next images is used as the temporal change amount of the image data, and the luminance change amount of the subject is used. However, the present invention is not limited to this. Any change in the subject can be detected, such as calculating the amount of movement of the subject.

  In one embodiment of the present invention, the image data addition process is started when the subject changes (see S59 in FIG. 3 → FIG. 4). As in the prior art, it is performed in response to pressing of the release button, and the addition process is ended when there is no change in the subject as in the embodiment of the present invention, or when a predetermined number of addition processes are performed. May be.

  Further, in the embodiment of the present invention, the addition process is terminated when the subject is no longer changed (S95 → Pe <Te). However, the present invention is not limited to this, and the number of additions exceeds a predetermined value. Then, you may make it complete | finish an addition process. In this case, a warning display may be displayed, and the addition process may be continued if there is an intention to continue.

  In the embodiment of the present invention, 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, such as a video camera or a movie camera. It may be a camera for moving images, or may be a camera built in a mobile phone, a personal digital assistant (PDA), a game device, or the like.

  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 10 ... Camera, 11 ... Lens, 13 ... Shutter, 15 ... Image sensor, 17 ... Image processing part, 19 ... Internal memory, 21 ... Image processing part, 23. ..Display unit 25 ... External memory 31 ... System control unit 33 ... CPU 35 ... Addition control unit 37 ... Shooting condition setting unit 39 ... Instruction unit

Claims (9)

In a bulb imaging device that takes an image while displaying an image taken during exposure in bulb photography,
An imaging unit that continuously captures images in a time-sharing manner and generates image data;
A detection unit for detecting a temporal change amount of the image data captured by the imaging unit;
A determination unit for determining whether the temporal change amount of the image data detected by the detection unit is equal to or greater than a predetermined value;
An image data adding unit that starts an operation of sequentially adding the image data captured by the imaging unit when the determination unit determines that the temporal change amount is equal to or greater than a predetermined value;
A display unit for displaying the image represented by the image data added by the image data addition unit in a time series;
A control unit that detects that the number of additions of the image data by the image data addition unit is equal to or greater than a predetermined value that is set in advance, and performs control to end the addition of the image data by the image data addition unit;
A valve imaging apparatus comprising: When the number of additions of the image data by the image data addition unit is equal to or greater than a predetermined value, the photographer further includes an instruction unit for giving an instruction to continue the addition of the image data by the image data addition unit,
When the photographer gives an instruction to continue the addition of the image data by the image data addition unit, the control unit continues the imaging by the imaging unit and adds the image data captured by the imaging unit. Control to continue,
The valve imaging apparatus according to claim 1. In a bulb imaging device that takes an image while displaying an image taken during exposure in bulb photography,
An imaging unit that continuously captures images in a time-sharing manner and generates image data;
A detection unit for detecting a temporal change amount of the image data captured by the imaging unit;
A determination unit for determining whether the temporal change amount of the image data detected by the detection unit is equal to or greater than a predetermined value;
An image data adding unit that sequentially adds image data picked up by the image pickup unit when the determination unit determines that the amount of temporal change is equal to or greater than a predetermined value ;
A display unit for displaying the image represented by the image data added by the image data addition unit in a time series;
After the addition of the image data by the image data addition unit is started, when the determination unit determines that the temporal change amount is equal to or less than a predetermined value, the addition of the image data by the image data addition unit is ended. A control unit for performing control to
A valve imaging apparatus comprising:   The image data adding unit starts an operation of sequentially adding the image data captured by the imaging unit when the determination unit determines that the temporal change amount is equal to or greater than a predetermined value. The valve imaging device according to claim 3. Before starting the addition of the image data by the image data addition unit, when the number of times of imaging by the imaging unit is equal to or greater than a predetermined value, an instruction unit that instructs the photographer to continue bulb photography,
The control unit continues the imaging by the imaging unit when the photographer gives an instruction to continue the bulb photography.
The valve imaging apparatus according to claim 3. When the number of additions of the image data by the image data addition unit is equal to or greater than a predetermined value, the photographer further includes an instruction unit for giving an instruction to continue the addition of the image data by the image data addition unit,
When the photographer gives an instruction to continue the addition of the image data by the image data addition unit, the control unit continues the imaging by the imaging unit and adds the image data captured by the imaging unit. Control to continue,
The valve imaging apparatus according to claim 3.   The control unit detects that the number of additions of the image data by the image data addition unit is equal to or greater than a predetermined value, and performs control for terminating the addition of the image data by the image data addition unit. The imaging device according to claim 3. In a bulb imaging method for imaging while displaying an image taken during exposure in bulb imaging,
A step of continuously taking images in a time-division manner and generating image data by an imaging unit;
Detecting a temporal change amount of image data captured by the imaging unit by the detection unit;
A step of determining by the determination unit whether or not the temporal change amount of the image data detected by the detection unit is a predetermined value or more;
The image data adding unit, when the temporal variation amount by the determination unit is determined to be greater than a predetermined value, and initiating an operation of sequentially adding the image data captured by the imaging unit,
Displaying the images represented by the image data added by the image data adding unit in a time series by the display unit;
A step of detecting by the control unit that the number of additions of the image data by the image data addition unit is equal to or greater than a predetermined value set in advance, and performing control for terminating the addition of the image data by the image data addition unit When,
A valve imaging method characterized by comprising: In a bulb imaging method for imaging while displaying an image taken during exposure in bulb photography,
A step of continuously taking images in a time-division manner and generating image data by an imaging unit ;
Detecting a temporal change amount of the image data captured by the imaging unit by a detection unit;
A step of determining by the determination unit whether or not a temporal change amount of the image data detected by the detection unit is a predetermined value or more;
A step of sequentially adding image data picked up by the image pickup unit when the determination unit determines that the temporal change amount is equal to or greater than a predetermined value by the image data adding unit ;
Displaying the images represented by the image data added by the image data adding unit in a time series by the display unit;
When the control unit determines that the temporal change amount is equal to or less than a predetermined value after the image data adding unit starts adding the image data , the image data added by the image data adding unit Ending the addition of
A valve imaging method characterized by comprising: