JP5972055B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus.

  In an imaging apparatus such as a digital still camera or a digital video camera, a CCD, a CMOS, or the like is used as an imaging element. In these image sensors, it is known that a dark current is generated depending on temperature and charge accumulation time, and a dark current is generated even when the image sensor is not exposed. For example, when the temperature rises by 8 to 10 ° C., the dark current amount increases about twice, and the dark current increases in proportion to the charge accumulation time.

  The dark current generated in the CCD is roughly classified into two types, one generated in a photodiode and one generated in a vertical transfer path. Since the amount of dark current generated in the photodiode differs for each pixel, the image appears as fixed pattern noise (hereinafter referred to as FPN) for each pixel. On the other hand, the amount of dark current generated in the vertical transfer path differs for each vertical transfer column. Further, when driving such as smear high-speed ejection, the amount of generation differs between the vertical transfer columns, so that fixed pattern noise and vertical shading are generated for each column.

  In such a situation, one of the methods for removing the influence of dark current is as follows. That is, immediately before or after the subject photographing operation is performed, an image containing only a dark current component (hereinafter, a black image) is performed by performing a photographing operation (light-shielding photographing operation) with the mechanical shutter closed and the entire image sensor shielded from light. And subtract the black image from the actual subject captured image. By such processing, FPN due to dark current components can be removed.

  It is desirable that the black image acquired when the FPN subtraction process using the dark current component is performed from the subject photographed image, is captured under the same photographing conditions as the subject photographing while being shielded from light. For this reason, in the case where both the subject photographed image and the black image are acquired in one subject photographing, it takes about twice the photographing time as compared with the normal subject photographing time in order to perform the light shielding photographing operation. Become.

  As described above, FPN due to dark current depends on the temperature and charge accumulation time. However, when the temperature is low or the accumulation time is short, the control ratio of random noise is higher than that of FPN, and subtraction processing is performed. On the contrary, S / N sometimes deteriorates. Therefore, a determination table for determining whether to perform the light-shielding shooting operation and the black image subtraction process according to the image improvement degree after the black image subtraction process based on the imaging element ambient temperature and the shooting condition is created, and based on the determination table There is also a method of performing a subtraction process only when necessary (see Patent Document 1). When the subtraction process is performed only when necessary based on the determination table, the frequency of frame speed reduction and noise deterioration is reduced.

Japanese Laid-Open Patent Publication No. 1-147973

  However, in the case of the determination method based on the determination table described above, the ambient temperature of the image sensor is also one of the determination items. For this reason, when a plurality of shooting operations are performed continuously, the control of whether to perform the light-shielding shooting operation and the black image subtraction processing is changed for each shooting due to the temperature change of the image sensor.

  As described above, since a series of shooting times differ greatly between when the light-shielding shooting operation is performed and when it is not performed, a change in the shooting interval due to the presence or absence of the light-shielding shooting operation during continuous shooting may cause discomfort to the user. .

  SUMMARY An advantage of some aspects of the invention is that it provides an imaging apparatus capable of suppressing a change in imaging interval when a plurality of images are continuously captured.

An image pickup apparatus according to the present invention executes an image capturing unit that captures an image of a subject using an image sensor and generates a subject image, and performs a light-shielded image capturing operation performed immediately before or immediately after the subject image capturing operation is performed by the image capturing unit. A determination unit that determines whether it is necessary or not according to shooting conditions, and when performing continuous shooting in which a plurality of subjects are continuously shot by the imaging unit, the continuous shooting is performed regardless of whether or not the shading shooting operation is performed. Control means for controlling the shooting interval of shooting to be substantially constant, and the control means needs to execute the light-shielding shooting operation from the middle of shooting a plurality of frames of the continuous shooting by the determination means. When there is a possibility that it is determined, the control is performed such that the shooting interval of the continuous shooting is gradually increased .

According to another aspect of the present invention, there is provided a control method for an image pickup apparatus including an image pickup unit that shoots a subject by using an image pickup device and generates a subject image. A determination step for determining whether or not a light-shielding photographing operation by the imaging unit needs to be performed immediately before or immediately after the subject photographing operation is performed, and a plurality of subjects are continuously photographed by the imaging unit. A control step in which control means controls so that the shooting interval of the continuous shooting becomes substantially constant regardless of whether or not the light-shielding shooting operation is performed when performing continuous shooting, and in the control step, the determination step If it is determined that it is necessary to execute the light-shielding shooting operation during the shooting of a plurality of frames of the continuous shooting, the shooting interval of the continuous shooting And controlling so as to gradually increase.

  According to the present invention, the operation of reducing fixed pattern noise due to dark current is appropriately performed, the change in the shooting interval when performing continuous shooting of a plurality of images is suppressed, and the user does not feel uncomfortable during continuous shooting. Can be.

It is a block diagram for demonstrating the digital camera of Example 1 of this invention. It is a flowchart figure for demonstrating the operation example of the digital camera of Example 1 of this invention. It is a flowchart for demonstrating an imaging condition similarity determination method. It is an example of the table which divided | segmented the shutter speed used for imaging condition similarity determination for every range. It is a figure which shows an example of a black image subtraction determination table. It is an example of the graph which showed the temperature rise characteristic around an image pick-up element. It is a figure which shows an example of an imaging | photography space | interval adjustment determination table. It is a figure which shows an example of the relationship of the imaging | photography interval in each temperature difference. It is a flowchart figure for demonstrating the operation example of the digital camera of Example 3 of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1
FIG. 1 is a block diagram for explaining a digital camera (imaging device) according to a first embodiment of the present invention. In FIG. 1, the lens unit 101 forms a subject image on the image sensor 106. At this time, the lens driving unit 102 performs a zoom operation and a focusing operation of the lens unit 101 and drives a diaphragm and the like in the lens unit 101. The infrared cut filter 103 is disposed between the lens unit 101 and the image sensor 106 and cuts the wavelength of the infrared region of the subject light incident on the image sensor 106.

  The mechanical shutter 104 exposes / shields incident light to the image sensor 106 by performing an opening / closing operation. In this embodiment, the shutter driving unit 105 drives the mechanical shutter 104 at the time of still image shooting to expose the image light of the subject imaged by the lens unit 101 to the image sensor 106 for a certain period.

  The image sensor 106 converts the image light of the subject into an analog voltage signal that is an electrical signal. In this embodiment, the image sensor 106 is described as a CCD having a Bayer color filter, but the present invention is not limited to this. The temperature detection unit 107 is composed of, for example, a thermistor and detects the temperature around the image sensor 106.

  The A / D converter 108 converts the analog voltage signal output from the image sensor 106 into a digital signal having a predetermined number of bits. The image signal processing circuit 109 generates image data by performing white balance control, various corrections, compression processing, and the like on the digital signal converted by the A / D converter 108.

  The timing generator 110 generates a timing signal for driving the image sensor 106. The memory unit 111 temporarily stores the image data generated by the image signal processing circuit 109. The overall control unit 112 executes overall control of the apparatus and various arithmetic processes. The black image subtraction processing determination unit 113 obtains a black image by executing a light-shielding shooting operation in a state where the mechanical shutter is closed and the entire image sensor is shielded, and a black image is obtained by subtracting the black image from the actual subject captured image. It is determined whether or not subtraction processing is performed. Details will be described later. The shooting condition similarity determination unit 114 determines whether shooting conditions described later are similar. The shooting interval adjustment determination unit 115 determines whether or not to perform shooting interval adjustment determination described later.

  A recording medium control I / F (interface) unit 116 records or reads image data on a removable recording medium 118 such as a semiconductor memory. The display unit 117 displays image data or a user interface. An external I / F (interface) unit 119 is an interface for communicating with an external PC or the like. The photometry unit 120 detects the brightness information of the subject, and the distance measurement unit 121 detects the distance information to the subject. Next, the basic operation of the digital camera according to the first embodiment will be described. The basic control of the digital camera and various arithmetic processes here are performed by the overall control unit 112. Light from the subject passes through the lens unit 101 and the infrared cut filter 103 and is imaged on the image sensor 106 when the shutter driving unit 105 drives the mechanical shutter 104 to be exposed. An analog voltage signal output from the image sensor 106 on which the subject image is formed is converted into a digital signal having a predetermined number of bits by the A / D converter 108.

  The digital signal converted by the A / D converter 108 is subjected to processes such as white balance control, various correction processes, and compression processes by the image signal processing circuit 109 to generate subject image data. The created subject image data is finally recorded on the recording medium 118 via the recording medium control I / F unit 116.

  Next, the operation of the digital camera of this embodiment will be described with reference to FIG. 2 is executed by the CPU or the like of the overall control unit 112 after a control program stored in a storage unit such as a ROM is loaded into the RAM.

  When the start of shooting is instructed, the main image of the subject is shot (step S701). The overall control unit 112 acquires the ambient temperature of the image sensor 106 at that time from the temperature detection unit 107 and stores it in the memory unit 111 (step S702). Further, the overall control unit 112 records and holds other shooting conditions, for example, in this embodiment, the shutter speed and ISO sensitivity (shooting sensitivity) setting at the time of actual image shooting in the memory unit 111 (step S703).

  Here, when performing continuous shooting in which multiple subjects are shot continuously under the same shooting conditions, if the temperature changes (increases) during continuous shooting, immediately before or immediately after the subject shooting operation is performed. The shading operation and the black image subtraction process are executed. Therefore, in the present embodiment, the following processing is performed in order to avoid a change in the photographing interval due to the execution of the shading photographing operation and the black image subtraction processing. That is, when there is a possibility that a light-shielding shooting operation for black image subtraction processing is performed during continuous shooting, control is performed so that the shooting interval is adjusted from the first shooting of the first frame. Regardless of whether or not the light-shielding shooting operation is performed, control is performed so that the shooting interval of the continuous shooting becomes substantially constant so that the user does not feel uncomfortable due to the change of the shooting interval. However, if the shooting interval is adjusted, the shooting interval becomes longer. Therefore, the shooting interval adjustment is determined based on the shooting interval adjustment determination table, and the shooting interval adjustment is not performed when the shooting interval adjustment is not necessary. By doing so, a decrease in the frame speed is suppressed.

  In general, if the time interval from the previous shooting to the next shooting is long, even if the shooting was performed under the same shooting conditions as the previous shooting, shooting with or without shading shooting operation for black image subtraction processing It is difficult to feel the change in the interval. Therefore, in this embodiment, even when images of a plurality of frames (a plurality of images) are captured, they are not regarded as continuous shooting when the shooting interval T is long. In addition, when the difference between the shutter speed in the previous frame shooting and the shutter speed in the current frame shooting is large, it is difficult to feel the change in the shooting interval due to the execution of the shading shooting operation for the black image subtraction process. Therefore, in this embodiment, in the case of continuous shooting, it is also determined whether or not the shooting conditions for the previous frame shooting and the shooting conditions for the current frame shooting are similar.

  FIG. 3 is a flowchart showing the continuous shooting and the determination process similar to the shooting conditions of the present embodiment. 3 is executed by the CPU or the like of the overall control unit 112 after a control program stored in a storage unit such as a ROM is loaded into the RAM.

  First, it is determined whether or not continuous shooting is performed by comparing the shooting interval T from the previous frame shooting to the current frame shooting with a predetermined time T0 (step S301). First, it is detected whether or not the shutter button is pressed by the user when the development processing of the photographed image is completed (including a case where the shutter button is continuously pressed by the user). When the shutter button is not pressed, a timer for measuring the shooting interval T is started from the time when the development processing of the shot image is completed. Then, when it is detected that the user has pressed the shutter button to capture the next frame, the timer is stopped and the time is measured. A predetermined time T0 used for comparison at the time of determination is set in advance. If the measured time T is T> T0, it is determined that the continuous shooting is not performed, the determination process ends, and the process proceeds to S705 in FIG. When the measured time T is T ≦ T0, it is determined that continuous shooting is performed, and the process proceeds to step S302.

  In step S302, it is determined whether the previous and current shooting conditions are similar based on the amount of change in shutter speed between the previous frame shooting and the current frame shooting. For determining the change amount of the shutter speed, a table in which the shutter speeds are classified into a plurality of groups as shown in FIG. 4 is used.

  For example, when the shutter speed in the previous frame shooting is 1/20 second, the shutter speed group (TvC (i)) is Class1. Further, when the shutter speed in the current frame shooting is 1/25 seconds, the shutter speed group (TvC (i + 1)) is Class 1 as in the previous frame shooting. Then, the group TvC (i) to which the shutter speed in the previous frame shooting belongs is compared with the group TvC (i + 1) to which the shutter speed in the current frame shooting belongs. When TvC (i) = TvC (i + 1), it is determined that the shooting conditions of the previous frame and the current frame are similar, the determination process is terminated, and the process proceeds to S708 in FIG.

  On the other hand, when the shutter speed in the previous frame shooting is 1/20 second, the shutter speed group (TvC (i)) is Class1. On the other hand, when the shutter speed in the current frame shooting is 1/5 second, the shutter speed range (TvC (i + 1)) is Class2. In this case, TvC (i) ≠ TvC (i + 1), and it is determined that the shooting conditions of the previous frame and the current frame are not similar, the determination process ends, and the process proceeds to S705 in FIG.

  By the determination process in the flowchart shown in FIG. 3, it is determined whether or not the shooting executed in step S701 in FIG. 2 corresponds to continuous shooting. Then, if it is determined that the shooting is applicable to the continuous shooting, it is determined whether or not the shooting conditions of the previous time and the current time are similar (step S704). In step S704, if it is determined that the shooting is not continuous shooting, or if it is determined that the shooting conditions of the previous frame and the current frame are not similar even in continuous shooting, the shooting interval adjustment determination table. To determine whether or not the shooting interval adjustment is necessary (step S705).

  The shooting interval adjustment determination table is created based on the black image subtraction determination table and the temperature rise characteristics around the image sensor. FIG. 5 shows an example of the black image subtraction determination table stored in the storage area in the overall control unit 112. In this embodiment, the black image subtraction process determination unit 113 determines whether or not the light-shielding shooting operation and the black image subtraction process need to be performed immediately before or after the subject shooting operation is performed. The light-shielding shooting operation is a shooting operation in a state where the image sensor 106 for generating a black image is shielded from light. Further, the black image subtraction process is a process of subtracting a black image from a subject image (hereinafter referred to as a main image) obtained by a subject photographing operation in which the image sensor 106 is exposed and photographed.

  It is known that FPN (solid pattern noise) generated by the dark current of the image sensor depends on the temperature of the image sensor and the charge accumulation time. Therefore, in this embodiment, the black image subtraction processing determination unit 113 performs the shading shooting operation based on the three parameters of the ambient temperature of the image sensor obtained from the temperature detection unit 107, the ISO sensitivity setting at the time of shooting, and the shutter speed at the time of shooting. And whether or not it is necessary to execute black image subtraction processing. In the determination table of FIG. 5, the mark ● indicates that the light-shielding shooting operation and the condition for executing the black image subtraction process (black image subtraction process ON) are met. In addition, a mark “X” indicates that the light-shielding photographing operation and the black image subtraction process are not executed (black image subtraction process OFF).

  Next, FIG. 6 is an example of a temperature rise characteristic used for creating the shooting interval adjustment determination table. In FIG. 6, when the first image (first frame) is shot at an image sensor ambient temperature of 25 ° C., and then the temperature gradually rises and the sixth (6th frame) and subsequent images are shot. The temperature around the image sensor is saturated at 35 ° C. The difference between the temperature at the start of photographing and the temperature at the time of saturation (hereinafter, saturation temperature) is 10 ° C. In this embodiment, in the case of continuous shooting, when the difference between the temperature at the time of shooting the first image and the temperature at which the shading shooting operation and the black image subtraction processing specified by the black image subtraction determination table are greater than the saturation temperature. Does not adjust the shooting interval. This is because the possibility of reaching the temperature at which the light-shielding shooting operation and the black image subtraction process are executed is low even when shooting of a plurality of frames is repeated.

  If the difference between the temperature at the time of shooting the first image and the temperature at which the black image subtraction processing specified by the black image subtraction determination table is performed is smaller than the saturation temperature, the shooting interval is adjusted. This is because if a plurality of frames are shot repeatedly, the temperature at which the light-shielding shooting operation and the black image subtraction process are performed may be reached in the middle of continuous shooting. That is, when the temperature at the time of shooting the first image (first frame) in the continuous shooting is included in the range from the temperature at which the shading shooting operation and the black image subtraction process are performed to a temperature lower by the saturation temperature, Make adjustments.

  FIG. 7 shows an example of the shooting interval adjustment determination table. The shooting interval adjustment determination table in FIG. 7 is created based on the black image subtraction determination table shown in FIG. 5 and the temperature rise characteristic shown in FIG. Here, the table is such that the shooting interval adjustment is performed from a temperature that is lower by 10 ° C. which is the saturation temperature than the temperature at which the shading shooting operation and the black image subtraction process are performed. In the table of FIG. 7, the mark “○” indicates that the shooting time adjustment is executed (shooting time adjustment ON), and the mark “X” indicates that the shooting time is adjusted. This indicates that the condition is not executed (imaging time adjustment OFF).

  In determining whether or not the shooting interval adjustment is necessary in step S705 in FIG. 2, the temperature, shutter speed, ISO sensitivity setting obtained in steps S702 and S703 and held in the memory unit 111, and the shooting interval as shown in FIG. Check the adjustment judgment table. As a result of the collation, if it corresponds to the x mark in the determination table, “0” indicating that the photographing interval is not adjusted is set in the flag FL (step S707). If the mark in the determination table corresponds to ○, “1” indicating that the shooting interval is to be adjusted is set in the flag FL (step S706).

  For example, when the temperature obtained in step S702 is 33 ° C., the shutter speed obtained in step S703 is 1/30 seconds, and the ISO sensitivity is ISO100, the condition of case 1 in the determination table of FIG. Therefore, “0” is set in the flag FL. Further, when the temperature obtained in step S702 is 38 ° C., the shutter speed obtained in step S703 is 1/30 seconds, and the ISO sensitivity is ISO400, the condition of case 2 in the determination table of FIG. 7 is satisfied. Therefore, “1” is set in the flag FL.

  On the other hand, if it is determined in step S704 that the continuous shooting is performed and the shooting conditions of the previous frame and the current frame are similar, the necessity determination of the shooting interval adjustment is not performed. In this case, since the previous set value is inherited as it is as the set value of the flag FL, the previously set flag FL is determined (step S708). When the value set in the flag FL is “0”, the imaging interval is not adjusted, and the imaging signal processing circuit 109 performs development processing, white balance control, and other corrections on the main image (subject image). Image data is created by performing processing, compression processing, and the like. And it records on the recording medium 115 (step S709), and an imaging | photography process is complete | finished. On the other hand, if the value set in the flag FL is “1”, the black image subtraction process determination unit 113 determines whether or not the light-shielding shooting operation and the black image subtraction process are necessary (step S710).

  In determining whether or not the light-shielding shooting operation and the black image subtraction process are necessary, the temperature, shutter speed, and ISO sensitivity settings obtained in steps S702 and S703 and held in the memory unit 111, and the black image subtraction as shown in FIG. Check the judgment table. For example, when the temperature obtained in step S702 is 33 ° C., the shutter speed obtained in step S703 is 1/30 seconds, and the ISO sensitivity is ISO100, the condition of case 1 in the determination table of FIG. 5 is satisfied. . In the black image subtraction determination table, since Case 1 is marked with x, it is determined that the shading photographing operation and the black image subtraction processing operation are not performed (OFF). If it is determined that the light-shielding shooting operation and the black image subtraction processing operation are not performed, the overall control unit 112 adjusts the shooting interval (step S711).

  As described above, the black image with only the dark current component acquired when performing the black image subtraction process is acquired by shooting under the same shooting conditions as the main shooting for shooting the subject. Therefore, the adjustment of the shooting interval in the present embodiment is performed so that the same shooting interval as that in the case of performing the light-shielding shooting operation is performed by waiting for the same time as the exposure time at the time of shooting the main image after shooting the main image. Adjust to.

  In the present embodiment, the example in which the standby is performed for the same time as the exposure time at the time of adjusting the shooting interval has been described, but if the user does not notice the difference from the shooting interval when performing the shading shooting operation, Any adjustment time may be set. In addition, processing such as noise reduction processing and defective pixel (scratch) correction processing may be performed during the shooting interval adjustment to improve image quality. Thereafter, the imaging signal processing circuit 109 performs development processing, white balance control, other correction processing, compression processing, and the like on the main image (subject image) to create image data, which is recorded on the recording medium 115 (step S712). The shooting process is terminated.

  On the other hand, when the temperature obtained in step S702 is 42 ° C., the shutter speed obtained in step S703 is 1/30 seconds, and the ISO sensitivity is ISO400, the condition of case 2 in the determination table of FIG. . In the black image subtraction determination table, since Case 2 is marked with ●, it is determined that the light-shielding shooting operation and the black image subtraction processing operation are performed (ON).

  When it is determined that the light-shielding photographing operation and the black image subtraction processing operation are performed, the overall control unit 112 closes the mechanical shutter 104 and shields the incident light to the image sensor 106, and then the black image is captured by the image sensor 106. A shading photographing operation for photographing is executed (step S713). Then, the captured black image is temporarily stored in the memory unit 111. The black image shooting conditions are the same as those for the main image shooting in step S701.

  Next, the overall control unit 112 performs black image subtraction processing for subtracting the black image captured in step S713 in units of pixels from the main image (subject image) captured in step S701 (step S714). Thereafter, the image pickup signal processing circuit 109 performs development processing, white balance control, other correction processing, compression processing, and the like on the main image (subject image) obtained by subtracting the black image, and creates subject image data on the recording medium 115. Recording is performed (step S715), and the photographing process is terminated.

  As described above, in this embodiment, the black pattern generation by the light-shielding shooting operation and the subtraction process from the subject image are performed at appropriate timing, thereby reducing the fixed pattern noise while suppressing the deterioration of the random noise. it can. Further, the following effects can be obtained by performing the shooting interval adjustment processing when the shooting conditions of the previous frame and the current frame are similar during continuous shooting. That is, it is possible to eliminate the change in the shooting interval due to the execution of the light-shielding shooting operation for the black image subtraction process during the continuous shooting, and to prevent the user from feeling uncomfortable during the continuous shooting.

(Example 2)
Next, a digital camera according to a second embodiment of the present invention will be described. In addition, about the part which overlaps with the said Example 1, drawing and a code | symbol are diverted and the description is abbreviate | omitted. In the first embodiment, as the adjustment of the shooting interval, the shooting interval is adjusted by providing a standby time after shooting so that the shooting interval is equivalent to that when performing the light-shielding shooting operation for the black image subtraction process. Explained. However, since it is required to reduce the frame speed as much as possible during continuous shooting, in this embodiment, the shooting interval is determined by the difference between the shading shooting operation specified by the black image subtraction determination table and the start temperature of the black image subtraction process. Change T. That is, when there is a possibility that the black image subtraction processing determination unit 113 determines that it is necessary to execute the light-shielding shooting operation for the black image subtraction process from the middle of the shooting of a plurality of continuous shooting frames, the continuous shooting is performed. The shooting interval is controlled to gradually increase.

The shooting interval T in the present embodiment is calculated using the equation (1) from the coefficient K and the shutter speed Tv for each difference between the temperature at each shooting and the temperature at which the shading shooting operation and the black image subtraction process are executed. Here, the coefficient K is a variable that is set so that the temperature at the time of shooting approaches the temperature at which the light-blocking shooting operation and the black image subtraction process are performed by performing the calculation of Expression (1). Then, by changing the coefficient K and performing the calculation of Expression (1), the photographing interval is adjusted to gradually increase as the difference between the temperature at which the light-shielding photographing operation and the black image subtraction process are performed becomes small. To do.
T = Tv + K * Tv (1)

  FIG. 8 shows the relationship between the photographing intervals at each temperature difference when the horizontal axis represents the difference between the temperature at which the light-shielding photographing operation and the black image subtraction are performed, and the vertical axis represents the photographing interval. . The shooting interval indicated by the ● mark of each temperature difference is the shooting interval when the adjustment of the shooting interval is not performed. When the shooting interval is not adjusted, the shooting interval is doubled from T0 to 2T0 from the temperature at which the shading shooting operation and the black image subtraction process are executed. On the other hand, the shooting interval indicated by a circle mark of each temperature difference is the shooting interval when the shooting interval is adjusted in this embodiment. In the case of FIG. 8, the shooting interval is adjusted from a temperature that is 10 ° C. lower than the temperature at which the shading shooting operation and the black image subtraction process are performed, and the temperature at which the shading shooting operation and the black image subtraction process are performed. As the difference becomes smaller, the shooting interval is adjusted to gradually increase.

  As described above, according to the present embodiment, the shooting interval is gradually changed according to the temperature at each shooting during continuous shooting. In addition, it is possible to eliminate a sudden change in the shooting interval during the continuous shooting, and to prevent the user from feeling uncomfortable during the continuous shooting, and it is possible to suppress a decrease in the frame speed.

(Example 3)
Next, a digital camera according to a third embodiment of the present invention will be described. In addition, about the part which overlaps with the said Example 1 and 2, drawing and a code | symbol are diverted and the description is abbreviate | omitted.

  In the first and second embodiments, a process different from the black image subtraction process is performed to adjust the shooting interval. However, the amount of random noise varies depending on whether the black image subtraction process is performed or not. It is also conceivable that the image quality changes during the process. Therefore, in this embodiment, when it is determined that the shooting interval adjustment is required as a result of determining whether or not the shooting interval adjustment is necessary, the black image subtraction process is always performed to eliminate the change in image quality during the continuous shooting. To control.

  With reference to FIG. 9, an operation example of the digital camera of the present embodiment will be described.

  Steps S901 to S907 are the same as steps S701 to S707 in FIG. If the setting value of the flag FL is “1” in the determination of whether or not the shooting interval adjustment is necessary in step S906, black image subtraction processing is performed. The operation of the black image subtraction process (step S908 to step S910) is the same as the operation of the black image subtraction process described in step S713 to step S715 in FIG.

  As described above, according to the present embodiment, the black image subtraction process is always performed when the shooting interval is adjusted. Further, fixed pattern noise can be reduced, and a change in the shooting interval during the continuous shooting can be eliminated so that the user does not feel uncomfortable during the continuous shooting.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 101 Image sensor 107 Temperature detection part 112 Overall control part 113 Black image subtraction process determination part 114 Shooting condition similarity determination part 115 Shooting interval adjustment determination part

Claims (7)

Imaging means for photographing a subject using an imaging element to generate a subject image;
A determination unit that determines whether or not it is necessary to execute a light-shielding shooting operation by the imaging unit immediately before or after execution of a subject shooting operation by the imaging unit;
Control means for controlling the shooting interval of the continuous shooting to be substantially constant regardless of whether or not the light-shielding shooting operation is performed when performing continuous shooting of continuously shooting a plurality of subjects by the imaging unit;
Equipped with a,
The control unit may gradually increase the shooting interval of the continuous shooting when the determination unit may determine that the light-shielding shooting operation needs to be executed in the middle of shooting of a plurality of frames of the continuous shooting. An imaging device that is controlled to be long . And a subtracting means for subtracting a black image generated by executing the shading photographing operation from the subject image,
The imaging apparatus according to claim 1, wherein the determination unit determines whether it is necessary to execute the light-shielding shooting operation and a subtraction process by the subtraction unit according to the shooting condition. Furthermore, a temperature detection means for detecting the temperature around the image sensor is provided,
2. The imaging according to claim 1, wherein the determination unit determines whether or not the light-shielding imaging operation needs to be executed based on the imaging condition and the temperature detected by the temperature detection unit. apparatus. Furthermore, a temperature detection means for detecting the temperature around the image sensor is provided,
The determination unit determines whether or not the light-shielding photographing operation and the subtraction process need to be executed based on the photographing condition and the temperature detected by the temperature detecting unit. The imaging device described in 1. Furthermore, a temperature detection means for detecting the temperature around the image sensor is provided,
Said control means on the basis of the imaging conditions and the temperature detecting means temperature sensed by, according to claim 1, characterized in that control whether to perform the adjustment of the photographing interval of the continuous shooting Imaging device. The imaging conditions, the imaging apparatus according to any one of claims 1 to 5, characterized in that it comprises a shutter speed and imaging sensitivity. A method for controlling an imaging apparatus including an imaging unit that shoots a subject using an imaging element to generate a subject image,
A determining step in which a determining unit determines whether or not it is necessary to execute a light-shielding shooting operation by the imaging unit immediately before or immediately after execution of a subject shooting operation by the imaging unit, depending on shooting conditions;
A control step in which the control means controls the shooting interval of the continuous shooting to be substantially constant regardless of whether or not the light-shielding shooting operation is performed when performing continuous shooting in which a plurality of subjects are continuously shot by the imaging means. When,
Equipped with a,
In the control step, when there is a possibility that the shading shooting operation needs to be executed in the middle of the shooting of the plurality of frames of the continuous shooting in the determination step, the shooting interval of the continuous shooting is gradually increased. A control method for an imaging apparatus, wherein the control is performed so as to be long .

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