JP2016092708A - Image pickup device, interval shooting method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image of optimum tone reproduction while preventing the flickering, in interval shooting.SOLUTION: When there is a predetermined change or more in the AE setting for a captured image, in a series of shooting in interval shooting mode, a CPU18 controls an image processing section 16 to perform gamma analysis, as usual, base on a captured image, to generate a gamma correction curve based on the analysis results, and to perform auto gamma correction for correcting the contrast of a captured image, according to the gamma correction curve. Meanwhile, when there is not a predetermined change or more in the AE setting for a captured image, the CPU18 controls the image processing section 16 to correct contrast of a captured image, by using the gamma correction curve for one previous image.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image capturing device, an interval capturing method, and a program.

  2. Description of the Related Art Conventionally, in an imaging apparatus such as a digital camera, interval shooting for capturing a plurality of images at a predetermined shooting interval and the number of shooting times is known (for example, see Patent Documents 1 and 2). In the imaging apparatus, it is possible to reproduce a moving image with reduced time by continuously reproducing a plurality of captured images.

JP 2006-229481 A JP 2011-107720 A

  By the way, in interval shooting, auto gamma correction is performed for each shooting in order to correct the contrast for each captured image. Auto gamma correction is a function that acquires a luminance histogram from input image data and corrects the contrast of the image based on a gamma correction curve generated based on the acquired histogram. It is a useful technique that is also effective in compensating for the performance of the lens.

  However, since auto gamma correction is performed for each captured image in interval shooting, even if the light source environment (exposure) is the same, the contrast may change with a slight change in the subject. Therefore, when a plurality of captured images are connected and viewed at the time of reproduction, there is a problem that flickering occurs between the images even if each image has an optimum contrast.

  Accordingly, an object of the present invention is to obtain an image with optimum gradation reproduction while preventing flickering in interval shooting.

  An image capturing apparatus according to the present invention is an image capturing apparatus that performs interval shooting for capturing a plurality of images at a predetermined shooting interval, and includes an imaging unit, an exposure setting unit that sets an exposure at the predetermined shooting interval, Based on the exposure set by the exposure setting means, a control means for picking up an image by the image pickup means, and for each image picked up by the image pickup means, the exposure set by the exposure setting means changes more than a predetermined amount A determination means for determining whether or not there is a change, and for each image captured by the imaging means, if the determination means determines that there has been a predetermined change or more, based on the image captured by the imaging means When the gamma correction is performed using the correction parameter updated in the meantime, and the determination means determines that there is no change more than a predetermined value, A gamma correction unit for performing gamma correction without updating the positive parameters, characterized in that it comprises a.

  The interval shooting method according to the present invention is an interval shooting method in which a plurality of images are picked up at a predetermined shooting interval by an imaging unit, and the step of setting exposure at the predetermined shooting interval and the set exposure are used. The step of taking an image by the image pickup unit, the step of determining whether or not the set exposure has changed more than a predetermined value for each image taken by the image pickup unit, and the image pickup by the image pickup unit When it is determined that there is a change greater than or equal to the predetermined value for each image, gamma correction is performed using the correction parameter updated based on the image captured by the imaging unit, while the change greater than or equal to the predetermined value is performed. A step of performing gamma correction without updating the correction parameter when it is determined that the correction parameter is not determined. .

  The program according to the present invention is based on the function of setting an exposure at the predetermined shooting interval to the computer that controls the image capturing apparatus that performs interval shooting for capturing a plurality of images at the predetermined shooting interval, and the set exposure. A function of capturing an image by the imaging unit, a function of determining whether or not the set exposure has changed more than a predetermined value for each image captured by the imaging unit, and an image captured by the imaging unit When it is determined that there is a change greater than or equal to the predetermined value every time, gamma correction is performed using a correction parameter generated based on the image captured by the imaging unit, while there is no change greater than the predetermined value. If it is determined, a function of performing gamma correction without updating the correction parameter is realized.

  According to the present invention, it is possible to obtain an image with optimum gradation reproduction while preventing flickering in interval shooting.

1 is a block diagram illustrating a configuration of an image capturing apparatus 10 according to an embodiment of the present invention. It is a flowchart for demonstrating the imaging operation of the image imaging device 10 by this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A. Configuration of Embodiment FIG. 1 is a block diagram showing a configuration of an image capturing apparatus 10 according to an embodiment of the present invention. In the figure, the image pickup apparatus 10 is composed of, for example, a digital camera, and includes an image pickup lens 11, an aperture / shutter 12, a CCD 13, a TG (Timing Generator) 14, a unit circuit 15, an image processing unit 16, a lens driving unit 17, a CPU 18, A DRAM 19, a memory 20, a flash memory 21, a display unit 22, a key input unit 23, a card I / F 24, and a memory card 25 are provided.

  The imaging lens 11 includes a zoom lens and a focus lens, and a lens driving unit 17 is connected thereto. The lens driving unit 17 drives the imaging lens 11 in accordance with a control signal from the CPU 18, and performs autofocus driving, zoom driving, and the like. The diaphragm / shutter 12 includes a drive circuit (not shown), and operates according to a control signal sent from the CPU 18 by the drive circuit. The diaphragm / shutter 12 controls the amount of light entering from the imaging lens 11. The CCD (imaging device) 13 converts the light of the subject projected through the imaging lens 11 and the diaphragm / shutter 12 into an electrical signal, and outputs the electrical signal to the unit circuit 15. The CCD 13 is driven according to the timing signal generated by the TG 14.

  The unit circuit 15 includes a CDS (Correlated Double Sampling) circuit that holds the imaging signal output from the CCD 13 by correlated double sampling, an AGC (Automatic Gain Control) circuit that performs automatic gain adjustment of the imaging signal after the sampling, It is composed of an A / D converter that converts an analog imaging signal after automatic gain adjustment into a digital signal. The unit circuit 15 is driven according to the timing signal generated by the TG 14. The image pickup signal of the CCD 13 is sent to the image processing unit 16 as a digital signal through the unit circuit 15.

  The image processing unit 16 performs image processing (pixel interpolation processing, gamma (γ) correction, luminance color difference signal generation, white balance processing, exposure correction processing, etc.) of the image data sent from the unit circuit 15 and compression of the image data. Processing such as decompression (for example, compression / decompression in JPEG format, M-JPEG format, or MPEG format), trimming of a captured image, digital zooming of a captured image, and the like are performed. The image processing unit 16 is driven according to the timing signal generated by the TG 14.

  The CPU 18 is a one-chip microcomputer that controls each unit of the image capturing apparatus 10. In particular, in the present embodiment, the CPU 18 controls the lens driving unit 17 for autofocus, adjustment of shutter speed and aperture, adjustment of ISO sensitivity, etc. (AE; Automatic Exposure), and an image for an image captured by the image processing unit 16. It controls processing (auto gamma correction, etc.), operation of displaying captured images on the display unit 22 (live view display), and the like.

  The DRAM 19 is used as a buffer memory for temporarily storing image data sent to the CPU 18 after being imaged by the CCD 13 and also as a working memory for the CPU 18. The CPU 18 controls the captured image stored in the DRAM 19 to perform the above-described processing. The memory 20 stores a program necessary for controlling each part of the image pickup apparatus 10 by the CPU 18 and data necessary for controlling each part. The CPU 18 performs processing according to this program. The flash memory 21 and the memory card 25 are recording media for storing image data captured by the CCD 13.

  The display unit 22 includes a color liquid crystal display and a driving circuit thereof, and displays a captured image captured by the CCD 13 as a live view image when in an imaging standby state. When reproducing a recorded image, the display unit 22 Display the recorded image read from the card 25 and expanded. The key input unit 23 includes operation keys such as a shutter button, a shooting mode setting dial, a zoom switch, a SET key, and a cross key, and outputs an operation signal corresponding to the user's key operation to the CPU 18. A memory card 25 is detachably attached to the card I / F 24 via a card slot (not shown) of the main body of the image pickup apparatus 10.

  In the present embodiment, the CPU 18 performs exposure setting (AE; Automatic Exposure), gamma analysis & gamma setting of a captured image, development processing, and the like in the interval shooting mode. More specifically, in a series of shootings in the interval shooting mode, the CPU 18 uses the image processing unit 16 based on the captured image as usual when there is a predetermined change in the AE setting for the captured image. Gamma analysis is performed, a gamma correction curve is generated based on the analysis result, and auto gamma correction for correcting the contrast of the captured image is executed according to the gamma correction curve. Thereby, it is possible to obtain an image of optimum gradation reproduction according to the change in exposure.

  On the other hand, when the AE setting for the captured image does not change more than a predetermined value, the CPU 18 corrects the contrast of the captured image using the gamma correction curve for the previous image by the image processing unit 16. Thereby, even if the contrast changes due to a slight change in the subject, if the light source environment (exposure) is the same, the change between images can be reduced, and flicker can be prevented.

B. Operation of Embodiment Next, the operation of the above-described embodiment will be described.
FIG. 2 is a flowchart for explaining the shooting operation of the image pickup apparatus 10 according to the present embodiment.

  First, the CPU 18 takes the first image in steps S10 to S20. The CPU 18 sets the shooting interval, the number of shots (shooting time) and the like as the interval shooting mode (step S10). Next, the CPU 18 sets the first exposure (AE) based on the image taken in via the CCD 13 (step S12). Subsequently, the CPU 18 captures an image with the set AE via the CCD 13 (step S14).

  Next, the CPU 18 performs gamma analysis based on the captured image (step S16), and performs gamma setting based on the analysis result (step S18). Specifically, the CPU 18 uses the image processing unit 16 to acquire a luminance histogram from the captured image data, and generates a gamma correction curve based on the acquired histogram. Thereafter, the CPU 18 performs a developing process for correcting the contrast of the image captured according to the generated gamma correction curve by the image processing unit 16 (step S20). A series of processes in steps S16 to S20 corresponds to auto gamma correction. The image data (first image) after the development processing is stored in the memory 20, the memory card 25, or the like.

  Next, the CPU 18 performs the second and subsequent photographing in steps S22 to S36. The CPU 18 sets the second exposure (AE) based on the image taken in via the CCD 13 (step S22). Subsequently, the CPU 18 captures an image with the set AE via the CCD 13 (step S24).

  Here, the CPU 18 determines whether or not the AE (exposure) setting has changed more than a predetermined value based on the captured image data (step S26). If the AE (exposure) setting changes more than a predetermined value (YES in step S28), the CPU 18 performs gamma analysis on the basis of the captured image, as with the first image, by the image processing unit 16 ( In step S28, gamma setting is performed based on the analysis result (step S30). Thereafter, the CPU 18 performs a developing process for correcting the contrast of the captured image according to the generated gamma correction curve by the image processing unit 16 (step S32). That is, the auto gamma process is executed by a series of processes in steps S28 to S32. The image data after the development processing (second and subsequent images) is stored in the memory 20, the memory card 25, or the like.

  In this way, when the AE (exposure) setting changes more than a predetermined value in the second and subsequent shots, auto correction is performed to correct the contrast of the captured image according to the gamma correction curve generated based on the captured image. Since the gamma correction is performed, an image with optimum gradation reproduction according to the change in exposure can be obtained.

  On the other hand, if the AE (exposure) setting does not change more than a predetermined value (NO in step S28), the CPU 18 performs development processing for correcting the contrast of the captured image according to the gamma correction curve set in the previous shooting. This is performed (step S34). That is, in this case, auto gamma processing is not executed. The image data after the development processing (second and subsequent images) is stored in the memory 20, the memory card 25, or the like.

  As described above, when the AE (exposure) setting does not change more than a predetermined value in the second and subsequent shootings, the gamma correction curve set in the previous shooting is not set, but a new gamma correction curve is set. Therefore, if the light source environment (exposure) is the same, even if the contrast changes due to a slight change in the subject, the change between images can be reduced. Flicker can be prevented.

  In any case, when the development process is completed, the CPU 18 determines whether or not the specified number of images has been captured (step S36). If the prescribed number of images has not been shot (NO in step S36), the CPU 18 returns to step S22 and repeats the above steps S22 to S36 to fix the gamma correction while the exposure is constant. Then, images are taken at predetermined time intervals until the specified number of images is reached while the auto-gamma correction is performed again from the shooting frame whose exposure has changed. Then, when the prescribed number of photographings is finished, the process is finished.

  According to the above-described embodiment, the gamma correction is fixed while the exposure is constant, and the auto gamma correction is operated again from the shooting frame in which the exposure has changed. An image can be obtained.

  More specifically, according to the above-described embodiment, when it is determined that the exposure has changed more than a predetermined amount, a gamma correction curve is generated based on a luminance histogram acquired from an image captured by the CCD 13. Then, the contrast of the captured image is corrected according to the gamma correction curve, and if it is determined that there is no change in exposure more than a predetermined value, the imaging is performed according to the gamma correction curve used for the previously captured image. Since the contrast of the generated image is corrected, it is possible to obtain an image with optimum gradation reproduction while preventing flickering.

  In the above-described embodiment, the change in exposure (AE) is determined. Further, based on the luminance histogram, the exposure change of the entire image or the partial luminance change of the subject or the like. You may make it determine whether it is. Then, if the exposure change of the entire image, auto gamma correction is executed, and if it is a partial brightness change, the contrast of the image may be corrected according to the gamma correction curve used for the previously captured image. Good.

As mentioned above, although several embodiment of this invention was described, this invention is not limited to these, The invention described in the claim, and its equal range are included.
Below, the invention described in the claims of the present application is appended.

(Appendix 1)
The invention according to appendix 1 is an image capturing apparatus that performs interval shooting for capturing a plurality of images at a predetermined shooting interval, the imaging unit, an exposure setting unit that sets an exposure at the predetermined shooting interval, Based on the exposure set by the exposure setting means, the control means for taking an image by the imaging means, and the exposure set by the exposure setting means changes more than a predetermined value for each image taken by the imaging means. A determination unit that determines whether or not there is a change, and for each image captured by the imaging unit, if the determination unit determines that there has been a predetermined change or more, based on the image captured by the imaging unit While gamma correction is performed using the updated correction parameter, when the determination unit determines that there is no change beyond a predetermined level, the correction parameter is used. A gamma correction unit for performing gamma correction without updating the over data, an image capturing apparatus comprising: a.

(Appendix 2)
According to the second aspect of the present invention, the gamma correction unit is imaged by the imaging unit when the determination unit determines that there is a change greater than or equal to a predetermined value for each image captured by the imaging unit. A correction parameter is generated based on the image, and gamma correction is performed using the generated correction parameter. On the other hand, when the determination unit determines that there is no change more than a predetermined value, the imaging unit captures the previous image. The image pickup apparatus according to appendix 1, wherein gamma correction is performed using a correction parameter used for the obtained image.

(Appendix 3)
According to the third aspect of the present invention, the gamma correction unit performs gamma correction based on a luminance histogram obtained from an image captured by the imaging unit when the determination unit determines that a change of a predetermined value or more has occurred. A correction curve is generated, and the contrast of the image captured by the imaging unit is corrected according to the gamma correction curve. On the other hand, if the determination unit determines that there is no change beyond a predetermined level, the imaging unit performs the previous imaging. The image imaging apparatus according to appendix 2, wherein the contrast of the image captured by the imaging unit is corrected according to the gamma correction curve used for the captured image.

(Appendix 4)
The invention according to appendix 4 is an interval shooting method in which a plurality of images are captured at a predetermined shooting interval by an imaging unit, wherein an exposure is set at the predetermined shooting interval, and based on the set exposure A step of capturing an image by the imaging unit, a step of determining whether or not the set exposure has changed more than a predetermined value for each of the images captured by the imaging unit, and an image captured by the imaging unit When it is determined that there is a change greater than or equal to the predetermined value for each image, gamma correction is performed using the correction parameter updated based on the image captured by the imaging unit, while there is no change greater than or equal to the predetermined value. If it is determined, the step of performing gamma correction without updating the correction parameter is included. It is a method.

(Appendix 5)
The invention according to appendix 5 includes a function of setting an exposure at the predetermined shooting interval in a computer that controls an image pickup apparatus that performs interval shooting in which a plurality of images are picked up at a predetermined shooting interval by the imaging unit. A function of capturing an image by the imaging unit based on the exposure, a function of determining whether or not the set exposure has changed more than a predetermined value for each image captured by the imaging unit, and by the imaging unit When it is determined that there is a change greater than or equal to the predetermined value for each captured image, gamma correction is performed using a correction parameter generated based on the image captured by the imaging unit, while the predetermined or greater value is detected. When it is determined that there is no change, the function of performing gamma correction without updating the correction parameter is realized. Is a program.

DESCRIPTION OF SYMBOLS 10 Image pick-up apparatus 11 Imaging lens 12 Shutter combined shutter 13 CCD
14 TG (Timing Generator)
15 Unit Circuit 16 Image Processing Unit 17 Lens Drive Unit 18 CPU
19 DRAM
20 Memory 21 Flash Memory 22 Display Unit 23 Key Input Unit 24 Card I / F
25 Memory card

Claims (5)

An image capturing apparatus that performs interval shooting for capturing a plurality of images at a predetermined shooting interval,
Imaging means;
Exposure setting means for setting exposure at the predetermined shooting interval;
Control means for capturing an image by the imaging means based on the exposure set by the exposure setting means;
Determining means for determining whether or not the exposure set by the exposure setting means has changed more than a predetermined value for each image captured by the imaging means;
For each image captured by the imaging unit, when the determination unit determines that there has been a predetermined change or more, gamma correction is performed using a correction parameter updated based on the image captured by the imaging unit. On the other hand, when it is determined by the determination means that there is no change more than a predetermined value, gamma correction means for performing gamma correction without updating the correction parameter;
An image pickup apparatus comprising: The gamma correction unit generates a correction parameter based on the image captured by the imaging unit when the determination unit determines that there has been a predetermined change or more for each image captured by the imaging unit. On the other hand, when the gamma correction is performed using the generated correction parameter, and the determination unit determines that there is no change more than a predetermined value, it is used for the image previously captured by the imaging unit. Perform gamma correction using correction parameters,
The image capturing apparatus according to claim 1, wherein The gamma correction unit generates a gamma correction curve based on a luminance histogram acquired from the image captured by the imaging unit when the determination unit determines that there is a change greater than or equal to a predetermined value. While correcting the contrast of the image captured by the imaging unit according to the correction curve, when the determination unit determines that there is no change beyond a predetermined level, the image used for the image previously captured by the imaging unit is used. Correcting the contrast of the image captured by the imaging means according to a gamma correction curve;
The image capturing apparatus according to claim 2, wherein An interval photographing method for photographing a plurality of images at a predetermined photographing interval by an imaging means,
Setting an exposure at the predetermined shooting interval;
Imaging an image by the imaging means based on the set exposure;
Determining whether or not the set exposure has changed more than a predetermined value for each image captured by the imaging means;
When it is determined that there is a change greater than or equal to the predetermined value for each image captured by the imaging unit, gamma correction is performed using a correction parameter updated based on the image captured by the imaging unit. If it is determined that there is no change greater than the predetermined, performing gamma correction without updating the correction parameter;
The interval imaging | photography method characterized by including. A computer that controls an image capturing apparatus that performs interval shooting in which a plurality of images are captured at a predetermined shooting interval by an imaging unit;
A function of setting exposure at the predetermined shooting interval;
A function of taking an image by the imaging means based on the set exposure;
A function of determining whether or not the set exposure has changed more than a predetermined value for each image captured by the imaging unit;
When it is determined that there is a change greater than or equal to the predetermined value for each image captured by the image capturing unit, gamma correction is performed using a correction parameter generated based on the image captured by the image capturing unit. A function of performing gamma correction without updating the correction parameter when it is determined that there is no change beyond the predetermined value;
A program characterized by realizing.

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