JP2014150370A - Image pickup device, control method thereof, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a suitable photographed image among photographed images acquired by consecutive photographing, to be recorded, for example, by RAW mode recording, thereby suppressing a decline in the performance of consecutive photographing and avoiding putting pressure on a capacity of a recording medium.SOLUTION: A digital camera selects RAW-mode recording as a recording format and executes recording of a photographed image when a main subject detected from the photographed image is within an angle of view and a contrast value of the main subject is less than or equal to a prescribed value; otherwise, the digital camera selects a JPEG mode as the recording format and executes recording of the photographed image. In this way, prescribed evaluation is performed for each one of photographed images, and a recording format for each of the photographed images is selected according to the result of this evaluation, so that, when photographed by panning, it is possible to record a suitable photographed image by RAW-mode recording, and to record an unsuitable photographed image (failed image) in a JPEG mode.

Description

  The present invention relates to an imaging apparatus capable of recording a captured image in a recording format selected from a plurality of recording formats, a control method thereof, and a program.

  In digital single-lens reflex cameras, a system compliant with DCF (Digital Camera Format) is widely used as a recording format for various media. In DCF, the management information of photographing data is defined to ensure mutual compatibility. In particular, a JPEG (Joint Picture Expert Group) baseline method is used as a method for encoding captured data. In the JPEG method, the color depth of each pixel is defined as 8 bits.

On the other hand, since the effective value of the dynamic range of an image sensor mounted on a digital single-lens reflex camera has 8 bits or more, many products capable of recording data of about 12 to 14 bits without converting to 8 bits are provided. Yes. In general, this is called RAW mode recording. The image data recorded in the RAW mode, for example, records the A / D conversion value for each pixel of the Bayer-arranged sensor as it is and cannot be viewed on a PC or the like as it is. The data after development is recorded again by the JPEG method.
As described above, in the RAW mode recording, an image having a wider dynamic range can be recorded as it is, but since the file size becomes large, the continuous shooting performance is lacking, and the total number of sheets that can be recorded on the recording medium is reduced. There is a drawback. In addition, compared with JPEG files, a post process called development processing is required, so that there is a lack of immediate viewability, and different development processing is required for each model, so that compatibility is also lacking.

Due to the advantages and disadvantages of the RAW mode recording as described above, a mode (RAW + JPEG mode) for simultaneously recording in both JPEG and RAW mode recording in one shooting is also in practical use.
Table 1 shows the characteristics of each mode. ○ represents an advantageous point, × represents a disadvantage, and Δ represents a medium defect. In the RAW + JPEG mode, since files of two different formats are recorded, naturally, the total file size per shooting is also increased, and the continuous shooting performance is most deteriorated.

In addition, as one of photographing techniques of a digital camera, a technique generally called “panning” is known. Panning is a special shooting technique used to emphasize the speed of an object moving at high speed. Specifically, the ISO sensitivity is set as low as possible, and the camera is moved according to the moving speed of the moving object by setting the aperture as low as possible to slow down the shutter speed and increase the subject blurring. To be executed.
FIG. 6 shows the shooting situation of panning. Reference numeral 601 denotes a moving object (automobile in the illustrated example) as a subject, and 602 denotes a moving direction of the moving object 601. Reference numerals 603 to 605 denote a moving digital camera, and reference numeral 606 denotes a moving direction of the camera (swing operation by human power). Thus, since it is necessary to move the camera itself in accordance with the speed of the moving object 601, it is difficult to place the moving object 601 within the angle of view. Therefore, generally, in panning, a method of acquiring a plurality of images by a continuous shooting function and selecting a suitable image from the images is often employed.

Japanese Patent Application Laid-Open No. 2004-133620 proposes a method of continuously capturing a subject image to generate a plurality of frames of RAW data, and selecting and storing highly evaluated ones from the RAW data.
Japanese Patent Application Laid-Open No. 2004-228561 determines whether or not image data captured by the imaging unit under the imaging condition is dangerous based on a measurement unit that measures an imaging condition of the imaging unit and a measurement result of the measurement unit. A method has been proposed that includes a determination unit and a selection unit that selects a non-development recording format from a plurality of recording formats when the determination unit determines that the image data captured by the imaging unit is dangerous. Yes.

JP 2003-348429 A JP 2011-44803 A

In the panning technique, shooting is performed while moving the camera in accordance with a moving object that is a subject. Therefore, the entire moving object is not always properly shot.
In FIG. 7, reference numeral 703 denotes a suitable photographing example. On the other hand, 701 is a failure example in which the rear end portion of the moving object 601 is missing and 702 is missing the front end portion. Reference numeral 704 is a failure example in which the subject itself is blurred because the moving speed of the camera and the speed of the moving object 601 do not match.
As described above, since various conditions overlap and the yield of shooting is poor, a large number of shots are required, and it is necessary to select the best shot among them, which is a difficulty of the panning technique. In addition, since a large number of captured images are acquired by continuous shooting, there is a problem of pressing the recording medium.

  The present invention has been made in view of the above points, and among the captured images obtained by continuous shooting, suitable captured images can be recorded, for example, in RAW mode recording, so that continuous shooting performance is improved. An object is to suppress the decrease and prevent the recording medium from being pressed.

  An imaging apparatus according to the present invention includes an imaging unit, an evaluation unit that performs a predetermined evaluation for each captured image obtained by the imaging unit, and a plurality of recording formats of the captured image according to the evaluation result of the evaluation unit. And a control means for selecting from the recording format.

  According to the present invention, a suitable photographed image obtained by continuous shooting can be recorded by, for example, RAW mode recording, so that deterioration in continuous shooting performance is suppressed and the recording medium is not compressed. Can be.

It is a figure which shows the structure of the digital camera which concerns on 1st Embodiment. 6 is a flowchart showing recording format selection processing in the digital camera according to the first embodiment. It is a figure which shows the structure of the digital camera which concerns on 2nd Embodiment. It is a figure which shows the structure of the digital camera which concerns on 3rd Embodiment. 10 is a flowchart illustrating JPEG recording processing in a digital camera according to a third embodiment. It is a figure which shows the imaging | photography condition of a panning shot. It is a figure which shows the example of the picked-up image acquired by imaging | photography of a panning shot.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
(First embodiment)
FIG. 1 shows the configuration of a digital camera according to the first embodiment.
A CPU 101 controls the entire digital camera. Reference numeral 104 denotes an optical lens. Reference numeral 103 denotes an image sensor which is an imaging unit, and acquires an image condensed by the optical lens 104. Reference numeral 102 denotes an A / D converter that digitizes pixel values read by the image sensor 103. An image processing unit 105 performs various corrections and development processes on the digitized pixel values.

  Reference numeral 106 denotes a subject detection unit that detects a subject group from a captured image obtained by the image sensor 103. A subject evaluation unit 107 determines a main subject from among the subject group detected by the subject detection unit 106, and determines whether the subject is within the angle of view. The contrast of the main subject is also evaluated. Reference numeral 108 denotes a format determination unit, which selects the recording format of the captured image from the JPEG method and the RAW mode recording in which the readout pixels of the image sensor 103 are recorded as they are according to the evaluation result from the subject evaluation unit 107.

Reference numeral 109 denotes a RAW codec. The encoding format in RAW mode recording is not directly related to the present invention and is not specified. However, since it is an image before development, it can handle image data of 8 bits or more and has a low compression rate (or completely reversible). N) is preferred. Reference numeral 110 denotes a JPEG codec.
Reference numeral 111 denotes a recording medium that records compressed data. Specifically, SD cards, compact flash (registered trademark) cards and the like are widely used.

FIG. 2 shows a recording format selection process in the digital camera according to the first embodiment. In the following description, the subject is described as a digital camera, but the flowchart of FIG. 2 is realized by the CPU 101 of the digital camera executing a program.
In step S201, the digital camera detects all subjects from the captured image.
In step S202, the digital camera repeats the subject detection in step S201 until all the subjects within the angle of view of the captured image are detected. When all the subjects are detected, the process proceeds to step S203.
In step S203, the digital camera determines a main subject from the detected subject group.
In step S204, the digital camera evaluates whether or not the main subject determined in step S203 is within the angle of view. If the main subject is within the angle of view, the process proceeds to step S205. If the main subject is not within the angle of view, the process proceeds to step S206.
In step S205, the digital camera determines whether the contrast value of the main subject determined in step S203 is equal to or less than a specified value A. If the contrast value of the main subject is equal to or less than the specified value A, the process proceeds to step S207. If the contrast value of the main object is not equal to or less than the specified value A, the process proceeds to step S206.
In step S206, the digital camera selects the JPEG method as the recording format and executes recording of the captured image. On the other hand, in step S207, the digital camera selects RAW mode recording as the recording format and executes recording of the captured image.

As described above, a predetermined evaluation can be performed for each captured image, and the recording format of each captured image can be selected according to the result. Thus, for example, when shooting by panning, a suitable captured image can be recorded by RAW mode recording, and an unsuitable captured image (failed image) can be recorded by the JPEG method. Accordingly, it is possible to suppress the continuous shooting performance from being lowered and to prevent the recording medium from being pressed. Further, for suitable images, development parameter correction and image processing can be performed in a later process, which is a feature of RAW mode recording.
In the present embodiment, JPEG and RAW mode recording has been described as a plurality of recording formats, but the present invention is not limited to this. A plurality of recording formats may include recording formats having different dynamic ranges, or may include recording formats that differ depending on whether they are lossless compression or lossy compression in the encoding process.

(Second Embodiment)
FIG. 3 shows the configuration of a digital camera according to the second embodiment. In addition, the same code | symbol is attached | subjected to the component equivalent to the digital camera which concerns on 1st Embodiment, and the description is abbreviate | omitted.
Reference numeral 112 denotes a panning determination unit that automatically determines whether or not the photographer intends to perform shooting by panning. Specifically, the panning determination can be realized by detecting movement in the horizontal direction between shootings with a gyro sensor.
In the present embodiment, the process shown in FIG. 6 is executed only when the panning determination unit 211 determines that the panning shooting is being performed. Therefore, when it is determined that the shot is not a panning shot, it is impossible that the yield is particularly bad, and therefore the recording format set by the user is always selected.

(Third embodiment)
FIG. 4 shows the configuration of a digital camera according to the third embodiment. In addition, the same code | symbol is attached | subjected to the component equivalent to the digital camera which concerns on 2nd Embodiment, and the description is abbreviate | omitted.
Reference numeral 113 denotes an image scaling unit, which can reduce a captured image.

FIG. 5 shows a JPEG recording process in the digital camera according to the third embodiment. In the third embodiment, when the JPEG method is selected as the recording format in the flowchart of FIG. 2 (step S206), it is determined in step S501 whether the contrast value of the main subject is equal to or less than the specified value B. If the contrast value of the main subject is not equal to or less than the specified value B, the process proceeds to step S503, and the captured image is recorded. On the other hand, if the contrast value of the main subject is equal to or less than the specified value B, the process proceeds to step S502, the captured image is reduced by the image scaling unit 113, and then the process proceeds to step S503 to record the captured image.
Here, the prescribed value B is compared with the prescribed value A described above,
Specified value B ≤ Specified value A
Shall be satisfied. Therefore, when JPEG recording is selected, images of different sizes are adaptively recorded.

  As described above, for failed images, not only automatically switching to JPEG mode but also reducing processing can reduce the total recording capacity and improve the maximum number of shots on a specific recording medium. It is possible to make it. In particular, in the case of panning, the remaining amount of recording media tends to be quickly pressed by a large number of shot images due to panning, but this can also be avoided.

  By letting the user know the mode for adaptively performing RAW recording on the camera side as the Auto RAW mode as described above, when viewing the recorded image, the user is notified of the situation where the format and image size are different. It is possible. Table 2 shows examples of modes that can be selected by the user.

(Other embodiments)
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, etc.) of the system or apparatus reads the program. It is a process to be executed.

  101: CPU, 102: A / D converter, 103: image sensor, 104: optical lens, 105: image processing unit, 106: subject detection unit, 107: subject evaluation unit, 108: format determination unit, 109: RAW codec, 110: JPEG codec, 111: recording medium, 112: panning determination unit, 113: image scaling unit

Claims (11)

Imaging means;
Evaluation means for performing a predetermined evaluation for each captured image obtained by the imaging means;
An image pickup apparatus comprising: a control unit that selects a recording format of the photographed image from a plurality of recording formats in accordance with an evaluation result of the evaluation unit.   The imaging apparatus according to claim 1, wherein the evaluation unit detects a main subject from a photographed image and evaluates whether the subject is within an angle of view.   The imaging apparatus according to claim 1, wherein the evaluation unit detects a main subject from a captured image and evaluates contrast. It has a panning judgment means for judging whether it is a panning,
The control means selects the recording format of the photographed image from the plurality of recording formats according to the evaluation result of the evaluation means only when it is determined that the panning is determined by the panning determination means. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus.   The imaging apparatus according to claim 1, wherein the plurality of recording formats include recording formats having different dynamic ranges of images.   5. The imaging apparatus according to claim 1, wherein the plurality of recording formats include recording formats that differ depending on whether the encoding process is lossless compression or lossy compression. .   5. The imaging apparatus according to claim 1, wherein the plurality of recording formats include JPEG format and RAW mode recording in which the readout pixels of the imaging unit are recorded as they are.   When a predetermined recording format is selected from the plurality of recording formats by the control means, and the contrast value of the main subject of the photographed image is not more than a specified value, the photographed image is reduced and recorded. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is a feature.   9. The control unit allows a user to select a mode for selecting a recording format of the photographed image from a plurality of recording formats in accordance with an evaluation result of the evaluation unit. The imaging device according to any one of the above. A method for controlling an imaging apparatus including an imaging means,
An evaluation step for performing a predetermined evaluation for each captured image obtained by the imaging means;
And a control step of selecting a recording format of the photographed image from a plurality of recording formats according to the evaluation result in the evaluation step. A program for controlling an imaging apparatus provided with imaging means,
Processing for performing a predetermined evaluation for each captured image obtained by the imaging means;
A program for causing a computer to execute a process of selecting a recording format of the photographed image from a plurality of recording formats in accordance with an evaluation result in the process of performing the predetermined evaluation.

Images