JP2014207613A - Imaging apparatus and imaging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for keeping consecutive imaging at equal intervals without memory collapse.SOLUTION: An imaging apparatus for successively writing and recording, on a recording medium, static image data generated by consecutive imaging comprises: imaging means; temporary storage means for temporarily storing the static image data; threshold setting means which sets a first threshold and a second threshold for determining an amount of the static image data stored by the temporary storage means; writing means for successively writing on the storage medium the static image data stored by the temporary storage means; determination means which determines the amount of the static image data stored by the temporary storage means on the basis of the first threshold and the second threshold; and control means for controlling the whole operation. When the amount of the static image data determined by the determination means becomes the first threshold or more, the control means sets a rate of consecutive imaging on the basis of a recording data rate insured by the recording medium and when the amount becomes the second threshold or less, sets the rate of consecutive imaging to a predetermined rate.

Description

  The present invention relates to an image pickup apparatus and an image pickup method, and more particularly to a technique suitable for use in an image pickup apparatus having a continuous shooting function for continuously taking still images.

  Conventionally, a digital camera has a continuous shooting function for repeatedly taking still images in a short time. In the continuous shooting function, a plurality of still images are continuously captured at regular intervals, the captured still images are compressed and stored in a memory, and then sequentially written and recorded on a recording medium.

  At this time, if the speed at which the still image data is written to the recording medium is low and the recording data rate (bit / second) of the recording medium is smaller than the data rate (bit / second) of the still image obtained by continuous shooting, The amount of still image data (bits) in the memory increases. As a result, there is no space in the memory and it is difficult to continue continuous shooting.

  In order to avoid this problem, a threshold is set in the memory, and when the amount of still image data in the memory exceeds the set threshold, it is determined that the writing speed of the recording medium is low. An imaging apparatus that switches to a preset continuous shooting speed (slower than the initial setting continuous shooting speed) is known (Patent Document 1).

JP 2006-93984 A

  However, in the configuration of the above-described prior art, when the data rate of the still image obtained at the switched continuous shooting speed is higher than the recording data rate of the recording medium, the amount of still image data in the memory increases, and the memory space becomes free. Disappears. If there is no memory available, continuous shooting cannot be performed until the memory is available, so the shooting interval depends on the recording data rate of the recording medium, and the continuous shooting interval becomes irregular. There was a problem.

Further, as the data amount in the memory increases, the continuous shooting speed decreases, so that it is difficult to perform desired shooting when it is desired to perform continuous shooting at a high speed after switching the continuous shooting speed.
In view of the above-described problems, an object of the present invention is to enable continuous shooting to be continued at regular intervals without controlling the continuous shooting speed and causing a memory failure.

  An image pickup apparatus according to the present invention is an image pickup apparatus that sequentially writes and records still image data generated by continuous shooting on a recording medium, and temporarily stores image pickup means and compression-encoded data obtained by compression-encoding the still image data. Temporary storage means, a first threshold value for determining the amount of still image data stored in the temporary storage means, a threshold value setting means for setting a second threshold value that is less than the first threshold value, and the temporary storage means Writing means for sequentially writing the still image data stored in the recording medium to the recording medium, and the still image data amount stored in the temporary storage means as the first threshold and the second threshold set by the threshold setting means. A determination unit that determines based on the control unit, and a control unit that controls the overall operation, wherein the control unit has a still image data amount determined by the determination unit equal to or greater than the first threshold value. The continuous shooting speed is set based on the recording data rate guaranteed by the recording medium, and when the amount of still image data determined by the determining means is less than or equal to the second threshold, The shooting speed is set to a predetermined continuous shooting speed.

  According to the present invention, in the case of continuous shooting of still images, when the amount of still image data in the memory increases, the continuous shooting interval is controlled at an equal interval by setting a continuous shooting speed lower than the writing speed guaranteed by the recording medium. To do. When the amount of still image data in the memory decreases, the continuous shooting speed can be switched again to a predetermined speed for continuous shooting.

1 is a block diagram illustrating an exemplary configuration of an imaging apparatus according to an embodiment of the present invention. It is the flowchart which showed the process sequence which controls the continuous shooting speed of 1st Embodiment. It is the figure which showed the relationship between the continuous shooting speed and memory usage of 1st Embodiment. It is the flowchart which showed the process sequence which controls the continuous shooting speed of 2nd Embodiment. It is a flowchart which shows the process sequence of a moving image still image simultaneous imaging | photography.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
In the first embodiment, an example will be described in which the setting of the continuous shooting speed during still image continuous shooting is controlled according to the amount of still image data in the memory.
FIG. 1 is a block diagram illustrating a configuration example of the imaging apparatus according to the present embodiment.
An imaging apparatus 100 according to the present embodiment illustrated in FIG. 1 includes an imaging unit 101, an image processing unit 102, an image compression unit 103, an interface 104, a display unit 105, a recording medium 106, a memory 107, and a CPU 108. , An operation unit 109 and a bus 110 are provided. Then, still image data generated by continuous shooting is temporarily stored in the memory 107, and the still image data stored in the memory 107 is sequentially written in the recording medium 106.

The bus 110 exchanges data between the blocks. Hereinafter, description of processing of the bus 110 is omitted when data is transferred between the blocks.
The imaging unit 101 includes a lens, an imaging element, and an AD converter. Import image data taken by the user.

The image processing unit 102 performs arithmetic processing such as image enlargement / reduction by resizing processing or conversion to YCC data by color conversion processing on the image data captured from the imaging unit 101.
The image compression unit 103 performs compression coding processing on the image data transmitted from the image processing unit 102 according to a known JPEG (Joint Photographic Experts Group) method or MPEG (Moving Picture Experts Group) method.
The interface 104 causes the display unit 105 to display the image data from the image processing unit 102. Further, the compressed data from the memory 107 is recorded on the recording medium 106.

The display unit 105 receives image data from the image processing unit 102 via the interface 104 and displays the image data to the user.
The recording medium 106 uses a flash memory such as an SD card. The recording medium 106 receives the compression-encoded data from the memory 107 via the interface 104, and performs a data writing process. In this embodiment, a memory card that guarantees a predetermined data rate as a recording data rate is used as the recording medium 106.
The memory 107 temporarily stores the compression-encoded data from the image compression unit 103.

The CPU 108 controls the entire imaging apparatus.
The operation unit 109 is an operation unit for inputting various operation instructions to the CPU 108. For example, a shutter button, a power button, a mode switching button (a button for switching an operation mode to any one of a still image recording mode, a moving image recording mode, a reproduction mode, etc.) is used when the user operates the imaging apparatus 100. Is.

Next, a processing procedure in which the CPU 108 controls the continuous shooting speed will be described with reference to FIGS. 2 and 3. This processing is realized by the CPU 108 executing the program recorded on the recording medium 106 in the work area of the memory 107.
FIG. 2 is a diagram illustrating a processing procedure in which the CPU 108 controls the continuous shooting speed. FIG. 3 is a diagram showing the relationship between the continuous shooting speed and the memory usage.
In step S <b> 201, the CPU 108 performs threshold setting for setting the first threshold and the second threshold with respect to the usage amount of the memory 107 (first threshold> second threshold). Details of the first threshold and the second threshold will be described later together with the processing contents of S207 and S208.

  In step S <b> 202, the CPU 108 starts continuous shooting at a set continuous shooting speed based on a user input from the operation unit 109. When the continuous shooting process is started, the CPU 108 sets the fastest speed (maximum continuous shooting speed) among the continuous shooting speeds prepared in advance in the imaging apparatus 100. Further, the CPU 108 appropriately changes and sets the continuous shooting speed during the continuous shooting process by the following processing. Here, the number of still images taken per unit time is defined as the continuous shooting speed. The CPU 108 outputs the digitally converted image data generated by the imaging unit 101 to the image processing unit 102.

  In S203, the image processing unit 102 performs color conversion processing on the still image data output from the imaging unit 101, performs resizing processing such as conversion to YCC image data and image enlargement / reduction, and after completion of the calculation, The CPU 108 is notified. After receiving the calculation processing completion notification from the image processing unit 102, the CPU 108 outputs the still image data after the calculation processing to the image compression unit 103.

In step S204, the image compression unit 103 performs compression processing on the still image data output from the image processing unit 102, and notifies the CPU 108 after the compression is completed.
In step S <b> 205, the CPU 108 receives the compression completion notification from the image compression unit 103, and then outputs the compression-encoded still image data to the memory 107. The CPU 108 has an internal variable N indicating the data accumulation amount in order to manage the data amount in the memory 107. The CPU 108 adds the still image data amount output to the memory 107 in S205 to the internal variable N.

  In S206, the CPU 108 outputs the still image data in the memory 107 to the recording medium 106 via the interface 104, and performs a writing process. In the present embodiment, the writing process to the recording medium 106 during continuous shooting is always performed in a state where the recording data rate is guaranteed. The CPU 108 subtracts the amount of still image data output to the recording medium 106 in S206 from the internal variable N described above.

  In S207, the CPU 108 determines whether or not the internal variable N representing the amount of still image data in the memory 107 is equal to or greater than the first threshold value. If the internal variable N is less than the first threshold value, the process proceeds to S208. If the internal variable N is equal to or greater than the first threshold value, it is determined that the free space in the memory 107 is nearly insufficient, and the process proceeds to S210.

FIG. 3 is a diagram showing the relationship between the continuous shooting speed and the memory usage. For example, if the current memory usage is the area A, the memory usage is less than the first threshold value, so the process proceeds to S208.
In step S <b> 208, the CPU 108 determines whether the internal variable N representing the amount of still image data in the memory 107 is equal to or less than the second threshold value. If the internal variable N is equal to or smaller than the second threshold value, it is determined that there is sufficient free space in the memory 107, and the process proceeds to S209. If the internal variable N exceeds the second threshold value, the process proceeds to S211.

In FIG. 3, if the current memory usage is area A, the process proceeds to S209.
In step S209, the CPU 108 controls the imaging unit 101 to set the continuous shooting speed to the maximum continuous shooting speed.
In FIG. 3, since shooting is currently performed at the maximum continuous shooting speed in the area A, the process proceeds to S211 without performing the processing.

In step S <b> 211, the CPU 108 determines whether continuous shooting is continued based on an input from the operation unit 109. If continuous shooting continues, the process returns to S202. When the continuous shooting is finished, the whole process is finished. Here, it is determined that continuous shooting continues, and the process returns to S202.
After returning to S202, the above-described processing is repeated.

  In FIG. 3, in region A, since shooting is performed at the maximum continuous shooting speed, the amount of still image data in the memory 107 increases significantly. After the continuous shooting is continued, in S207, when the CPU 108 determines that the internal variable N is equal to or greater than the first threshold ((1) in FIG. 3), the process proceeds to S210.

In S <b> 210, the CPU 108 sets the continuous shooting speed so that the data rate of the still image obtained by continuous shooting is smaller than the recording data rate guaranteed by the recording medium 106 in order to increase the free space of the memory 107.
For example, in the present embodiment, when determining the continuous shooting speed, first, the maximum number of still images that can be processed per second at the recording data rate guaranteed by the recording medium 106 is obtained from the following equation.

“Recording data rate guaranteed by the recording medium (bits / second) / still image data amount (bits / sheet) = maximum number of sheets (sheets / second) that can be processed per second at a recording data rate guaranteed by the recording medium”
The CPU 108 sets the continuous shooting speed by controlling the imaging unit 101 so that the recording medium 106 obtained by the above-described formula does not exceed the maximum number of still images that can be processed per second at the guaranteed recording data rate. In this embodiment, in order to increase the free space of the memory 107 while continuing continuous shooting, the continuous shooting speed is set so that the number of still images taken per second is half of the maximum number of still images.

  For example, in the case where up to about 4 still image data can be written per second, the data amount for 2 frames per second is reduced from the memory 107 by setting the continuous shooting speed to a speed at which 2 images are captured per second. be able to.

In this embodiment, since the continuous shooting speed is determined based on the recording data rate guaranteed by the recording medium 106,
“Recording data rate guaranteed by the recording medium (bits / second)> Still image data amount obtained by continuous shooting (bits / second)”
Thus, even if continuous shooting is continued at the continuous shooting speed set in S210, continuous shooting can be continued at equal intervals without overflowing unrecorded still image data from the memory 107. Further, when the continuous shooting speed is set by the above-described equation, the memory usage of the memory 107 decreases as in the area B of FIG.

When continuous shooting is continued at the continuous shooting speed set in S210, and in S208, the CPU 108 determines that the internal variable N representing the amount of still image data in the memory 107 is equal to or smaller than the second threshold (FIG. 3). (2)) As described above, the process proceeds to S209. In step S209, the CPU 108 determines that there is sufficient space in the memory 107, and controls the imaging unit 101 to set the continuous shooting speed to the maximum continuous shooting speed.
After the maximum continuous shooting speed is set in S209, the processing is continued at the set speed (area C in FIG. 3).

  As described above, in the present embodiment, when shooting is performed at a predetermined continuous shooting speed and the usage amount of the memory 107 exceeds the set first threshold, the recording data rate guaranteed by the recording medium 106 and the static Set the continuous shooting speed based on the image data amount. When the usage amount of the memory 107 becomes equal to or less than the set second threshold, the continuous shooting speed is set again to a predetermined continuous shooting speed. By performing the processing described above, the continuous shooting interval does not become unstable even when the amount of use of the memory 107 increases, and it is possible to repeatedly perform shooting at a predetermined continuous shooting speed.

[Second Embodiment]
In the second embodiment, an example of controlling the setting of the continuous shooting speed in accordance with the amount of still image data in the memory in still image continuous shooting during moving image shooting will be described.
The basic configuration of this embodiment is the same as the basic configuration of the first embodiment shown in FIG. The present embodiment is characterized in that the continuous shooting speed changing method in S410 is controlled from the minimum recording data rate guaranteed by the recording medium 106, the amount of still image data, and the bit rate of moving images.

  Since the present embodiment is processing related to still image shooting during moving image shooting, first, the overall operation of shooting processing including moving image shooting performed by the imaging apparatus 100 will be described with reference to the flowchart of FIG.

FIG. 5 is a flowchart showing the moving image and still image recording processing of the imaging apparatus 100.
In S501, the imaging apparatus 100 accepts a shooting instruction.
In S502, it is determined whether the shooting instruction is a moving image shooting instruction or a still image shooting instruction. In the case of a moving image shooting instruction, the pressing of the moving image recording / stop SW is detected. In the case of a still image shooting instruction, pressing of the release switch is detected. In the case of a moving image shooting instruction, the process proceeds to S504, and in the case of a still image shooting instruction, the process proceeds to S503.

In S503, since it is a still image shooting instruction, a still image is shot and a still image is recorded. If the release switch is operated continuously, the process of FIG. 2 is executed as the still image shooting process of S503.
In S504, since it is a moving image shooting instruction, the shooting start time is acquired from the system time managed by the imaging apparatus 100. In addition, position information is acquired according to information obtained from a GPS communication unit (not shown) of the imaging apparatus 100. The acquired time and position information are held on the memory of the CPU. In addition, a movie is taken and a movie is recorded. When recording a moving image, identification information for managing the moving image is given. This identification information is attached information of the moving image file after the moving image shooting is completed.

  In step S <b> 505, it is determined whether or not a still image has been shot during moving image shooting by detecting the release switch being pressed during moving image shooting. If it is detected that the release switch is pressed during moving image shooting, the process proceeds to S506. If the release switch is not detected during moving image shooting, the process proceeds to S508. If the release switch is operated continuously, the process of FIG. 4 is executed as the still image shooting process of S506.

  In step S506, a still image is captured and the still image is recorded. The attached information (for example, Exif information) is stored in the file when the still image is recorded. Exif information can store various attached information such as shooting date and time, image resolution, shooting conditions (such as shutter speed and aperture value), and position information. For example, shooting date / time, position information (latitude, longitude), person information (person 1, person 2, person 3, person 4), and simultaneous shooting moving picture information can be stored.

  In S507, in order to associate a moving image with the captured still image, moving image identification information is added to the Exif information of the still image data.

  In S508, it is detected whether or not the moving image recording / stop SW has been pressed, and it is determined whether or not the moving image shooting has ended. If it is detected that the moving image recording / stop SW has been pressed, it is determined that the moving image recording has ended, and the process proceeds to S509. If it is not detected that the moving image recording / stop SW has been pressed, the flow proceeds to S505. Return processing and continue movie shooting.

  In S509, a person is identified from one frame of the still image captured in S506 or a moving image at the timing when the still image was captured, and the identified person image (face image) and a pre-registered person image are displayed. Match to get the name of the person. Since matching of images is a well-known technique, description thereof is omitted, but an image having a high similarity is determined from the similarity of images, and a person name assigned to the image is acquired.

In S510, the data (shooting start date and time information and position information) acquired in S504 and the data (person name) acquired in S509 are attached to the moving image as metadata.
In step S <b> 511, the image capturing in the imaging apparatus 100 ends.

Next, a method for controlling the still image continuous shooting speed during moving image shooting will be described with reference to FIG.
FIG. 4 is a diagram showing a processing procedure in which the CPU 108 controls the continuous shooting speed. The processing other than S410 is the same as the processing procedure for controlling the continuous shooting speed of the first embodiment shown in FIG.
If the CPU 108 determines that the usage amount of the memory 107 is equal to or greater than the first threshold value in S207, the continuous shooting speed is changed in S410.

  In S410, in order to increase the free space in the memory 107, the CPU 108 continuously increases the bit rate of the moving image and the data rate of the still image obtained by continuous shooting so as to be smaller than the recording data rate guaranteed by the recording medium 106. Set the shooting speed.

For example, in this embodiment, when determining the continuous shooting speed, first, a recording data rate that can be guaranteed by the recording medium 106 during recording of moving image data is obtained from the following equation.
“Recording data rate guaranteed by the recording medium (bits / second) −Video bit rate (bits / second) = Recording data rate guaranteed by the recording medium during recording of moving picture data (bits / second)”
The maximum number of still images that can be processed per second at the recording data rate guaranteed by the recording medium during the recording of the moving image data, obtained by the above-described equation, is obtained.

“Recording data rate guaranteed by the recording medium during recording of moving image data (bits / second) / Still image data amount (bits / sheet) = Processing per second at a recording data rate guaranteed by the recording medium while recording moving image data Maximum number of still images that can be made (sheets / second) "
The CPU 108 controls and sets the imaging unit 101 so that the continuous shooting speed does not exceed the maximum number of still images that can be processed in one second by the recording medium 106 obtained by the above formula.

  In this embodiment, in order to increase the free capacity of the memory 107 while simultaneously recording the moving image data and still image continuous shooting, the number of still images taken per second is reduced to half of the maximum number of still images. Set the continuous shooting speed.

In the present embodiment, the continuous shooting speed is determined by the following equation based on the recording data rate guaranteed by the recording medium 106.
"Recording data rate guaranteed by the recording medium (bit / second)> Video bit rate (bit / second) + Still image data amount obtained by continuous shooting (bit / second)"
It is. By determining in this way, even if continuous shooting is continued at the continuous shooting speed set in S410 during moving image shooting, continuous shooting can be continued at equal intervals without the memory 107 failing. Further, when the continuous shooting speed is set by the above-described equation, the memory usage of the memory 107 decreases.

  As described above, in the present embodiment, in still image continuous shooting during moving image shooting, continuous shooting of still images is performed at the maximum continuous shooting speed. When the usage amount of the memory 107 exceeds the set first threshold value, the continuous shooting speed is set based on the recording data rate guaranteed by the recording medium 106, the moving image bit rate, and the still image data amount. . When the usage amount of the memory 107 becomes equal to or less than the set second threshold, the continuous shooting speed is set again to the maximum continuous shooting speed.

  By performing the above-described processing, the continuous shooting interval does not become unstable even when the amount of use of the memory 107 increases in the continuous shooting of still images performed during moving image shooting. Shooting can be repeated.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (computer program) that implements the functions of the above-described embodiments is supplied to a system or apparatus via a network or various computer-readable storage media. Then, the computer (or CPU, MPU, etc.) of the system or apparatus reads out and executes the program.

DESCRIPTION OF SYMBOLS 100 Imaging device 101 Imaging part 102 Image processing part 103 Image compression part 104 Interface 105 Display part 106 Recording medium 107 Memory 108 CPU
109 Operation unit 110 Bus

Claims (8)

In an imaging apparatus for sequentially writing and recording still image data generated by continuous shooting on a recording medium,
Imaging means;
Temporary storage means for temporarily storing compression-encoded data obtained by compression-encoding the still image data;
Threshold setting means for setting a first threshold for determining the amount of still image data stored in the temporary storage means, and a second threshold that is less than the first threshold;
Writing means for sequentially writing still image data stored in the temporary storage means to the recording medium;
Determining means for determining the amount of still image data stored in the temporary storage means based on the first threshold value and the second threshold value set by the threshold value setting means;
Control means for controlling the overall operation,
The control means includes
If the still image data amount determined by the determining means is equal to or greater than the first threshold, the continuous shooting speed is set based on the recording data rate guaranteed by the recording medium,
An image pickup apparatus, wherein the continuous shooting speed is set to a predetermined continuous shooting speed when the amount of still image data determined by the determining means is equal to or less than the second threshold value. The control means includes
The imaging apparatus according to claim 1, wherein writing to the recording medium is controlled from a start to an end of continuous shooting at a recording data rate guaranteed by the recording medium. The control means includes
When the still image data amount determined by the determining means is equal to or greater than the first threshold, the recording data rate that the recording medium guarantees the continuous shooting speed, the still image data amount, and the moving image bit rate. Control
2. The imaging according to claim 1, wherein when the amount of still image data determined by the determination unit is equal to or less than the second threshold, the continuous shooting speed is set to the predetermined continuous shooting speed. apparatus. In an imaging method for sequentially writing and recording still image data generated by continuous shooting on a recording medium,
Imaging process;
A temporary storage step of temporarily storing the compression-encoded data obtained by compression-encoding the still image data in a storage medium;
A threshold setting step for setting a first threshold for determining the amount of still image data stored in the storage medium and a second threshold that is less than the first threshold;
A writing step of sequentially writing still image data stored in the storage medium to the recording medium;
A determination step of determining the amount of still image data stored in the storage medium based on the first threshold and the second threshold set in the threshold setting step;
A control process for controlling the entire operation,
The control step includes
If the still image data amount determined in the determination step is equal to or greater than the first threshold, the continuous shooting speed is set based on the recording data rate guaranteed by the recording medium,
An imaging method comprising: setting the continuous shooting speed to a predetermined continuous shooting speed when the amount of still image data determined in the determining step is equal to or less than the second threshold value. The control step includes
5. The imaging method according to claim 4, wherein the control is performed so that writing to the recording medium is performed at a recording data rate guaranteed by the recording medium from the start to the end of continuous shooting. The control step includes
When the still image data amount determined in the determination step is equal to or greater than the first threshold, the recording data rate that the recording medium guarantees the continuous shooting speed, the still image data amount, and the moving image bit rate. Control
6. The imaging according to claim 5, wherein when the amount of still image data determined in the determination step is equal to or less than the second threshold, the continuous shooting speed is set to the predetermined continuous shooting speed. Method. In a program for causing a computer to execute each step of an imaging method for sequentially writing and recording still image data generated by continuous shooting on a recording medium,
Imaging process;
A temporary storage step of temporarily storing the compression-encoded data obtained by compression-encoding the still image data in a storage medium;
A threshold setting step for setting a first threshold for determining the amount of still image data stored in the storage medium and a second threshold that is less than the first threshold;
A writing step of sequentially writing still image data stored in the storage medium to the recording medium;
A determination step of determining the amount of still image data stored in the storage medium based on the first threshold and the second threshold set in the threshold setting step;
And let the computer execute the control process to control the overall operation,
The control step includes
If the still image data amount determined in the determination step is equal to or greater than the first threshold, the continuous shooting speed is set based on the recording data rate guaranteed by the recording medium,
A program for controlling a computer to set the continuous shooting speed to a predetermined continuous shooting speed when the amount of still image data determined in the determining step is equal to or less than the second threshold value.   A computer-readable storage medium storing the program according to claim 7.

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