JP4921118B2 - Video signal processing apparatus, video signal processing method, and program - Google Patents

Description

  The present invention relates to a video signal processing apparatus and method, a program, and a storage medium, and in particular, a video signal processing apparatus and method suitable for an electronic still camera that has a liquid crystal monitor as a finder and operates exclusively by a battery. And a program and a storage medium.

  In general, in an image pickup apparatus having a lens system and an image pickup device, there is a possibility that an image to be picked up may be damaged due to, for example, a decrease in peripheral light amount or distortion due to the lens system. For such obstacles, for example, a lens system is designed with a large number of lenses to prevent the occurrence of the obstacle, but such a lens system designed with a large number of lenses is expensive and is a compact camera. Are often difficult to adopt.

  On the other hand, for example, when a signal is extracted according to XY coordinates as in a device using a semiconductor image sensor, an image can be corrected by digital processing on the extracted video signal. Therefore, conventionally, for example, a technique has been proposed for digitally correcting distortion generated due to imaging with an inexpensive lens system, peripheral light loss, color blur, and the like.

  In addition, since the degree of peripheral light loss and distortion changes depending on the magnification of the optical zoom, a compact electronic still camera that digitally corrects the peripheral light loss and distortion of the lens system using the above-described technology, the optical zoom used for shooting In general, correction is applied for each magnification.

Further, a technique for recording not only the corrected image but also the image before correction so that the photographed image can be taken into a personal computer or the like and corrected according to the user's preference has been proposed (see, for example, Patent Document 1). ).
JP-A-2005-122320

  However, in the technique of Patent Document 1, since data to be recorded for one image is two or more, a recording medium such as a flash memory having a limited capacity has a recording number of 1/2 as compared with normal shooting. There is a problem that it is limited to the following.

An object of the present invention is to provide a video signal processing device, a video signal processing method, and a program capable of suppressing the amount of data per image.

To achieve the above object, a video signal processing apparatus according to the present invention, before a correction unit that performs distortion correction after performing a peripheral light amount correction for the image data, which is the distortion correction by the correction means is performed And obtaining difference image data between the first image data after the peripheral light amount correction is performed and the original image data before the peripheral light amount correction is performed by the correction unit , Compression means for generating image data obtained by reversibly compressing the difference image data, second image data after the distortion correction is performed on the first image data, and the reversibly compressed image data. And recording means to be stored in the memory.

According to the present invention, the amount of data per image can be suppressed.

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

  FIG. 1 is a diagram schematically showing a block configuration of an electronic still camera as a video signal processing apparatus according to an embodiment of the present invention.

  In FIG. 1, the electronic still camera includes the following means centered on a memory control unit 101 and a system control unit 102. The function of the means will be described below together with the operation.

  The imaging lens 103 optically forms a captured image. The shutter 104 adjusts the exposure of the captured image. The image sensor 105 converts a captured image into an analog electrical signal. The A / D converter 106 converts an analog signal output from the image sensor 105 into a digital signal.

  The image processing unit 107 performs development processing and resizing processing such as predetermined pixel interpolation processing and color conversion processing on captured or recorded image data.

  The memory 108 is used to expand the data in the ROM 109 or temporarily store captured image data, and has a recording capacity sufficient to store a predetermined number of still images and a predetermined time of moving images. Yes. For example, the image data output from the A / D converter 106 is written into the memory 108 via the memory control unit 101, the image processing unit 107, the compression / decompression unit 110, or directly via the memory control unit 101.

  The memory control unit 101 includes data to the A / D converter 106, D / A converter 111, storage medium 112, image processing unit 107, memory 108, compression / expansion unit 110, peripheral light amount correction unit 113, and distortion correction unit 114. Control the flow.

  Display image data written in the memory 108 is converted from digital data to analog data via a D / A converter 111 and displayed on an image display unit 115 including a TFT, an LCD, and the like. In addition, by continuously reading out video signals from the image sensor 105 and displaying them on the image display unit 115, an electronic viewfinder (EVF) function is realized.

  The compression / decompression unit 110 compresses / decompresses image data. A storage medium 112 such as a memory card or a hard disk records captured image data. The peripheral light amount correction unit 113 corrects peripheral image quality deterioration due to a decrease in the peripheral light amount of the lens. The distortion correction unit 114 corrects peripheral image quality degradation due to lens distortion.

  The system control unit 102 controls the operation of the entire electronic still camera according to the setting by the mode dial switch of the operation unit 115 and according to the contents stored in the ROM (read only memory) 109.

  For example, the operation unit 116 can switch and set each function mode such as power-off, shooting mode, and playback mode. The ROM 109 stores programs used by the system control unit 102 in advance.

Hereinafter, recording of corrected image data and image compression data subjected to peripheral light amount correction and distortion correction according to the present embodiment will be described with reference to FIGS.

  FIG. 2 is a flowchart showing a procedure of a first example of image compression processing executed by the electronic still camera of FIG.

  This process is executed by the system control unit in FIG.

In FIG. 2, first, the image data output from the image sensor 105 converted by the A / D converter 106 is corrected in the order of peripheral light amount correction and distortion correction by the peripheral light amount correction unit 113 and the distortion correction unit 114 ( Steps S201 and S202) . The original image and the corrected image are temporarily stored in the memory 108.

Its obtains a difference image from the corrected image and the original image, and lossless compressing the difference image by the compression and expansion unit 110, to generate the images compressed data (step S203). The compressed image data is temporarily stored in the memory 108.

Finally, the lens information (the lens type and the zoom position at the time of shooting, etc.), images compressed data, to save the corrected image data in one file (step S204), and terminates the process.

In this embodiment, instead of the original image , an image obtained by reversibly compressing the difference image between the original image and the corrected image is stored. However, instead of the corrected image, the difference image between the original image and the corrected image is reversibly compressed . You may make it preserve | save an image . Further, in the present embodiment, after the difference image is reversibly compressed, the corrected image may be reversibly compressed within the frame.

  FIG. 3 is a diagram showing a first example of a recording file format recorded in the memory in FIG.

In FIG. 3, the image size is 1600 × 1200, and the data width of the A / D converter 106 is 12 bits. In this case, the data size of the corrected image is
1600 × 1200 × 12/8 = 2.74MB
It is. Further, it is assumed that the original image can be compressed at a compression rate of about 1/8.

  The area starting from address 0x0000 — 0000 is a header area, in which pointer information to image data and information such as the number and type of image data are recorded.

  The address 0x0000 — 0020 is a lens information area in which information such as the type of lens and the zoom position at the time of shooting is recorded.

  From 0x0000 — 0080 is a corrected image data area, and in this example, 2.74 MB of image data is recorded.

The address 0x002B_F280 is an image compression data area. This address varies depending on the size of the corrected image and is recorded in the header area.

  Hereinafter, an operation when the original image is decompressed in order to perform a desired correction later by the recorded video signal processing apparatus (electronic still camera) or a personal computer will be described with reference to FIG.

  FIG. 4 is a flowchart showing the procedure of the first example of the image expansion process executed by the electronic still camera of FIG.

  This process is executed by the system control unit in FIG.

In FIG. 4, the corrected image and the compressed image data are read from the header information of the recording file, and the original image is restored by adding the differential image obtained by expanding the compressed image data by the compression / decompression unit 110 and the corrected image ( Step S401).

  FIG. 5 is a flowchart showing the procedure of the second example of the image compression processing executed by the electronic still camera of FIG.

  This process is executed by the system control unit in FIG.

In FIG. 5, the peripheral light amount correction unit 113 performs peripheral light amount correction on the image data output from the image sensor 105 converted by the A / D converter 106 (step S501) . The original image and the peripheral light amount correction image are temporarily stored in the memory 108.

A difference image is obtained from the peripheral light amount correction image and the original image, and the difference image is reversibly compressed by the compression / decompression unit 110 to generate compressed image data (step S502) . The compressed image data is temporarily stored in the memory 108.

Next, a distortion correction image is generated from the peripheral light amount correction image by the distortion correction unit 114 (step S503) . Finally, the lens information (lens type, zoom position at the time of photographing, etc.), compressed image data, and corrected image data are stored in one file (step S504) , and this process is terminated.

In this embodiment, instead of the original image , an image obtained by reversibly compressing the difference image between the original image and the corrected image is stored. However, instead of the corrected image, the difference image between the original image and the corrected image is reversibly compressed . You may make it preserve | save an image . Further, in the present embodiment, after the difference image is reversibly compressed, the corrected image may be reversibly compressed within the frame.

  FIG. 6 is a diagram showing a second example of the recording file format recorded in the memory in FIG.

In FIG. 6, the image size is 1600 × 1200, and the data width of the A / D converter 106 is 12 bits. In this case, the data size of the corrected image is
1600 × 1200 × 12/8 = 2.74MB
It is. Further, it is assumed that the original image can be compressed at a compression rate of about 1/32.

  The area starting from address 0x0000 — 0000 is a header area, in which pointer information to image data and information such as the number and type of image data are recorded.

  The address 0x0000 — 0020 is a lens information area in which information such as the type of lens and the zoom position at the time of shooting is recorded.

  From 0x0000 — 0080 is a corrected image data area, and in this example, 2.74 MB of image data is recorded.

The address 0x002B_F280 is an image compression data area. This address varies depending on the size of the corrected image and is recorded in the header area.

  In the following, the operation when the original image is decompressed in order to make a desired correction later by the recorded video signal processing apparatus (electronic still camera) or personal computer will be described with reference to FIG.

  FIG. 7 is a flowchart showing the procedure of the second example of the image expansion process executed by the electronic still camera of FIG.

  This process is executed by the system control unit in FIG.

In FIG. 7, the corrected image and lens information are read from the header information of the recording file, and the corrected image is subjected to reverse distortion correction by the distortion correction unit 114 (or software such as a personal computer) to restore the image before distortion correction (step S701). .

The compressed image data is read from the header information of the recording file, and the differential image obtained by decompressing the compressed image data by the compression / decompression unit 110 (or software such as a personal computer) is added to the restored image before distortion correction. Thus, the original image is restored (step S702), and this process is terminated.

  According to the embodiment of the present invention, the amount of data per image can be suppressed in a video signal processing device such as an electronic still camera that records a corrected image together with an uncorrected image.

  In addition, the amount of data per image can be suppressed in a video signal processing apparatus such as an electronic still camera that performs correction with coordinate conversion and records the corrected image together with the uncorrected image.

  In addition, in a video signal processing apparatus such as an electronic still camera that records an uncorrected image together with a corrected image, the amount of data per image can be suppressed.

  In addition, the amount of data per image can be suppressed in a video signal processing apparatus such as an electronic still camera that performs correction with coordinate conversion and records an uncorrected image together with the corrected image.

  In addition, correction can be performed with high accuracy in a video signal processing apparatus such as an electronic still camera that performs peripheral light amount drop correction and distortion correction.

Furthermore, since the image quality deterioration due to peripheral light amount drop of the lens without coordinate transformation, by recording the image data obtained by lossless compressing a difference image between the original image and the peripheral light amount auxiliary Seigo image, further reducing the image size Can do .

  Further, the uncorrected image can be taken into a personal computer or the like and corrected according to the user's preference.

  The object of the present invention is achieved by executing the following processing. That is, a storage medium that records a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and a computer (or CPU, MPU, etc.) of the system or apparatus is stored in the storage medium. This is the process of reading the code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Moreover, the following can be used as a storage medium for supplying the program code. For example, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM or the like. Alternatively, the program code may be downloaded via a network.

  Further, the present invention includes a case where the function of the above-described embodiment is realized by executing the program code read by the computer. In addition, an OS (operating system) running on the computer performs part or all of the actual processing based on an instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Is also included.

  Furthermore, a case where the functions of the above-described embodiment are realized by the following processing is also included in the present invention. That is, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

It is a figure which shows schematically the block configuration of the electronic still camera as a video signal processing apparatus concerning embodiment of this invention. It is a flowchart which shows the procedure of the 1st example of the image compression process performed with the electronic still camera of FIG. It is a figure which shows the 1st example of the recording file format recorded on the memory in FIG. It is a flowchart which shows the procedure of the 1st example of the image expansion process performed by the electronic still camera of FIG. 7 is a flowchart illustrating a procedure of a second example of image compression processing executed by the electronic still camera of FIG. 1. It is a figure which shows the 2nd example of the recording file format recorded on the memory in FIG. 7 is a flowchart showing a procedure of a second example of image decompression processing executed by the electronic still camera of FIG. 1.

Explanation of symbols

101 Memory Control Unit 102 System Control Unit 107 Image Processing Unit 108 Memory 109 ROM
113 Ambient light amount correction unit 114 Distortion correction unit

Claims (7)

Correction means for performing distortion correction after performing peripheral light amount correction on image data;
Even before the distortion correction is performed by the correction means, and the first image data after the peripheral light amount correction is performed, the original before the said peripheral light amount correction by the correction means is performed obtaining a difference image data between the image data, and compression means for generating image data obtained by lossless compressing said difference image data,
Recording means for storing, in a memory, second image data after the distortion correction is performed on the first image data, and the reversibly compressed image data;
A video signal processing apparatus comprising: Comprising decompression means for decompressing the reversibly compressed image data ;
The correction means performs reverse distortion correction on the second image data to restore the first image data,
The decompression means restores the original image data using the difference image data restored by decompressing the losslessly compressed image data and the first image data restored by the correction means. The video signal processing apparatus according to claim 1. The recording unit records the lens information used when generating the original image data together with the second image data and the reversibly compressed image data. The video signal processing apparatus described. 4. The video signal processing apparatus according to claim 3, wherein the lens information includes a lens type and a zoom position . A correction step for performing distortion correction after performing peripheral light amount correction on image data;
The difference image data between the first image data before the distortion correction is performed and after the peripheral light amount correction is performed, and the original image data before the peripheral light amount correction is performed. A compression step for generating image data obtained by reversibly compressing the difference image data ;
A recording step of storing, in a memory, the second image data after the first distortion correction is performed on the first image data and the reversibly compressed image data;
A video signal processing method comprising: The second image data is subjected to inverse distortion correction to restore the first image data, the losslessly compressed image data is decompressed and restored, and the restored first image data is restored. 6. The video signal processing method according to claim 5, further comprising a restoration step of restoring the original image data using the image data . A video signal processing program comprising a program code for causing a computer to execute the video signal processing method according to claim 5 .

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