WO2012011211A1

WO2012011211A1 - Thumbnail image generation device, magnified image generation device, thumbnail image generation method, and magnified image generation method

Info

Publication number: WO2012011211A1
Application number: PCT/JP2011/001780
Authority: WO
Inventors: 石井秀樹
Original assignee: パナソニック株式会社
Priority date: 2010-07-22
Filing date: 2011-03-25
Publication date: 2012-01-26

Abstract

The present invention provides storage processing in which thumbnail image generation processing generates a thumbnail image by minimizing an image to be reduced and stores image data of the image in image memory, whereupon the image data contains pixel information which indicates the color of a pixel for each of the pixels contained in the image; DMA control processing which specifies the readout address of the image memory such that reading out of the image data from the image memory is performed so as to decimate a portion of the pixel information for each group of a plurality of a predetermined number of units of pixel information; and thumbnail image output processing for outputting thumbnail images which are based on the image data which has been read out from the image memory.

Description

Thumbnail image generation device, enlarged image generation device, thumbnail image generation method, and enlarged image generation method

The present invention relates to a technique for generating thumbnail images / enlarged images by reducing / enlarging images.

In Patent Document 1, an intermediate image is generated by repeating image conversion that halves the number of pixels with respect to an original image, and further, interpolation processing is performed on the intermediate image to obtain the set number of pixels. An image conversion device that acquires a final image is disclosed.

In Patent Document 2, a DC (Direct Current) component (direct current component) of JPEG image data is extracted, and the thumbnail image is enlarged / reduced to the image size and image processing is performed based on the extracted DC component. An image processing apparatus that performs output is disclosed.

JP 2000-156777 A JP 2000-59612 A

Today, as the capacity of storage devices such as SD cards increases and the number of captured images of a digital camera stored in the storage device increases, thumbnail images are generated and displayed at high speed by reducing the captured images. There is a growing need.

However, if a large number of thumbnail images are generated by the method of Patent Document 1 and displayed on the liquid crystal screen of the digital camera to allow the user to select a thumbnail image, it takes time to generate the thumbnail image and the usability of the user deteriorates. This is because, in Patent Document 1, when the reduction ratio of the final image with respect to the original image is low, the number of times of image conversion to halve the number of pixels increases, and it takes time to acquire the final image.

In Patent Document 1, since the image conversion apparatus is provided with both an image conversion processing function for doubling the number of pixels and an interpolation calculation function, these functions are realized by an electronic circuit (hardware). The circuit area increases. On the other hand, when these functions are realized by software, the amount of calculation of the CPU or the like increases. Such a problem becomes particularly noticeable when the image size of the original image is large, such as 10 million pixels, 20 million pixels, or 20 million pixels.

In Patent Document 2, since the reduction is performed by extracting the DC component, the original image can be reduced only 1/8 times in the vertical and horizontal directions. Therefore, when the reduction ratio of the thumbnail image to the original image is significantly lower than 1/8, the DC component needs to be further greatly reduced. Accordingly, this DC component reduction processing takes time, and as a result, the time taken to generate thumbnail images becomes longer. Further, when the electronic circuit (hardware) executes the reduction of the DC component, a circuit such as an interpolation filter is required, and the circuit area increases. On the other hand, when the reduction of the DC component is realized by software, calculation processing such as interpolation filter processing is required, and the calculation amount of the CPU or the like increases.

In general, there is a demand for reducing the time required to generate an enlarged image by enlarging the image and preventing an increase in circuit area and calculation amount necessary for the enlarged image generation processing.

In view of the above points, an object of the present invention is to reduce the generation time of thumbnail images and to prevent an increase in circuit area and calculation amount necessary for thumbnail image generation processing.

It is another object of the present invention to shorten the generation time of the enlarged image and prevent an increase in circuit area and calculation amount necessary for the enlarged image generation process.

In order to solve the above-described problem, an aspect of the present invention is a thumbnail image generation process for generating a thumbnail image by reducing a reduction target image, storing image data of the reduction target image in an image memory, and For each pixel included in the image, the image data includes pixel information indicating the color of the pixel, and a process of reading out the image data from the image memory includes some pixels for each of a plurality of predetermined pixel information. A DMA (Direct Memory Access) control process for designating a read address of an image memory so that information is thinned out, and a thumbnail image output process for outputting a thumbnail image based on image data read from the image memory Yes.

According to this aspect, image data is read from the image memory by thinning out some pieces of pixel information for each of a plurality of predetermined pieces of pixel information by controlling the read address by the DMA control process. The image indicated by the image data read out from is an image obtained by reducing the reduction target image. In this way, the image to be reduced can be reduced without separately providing a circuit for the reduction process or separately performing an operation for the reduction process, so that the circuit area and the calculation amount necessary for the thumbnail image generation process can be increased. Can be prevented. Even when the degree of reduction is large, the processing time does not increase, so the generation time of thumbnail images can be shortened.

Another aspect of the present invention is thumbnail image generation processing for generating a thumbnail image by reducing a reduction target image, storing image data, and the image data is stored for each pixel included in the image. The image data of the reduction target image is written to the image memory including the pixel information indicating the color of the pixel so that a part of the pixel information is thinned out for each of a plurality of predetermined pixel information. A DMA control process for designating a write address of the image memory and a thumbnail image output process for outputting a thumbnail image based on the image data stored in the image memory are provided.

According to this aspect, by controlling the write address by the DMA control process, the writing of the image data to the image memory is performed by thinning out a part of the pixel information for each of a plurality of predetermined pieces of pixel information. The image indicated by the stored image data is an image obtained by reducing the reduction target image. In this way, the image to be reduced can be reduced without separately providing a circuit for the reduction process or separately performing an operation for the reduction process, so that the circuit area and the calculation amount necessary for the thumbnail image generation process can be increased. Can be prevented. Even when the degree of reduction is large, the processing time does not increase, so the generation time of thumbnail images can be shortened.

Further, another aspect of the present invention is an enlarged image generation process for generating an enlarged image by enlarging the enlargement target image, outputting image data of the enlargement target image, and the image data is included in the image When the image data of the enlargement target image is output to the enlargement target image output unit that includes pixel information indicating the color of each pixel, the pixel information of each pixel is repeated as pixel information of a plurality of pixels. DMA control processing for performing output control, storage processing for storing image data output by the enlargement target image output unit in an image memory, and an enlarged image for outputting an enlarged image based on the image data stored in the image memory Output processing.

According to this aspect, the enlargement target image output unit outputs the pixel information of each pixel as pixel information of a plurality of pixels by the control of the enlargement target image output unit by the DMA control processing, and as a result, the image stored in the image memory The image indicated by the data is an image obtained by enlarging the enlargement target image. In this way, the enlargement target image can be enlarged without providing a large-scale circuit for the enlargement process or performing a large-scale operation for the enlargement process. An increase in the amount can be prevented. Further, even when the enlargement degree is large, the processing time does not increase significantly, so that the generation time of the enlarged image can be shortened.

According to the present invention, it is possible to prevent an increase in circuit area and calculation amount necessary for the thumbnail image generation processing, and to shorten a thumbnail image generation time.

Also, an increase in circuit area and calculation amount necessary for the enlarged image generation process is prevented, and the generation time of the enlarged image is shortened.

FIG. 1 is a block diagram showing a configuration of a thumbnail image generating apparatus according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram illustrating the color sampling format 4: 2: 0 according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram illustrating the color sampling format 4: 2: 2 according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram illustrating the color sampling format 4: 4: 4 according to the first embodiment of the present invention. FIG. 5A is an explanatory diagram illustrating pixel information included in the decoded data according to the first embodiment of the present invention. FIG. 5B is an explanatory diagram showing pixel information included in the upsampling data. FIG. 5C is an explanatory diagram showing the thinning process by the DMA control unit. FIG. 5D is an explanatory diagram illustrating pixel information included in read data. FIG. 6 is a flowchart showing the operation of the thumbnail image generating apparatus according to the first embodiment of the present invention. FIG. 7 is a block diagram showing the configuration of the thumbnail image generating apparatus according to the third embodiment of the present invention. FIG. 8 is a flowchart showing the operation of the thumbnail image generating apparatus according to the third embodiment of the present invention.

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

Embodiment 1
As shown in FIG. 1, the thumbnail image generating apparatus 100 according to the first embodiment of the present invention includes a first memory 101, a decoding unit 102, an upsampling unit 103, a second memory 104, a DMA control unit 105, an enlargement / reduction process, Unit 106 and image processing unit 107. The enlargement / reduction processing unit 106 and the image processing unit 107 constitute a thumbnail image output unit 108.

The thumbnail image generating apparatus 100 acquires the decoded data S12 indicating the original image by decoding the compressed image data S11. Then, thumbnail image data S16 indicating a thumbnail image obtained by reducing the original image is output. Hereinafter, an example in which the original image is 5120 × 3840 pixels and the thumbnail image is 200 × 120 pixels will be described. However, the image size of the original image and the thumbnail image is not limited to this combination, and other image sizes are set. Is possible.

The thumbnail image generating apparatus 100 is provided in a digital camera having a liquid crystal display unit, and a plurality of thumbnail images indicated by the thumbnail image data S16 are displayed on the liquid crystal display unit. The user can select an image to be enlarged and displayed from the thumbnail images displayed on the liquid crystal display unit. The thumbnail image generating apparatus 100 can be provided not only in a digital camera but also in a camera-equipped mobile phone, a digital video camera, a Blu-ray recorder / player, and the like.

The first memory 101 stores and outputs compressed image data S11 indicating a JPEG (Joint Photographic Experts Group) compressed image.

The decoding unit 102 obtains the decoded data S12 by performing a decoding process on the compressed image data S11 output from the first memory 101.

The upsampling unit 103 performs upsampling described later on the decoded data S12 acquired by the decoding unit 102, and outputs upsampling data S13.

Here, the color sampling format will be described with reference to FIGS.

The decoded data S12 includes pixel information for each pixel included in the image. Each pixel information represents a color by the YCbCr color system, and includes a set 110 of a luminance Y signal 109, a color difference Cb signal, and a color difference Cr signal. Here, the horizontal sampling factor for luminance Y is H0, the vertical sampling factor for luminance Y is V0, the horizontal sampling factor for color difference Cb is H1, the vertical sampling factor for color difference Cb is V1, the horizontal sampling factor for color difference Cr is H2, and the color difference Cr The vertical sampling factor is expressed as V2.

The color sampling format 4: 2: 0 is a format in which H0 = 2, V0 = 2, H1 = 1, V1 = 1, H2 = 1, and V2 = 1 as shown in FIG. In other words, for the luminance Y signal 109 for four pixels, a set 110 of the color difference Cb signal and the color difference Cr signal is recorded for each one pixel, and the color difference Cb signal and the color difference Cr signal (upsampling target component) are four. Each piece of pixel information is included in only one piece of pixel information.

Also, the color sampling format 4: 2: 2 is a format in which H0 = 2, V0 = 1, H1 = 1, V1 = 1, H2 = 1, and V2 = 1 as shown in FIG. That is, for the luminance Y signal 109 for 4 pixels, a set 110 of the color difference Cb signal and the color difference Cr signal is recorded for each 2 pixels, and the color difference Cb signal and the color difference Cr signal (upsampling target component) are 2 Each piece of pixel information is included in only one piece of pixel information.

Furthermore, the color sampling format 4: 4: 4 is a format in which H0 = 2, V0 = 2, H1 = 2, V1 = 2, H2 = 2, and V2 = 2 as shown in FIG. In other words, for a luminance Y signal 109 for one pixel, a set 110 of color difference Cb signal and color difference Cr signal is recorded for each pixel, and a set 110 of luminance Y signal 109, color difference Cb signal and color difference Cr signal, and Is the same number of pixels.

The upsampling unit 103 performs upsampling to convert the decoded data S12 acquired by the decoding unit 102 into a color sampling format 4: 4: 4, and outputs upsampling data S13. When the decoded data S12 is in the color sampling format 4: 2: 0, both the color difference Cb signal and the color difference Cr signal of the decoded data S12 are doubled in the horizontal direction and the vertical direction, respectively. When the decoded data S12 has the color sampling format 4: 2: 2, both the color difference Cb signal and the color difference Cr signal of the decoded data S12 are each doubled in the vertical direction.

The second memory 104 stores the upsampling data S13 output by the upsampling unit 103, and outputs the data at the address specified by the DMA control unit 105 as read data S14.

The DMA control unit 105 calculates a reduction rate based on the image size of the original image and the image size of the thumbnail image, specifies the read address of the second memory 104 based on the calculated reduction rate, and specifies the read address to be specified Is output. The DMA control unit 105 reads out the upsampling data S13 from the second memory 104, thins out the luminance Y signal of 8191 pixels for each luminance Y signal of 256 pixels × 32 lines = 8192 pixels, and 256 pixels × 64 lines = In the second memory 104, the color difference Cb signal of 16383 pixels is thinned out for each color difference Cb signal of 16384 pixels, and the color difference Cr signal of 16383 pixels is thinned out for each color difference Cr signal of 256 pixels × 64 lines = 16384 pixels. Specifies the read address. Thereby, data obtained by thinning out pixel information of 8191 pixels for each pixel information of 256 pixels × 32 lines = 8192 pixels from the upsampling data S13 is read from the second memory 104 as read data S14.

For example, it is assumed that the read address is composed of a column designation value that designates a column and a row designation value that designates a row, the column designation value is 1 to 5120, and the row designation value is 1 to 3840. In this case, the DMA control unit 105 increments the column designation value of the readout address of the luminance Y signal by 256, 0, 256, 512,... And sets the row designation value of the readout address of the luminance Y signal to 0, 32. , 64,... That is, the DMA control unit 105 sets the read address where the combination of the column designation value and the row designation value is (0, 0), (256, 32), (512, 64),. Specify sequentially as read addresses.

Further, the DMA control unit 105 increments the column designation values of the read addresses of the color difference Cb signal and the color difference Cr signal by 256, 0, 256, 512,... And the read address of the color difference Cb signal and the color difference Cr signal. The row designation value is incremented by 64, 0, 64, 128,. That is, the DMA control unit 105 uses the color difference Cb signal and the read address where the combination of the column designation value and the row designation value is (0, 0), (256, 64), (512, 128),. The color difference Cr signal is sequentially specified as a read address.

Thereby, the read data S14 read by the second memory 104 is compared with the upsampling data S13 in the horizontal direction (200/5120) × (1/10) = 1/256 times the luminance Y signal, and the vertical direction 120 / 3840 = 1/32 times reduction, color difference Cb signal and color difference Cr signal horizontal direction (200/5120) × (1/10) = 1/256 times, vertical direction (120/3840) × (1/2) = The data is reduced by 1/64 times. Therefore, the read data S14 is data of a color sampling format 4: 2: 2 indicating an image of 20 × 120 pixels.

The enlargement / reduction processing unit 106 performs the enlargement process of the luminance Y signal, the color difference Cb signal, and the color difference Cr signal 10 times in the horizontal direction on the read data S14 read by the second memory 104, and the image data after the enlargement process Is output as reduced image data S15 indicating a reduced image. The reduced image data S15 is data of a color sampling format 4: 2: 2 indicating an image of 200 × 120 pixels.

The image processing unit 107 performs predetermined image processing on the reduced image data S15 output from the enlargement / reduction processing unit 106, and outputs thumbnail image data S16 indicating a 200 × 120 pixel thumbnail image.

In FIG. 5, the decoded data S12 acquired by the decoding unit 102 is in the color sampling format 4: 2: 2 as shown in FIG. 5A, and the image indicated by the read data S14 is the upsampled data S13. Data processing in the thumbnail image generating apparatus 100 when the image indicated by is scaled 1/128 times in the horizontal direction and 1/32 times in the vertical direction is shown.

For the decoded data S12 shown in FIG. 5 (a), the upsampling unit 103 performs upsampling to double the color difference Cb signal and the color difference Cr signal in the vertical direction. As a result, upsampling data S13 in the color sampling format 4: 4: 4 shown in FIG. 5B is obtained. The upsampling data S13 is stored in the second memory 104. Then, based on the control by the DMA control unit 105, data is read from the second memory 104 while performing thinning as shown in FIG. That is, under the control of the DMA control unit 105, the luminance Y signal is read by designating the column designation value of the read address for every 128 pixels and the row designation value for every 32 lines, and reading out the color difference Cb signal and the color difference. Each Cr signal is read by designating the column designation value of the read address for every 128 pixels and designating the row designation value for every 64 lines. As a result, as shown in FIG. 5D, read data S14 obtained by reducing the up-sampling data S13 by 1/128 times in the horizontal direction and 1/32 times in the vertical direction is obtained. The read data S14 is data in the color sampling format 4: 2: 2.

Next, the operation of the thumbnail image generating apparatus 100 configured as described above will be described with reference to the flowchart of FIG.

The decoding unit 102 reads the compressed image data S11 stored in the first memory 101 in (S1001), decodes the compressed image data S11 read in (S1001) in (S1002), and in (S1003) , (S1002), the decoded data S12 obtained by the decoding is written into a memory (not shown). Next, in (S1004), the upsampling unit 103 reads the decoded data S12 obtained by decoding in (S1002) from a memory (not shown), and in (S1005), the decoded data S12 read in (S1004) is read. Upsampling is performed. The sampling format of the decoded data S12 is 4: 2: 0 or 4: 2: 2. The upsampling performed in (S1005) is a process of converting the sampling format to 4: 4: 4 by increasing the color difference Cb signal and the color difference Cr signal of the decoded data S12. Then, in (S1006), the upsampling unit 103 writes the data after the conversion processing in (S1005) into the second memory 104 as upsampling data S13. The upsampling data S13 written in the second memory 104 is read in (S1007). At this time, for example, when the column designation value of the readout address is designated for every 128 pixels and the row designation value is designated for every 28 lines, the readout data S14 is obtained by multiplying the upsampling data S13 by 1/128 times in the horizontal direction and vertical The data is 1/28 times the direction. The read data S14 read in (S1007) is output and displayed after being enlarged by the enlargement / reduction processing unit 106 in (S1008).

As described above, when data is read from the second memory 104, the filter processing is performed by designating the column designation value of the read address for each of a plurality of predetermined pixels and designating the row designation value for each of a plurality of predetermined lines. Since the data can be easily reduced without any problem, thumbnail images can be created easily and at high speed. Further, there is no need to provide a filter circuit.

According to the present embodiment, by reading address control by the DMA control unit 105, reading of image data from the second memory 104 is performed by thinning out some pieces of pixel information for each of a plurality of predetermined pieces of pixel information. As a result, the read data S14 read from the second memory 104 is an image obtained by reducing the reduction target image. As described above, since the reduction target image can be reduced without separately providing a circuit for reduction processing or separately performing calculation for reduction processing, it is possible to prevent an increase in necessary circuit area and calculation amount. In addition, since reduction is performed by thinning, the processing time does not increase even when the reduction degree is large, such as when generating a thumbnail image with a small image size from an image exceeding 10 million pixels, so the generation time of the thumbnail image is reduced. it can.

Also, since the upsampling is performed by the upsampling unit 103, it is possible to suppress image quality deterioration due to reduction.

In addition, the image sizes of the original image and the thumbnail image are variable, and the DMA control unit 105 designates the read address of the second memory 104 based on the image size of the original image and the thumbnail image. Reduction can be realized.

<< Variation 1 of Embodiment 1 >>
In the thumbnail image generation apparatus 100 according to the first modification of the first embodiment of the present invention, when the original image is 5120 × 3840 pixels and the thumbnail image is 200 × 120 pixels, the DMA control unit 105 performs the second operation. When the upsampling data S13 is read out from the memory 104, 4095 pixel luminance Y signals are thinned out for every 128 pixels × 32 lines = 4096 pixel luminance Y signals, and 128 pixel × 64 lines = 8192 pixel color difference Cb signals. The read address of the second memory 104 is designated so that the color difference Cb signal of 8191 pixels is thinned out and the color difference Cr signal of 8191 pixels is thinned out for each color difference Cr signal of 128 pixels × 64 lines = 8192 pixels.

More specifically, the DMA control unit 105 increments the column designation value of the readout address of the luminance Y signal by 128, 0, 128, 256,... And sets the row designation value of the readout address of the luminance Y signal to 0, 32. , 64,... That is, the DMA control unit 105 sets the read address where the combination of the column designation value and the row designation value is (0, 0), (128, 32), (256, 64),. Specify sequentially as read addresses.

In addition, the DMA control unit 105 increments the column designation value of the read address of the color difference Cb signal and the color difference Cr signal by 128, 0, 128, 256,... And the read address of the color difference Cb signal and the color difference Cr signal. The row designation value is incremented by 64, 0, 64, 128,. That is, the DMA control unit 105 uses the color difference Cb signal and the read address where the combination of the column designation value and the row designation value is (0, 0), (128, 64), (256, 128),. The color difference Cr signal is sequentially specified as a read address.

Thus, the read data S14 read by the second memory 104 is reduced by 1/128 times the luminance Y signal in the horizontal direction and 1/32 times the vertical direction, the color difference Cb signal and the color difference Cr signal with respect to the upsampling data S13. Is reduced to 1/128 times the horizontal direction and 1/64 times the vertical direction. Therefore, the read data S14 is data of a color sampling format 4: 2: 2 indicating an image of 40 × 120 pixels.

The enlargement / reduction processing unit 106 performs the enlargement process of the luminance Y signal, the color difference Cb signal, and the color difference Cr signal 5 times in the horizontal direction on the read data S14 read by the second memory 104, thereby showing a reduced image. Reduced image data S15 is output. The reduced image data S15 is data of a color sampling format 4: 2: 2 indicating an image of 200 × 120 pixels.

Other configurations are the same as those in the first embodiment, and thus the description thereof is omitted. *

<< Modification 2 of Embodiment 1 >>
In the thumbnail image generation apparatus 100 according to the second modification of the first embodiment of the present invention, when the original image is 5120 × 3840 pixels and the thumbnail image is 200 × 120 pixels, the DMA control unit 105 performs the second operation. When the upsampling data S13 is read out from the memory 104, 2047 pixels of luminance Y signals are thinned out for every 64 pixels × 32 lines = 2048 pixels of luminance Y signals, and 64 × 64 lines = 4096 pixels of color difference Cb signals. The read address of the second memory 104 is designated so that the color difference Cb signal of 4095 pixels is thinned out and the color difference Cr signal of 4095 pixels is further thinned out for every 64 pixels × 64 lines = 4096 pixel color difference Cr signals.

Specifically, the DMA control unit 105 increments the column designation value of the readout address of the luminance Y signal by 64, 0, 64, 128, 192, 256,... And the row designation value of the readout address of the luminance Y signal. Are incremented by 32, 0, 32, 64,. That is, the DMA control unit 105 sets the read address where the combination of the column designation value and the row designation value is (0, 0), (64, 32), (128, 64),. Specify sequentially as read addresses.

Further, the DMA control unit 105 increments the read address column designation values of the color difference Cb signal and the color difference Cr signal by 0, 64, 128,... 64, and also sets the read address of the color difference Cb signal and the color difference Cr signal. The row designation value is incremented by 64, 0, 64, 128,. That is, the DMA control unit 105 uses the color difference Cb signal and the read address where the combination of the column designation value and the row designation value is (0, 0), (64, 64), (128, 128),. The color difference Cr signal is sequentially specified as a read address.

Thereby, the read data S14 read by the second memory 104 is reduced by 1/64 times in the horizontal direction and 1/32 times in the vertical direction, the color difference Cb signal and the color difference Cr signal with respect to the upsampling data S13. The data is reduced 1/64 times in the horizontal direction and 1/64 times in the vertical direction. Therefore, the read data S14 is data of a color sampling format 4: 2: 2 indicating an 80 × 120 pixel image.

The enlargement / reduction processing unit 106 performs an enlargement process of the luminance Y signal, the color difference Cb signal, and the color difference Cr signal 5/2 times in the horizontal direction on the read data S14 read by the second memory 104, thereby reducing the reduced image. Is output reduced image data S15. The reduced image data S15 is data of a color sampling format 4: 2: 2 indicating an image of 200 × 120 pixels.

Other configurations are the same as those in the first embodiment, and thus the description thereof is omitted.

<< Modification 3 of Embodiment 1 >>
The thumbnail image generating apparatus 100 according to the third modification of the first exemplary embodiment of the present invention includes first to third reductions described later when the original image is 5120 × 3840 pixels and the thumbnail image is 200 × 120 pixels. The process can be executed, and any one of the first to third reduction processes specified by the control signal input from the outside is selected and executed. As in the first embodiment, the first reduction processing reads data indicating an image of 20 × 120 pixels as read data S14 and performs enlargement processing 10 times in the horizontal direction by the enlargement / reduction processing unit 106. In the second reduction process, as in the first modification of the first embodiment, data indicating an image of 40 × 120 pixels is read as read data S14, and the enlargement / reduction processing unit 106 performs the enlargement process 5 times in the horizontal direction. is there. In the third reduction process, similarly to the second modification of the first embodiment, data indicating an image of 80 × 120 pixels is read as read data S14, and the enlargement / reduction processing unit 106 enlarges the image by 5/2 times in the horizontal direction. Is to do.

<< Modification 4 of Embodiment 1 >>
In the first embodiment, the DMA control unit 105 reads out data indicating an image obtained by enlarging the image indicated by the upsampling data S13 by repeatedly specifying the read address of each pixel information a plurality of times. Data S14 can be used. In this case, pixel information of each pixel is repeatedly read in (S1007) of FIG. For example, if the pixel information of each pixel is repeatedly read out twice in the horizontal direction and the pixel information of each line is repeatedly read out twice in succession, the image indicated by the upsampling data S13 is horizontal. Data indicating an image doubled in the direction and doubled in the vertical direction is read data S14.

<< Embodiment 2 >>
In the thumbnail image generating apparatus 100 according to the second embodiment of the present invention, the DMA control unit 105 designates a write address instead of the read address of the second memory 104. The DMA control unit 105 outputs a control signal indicating a designated write address as the control signal S17. By specifying the write address of the DMA control unit 105, the writing of the upsampling data S13 to the second memory 104 thins out the luminance Y signal of 8191 pixels for every luminance Y signal of 256 pixels × 32 lines = 8192 pixels. For each color difference Cb signal of pixels × 64 lines = 16384 pixels, the color difference Cb signal of 16383 pixels is thinned out, and for each color difference Cr signal of 256 pixels × 64 lines = 16384 pixels, the color difference Cr signal of 16383 pixels is thinned out. At the time of reading, thinning is not performed, and the data stored in the second memory 104 is read as it is as read data S14.

<< Embodiment 3 >>
As shown in FIG. 7, the thumbnail image generating apparatus 200 according to the third embodiment of the present invention replaces the decoding unit 102, the upsampling unit 103, and the DMA control unit 105 according to the first embodiment with a decoding unit 202 and DMA control. The unit 205 is provided.

The decoding unit 202 obtains decoded data by performing a decoding process on the compressed image data S11 output from the first memory 101. Then, up-sampling data S23 in a state where up-sampling is performed on the obtained decoded data is written in the second memory 104. Note that the decoded data acquired by the decoding unit 202 has a color sampling format 4: 2: 0.

The DMA control unit 205 uses the control signal S25 to decode both the color difference Cb signal and the color difference Cr signal of the decoded data so as to be written in the second memory 104 by being doubled in the horizontal direction and the vertical direction, respectively. 202 is controlled. As a result, the decoding unit 202 repeatedly outputs the obtained color difference Cb signal and color difference Cr signal of the decoded data four times. At this time, the DMA control unit 205 designates the write address of the second memory 104 by the control signal S24 so that the data output from the decoding unit 202 is stored in the second memory 104 as it is.

For example, the decoding unit 202 acquires A, B, C, D,... As the decoding result of the color difference Cb signal and the color difference Cr signal, and A, B, C, D,. The corresponding color difference Cb signal or color difference Cr signal is assumed. At this time, the decoding unit 202 repeatedly outputs A, A, B, B, C, C, D, D,... And each color difference Cb signal or color difference Cr signal twice. Furthermore, the color difference Cb signal or color difference Cr signal of each line is converted into A, A, B, B, C, C, D, D,... A, A, B, B, C, C, D, D,.・ Repeat and output twice.

As a result, the upsampling data S23 output by the decoding unit 202 becomes data obtained by enlarging both the color difference Cb signal and the color difference Cr signal of the decoded data twice in the horizontal direction and the vertical direction, respectively, and the color sampling format 4: 4. : 4 data. That is, the upsampling data S23 is data obtained by adding the color difference Cb signal and the color difference Cr signal to pixel information not including the color difference Cb signal and the color difference Cr signal among the pixel information included in the decoded data. The upsampling data S23 is stored in the second memory 104 as it is.

Further, when the DMA control unit 205 reads the upsampling data S23 from the second memory 104, the DMA control unit 205 designates the read address by the control signal S17. Since the method for designating the read address is the same as that in the first embodiment, the description thereof is omitted.

Next, the operation of the thumbnail image generating apparatus 200 configured as described above will be described with reference to the flowchart of FIG.

The decoding unit 202 reads the compressed image data S11 stored in the first memory 101 in (S2001), decodes the compressed image data S11 read in (S2001) in (S2002), and in (S2003). The up-sampling data S23 obtained by up-sampling the decoded data obtained by the decoding in (S2002) is written into the second memory 104. At this time, for example, when the decoded data has a color sampling format 4: 2: 0, writing of the color difference Cb signal and the color difference Cr signal included in the decoded data is performed for two pixels in the horizontal direction and two lines in the vertical direction. By repeatedly performing the process in increments of minutes, the upsampling data S23 having the sampling format 4: 4: 4 can be written in the second memory 104. The up-sampling data S23 written in the second memory 104 is read in (S2004), and is output and displayed through enlargement processing by the enlargement / reduction processing unit 106 in (S2005). Even at the time of data reading in (S2004), the column designation value of the read address is designated for each predetermined plurality of pixels, and the row designation value is designated for each predetermined plurality of lines, thereby being indicated by the upsampling data S23. The image can be reduced.

In the third embodiment, as in the first modification of the first embodiment, data indicating an image of 40 × 120 pixels is read as read data S14, and the enlargement / reduction processing unit 106 performs the enlargement process 5 times in the horizontal direction. You may do it. Similarly to the second modification of the first embodiment, data indicating an image of 80 × 120 pixels may be read as read data S14 and the enlargement / reduction processing unit 106 may perform enlargement processing 5/2 times in the horizontal direction. . Similarly to the third modification of the first embodiment, the thumbnail image generating apparatus 200 may select and execute one reduction process from the first to third reduction processes.

According to the present embodiment, the same effects as those of the first embodiment can be obtained, and the upsampling can be performed without providing the upsampling circuit, so that the circuit area and the calculation processing amount can be reduced.

<< Variation 1 of Embodiment 3 >>
In the third embodiment, the decoding unit 202 may write the acquired decoded data as it is in the second memory 104.

In this case, the data stored in the second memory 104 is the color sampling format 4: 2: 0. Accordingly, the DMA control unit 105 increments the column designation value of the read address of the color difference Cb signal and the color difference Cr signal by 256, 0, 256, 512,... And the read address of the color difference Cb signal and the color difference Cr signal. The row designation value is incremented by 32, 0, 32, 64,. That is, the DMA control unit 105 uses the color difference Cb signal and the read address where the combination of the column designation value and the row designation value is (0, 0), (256, 32), (512, 64),. The color difference Cr signal is sequentially specified as a read address.

Thereby, the read data S14 read by the second memory 104 is compared with the upsampling data S23 in the horizontal direction (200/5120) × (1/10) = 1/256 times the luminance Y signal, and the vertical direction 120 / 3840 = 1/32 times reduction, color difference Cb signal and color difference Cr signal horizontal direction (200/5120) × (1/10) = 1/256 times, vertical direction 120/3840 = 1/32 times reduction Data. Therefore, the read data S14 is data of a color sampling format 4: 2: 2 indicating an image of 20 × 120 pixels.

Other configurations are the same as those in the third embodiment, and thus description thereof is omitted.

<< Modification 2 of Embodiment 3 >>
In the third embodiment, the DMA control unit 205 shows an enlarged image of the image indicated by the upsampling data S23 by repeatedly specifying the read address of each pixel information a plurality of times by the control signal S17. The data can be read data S14. In such a case, pixel information of each pixel is repeatedly read in (S2004) of FIG. For example, if the pixel information of each pixel is repeatedly read out twice in the horizontal direction and the pixel information of each line is repeatedly read out twice in succession, the image indicated by the upsampling data S13 is horizontal. Data indicating an image doubled in the direction and doubled in the vertical direction is read data S14.

<< Embodiment 4 >>
In the thumbnail image generating apparatus 200 according to Embodiment 4 of the present invention, the DMA control unit 205 stores the decoded data (color sampling format 4: 2: 0) acquired by the decoding unit 202 into the second memory 104. For writing, the luminance Y signal of 8191 pixels is thinned out for each luminance Y signal of 256 pixels × 32 lines = 8192 pixels, and the color difference Cb signal of 8191 pixels is thinned out for each color difference Cb signal of 256 pixels × 32 lines = 8192 pixels. The decoding unit 202 is controlled so that the color difference Cr signal of 8191 pixels is thinned out for each color difference Cr signal of 256 pixels × 32 lines = 8192 pixels. The DMA control unit 205 controls the decoding unit 202 by outputting a control signal S25 to the decoding unit 202. As a result, the second memory 104 stores image data of a color sampling format 4: 2: 0 indicating an image of 200 × 120 pixels instead of the upsampling data S23.

Also, upsampling is performed on the data stored in the second memory 104 according to the designation of the read address by the DMA control unit 205. The read address is specified so that both the color difference Cb signal and the color difference Cr signal of the decoded data are read from the second memory 104 while being doubled in the horizontal direction and the vertical direction, respectively. That is, the DMA control unit 205 designates each read address twice in succession so that the color difference Cb signal and the color difference Cr signal stored in the second memory 104 are successively read twice.

For example, when each color difference signal is stored in order in the second memory 104 as A, B, C, D,..., The second memory 104 stores A, A, B, B, C, C, The DMA control unit 205 designates the read address of the second memory 104 so that each of the color difference signals D, D,... Is output twice. Thus, the image data read from the second memory 104 and input to the enlargement / reduction processing unit 106 is data that has been upsampled to the color sampling format 4: 2: 2. That is, the image data input to the enlargement / reduction processing unit 106 includes the color difference Cb signal and the pixel information not including the color difference Cb signal or the color difference Cr signal among the pixel information included in the data stored in the second memory 104. The data is obtained by adding the color difference Cr signal.

<Other variations>
In the second embodiment, the data stored in the second memory 104 is data indicating an image indicated by the upsampling data S13 output by the upsampling unit 103. However, the DMA control unit 105 repeatedly outputs each luminance Y signal, color difference Cb signal, and color difference Cr signal as the luminance Y signal, color difference Cb signal, and color difference Cr signal of a plurality of pixels, respectively, for the predetermined number of times. By controlling the upsampling unit (enlargement target image output unit) 103 as described above, data indicating an enlarged image of the image indicated by the upsampling data S13 acquired by the upsampling unit 103 is stored in the second memory 104. You may be made to do. That is, the DMA control unit 105 may control the upsampling unit 103 so as to repeatedly output each piece of pixel information as pixel information of a predetermined plurality of pixels. For example, by writing the same data to the second memory 104 twice in succession, the image indicated by the decoded data can be doubled in the horizontal direction or the vertical direction, respectively. Also, for example, by writing the same data to the second memory 104 three times in succession, the image indicated by the decoded data can be expanded three times in the horizontal direction or the vertical direction.

Similarly, in the fourth embodiment, the data stored in the second memory 104 is data indicating an image obtained by reducing the image indicated by the decoded data acquired by the decoding unit 202. However, the DMA control unit 205 may control the decoding unit (enlargement target image output unit) 202 so that each luminance Y signal, color difference Cb signal, and color difference Cr signal are repeatedly output a plurality of times. That is, the DMA control unit 205 may control the decoding unit 202 so that each piece of pixel information is repeatedly output as pixel information of a predetermined plurality of pixels. As a result, data indicating an image obtained by enlarging the image indicated by the decoded data acquired by the decoding unit 202 is stored in the second memory 104.

The thumbnail image generation apparatus and thumbnail image generation method according to the present invention are useful as a technique for generating thumbnail images / enlarged images by reducing / enlarging images.

100 Thumbnail image generation device (enlarged image generation device)
103 Upsampling unit (magnification target image output unit)
104 Second memory (image memory)
105 DMA control unit 106 Enlargement / reduction processing unit 108 Thumbnail image output unit (enlarged image output unit)
200 Thumbnail image generation device (enlarged image generation device)
202 Decoding unit (original image output unit, enlargement target image output unit)
205 DMA controller

Claims

A thumbnail image generation device that generates a thumbnail image by reducing a reduction target image,
Storing image data of the reduction target image, the image data including pixel information indicating the color of each pixel included in the image;
A DMA control unit for designating a read address of the image memory so that reading of the image data from the image memory is performed by thinning out some pixel information for each of a plurality of predetermined pieces of pixel information;
A thumbnail image generation apparatus comprising: a thumbnail image output unit that outputs a thumbnail image based on image data read from the image memory.
The thumbnail image generating apparatus according to claim 1,
The pixel information includes a plurality of components for representing a color in a predetermined color space,
The thumbnail image generation device
The upsampling target component for image data of a predetermined original image adopting a format in which the upsampling target component, which is one of the plurality of components, is included in only one pixel information per predetermined plurality of pixel information An upsampling unit that generates upsampling data by performing upsampling of
The thumbnail image generating apparatus, wherein the image memory stores upsampling data generated by the upsampling unit as image data of the reduction target image.
The thumbnail image generating apparatus according to claim 2,
The pixel information includes a luminance component Y and two color difference components Cb and Cr.
The image data of the original image has a color sampling format 4: 2: 0 or a color sampling format 4: 2: 2.
The upsampling performed by the upsampling unit is upsampling to a color sampling format 4: 4: 4.
The thumbnail image generating apparatus according to claim 1,
The DMA control unit reads out image data from the image memory by thinning out pixel information of some columns for each of a plurality of consecutive predetermined columns in an image, and for some rows for each of a plurality of consecutive predetermined rows. A thumbnail image generating apparatus, wherein a read address of the image memory is designated so that the pixel information is thinned out.
The thumbnail image generating apparatus according to claim 4, wherein
The read address is represented by a column designation value that designates a column and a row designation value that designates a row,
The DMA controller sequentially outputs read addresses, and the column designation values of the read addresses that are sequentially output specify columns in order from the horizontal end of the image every predetermined column, and the read addresses that are sequentially output The thumbnail designation value is for designating the rows in order at predetermined intervals from the vertical end of the image.
The thumbnail image generating apparatus according to claim 1,
The DMA control unit is configured to designate a read address of the image memory based on an image size of the reduction target image and the thumbnail image.
The thumbnail image generating apparatus according to claim 1,
The thumbnail image output unit includes an enlargement / reduction processing unit that reduces or enlarges an image indicated by the image data read from the image memory and outputs enlarged / reduced image data indicating an image after reduction or enlargement. A thumbnail image generating apparatus that outputs the thumbnail image based on the enlarged / reduced image data output by the unit.
The thumbnail image generating apparatus according to claim 1,
The pixel information includes a plurality of components for representing a color in a predetermined color space,
The thumbnail image generation device
Output image data of a predetermined original image, and the image data of the original image includes an up-sampling target component which is one of the plurality of components in only one pixel information for a predetermined plurality of pixel information. Further comprising an original image output unit adopting a format
The DMA control unit controls the original image output unit to output each upsampling target component in addition to pixel information not including the upsampling target component when outputting the image data of the original image. In addition, the thumbnail image generating apparatus is characterized by designating a write address of the image memory so that the image data output from the original image output unit is directly written in the image memory.
The thumbnail image generating apparatus according to claim 8, wherein
The pixel information includes a luminance component Y and two color difference components Cb and Cr.
The image data of the original image has a color sampling format 4: 2: 0 or a color sampling format 4: 2: 2.
The thumbnail image generating apparatus, wherein the image data written in the image memory has a color sampling format 4: 4: 4.
A thumbnail image generation device that generates a thumbnail image by reducing a reduction target image,
Storing image data, and the image data includes, for each pixel included in the image, an image memory including pixel information indicating a color of the pixel;
A DMA control unit for designating a write address of the image memory so that writing of the image data of the image to be reduced into the image memory is performed by thinning out part of the pixel information for each of a plurality of predetermined pieces of pixel information; ,
A thumbnail image generation apparatus comprising: a thumbnail image output unit that outputs a thumbnail image based on image data stored in the image memory.
The thumbnail image generating apparatus according to claim 10, wherein
The pixel information includes a plurality of components for representing a color in a predetermined color space,
The image data stored in the image memory employs a format in which the upsampling target component, which is one of the plurality of components, is included in only one piece of pixel information for a plurality of pieces of pixel information,
The DMA control unit designates a read address of the image memory so that each up-sampling target component is added to pixel information not including the up-sampling target component when the image data is read from the image memory. A thumbnail image generating apparatus as a feature.
The thumbnail image generating apparatus according to claim 10, wherein
The pixel information includes a plurality of components for representing a color in a predetermined color space,
The thumbnail image generation device
The upsampling target component for image data of a predetermined original image adopting a format in which the upsampling target component, which is one of the plurality of components, is included in only one pixel information per predetermined plurality of pixel information An upsampling unit that generates upsampling data by performing upsampling of
The thumbnail image generating apparatus, wherein the upsampling data generated by the upsampling unit is written in the image memory as image data of the reduction target image.
The thumbnail image generating apparatus according to claim 12,
The pixel information includes a luminance component Y and two color difference components Cb and Cr.
The image data of the original image has a color sampling format 4: 2: 0 or a color sampling format 4: 2: 2.
The upsampling performed by the upsampling unit is upsampling to a color sampling format 4: 4: 4.
The thumbnail image generating apparatus according to claim 10, wherein
The thumbnail image output unit includes an enlargement / reduction processing unit that reduces or enlarges an image indicated by the image data read from the image memory and outputs enlarged / reduced image data indicating an image after reduction or enlargement. A thumbnail image generating apparatus that outputs the thumbnail image based on the enlarged / reduced image data output by the unit.
An enlarged image generation device that generates an enlarged image by enlarging an enlargement target image,
Outputting image data of an enlargement target image, and the image data includes, for each pixel included in the image, an enlargement target image output unit including pixel information indicating a color of the pixel;
An image memory for storing the image data output by the enlargement target image output unit;
A DMA control unit that controls the enlargement target image output unit so as to repeatedly output pixel information of each pixel as pixel information of a plurality of pixels when outputting image data of the enlargement target image;
An enlarged image generating apparatus, comprising: an enlarged image output unit that outputs an enlarged image based on image data stored in the image memory.
A thumbnail image generation method for generating a thumbnail image by reducing a reduction target image,
Storing image data of the image to be reduced in an image memory, the image data including pixel information indicating the color of each pixel included in the image;
A DMA control step of designating a read address of the image memory so that reading of the image data from the image memory is performed by thinning out some pixel information for each of a plurality of predetermined pieces of pixel information;
And a thumbnail image output step of outputting a thumbnail image based on the image data read from the image memory.
A thumbnail image generation method for generating a thumbnail image by reducing a reduction target image,
Image data is stored, and for each pixel included in the image, the image data including the pixel information indicating the color of the pixel is written in a plurality of predetermined numbers. A DMA control step of designating a write address of the image memory so that a part of the pixel information is thinned out for each pixel information;
And a thumbnail image output step of outputting a thumbnail image based on the image data stored in the image memory.
An enlarged image generation method for generating an enlarged image by enlarging an enlargement target image,
The image data of the enlargement target image is output, and the image data includes, for each pixel included in the image, the enlargement target image output unit including pixel information indicating the color of the pixel. A DMA control step for performing control to repeatedly output pixel information of each pixel as pixel information of a plurality of pixels at the time of output;
Storing the image data output by the enlargement target image output unit in an image memory;
An enlarged image generation method comprising: an enlarged image output step of outputting an enlarged image based on the image data stored in the image memory.