WO2005031694A1 - Still image processing apparatus, and still image processing method - Google Patents

Abstract

A still image processing apparatus comprising a decoding part (101) for decoding compressed image data; a decoded image memory (102) for storing the image data as decoded by the decoding part (101); a scaling-up/scaling-down part (103); an image storage memory (108) for storing image data as scaled-up or scaled-down by the scaling-up/scaling-down part (103) such that the image data read from the decoded image memory (102) have image storage sizes; a display image memory (104) for storing image data as scaled-up or scaled-down by the scaling-up/scaling-down part (103) such that the image data read from the image storage memory (108) have display sizes; a display processing part (105) for reading from the display image memory (104) and displaying the image data; and an image storage control part (107) for deciding, based on externally inputted output device resolution information and output image setting information, the image storage sizes and the display sizes.

Description

 Description Still image processing apparatus and still image processing method

 The present invention relates to a still image processing apparatus that decodes a compressed image data, converts the decoded image into an arbitrary image size, and outputs the image, and a still image processing method.

When transmitting, recording, and reproducing various signals such as image signals and audio signals as digital signals, a compression / expansion technique for the amount of information is used. When compressing the amount of information in an image, for example, orthogonal transform such as Discrete Cosine Transform (DCT) that uses screen correlation, such as Moving Picture Coding Experts Group (MPEG) and Joint Photographic Coding Experts Group (JPEG), is common. It is possible to compress the signal to several tenths. On the other hand, in many cases, compressed image signals are subjected to image processing such as display size change on the decoded image data.

 Still images are applied to image databases, etc. In order to display high-quality images, it is necessary to store data at the maximum resolution in the image database. However, storing data at the maximum resolution requires an enormous amount of data to be stored. Also, storing large amounts of image data increases the system cost, such as increasing the memory capacity / data transfer performance.

 On the other hand, when the memory capacity is reduced or the system is simplified, the output image quality is reduced (for example, see Japanese Patent Application Laid-Open No. Hei 8-22543).

 FIG. 16 shows a processing configuration for decoding the compressed image data, converting the decoded image to an arbitrary image size, and outputting the image in the conventional image processing apparatus.

The image processing apparatus shown in FIG. 16 includes: a decoding processing unit 1 for decoding compressed input image data; a decoded image memory 2 for storing the decoded image data (decoded image data); Enlarging and reducing image data in the vertical and horizontal directions A large / small processing unit 3, a display image memory 4 for storing image data (display image data) that has been scaled by the scaling unit 3, and a display processing unit 5 for displaying and processing and outputting the display image data And the decoding processing unit 1, the scaling processing unit 3, the display processing unit 5, and the memory control unit 6 that transfers data between the memories 2 and 4.

 Next, the operation will be described.

 The input image data is decoded by the decoding processing unit 1 and stored in the decoded image memory 2. Here, the capacity of the decoded image memory 2 is a capacity that can store only a part of the decoded image because a huge capacity is required to store the entire decoded image. Therefore, while the decoded image data output from the decoding processing unit 1 is stored in the decoded image memory 2, the image data read from the decoded image memory 2 is enlarged and reduced by the scaling processing unit 3, and the display image memory 4 is displayed. To save.

 That is, the decoding processor 1 supplies a part of the decoded image data to the area processed by the scaling processor 3 out of the decoded image data storage area of the decoded image memory 2 and In the step 3, a predetermined enlargement / reduction process is performed on the decoded image data read from the decoded image memory 2, and the decoded image data is stored in the display image memory 4. This display image memory 4 stores one display image data.

 The display image data stored in the display image memory 4 is output after being subjected to predetermined display processing by the display processing unit 5.

 As described above, by simultaneously performing the decoding process and the scaling process, the image processing apparatus can be configured with a memory capacity independent of the decoded image size. However, when the display magnification or the like is changed for the same decoded image data, the decoding process of the same image needs to be performed again in order to create a display image. Since the processing amount of the decoding process is enormous compared to the image storage process and the scaling process performed by the scaling processor 103, it takes time to re-decode the same image.

In other words, the number of pixels processed by the decoding processing unit 101 is enormous compared to the resolution of the display device that affects the processing amount of the scaling processing unit 103 (for example, 720 x 480). (For example, 8192 x 8192), and compared to the scaling operation, Since the decoding processing operation is complicated, the re-display processing of the still image could not be performed at high speed.

 In order to prevent the same image from being re-decoded as described above, it is necessary to save all the decoded images.For example, if the decoded image size is 8192 pixels by 8192 lines x 8192 lines In this case, an enormous memory capacity of about 70 Mbit is required, so an enormous memory capacity for the decoded image size is required.

 SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a still image processing apparatus and a still image processing method that realize high-speed still image output processing without increasing the memory capacity The purpose is to provide. Disclosure of the invention

 The still image processing device according to claim 1 of the present invention, in a still image processing device that decodes and displays a compressed image data, a decoding processing unit that decodes the compressed image data, A first memory for storing the decoded image data, a scaling processing unit for expanding or reducing the image data read from the first memory, and an enlargement or reduction to an image storage size by the enlargement / reduction processing unit A second memory for storing the scaled image data, a third memory for storing the image data enlarged or reduced to the display size by the scaling processing unit, and an image data from the third memory. And a display processing unit for reading out and outputting. As a result, the re-output processing of the decoded image can be performed at high speed without performing the decoding processing again as in the related art or requiring a huge memory capacity corresponding to the size of the decoded image.

 Further, the still image processing device according to claim 2 of the present invention is the still image processing device according to claim 1, wherein the decoding processing unit, the scaling processing unit, and the display processing. And a memory control unit for controlling data transfer between the memories.

Thereby, the first to third memories can be configured by the common memory. The still image processing device according to claim 3 of the present invention is the still image processing device according to claim 1, wherein the output device resolution information input from the outside is provided. The image storage size is determined based on the information, and an image storage control unit is provided to notify the enlargement / reduction processing unit.

 As a result, image storage processing according to the output device resolution can be performed.

 Further, the still image processing device according to claim 4 of the present invention is the still image processing device according to claim 1, wherein the first, second, and third memories as a whole are provided. An image storage control unit that determines the image storage size based on the second memory capacity calculated from the capacity and the first and third memory usage capacities and notifies the enlargement / reduction processing unit. It is a thing.

 As a result, image storage processing according to the memory capacity can be performed.

 Further, the still image processing device described in claim 5 of the present invention is characterized in that:

2. The still image processing device according to item 1, further comprising an image storage control unit that controls a data transfer amount of the enlargement / reduction processing unit based on an externally input memory transfer performance.

 As a result, image storage processing according to the memory transfer performance can be performed.

 The still image processing device according to claim 6 of the present invention is the still image processing device according to claim 1, wherein the display is performed based on image setting information input from outside. It is provided with an image storage control unit that determines the size and notifies the enlargement / reduction processing unit.

 This makes it possible to create a display image according to the image output setting information.

 A still image processing device according to claim 7 of the present invention is a still image processing device that decodes and displays compressed image data, a decoding processing unit that decodes the compressed image data. A first memory for storing the decoded image data; a scaling processing unit for scaling up or down the image data read from the first memory; and a second memory for storing the scaled up or reduced image data. A rotation processing unit that rotates the image data read from the fourth memory, and stores the rotated image data in the fourth memory; and the rotation-processed image stored in the fourth memory. A display processing unit that reads out the data from the fourth memory and outputs the read data.

As a result, the re-output processing of the decoded image is performed again as in the past. It can be performed at high speed without requiring a huge memory capacity for the decoded image size.

 The still image processing device according to claim 8 of the present invention is the still image processing device according to claim 7, wherein the decoding processing unit, the scaling processing unit, and the rotation processing unit. , And the display processing unit, and a memory control unit that controls data transfer between the memories.

 Thus, each memory can be configured by a common memory.

 The still image processing device according to claim 9 of the present invention is the still image processing device according to claim 7, wherein the image to be stored in the fourth memory is 4: 4. : An image of 4-pixel sampling, wherein the display processing section obtains an image of 4: 2: 2 pixel sampling by thinning out the image data read from the fourth memory.

 This can prevent the rotation image from deteriorating.

 A still image processing device according to claim 10 of the present invention is the still image processing device according to claim 7, wherein the enlargement / reduction processing unit is configured to output from an external source. The display size is determined based on image setting information.

 This makes it possible to create a display image according to the image output setting information.

 The still image processing device according to claim 11 of the present invention is the still image processing device according to claim 7, wherein the rotation processing unit includes an image output setting input from outside. The rotation angle is determined based on the information.

 This makes it possible to perform a rotation process according to the image output setting information.

A still image processing method according to claim 12 of the present invention is a still image processing method for decoding and displaying compressed image data, wherein the compressed image data is decoded, A decryption storage processing step of storing the image data in the memory; an image storage processing step of reading the image data from the first memory, reducing the image data to an image storage size, and storing the image data in the second memory; A display image storage processing step for reading image data, enlarging or reducing the image data to a display size, and storing the image data in a third memory, and reading and outputting the image data from the third memory. And a display processing step.

 As a result, the re-output processing of the decoded image can be performed at high speed without performing the decoding processing again as in the related art or requiring a huge memory capacity corresponding to the size of the decoded image.

 Further, in the still image processing method according to claim 13 of the present invention, in the still image processing method according to claim 12, the image storage processing step is input from outside. The image storage size is determined based on output device resolution information.

 As a result, image storage processing according to the output device resolution can be performed.

 Further, the still image processing method according to claim 14 of the present invention is the still image processing method according to claim 12, wherein the image storage processing step includes the first and second steps. A memory free space usable as the second memory is calculated from the total memory space of the second and third memories and the used amount of the first and third memories, and based on the calculated memory free space, The image storage size is determined. As a result, image storage processing according to the memory capacity can be performed.

 Further, the still image processing method according to claim 15 of the present invention is the still image processing method according to claim 12, wherein the image storage processing step and the display image storage processing step are the same. In each case, the amount of data transferred to each memory is controlled based on the memory transfer performance input from the outside.

 As a result, image storage processing according to the memory transfer performance can be performed.

 Further, in the still image processing method according to claim 16 of the present invention, in the still image processing method according to claim 12, the display image storage processing step is externally input. The display size is determined based on the display setting information.

 This makes it possible to create a display image according to the image output setting information.

A still image processing method according to claim 17 of the present invention is a still image processing method for decoding and displaying compressed image data, the method comprising: decoding the compressed image data; A decoded image storage processing step of storing the decoded image data in the first memory; and A display image storage processing step to store the image data from the fourth memory, a rotation storage processing step to read and rotate the image data from the fourth memory, and store the image data in the fourth memory; A display processing step of reading out the stored rotated image data from the fourth memory and displaying and outputting the read out image data. As a result, the re-output processing of the decoded image can be performed at high speed without performing the decoding processing again as in the related art or requiring a huge memory capacity corresponding to the size of the decoded image.

 In addition, the still image processing method according to claim 18 of the present invention is the still image processing method according to claim 17, wherein the display image storage processing step is performed by the fourth memory The image to be stored in the memory is processed as a 4: 4: 4 pixel sampling image. In the display processing step, the image data read from the fourth memory is thinned out, and 4: 2: 2 pixels are processed. This is to obtain a sampled image.

 This can prevent the rotation image from deteriorating.

 Further, in the still image processing method according to claim 19 of the present invention, in the still image processing method according to claim 17, the display image storage processing step is externally input. The display size is determined based on the display setting information.

 This makes it possible to create a display image according to the image output setting information.

 A still image processing method according to claim 20 of the present invention is the still image processing method according to claim 17, wherein the rotation preservation processing step is input from an external unit. The rotation angle is determined based on the display setting information.

 This makes it possible to perform a rotation process according to the image output setting information. Brief Description of Drawings

 FIG. 1 is a diagram showing a configuration of a still image processing device according to Embodiment 1 of the present invention.

FIG. 2 shows details of a decoding processing unit included in the still image processing apparatus according to the first embodiment. FIG.

 FIG. 3 (a) is a diagram showing a frequency domain f (u, v), and FIG. 3 (b) is a diagram showing a spatial domain F (x, y).

 FIG. 4 is a diagram for explaining the enlargement / reduction processing of the enlargement / reduction unit included in the still image processing device according to the first embodiment.

 FIG. 5 is a size transition diagram of a decoded image, a stored image, and a display image in the still image processing of the first embodiment.

 FIG. 6 is a diagram illustrating a storage processing unit of a decoding processing unit included in the still image processing device according to the first embodiment.

 FIG. 7 is a process transition diagram by the still image processing device of the first embodiment. FIG. 8 is a diagram showing a configuration of a still image processing device according to Embodiment 2 of the present invention.

 FIG. 9 is a diagram showing an image of pixel sampling 4: 2: 2.

 FIG. 10 is a diagram showing a configuration of a still image processing device according to Embodiment 3 of the present invention.

 FIG. 11 is a diagram showing an image of pixel sampling 4: 4: 4.

 FIG. 12 is a diagram illustrating a detailed configuration of a rotation processing unit included in the still image processing device according to the third embodiment.

 Fig. 13 (a) is a diagram showing the pixels before the rotation processing of the pixel sampling 4: 2: 2 image, and Fig. 13 (b) is the rotation of the pixel sampling 4: 2: 2 image. FIG. 14 is a diagram illustrating a pixel after processing.

 Figure 14 (a) is a diagram showing the pixels before the rotation processing of the pixel sampling 4: 4: 4 image. Figure 14 (b) is the rotation of the pixel sampling 4: 4: 4 image. FIG. 14 is a diagram illustrating a pixel after processing.

 FIG. 15 is a diagram illustrating a detailed configuration of a display processing unit included in the still image processing device according to the third embodiment.

FIG. 16 is a diagram showing a configuration of a conventional still image processing device. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

 (Embodiment 1)

 FIG. 1 is a block diagram showing a configuration of a still image processing device according to Embodiment 1 of the present invention.

 The still image processing apparatus according to the present embodiment includes: a decoding processing unit 101 that decodes compressed image data; a decoded image memory 102 that stores the decoded image data; Image storage memory for storing the image data enlarged or reduced by the enlargement / reduction processing unit 103 for enlarging or reducing the image data read from 02 and the above-mentioned enlargement / reduction processing unit 103 10 8, a display image memory 104 for storing image data enlarged or reduced to the display size by the above-mentioned enlargement / reduction processing unit 103, and an image data from the above display image memory 104. A display processing unit 105 for reading out and displaying the evening, the decoding processing unit 101, the scaling processing unit 103, and the display processing unit 105, and memories 102, 100 Memory for controlling data transfer between 8, 104 A control unit 106, and an image storage control unit 107 that determines the image storage size and the display size based on output device resolution information and image output setting information input from the outside. .

 FIG. 2 is a diagram showing a detailed configuration of the decoding processing unit 101.

 The inverse quantization unit 111 constituting the decoding processing unit 101 obtains DCT coefficients by performing an inverse quantization process on the input image data (compressed data). The DCT coefficient is data in the frequency domain, and a large DCT coefficient indicates that the data contains many frequency components. The DCT coefficient is obtained from the compressed data X quantization coefficient.

 In addition, the inverse DCT transform unit 112 constituting the decoding processing unit 101 converts the frequency domain f (u, v) shown in FIG. Is converted into image data of a spatial area F (x, y) shown in FIG. 3 (b) to obtain decoded data.

 (Number 1)

 F (x, y) 2 2Α (ΑΧΒ) ∑∑ c (u) c (v) f (u, v) cos ((2x + l) 7T / 2A) cos ((2y + l) 7T / 2B)

 c (u) = l / 2 (u = 0),

l (u2 1,2,3 .A)

 A, B; Integer greater than 1

 FIG. 5 is a diagram showing an example of a size transition of a decoded image, a stored image, and a display image by the image storage control unit 107.

 The image storage control unit 107 detects the resolution required for the output device from the output device resolution information input from the outside, determines the image storage magnification, and notifies the enlargement / reduction processing unit 103. As a result, a stored image having the same resolution as that of the output device can be created, and image quality deterioration due to low resolution can be prevented.

 Further, the image storage control unit 107 determines the display image magnification from the image output setting information input from outside, and notifies the enlargement / reduction processing unit 103 of the determined magnification. Note that the image output setting information is information for determining a display image, and includes information on the display image size in the horizontal and vertical directions, and information on the horizontal and vertical enlargement / reduction ratio for the decoded image. It is a thing.

 For example, when the decoded image is horizontal X i pixels and vertical Y i lines, the display size as output setting information is horizontal Xo pixels and vertical Yo lines, and the output device resolution information is horizontal Xs pixels and vertical Ys lines. As shown in Fig. 5, the stored image size is horizontal Xs pixels and vertical Ys lines, and the display image size is horizontal Xo pixels and vertical Yo lines. As a result, the image storage control unit 107 controls the enlargement / reduction processing unit 103 with the image storage magnification as horizontal Xs ZXi, vertical Ys ZYi, and the display image magnification as horizontal Xo / Xs and vertical YoZYs. Do. In this way, the scaling processing unit 103 creates a stored image from the decoded image and creates a display image from the saved image.

 FIG. 4 is a diagram showing an example of a reduction process in the vertical direction of the image data by the enlargement / reduction processing unit 103.

The above-mentioned enlargement / reduction processing section 103 performs enlargement / reduction processing in the horizontal direction and the vertical direction on the data of the space area input according to the set magnification notified from the image storage control section 107. The output data X is obtained by aX K + bX (1—K) using the coefficient K (0≤K <1) representing the output phase, and the output data y is c XK + dX (1—K) Required by Note that the coefficient K is determined from the magnification set in the output setting information. The

 FIG. 6 is a diagram showing a storage processing unit in the decoded image memory 102 in the decoding processing unit 101.

 The decoding processing unit in the decoding processing unit 101 is a horizontal and vertical Xi pixel n line for one screen data horizontal and vertical Xi pixel Y i line (hereinafter, a decoded image n line is referred to as one bank). . The memory capacity of the decoding memory 102 is X i XY i X 2 X 2 bytes (2 banks), the image storage memory 104 is X s XY s X 2 bytes, and the display image memory 106 The memory capacity is X o XY o X 2 bytes.

 Next, the operation will be described with reference to FIG. FIG. 7 shows processing transition of the still image processing device according to the first embodiment.

 The decoding processing unit 101 performs a decoding process on the image data for one bank of the input image data, and stores the decoded image data in the decoded image memory 102. When the decoding process for one bank is completed, the fact is notified to the scaling unit 103 and the decoding process for the next puncture is started.

 The enlargement / reduction processing unit 103 starts the image storage processing in response to the end of the decoding processing for one bank, and reads the decoded image from the decoded image memory 102. Then, the read decoded image is reduced using the image storage magnification notified from the image storage control unit 107, and is stored in the image storage memory 108.

 When the image storage processing is completed, the enlargement / reduction processing section 103 starts display image creation processing, and reads out image data from the image storage memory 108. Then, the read image data is scaled using the display image magnification notified from the image storage control unit 107, and is stored in the display image memory 104.

 Further, the enlargement / reduction processing section 103 waits for the decoding processing of the next bank to be completed by the decoding processing section 101, and then performs image storage processing and display image creation processing on the data after the decoding processing. .

In the still image processing apparatus according to the first embodiment, the image storage processing is performed simultaneously with the decoding processing and the display image generation processing. When the information is updated, there is no need to repeat the decoding processing of the stored image with a large amount of processing, and as shown in FIG. Images can be output only by scaling processing, and the speed of still image output processing can be increased by a memory capacity independent of the decoded image size.

 Further, in the still image processing device according to the first embodiment, the entire image storage size of the decoded image data is determined from the output device resolution information input from the outside, and the storage process is performed based on the determined storage size. Therefore, it is possible to execute the image storage processing according to the output device resolution.

 (Embodiment 2)

 FIG. 8 is a block diagram showing a configuration of a still image processing device according to Embodiment 2 of the present invention.

 The still image processing apparatus according to the second embodiment determines the image storage size based on the entire memory capacity and the memory transfer performance instead of the image storage control unit 107 in the still image processing apparatus according to the first embodiment. An image storage control unit 207 is provided. Next, the operation will be described. Note that the decryption processing is the same operation as in the first embodiment, and therefore, the description is omitted.

 When performing the image storage processing, the decoded image is read from the decoded image memory 102 under the control of the image storage control section 207, and the scaling processing section 103 performs scaling processing to the image storage size. Save to the image storage memory 108.

 When the display image creation processing is performed, the stored image is read out from the image storage memory 108 under the control of the image storage control unit 207, and the display size is set to the display size by the enlargement / reduction processing unit 103. The image is scaled and transferred to the display image memory 104 as a display image.

 Next, the operation of the image storage control unit 207 will be described.

When performing the image storage processing, the available memory capacity as the image storage memory 108 is calculated from the total memory capacity and the used memory capacity, the image storage size is determined according to the calculated memory capacity, and the image storage size is determined. The storage magnification is notified to the enlargement / reduction processing section 103. Further, when performing the display image creation processing, the display size is detected from the image output setting information, the display image magnification is determined based on the display size, and the enlargement / reduction processing unit 103 is notified. Assuming that the total memory capacity is Zbyte, the used capacity of the decoded image memory 102 is I byte, and the used capacity of the display image memory 104 is Obyte, the image storage memory capacity is (Z—I -O) byte. Also, if the pixel sampling of the image to be stored in the image storage memory 108 is 4: 2: 2, and 1 byte per pixel, the size of the stored image can be calculated in the horizontal and vertical directions ((Z-I-0) / 2). it can. As shown in FIG. 9, the pixel sampling 4: 2: 2 image is an image signal in which four pixels of the luminance signal Y have two color difference signals Cb and Cr respectively.

 Further, the image storage control unit 207 calculates a transfer capacity that can be used for the image storage processing and the display image creation processing based on the memory transfer performance, and controls the transfer processing in the image storage processing and the display image creation processing.

 If the memory operating frequency is Lclock and the memory bit width is Mbit, the memory transfer performance will be L XMbps. Assuming that the maximum transfer rates for decoding and display processing are T i bps and To bps, respectively, the transfer capacity that can be used for image storage processing and display image creation processing is (LXM—T i—To) bps. . Therefore, the image storage control unit 207 accumulates the total transfer capacity Tbit at the time of reading and writing from the memory in the image storage processing and the display image creation processing in a fixed cycle, here, one line display period, and Controls transfer processing in storage processing and display image creation processing.

 For example, if the vertical synchronization frequency is 60 Hz and the number of vertical lines is 525, the transfer capacity condition for one line period should be such that the relationship of (LXM—T i -To) / (60 X 525) is satisfied. Reads and writes from memory in image storage processing and display image creation processing.

 On the other hand, when the transfer capacity condition during one line period is such that T≥ (LXM—Ti—Το) / (60 × 525), the transfer process is interrupted and the horizontal synchronization signal from the display processing unit 105 is interrupted. Transfer processing is resumed at the start of the next one-line display period determined by 105a.

 In such a still image processing apparatus according to the second embodiment, the capacity usable as the image storage memory 108 is calculated from the total memory capacity and the memory usage capacity, and the image storage processing and display image creation are performed based on the memory transfer performance. By controlling the transfer processing in the processing, high-speed image output processing of a still image according to an arbitrary memory capacity and memory transfer performance can be realized.

(Embodiment 3) FIG. I0 is a block diagram showing a configuration of a still image processing device according to Embodiment 3 of the present invention.

 The still image processing apparatus according to the third embodiment is externally input in place of the scaling processing section 103, the image storage processing section 107, and the display processing section 105 in the first embodiment. A display size is determined based on the display setting information, and an enlargement / reduction processing unit 303 that enlarges / reduces the image data read from the decoded image memory 102 so that the display size is obtained. A rotation processing unit that determines a rotation angle based on the image output setting information, and uses the rotation angle to perform rotation processing on the image data read from the display image memory 104; And a display processing unit 305 for performing display processing on the data. Note that the image output setting information includes information on a rotation angle with respect to the decoded image.

 As shown in FIG. 12, the rotation processing unit 3007 includes a rotation processing control unit 311, a rotation processing execution unit 312, a working memory A 3 13, a working memory B 3 14, and It has a working memory C 3 15.

 Further, as shown in FIG. 15, the display processing unit 300 has a Y-line buffer 321, a C-line buffer 32, a thinning-out processing unit 32, and a display execution unit 32. Things.

 Next, the operation will be described. Note that the decryption processing is the same as in the first embodiment, and a description thereof will not be repeated.

 The enlargement / reduction processing section 303 detects the display size from the image output setting information, and performs enlargement / reduction processing on the decoded image data read from the decoded image memory 102. As a result, the created display image is stored in the display image memory 104 at a pixel sampling ratio of 4: 4: 4. Pixel sampling 4: 4: 4 is an image signal in which four pixels of the luminance signal Y have four color difference signals Cb and Cr, respectively, as shown in FIG.

 After that, the rotation processing unit 307 performs a rotation process on the image data stored in the display image memory 104 at an angle of 90 degrees to save the data stored in the display image memory 104. Update.

Here, the operation of the rotation processing unit 307 will be described. The rotation processing control unit 311 starts the rotation processing upon receiving the end notification from the enlargement / reduction processing unit 303, detects the rotation angle from the image output setting information, notifies the rotation processing execution unit 312, and then displays the rotation image. The image data of NX N pixels (N is a natural number) is transferred from the 104 to the working memory A 313.

 The rotation processing execution unit 312 performs rotation processing on the image data stored in the working memory A 313 using the rotation angle notified from the rotation processing control unit 311 and stores the rotation in the working memory B 314. I do. At this time, during the rotation processing by the rotation processing execution unit 312, the rotation processing control unit 311 stores the image data of NX N pixels in the vertical and horizontal directions of the area to be stored in the display image memory 104 after the rotation processing from the display image memory 304. The data is saved in the memory C 315 and the data in the working memory B 314 is transferred to the display image memory 104 after the rotation processing of the rotation processing execution unit 312 is performed. Thus, the rotation process of the vertical and horizontal NX N pixels is completed.

 After that, the same rotation processing is performed on the image data of the vertical and horizontal NXN pixels saved in the working memory C315. In this way, the rotation processing of the entire screen is executed by continuously performing the rotation processing of the vertical and horizontal NXN pixels.

 When the pixel sampling of the image to be stored in the display image memory 104 is 4: 2: 2, as shown in FIG. 13 (a), as shown in FIG. , And C r are half the data amount, and as shown in Fig. 13 (b), the chrominance signals Dc b and Dcr for the luminance signal Dy are interpolated in the vertical direction of the data after 90 ° rotation. There is a need. In addition, the color difference signals Ac b and Ac r for the luminance signal Ay are unnecessary and are deleted. As described above, each time the rotation processing is performed on the image data stored in the display image memory 104, the color difference signals are interpolated, and the color difference signals before and after the rotation processing change, so that the image quality is reduced.

 Therefore, the pixel sampling of the image to be stored in the display image memory 104 is 4: 4: 4. FIG. 14 (a) shows an example of an image of pixel sampling 4: 4: 4, and FIG. 14 (b) shows the image after the rotation processing of the 14 (a) image. In this case, it is not necessary to perform interpolation during the rotation processing as shown in FIG. 13, so that it is possible to prevent a decrease in image quality.

Next, the operation of the display processing unit 305 will be described. In the input data, one line of data is buffered in the Y line buffer 321 for the luminance signal and the C line buffer 322 for the color difference signal. The luminance signal is input to the display execution unit 324, whereas the color difference signal is decimated by a factor of 2 by the decimation processing unit 323 and input to the display execution unit 324. As a result, the pixel sampling of the display execution unit 324 is converted to 4: 2: 2 and output. Since the output pixel sampling ratio is 4: 2: 2, the output signal is the same as the output signal of the conventional image processing circuit. 'In the still image processing apparatus according to the third embodiment, the pixel sampling of the image to be stored in the display image memory 104 is 4: 4: 4, and the pixel sampling 4: 4: 4 data is rotated. The rotation processing unit 307 that performs the rotation processing and the display processing unit 305 that converts the pixel sampling of the image after the rotation processing to 4: 2: 2 can prevent deterioration of the rotated image. Further, it is not necessary to perform re-decoding processing for re-rotation processing of the same image, so that still image output processing can be speeded up. Industrial applicability

 INDUSTRIAL APPLICABILITY The still image processing apparatus and the still image processing method according to the present invention have a function of outputting a still image at high speed and are useful for a JPEG image display device.

Claims

The scope of the claims 1. In a still image processing device that decodes and displays compressed image data, a decoding processing unit that decodes the compressed image data,  A first memory for storing the decoded image data,  An enlargement / reduction processing unit that enlarges or reduces the image data read from the first memory;  A second memory for storing image data enlarged or reduced to have an image storage size by the enlargement / reduction processing unit;  A third memory for storing image data that has been enlarged or reduced to the display size by the above-mentioned enlargement / reduction processing unit;  A display processing unit that reads image data from the third memory and outputs the read image data.  A still image processing apparatus characterized by the above-mentioned. 2. In the still image processing device according to claim 1,  The decoding processing unit, the scaling processing unit, and the display processing unit, and a memory control unit that controls data transfer between the memories.  A still image processing apparatus characterized by the above-mentioned. 3. In the still image processing device according to claim 1,  An image storage control unit that determines the image storage size based on output device resolution information input from the outside and notifies the enlargement / reduction processing unit;  A still image processing apparatus characterized by the above-mentioned. 4. In the still image processing device according to claim 1,  The image storage size is determined based on the second memory capacity, which is calculated from the first, second, and third memory total capacities and the first and third memory usage capacities, and the enlargement is performed. With an image storage control unit that notifies the reduction processing unit,  A still image processing apparatus characterized by the above-mentioned. 5. In the still image processing device according to claim 1, Based on the externally input memory transfer performance, the data transfer Equipped with an image storage control unit that controls the delivery amount,  A still image processing apparatus characterized by the above-mentioned.  6. The still image processing device according to claim 1,  An image storage control unit that determines the display size based on image output setting information input from outside and notifies the enlargement / reduction processing unit;  A still image processing apparatus characterized by the above-mentioned.  7. In a still image processing device for decoding and displaying compressed image data, a decoding processing unit for decoding the compressed image data,  A first memory for storing the decoded image data,  An enlargement / reduction processing unit that enlarges or reduces the image data read from the first memory;  A fourth memory for storing the enlarged or reduced image data,  A rotation processing unit that performs rotation processing on the image data read from the fourth memory, and stores the image data in the fourth memory;  A display processing unit that reads out the rotated image data stored in the fourth memory from the fourth memory, and displays and outputs the read image data.  A still image processing apparatus characterized by the above-mentioned.  8-The still image processing device according to claim 7,  A still image processing unit comprising: the decoding processing unit; the scaling processing unit; the rotation processing unit; and the display processing unit; and a memory control unit that controls data transfer between the memories. apparatus.  9. In the still image processing apparatus according to claim 7,  The image to be stored in the fourth memory is a 4: 4: 4 pixel sampling image,  The display processing unit is for obtaining an image of 4: 2: 2 pixel sampling by thinning out the image data read from the fourth memory.  A still image processing apparatus characterized by the above-mentioned.  10. The still image processing apparatus according to claim 7, The enlargement / reduction processing unit includes: A still image processing apparatus, wherein the display size is determined based on image output setting information input from the outside.  11. The still image processing apparatus according to claim 7,  The rotation processing unit,  Determining a rotation angle based on image output setting information input from the outside, and performing the rotation processing at the determined rotation angle;  A still image processing apparatus characterized by the above-mentioned.  12. A still image processing method for decoding and displaying compressed image data, comprising: decoding and storing processing for decoding the compressed image data and storing the decoded image data in a first memory. Reading, reducing the image to the image storage size, and storing the image in the second memory;  A display image storage processing step of reading image data from the second memory, enlarging or reducing the image data to the display size, and storing the image data in the third memory;  A display processing step of reading out image data from the third memory and displaying and outputting the image data;  A still image processing method, characterized in that:  1 3. In the still image processing method according to claim 1,  The image storage processing step is for determining the image storage size based on output device resolution information input from outside.  A still image processing method, characterized in that: 1 4. In the still image processing method according to claim 12,  The image storage processing step calculates a free memory space that can be used as the second memory from the first, second, and third memory total capacities and the first and third memory usage amounts, The image storage size is determined based on the calculated memory free space.  A still image processing method, characterized in that: 15. In the still image processing method according to claim 12, Each of the image storage processing step and the display image storage processing step It controls the amount of data transferred to each memory based on the memory transfer performance input from the unit.  A still image processing method, characterized in that:  1 6. In the still image processing method according to claim 1,  The display image storage processing step is for determining the display size based on image output setting information input from outside.  A still image processing method, characterized in that:  17. A still image processing method for decoding and displaying compressed image data, comprising: a decoded image storage processing step of decoding the compressed image data and storing the decoded image data in a first memory;  A display image storage processing step of reading image data from the first memory, enlarging or reducing the image data to a display size, and storing the image data in a fourth memory;  A rotation storage processing step of reading image data from the fourth memory, performing rotation processing, and storing the read image data in the fourth memory;  A display processing step of reading out the rotated image data stored in the fourth memory from the fourth memory and displaying and outputting the read out image data.  A still image processing method, characterized in that:  18. In the still image processing method according to claim 17,  The display image storage processing step is for processing the image to be stored in the fourth memory as a 4: 4: 4 pixel sampling image,  The display processing step is to obtain an image of 4: 2: 2 pixel sampling by thinning out image data read from the fourth memory.  A still image processing method, characterized in that:  1 9. In the still image processing method according to claim 17,  The display image storage processing step is for determining the display size based on image output setting information input from outside.  A still image processing method, characterized in that:  20. In the still image processing method according to claim 17, The rotation storage processing step is performed based on the image output setting information input from the outside. A still image processing method for determining a turning angle.