KR100612669B1 - Method for Displaying High-Resolution JPEG Pictures in Mobile Communication Terminal and Mobile Communication Terminal therefor - Google Patents

Abstract

The present invention relates to a method for displaying a high resolution JPEG image in a mobile communication terminal and a mobile communication terminal therefor.

A method for displaying a high resolution JPEG image in a mobile communication terminal of the present invention includes a format conversion unit for converting a high resolution JPEG image for each unit block, and a JPEG decoder for decoding the converted JPEG image. A method for displaying a high-resolution JPEG image in a mobile communication terminal, comprising: displaying the JPEG image data and a plurality of unit block image data so that a format converter can display a high-resolution JPEG image in units of blocks using the JPEG decoder; A format conversion step of converting a file format including an index for access to the image data for each block; A decoding block selection step of selecting at least a unit block constituting a partial image to be output to a display unit and extracting image data for each selected unit block using the index information according to a display command and a scroll action; And a decoding step of decoding the extracted block image data and outputting the same through a display unit.

Macroblock, DC coefficient

Description

Method for Displaying High-Resolution JPEG Pictures in Mobile Communication Terminal and Mobile Communication Terminal therefor}

1 is a conceptual diagram for explaining the data structure of a JPEG image;

2 is a conceptual diagram for explaining a high resolution JPEG image display method according to the present invention;

3 is a conceptual diagram for explaining a data structure of a JPEG image formatted and converted according to the present invention;

4 is a block diagram of a JPEG image file format according to an embodiment of the present invention;

5 is a block diagram of a mobile communication system according to an embodiment of the present invention;

6 is a configuration diagram of a mobile communication terminal of FIG. 5;

7 is a configuration diagram of a format conversion unit of FIG. 6;

8 is a configuration diagram of a DC coefficient conversion unit of FIG.

9 is a flowchart illustrating an image display process in a mobile communication terminal according to an embodiment of the present invention;

10 is a flowchart illustrating a DC coefficient conversion process of FIG. 9.

<Description of Symbols for Main Parts of Drawings>

100: whole image 101: unit block

200: JPEG image 201, 202: Macro block

210, 220: unit block 300: image file format

310: image header 320: additional information

330: index information 340: DC table for each block

350: encoded data 410: base station (BTS)

420: base station controller (BSC) 430: switchboard (MSC)

440: Short Message Service Center (SMSC)

450: Multimedia message service center (MMSC)

460: Packet data service node (PDSN)

470: Internet 480: image providing server

481: image data DB 490: computer terminal

500: mobile communication terminal 510: control unit

520: wireless transceiver 530: input unit

540: display unit 550: memory

551: decoding frame buffer 552: screen frame buffer

560: format conversion unit 561: image division unit

562: DC coefficient conversion unit 562a: Huffman decoding unit

562b: inverse quantization unit 562c: inverse DPCM unit

562d: DPCM section 562e: quantization section

562f: Huffman encoder 563: file generator

564: Thumbnail generation unit 570: Decoding block selection unit

580: JPEG decoder 590: external input port

591: camera

The present invention enables a high-speed JPEG image to be displayed at a high speed in a mobile communication terminal having a low resolution display means and a small amount of memory. More specifically, the JPEG image is converted into a predetermined block to enable partial display in units of blocks. It is possible to perform partial decoding of each block by dividing and compressing independently and compressing each block independently by configuring and encoding DC components without correlation with adjacent blocks.

Conventionally, when outputting image data to a terminal having a low resolution display means such as a mobile communication terminal, since the resolution of the real image and the resolution of the output terminal do not coincide, the image data is output at a resolution that the output terminal can support. Although the image data is reduced and output, the image data is reduced and output. Thus, a large amount of image data is lost and damaged during the reduction process, resulting in a problem of deterioration of image quality.

In addition, as a conventional image reproducing method, there is a method of decoding a whole compressed image, releasing it in large memory, and copying data of a position to be reproduced to a frame memory and outputting the compressed image stream to a display screen at once. Since the entire image to be decoded and stored in the memory must be stored in the memory, if the resolution of the image is very large, the memory requirement is very large and cannot be utilized where the system resources are limited such as a portable terminal device.

On the other hand, JPEG (Joint Photographic Expert Group), which is the most used image format, is compressed in units of blocks and retrieves a block data compression stream of a position to be decoded from the beginning of the file and retrieves and restores the position. If the compression method maintains the dependency of the data, it cannot be restored from some compressed streams.

More specifically, the baseline JPEG, which is a minimum specification of JPEG compression as a JPEG encoding method, converts image information from RGB to YIQ and converts the image of each color component (Y, I, Q) in units of macro blocks (8 X 8 pixels). Divide into macro blocks, then transform DCT (Discrete Cosign Transform) and linearly quantize the resulting DCT coefficients to different step sizes for each coefficient using a quantization table to visually important Reduce the amount of data by separating parts into less important parts, saving important parts and losing less important parts.

As described above, the DCT coefficients blocked and quantized in macroblock units are represented by one DC component (DC) and 63 AC components (AC), and the DC component has a difference from the adjacent previous block in consideration of the correlation between the adjacent signals. Differential Pulse Code Modulation (DPCM) and AC components are arranged in a line by zigzag scan for each block and then run-length coding.

In the structure of the data stream compressed by the JPEG compression method as described above, one image is bounded by a plurality of macroblocks 1, as shown in FIG. 1, and each macroblock 1 and 2 is one. DC components (1-1) (2-1) and EOB codes (1-2) (2-2) indicating the end of the block.

At this time, since the DC values (1-1, 2-1) of each macro block are coded for the difference signal with the previous block and are interdependent between the blocks, the JPEG format pictures cannot be decoded block by block, so There is a problem that a high speed hardware device is required because the entire file needs to be scanned in order to configure the display screen.

Accordingly, the present invention is to solve all the disadvantages and problems of the prior art as described above, the high-resolution JPEG image of each macro block constituting the JPEG image to partially display through a small display window using a small memory It is an object of the present invention to provide a method for displaying a high-resolution JPEG image in a mobile communication terminal having a JPEG decoder so that the DC coefficients are configured independently of each other and a mobile communication terminal therefor.

The above object of the present invention is a wireless transceiver for transmitting and receiving image data through a mobile communication network, an input unit for receiving a command from a user, a display unit for outputting an image, a memory for storing image data, and a JPEG image for decoding. A mobile communication terminal comprising a JPEG decoder, wherein the JPEG image data is divided into a plurality of unit block image data and each block image data so that a high resolution JPEG image can be displayed in block units using the JPEG decoder. A format converting unit converting the file format into an file format including an index for accessing the; A decoding block selection unit for selecting a minimum unit block constituting a partial image to be output to the display unit and extracting image data for each selected unit block using the index information; And a JPEG decoder that receives and decodes the block-specific image data extracted from the decoding block selection unit and outputs the same through the display unit.

In addition, the object of the present invention is a wireless transceiver for transmitting and receiving image data through a mobile communication network, an input unit for receiving a command from a user, a display unit for outputting an image, a memory for storing the image data, A method for displaying a high resolution JPEG image in a mobile communication terminal comprising a format converting unit for converting a high resolution JPEG image to allow access per unit block and a JPEG decoder for decoding the format converted JPEG image, The format converter includes an index for accessing the JPEG image data to a plurality of unit block image data and the image data for each block so that the JPEG converter can display a high-resolution JPEG image in block units using the JPEG decoder. A format conversion step of converting the file format; A decoding block selection step of selecting at least a unit block constituting a partial image to be output to the display unit and extracting image data for each selected unit block using the index information according to a display command and a scroll action; And decoding the extracted block-by-block image data and outputting the same through the display unit. A method of displaying a high-resolution JPEG image in a mobile communication terminal is performed.

Details of the above objects and technical configurations of the present invention and the effects thereof will be more clearly understood by the following detailed description based on the drawings showing the preferred embodiments of the present invention.

First, Fig. 2 is a conceptual diagram for explaining a high resolution JPEG image display method according to the present invention.

As shown, in order to implement a method for displaying a high-resolution JPEG image according to the present invention, the entire image 100 is divided into a plurality of unit blocks 101, each unit block 101 is block-specific data Independently compressed and stored so that there is no dependency between blocks to allow access, the compressed data is stored according to the file format of FIG.

Referring to the conceptual diagram of FIG. 2 in more detail, first, the entire image 100 to be scroll-displayed is divided into a predetermined size and composed of a plurality of unit blocks 101, as shown in FIG. The number of blocks is given.

At this time, the buffer for reproducing the image data is composed of a screen frame buffer and a decoding frame buffer, the screen frame buffer stores the data 110, 111 to be actually output to the display unit of the mobile communication terminal, the decoding frame buffer The decoded data 120 and 121 of the block unit including all the data 110 and 111 to be actually output are stored.

In this case, the size of the unit block 101 and the capacity of the decoding frame buffer may be determined according to the performance of the mobile communication terminal and the amount of available memory.

In FIG. 2, the data 110 of the current screen frame buffer including the image data output on the current screen is the data of block B23 and the partial data of blocks B13, B14, B15, B22, B24, B31, B32, and B33. The data 120 of the current decoding frame buffer includes all of B13, B14, B15, B22, B23, B24, B31, B32, and B33, and a part 110 of the data 120 of the decoding frame buffer. ) Is copied to the screen frame buffer and displayed.

In this case, when a scroll action for moving a display image occurs during display of the image in the mobile communication terminal, the mobile communication terminal recalculates a block to be decoded, and reads the block data from where the block data is stored. And decoding to modify the decoding frame buffer.

That is, for example, when the current screen frame is moved downward by the range to be scrolled by scrolling the image vertically downward, the data 111 buffered in the modified screen frame buffer does not include B13, B14, and B15. Including the parts of B40, B41, and B42, the data 121 of the modified decoding frame buffer at the position to be displayed again on the screen is partially outside the area of the current decoding frame buffer data 120.

Accordingly, blocks B40, B41, and B42 are further decoded and buffered in the modified decoding frame buffer, and data of blocks B13, B14, and B15 that are currently included in the decoded frame buffer are deleted.

As such, the data 121 buffered in the modified decoding frame buffer always includes all the data 111 of the screen frame buffer, and in this way, the minimum block unit necessary for displaying on the screen while modifying the decoding frame buffer. Only high resolution data is decoded so that a high resolution image is displayed at high speed through a small screen by automatic or manual scrolling with only a small amount of memory.

On the other hand, in order to display the image data in units of blocks as described above, each unit block should not have mutual dependence. The image data of the JPEG format in which a plurality of macro blocks constituting one image are mutually interdependent is used according to the present invention. Each unit block must be reconfigured to have no dependencies for display. This will be described with reference to FIG. 3.

3 is a conceptual diagram for explaining the data structure of a JPEG image that has been format converted according to the present invention.

As illustrated, one JPEG image 200 is divided into a plurality of unit blocks 210 to access data for each block, and each unit block 210 includes a plurality of macro blocks 201.

In this case, as described in FIG. 1, each macro block constituting the JPEG picture has a DC value that is mutually dependent, so that one JPEG picture 200 is divided into a plurality of unit blocks as shown in FIG. When divided into 210 and 220, the DC values between the unit blocks 210 and 220 do not have mutual dependency, so that the DC values 201-1 to 202-9 and 202-1 to the unit blocks 210 and 220 do not have mutual dependence. 202-9 may be an independent value to decode the JPEG image 200 in block units.

In this case, the decoding unit is a unit block (210, 220) unit divided into a predetermined size, the DC value is independent between each unit block (210, 220), one unit block (210, 220) The DC value of each of the macroblocks 201 and 202 constituting the is preferably configured to be a mutually dependent value in consideration of memory limitations.

That is, in FIG. 3, each DC value 201-1 to 201-9 of the nine macroblocks 201 constituting the first unit block 210 encodes only a difference value of the DC value of the previous macroblock. Each DC value 202-1 to 202-9 of the nine macroblocks 202 constituting the second unit block 220 is encoded using a DPCM coding scheme regardless of the previous unit block 210. .

Next, FIG. 4 is a configuration diagram of a JPEG image file format according to an embodiment of the present invention, which shows a file format stored in the mobile communication terminal 500 to be displayed by the display method of FIG.

As shown, the file format 300 of the JPEG picture used in the present invention is largely divided into an image header 310, additional information 320, index information 330, block-by-block DC table 340, and block-by-block encoded data. And 350.

The image header 310 includes information on the size of the entire image, such as the width and length, the number of bits per pixel, the size of each unit block, and the like as the information about the image.

The additional information 320 includes various pieces of information for additional display, such as a thumbnail of a high-resolution JPEG image, and includes a predetermined number of block position information constituting a portion initially displayed on the terminal, description of the image, and the like. Summary text information and the like.

The index information 330 is positional information for accessing the image data of each block stored in the file. The index information 330 refers to information for quickly accessing the image data of the corresponding block using the block information, and the encoding data 350 represents each block. Each block image data compressed and stored in units is included.

In addition, the block-specific DC table 340 has no mutual dependency between unit blocks as described with reference to FIG. 3, but stores the DC value itself re-encoded as a mutually dependent value between each macroblock in one unit block as a table. As this, according to the amount of memory supported by the terminal, each DC component may be stored together with the encoding data 350 for each block, or may be separately stored in the form of a table 340 as shown in the figure.

A method of displaying a high-resolution JPEG image on a small display window using the image file format as described above and an embodiment of a mobile communication terminal therefor will be described below with reference to FIGS. 5 to 10.

First, Figure 5 is a block diagram of a mobile communication system according to an embodiment of the present invention.

As shown, the mobile communication system is connected to the base station (BTS, 410) performing the wireless section communication with the mobile communication terminal 500, the base station controller (BSC, 420) for controlling the base station, the base station controller and call exchange A packet for data service to the mobile communication terminal 500 that is connected to an exchange (MSC) 430, a short message service center (SMSC, 440), a multimedia message service center (MMSC, 450), and the Internet 470, And a data service node (PDSN) 460.

The mobile communication terminal 500 receives image data in JPEG format from the image providing server 480 including the image data DB 481 and the multimedia message service center 450 through the packet data service node 460. The image providing server 480 may be connected via the Internet 470 using the computer terminal 490.

Referring to FIG. 6, a mobile communication terminal 500 for receiving and displaying image data in JPEG format through the mobile communication system as described above is described below.

6 is a block diagram of the mobile communication terminal 500 of FIG. 5, the mobile communication terminal 500 according to an embodiment of the present invention uses a format of JPEG image data received through the mobile communication system. It is configured to be able to convert as shown in FIG. 4 and display the format-converted image file as described with reference to FIG.

The mobile communication terminal 500 basically includes a control unit 510 for controlling the overall operation, a wireless transceiver 520 for receiving image data through the base station 410, a user such as a keypad or a touch screen panol. And an input unit 530 for receiving a command from the user, a display unit 540 for displaying an image or a video, and a memory 550 for storing each data.

In addition, the mobile communication terminal 500 decodes the decoding frame buffer 551 and the decoded frame buffer 551 for buffering data in block units including all of the portions displayed on the current screen as part of an image. Screen frame buffer 552 for copying and buffering only the data of the portion displayed on the current screen.

In addition, for the present invention, the mobile communication terminal 500 scrolls a format converter 560 for converting a format of image data received through the wireless transceiver 520 and the format-converted image file. A decoding block selecting unit 570 for selecting a block to be displayed on the display unit 540 of the terminal 500 to display in units of blocks, and a JPEG decoder 580 for decoding the selected block.

In addition, the mobile communication terminal 500 further includes an external input port 590 for receiving data from an external connection device such as a camera 591, and inputs the image data captured by the camera 591 to the external input. It may be inputted through the port 590 and converted and displayed.

On the other hand, the format conversion unit 560 is divided into a plurality of unit blocks to display the image data received through the wireless transceiver 520 or the external input port 590 in units of blocks and each It converts to a file format including an index for a block and stores it in the memory 550.

When the picture of the format-converted file is requested to be displayed, the decoding block selector 570 selects the minimum unit block constituting the partial image to be output to the display unit 540 and selects the selected unit block. Star image data is extracted using the index information, and a corresponding block is extracted by calculating a position to be displayed by a user input or an automatic scrolling action during display of the image.

The JPEG decoder 580 that decodes a JPEG image decodes the block-specific image data extracted from the decoding block selector 570 and outputs the decoded image data through the display unit 540. In this case, the decoding process is based on the compression method of the JPEG image. When the JPEG image compression method is a baseline method including a DCT process, a quantization process, and an entropy encoding (eg, Huffman encoding) process, the decoding process may include entropy decoding and inverse quantization. This includes reverse DCT courses.

Next, the memory 550 decodes a frame for buffering each unit block including a screen frame buffer 110 for buffering an image output to the display unit 540 and an image output to the display unit 540. It is preferable to include a buffer 120, the JPEG decoder 580 buffers the data for the extracted block in the decoding frame buffer 120, a portion of the data buffered in the decoding frame buffer 120 (Parts displayed on the screen) can be copied to the screen frame buffer 110 and output.

If the data of the extracted block and the data displayed on the screen are the same, it is obvious that the decoding frame buffer 120 and the screen frame buffer 110 need not be separately configured.

Next, FIG. 7 is a diagram illustrating the format converter 560 of FIG. 6.

As shown, the format converter 560 includes an image divider 561, a DC coefficient converter 562, a file generator 563, and a thumbnail generator 564. .

The image dividing unit 561 divides a JPEG image composed of a plurality of macro blocks into a plurality of unit blocks. In this case, the unit block is not limited to a specific size or shape, but is variable according to the performance of the terminal, the supportable resolution, the amount of memory, and the like, and the size or shape of each unit block does not have to be the same.

The DC coefficient converting unit 562 re-encodes the DC values for each macro block constituting the JPEG image as independent values for each unit block divided by the image dividing unit 561. The DC coefficient converter 562 will be described in more detail with reference to FIG. 8.

Next, the file generator 563 independently stores the re-encoded image data for each unit block, and sets an index for each block to quickly access the image data of each unit block to be recalled according to a scroll action. It is generated and stored together with the image data for each block. In this case, it is preferable to simultaneously generate the size of the entire image, the size information of each unit block, the positional information of the initial display block, and the like as the image header, and together generate the summary text information of the image as the additional information.

The thumbnail generator 564 generates a thumbnail image of a high-resolution JPEG image, and generates a thumbnail image by combining DC values for each macro block generated during a compression process of the JPEG image.

FIG. 8 is a configuration diagram of the DC coefficient converting unit 562 of FIG. 7 and shows a configuration of an embodiment for converting DC coefficients when a JPEG image is compressed by a general baseline compression method. The configuration can be changed by.

First, in order to explain the image compression method in JPEG format for the description of the DC coefficient converter 562, each picture element (Y, I, Q) constituting the image is divided into macroblocks of 8x8 pixels, The block provides 64 inputs of the DCT (Discrete Cosine Transform) function, and by the DCT process, one picture consists of 64 coefficient sets consisting of one DC component and 63 AC components.

Next, each coefficient value is divided into 64 divisors so that a coefficient with a value similar to 0 becomes 0, the remaining values are gathered into approximations, and quantized, and the quantized data is again Huffman Coding to reduce the amount of data. do.

As described above, the DC coefficient converting unit 562 for re-encoding the DC coefficients generated in the compression process of the JPEG format image is the Huffman decoding unit 562a, the inverse quantization unit 562b, and the inverse DPCM unit 562c. And a DPCM section 562D, a quantization section 562e, and a Huffman encoding section 562f.

The Huffman decoding unit 562a extracts the DC coefficient by Huffman decoding the DC component of the JPEG image data.

The extracted DC coefficient is a quantized value as described above, and the inverse quantization unit 562b inversely quantizes the quantized DC coefficient, and the inverse DPCM unit 562c inverse DPCMs the DC component to perform each macroblock. Find the DC component of. At this time, the result of the inverse DPCM is a difference value of the DC components between the macroblocks.

Next, the DPCM unit 562D obtains the original DC value, that is, the independent DC value, which is not the difference value between the macroblocks, by using the detected difference value of the DC component, and then DPCM-codes each of the unit blocks.

In this case, the DPCM unit 562D obtains original DC values of all macroblocks constituting the image and obtains only DC values of the first macroblock of the unit block constituting the image, without having to obtain differential values again in units of blocks. The DC value of the remaining macroblock of one unit block is encoded as it is a difference value from the DC value of the first macroblock. In this way, each DC component constituting the image becomes a dependent value only within the unit block.

Next, the quantization unit 562e quantizes the DPCM-coded DC component using a quantization table, and the Huffman encoding unit 562f encodes and encodes the quantized DC component by Huffman again and decodes it by the JPEG decoder 580. To be possible.

Meanwhile, in the above description, the format conversion process including the conversion of the DC coefficients for causing the image to be displayed in units of blocks by the JPEG decoder 580 of the mobile communication terminal 500 is performed inside the mobile communication terminal 500. Although configured to be performed, a separate server capable of transmitting and receiving data with the mobile communication terminal 500 includes a format conversion unit 560 to display a high-resolution JPEG image for each block by the JPEG decoder 580 of the terminal 500. It is also possible to convert the format so as to provide it to the mobile communication terminal (500).

Next, the operation of the mobile communication terminal 500 according to an embodiment of the present invention having the above configuration will be described with reference to FIGS. 9 and 10.

9 is a flowchart illustrating an image display process in a mobile communication terminal according to an embodiment of the present invention.

As shown, the mobile communication terminal 500 is a high-resolution JPEG format image from various image providing apparatuses such as an image providing server 480 or a camera 591 through a wireless transceiver 520 or an external input port 590. Upon receiving the data, the format conversion unit 560 loads an image for format conversion so that the JPEG image data can be displayed for each unit block (S110).

The format converter 560 divides the JPEG image into a plurality of unit blocks as described in FIG. 2 or FIG. The DC coefficients of the macroblocks are converted (S130). The conversion process of the DC coefficient will be described with reference to FIG.

Next, the format converter 560 independently stores the encoded data for each unit block divided as the DC coefficients are converted, and an index, an image header, and an append for quick access to the encoded data for each block. Information is generated and stored in the memory 550, a conversion file including encoded data per block according to the file format shown in FIG. 4 (S140).

In this case, the image header may include overall size information of an image and size information of each unit block, and the additional information may include a thumbnail of an image, position information of an initial display block, image summary text information, and the like. The thumbnail of the picture is generated by a combination of DC components of each macro block constituting the JPEG picture.

On the other hand, when the display command of the JPEG image converted in the format as described above in the mobile communication terminal 500 (S150), under the control of the control unit 510 parses the image header, additional information and index information of the JPEG image In operation S160, some information about the image is displayed on the display unit 540.

Next, the decoding block selector 570 extracts image data for an initial decoding block including an initial image (part of the entire image) to be displayed on the display 540 by using the index of the file format and decodes the image data. The data is passed to the JPEG decoder 580 (S170).

The JPEG decoder 580 decodes JPEG data of the corresponding block selected by the decoding block selector 570 and displays the JPEG data on the display unit 540 (S180).

The JPEG decoder 580 may buffer the corresponding data for the block in the decoding frame buffer and copy the data buffered in the decoding frame buffer to the screen frame buffer to display the initial image.

In this case, when automatic scrolling is set on the mobile communication terminal 500 or the JPEG image itself, or when a scroll action is generated by an input by a user's keypad or touch screen (S190), the decoding block selector 570 is configured to scroll. Accordingly, the screen is moved within the entire image to calculate a position to be displayed to extract a block to be decoded (S200).

The decoding block selector 570 determines whether the shifted block data is included in all of the blocks decoded in the previous decoding frame buffer, that is, whether there is a block to be further decoded and configures the moved screen. If any data to be found does not exist at all in the previous decoding frame buffer (if there are additional blocks to decode), then the newly decoded block is passed to the JPEG decoder 580, and the JPEG decoder 580 moves the corresponding move. By decoding the block data added according to the direction, the decoding frame buffer is corrected, the contents of the decoding frame buffer of the corresponding position are copied to the screen frame buffer, and the moving image is output through the display unit 540 (S210).

On the other hand, when the automatic scrolling is set, a series of processes for displaying an image are terminated as a user's key input for interrupting the automatic scrolling is generated, and the display process of the image is caused by scrolling by the user's input. If performed, the display process is terminated as the scroll input is interrupted by the user.

Finally, FIG. 10 is a flowchart showing the DC coefficient conversion process of FIG. 9, wherein the DC coefficient conversion process depends on the JPEG image compression method, and the present invention will be described only when the JPEG compression method is the baseline compression method. .

As shown, the DC coefficient converting unit 562 extracts the quantized DC coefficients by Huffman decoding DC components of the block-completed JPEG image data (S131), and inversely quantizes the extracted DC coefficients (S132). .

Next, the DC coefficient converting unit 562 decodes the dequantized DC coefficients by inverse DPCM, that is, DPCM, and detects a difference value of the DC components between the macroblocks (S133), and uses the detected difference values of the DC components. In operation S134, DPCM coding is performed in units of divided unit blocks.

That is, the DC coefficient converting unit 562 may add the difference value of the detected DC component and the DC value of the first macro block to obtain the original DC value of each macro block. Only the DC value of the first macro block of each unit block is converted to the original DC value so that each DC value is maintained as a mutually dependent value, and then DPCM coded for each unit block.

Next, the DC coefficient converter 562 quantizes the re-DPCM coded DC components using the quantization table as described above to enable decoding by the JPEG decoder 580 (S135), and Huffman again the quantized DC components. Encode and encode (S136).

The format conversion process including the conversion of the DC coefficients according to the present invention may be performed in a separate server, and as described above, the JPEG-compressed image for each unit block is part of the mobile communication terminal 500 according to the present invention. It may be decoded and displayed in unit blocks.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Accordingly, the method for displaying a high resolution JPEG image in the mobile communication terminal of the present invention and the mobile communication terminal for this purpose are to independently configure the high-resolution JPEG image by having the DC coefficients of each macro block constituting the JPEG image independent of each other. The JPEG decoder provided in the mobile communication terminal can be partially displayed through a small memory and a small display window.

Claims (8)

A wireless transmission and reception unit for transmitting and receiving image data through a mobile communication network, an input unit for receiving a command from a user, a display unit for outputting an image, a memory for storing image data, and a JPEG decoder for decoding a JPEG image. In the communication terminal, Convert the JPEG image data into a file format including an index for accessing the image data of a plurality of unit blocks and the image data of each block so that a high resolution JPEG image can be displayed in units of blocks using the JPEG decoder. A format conversion unit; A decoding block selection unit for selecting a minimum unit block constituting a partial image to be output to the display unit and extracting image data for each selected unit block using the index information; And A JPEG decoder which receives and decodes the block-specific image data extracted from the decoding block selection unit and outputs the same through the display unit; Mobile communication terminal, characterized in that comprises a. The method of claim 1, The format conversion unit, An image dividing unit for dividing a JPEG image composed of a plurality of macro blocks into a plurality of unit blocks; A DC coefficient converting unit which re-encodes DC values for each macro block constituting a JPEG image as independent values for each of the divided unit blocks; And A file generation unit for storing the re-encoded image data independently for each unit block and generating index information for access to the image data for each block; Mobile communication terminal, characterized in that comprises a. The method of claim 2, The DC coefficient converter, A Huffman decoding unit Huffman decoding the DC components of the JPEG image data to extract quantized DC coefficients; An inverse quantization unit inversely quantizing the quantized DC component; An inverse DPCM unit for inverse DPCM of the DC component to detect a difference value of the DC component between each macroblock; A DPCM unit for obtaining a DC value of the first macroblock of each divided unit block by using the detected DC component difference, and DPCM again for each unit block so that the DC component is interdependent only in each unit block; A quantizer for quantizing the DPCM-coded DC component using a quantization table; And A Huffman encoding unit which encodes the quantized DC components by Huffman encoding; Mobile communication terminal, characterized in that comprises a. The method of claim 2, The format conversion unit, And a thumbnail generator which extracts DC values for each macro block constituting the JPEG image to generate a thumbnail image. A wireless transmission / reception unit for transmitting and receiving image data through a mobile communication network, an input unit for receiving a command from a user, a display unit for outputting an image, a memory for storing image data, and a high-resolution JPEG image per unit block A method for displaying a high resolution JPEG image in a mobile communication terminal, comprising a format conversion unit for converting to be accessible and a JPEG decoder for decoding the format converted JPEG image, The format converter includes an index for accessing the JPEG image data to a plurality of unit block image data and the image data for each block so that the JPEG converter can display a high-resolution JPEG image in block units using the JPEG decoder. A format conversion step of converting the file format; A decoding block selection step of selecting at least a unit block constituting a partial image to be output to the display unit and extracting image data for each selected unit block using the index information according to a display command and a scroll action; A decoding step of decoding the extracted block-specific image data and outputting the same through the display unit; Method for displaying a high-resolution JPEG picture in a mobile communication terminal comprising a. The method of claim 5, The format conversion step, An image division step of dividing a JPEG image composed of a plurality of macro blocks into a plurality of unit blocks; A DC coefficient conversion step of re-encoding the DC values for each macro block constituting the JPEG image as independent values for each of the divided unit blocks; And A file generation step of storing the re-encoded image data independently for each unit block and generating index information for access to the image data for each block; Method for displaying a high-resolution JPEG picture in the mobile communication terminal characterized in that comprises a The method of claim 6, The DC coefficient conversion step, Huffman decoding the DC components of the JPEG image data to extract quantized DC coefficients; Dequantizing the quantized DC component; Reverse DPCM the DC components to detect differential values of the DC components between each macroblock; Obtaining a DC value of the first macroblock of each divided unit block using the detected difference of the DC component, and DPCM again for each unit block such that the DC component is interdependent only in each unit block; Quantizing the DPCM coded DC component using a quantization table; And Huffman encoding and encoding the quantized DC component again; Method for displaying a high-resolution JPEG picture in a mobile communication terminal comprising a. The method of claim 5, The format conversion step, Generating a thumbnail image by extracting DC values for each macro block constituting the JPEG image, and displaying the thumbnail image according to a display command; Method for displaying an image.

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