JP2014045290A - Image output device, image processing apparatus, image output control method and image output control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform format conversion of data and output the data to the outside while suppressing data traffic and memory capacity.SOLUTION: In an image display device 1, when a display control signal generation section 11 converts YCbCr data to target image data of an RGB format to be output to a display 20 by converting corresponding pieces of line data of planes, Cb and Cr planes of line data of the YCbCr data, which are planes with fewer lines, are lossless-compressed line by line by a static Huffman coding method in a compression processing section 12 and then retained in a storage section 13, and under the control of a control section 15, the Cb and Cr planes of line data from a system memory 30 and line data expanded in an expansion processing section 14 from the line data in the storage section 13 are alternately input into the display control signal generation section 11 in synchronism with a Y plane of line data from the system memory 30.

Description

  The present invention relates to an image output apparatus, an image processing apparatus, an image output control method, and an image output control program. More specifically, the present invention relates to an image output apparatus, an image processing apparatus, and an image output control that perform data format conversion and externally output data. The present invention relates to a method and an image output control program.

  In an image processing apparatus such as a printer apparatus, a copying apparatus, a composite apparatus, or a scanner apparatus, image data in a predetermined format stored in a memory of the image processing apparatus, for example, color difference (Cb, Cr) and luminance (Y) Image data formatted in YCbCr, for example, YCbCr420 (hereinafter simply referred to as YCbCr as appropriate) is displayed on a display unit such as an LCD (Liquid Crystal Display). ), Green, and blue) to display an image.

  Conventionally, the image processing apparatus converts the format of YCbCr image data in the memory of the image processing apparatus into RGB image data for each line by the image processing unit, and converts the RGB pixel data to the display unit in the scanning order. The image data is transferred and displayed on the display unit.

  However, the image data of YCbCr is configured as a frame in which three planes of Y plane, Cb plane, and Cr plane are overlapped. However, the number of samples in the sub-scanning direction of Cb plane and Cr plane is equal to that of Y plane. One half of the number of samples in the scanning direction.

  Therefore, the conventional image processing apparatus includes a line buffer in the image processing unit for the Cb plane and the Cr plane, and converts the two lines of the Y plane into RGB image data, while converting the Cb plane and the Cr plane of the line buffer. A method in which line data is converted to RGB corresponding to each line of the Y plane, or the image processing unit acquires line data of the Y plane, Cb plane, and Cr plane from the memory in the scanning order, and performs conversion processing. After performing one line, for the Y plane, the next line of the memory is accessed, and for the Cb plane and the Cr plane, the same line of the memory is accessed again to acquire line data and perform conversion processing. A method of repeating every time is used.

  However, the method using the line buffer for the Cb plane and the Cr plane requires a buffer having a capacity larger than the data amount for one line for each plane, so that the buffer having a larger capacity as the horizontal resolution of the display increases. There is a problem that the capacity of the buffer increases and the cost increases.

  In addition, with respect to one line of the Y plane, the method of accessing the memory twice for the Cb plane and the Cr plane is as follows. Therefore, there is a problem that a load is applied to the bus band between the memory side and the image processing unit.

  Conventionally, color image display data is divided into RGB color component planes, and the difference value between each pixel and a pixel adjacent in the scanning direction is calculated, and the difference value is determined for each predetermined processing pixel unit. Then, the compressed data storage method corresponding to the size of the difference value is set, the compressed information data indicating the compressed data storage method is stored in the compressed information buffer, and the compressed data corresponding to the compressed information data is compressed. Store in the data buffer. If any of the difference values exceeds a predetermined threshold value, the original data of each pixel is set as compressed data. If all the difference values are equal to or less than the threshold value, the difference value of each pixel is set as compressed data, and all the difference values are 0. In this case, a display data processing apparatus that eliminates compressed data has been proposed (see Patent Document 1).

  That is, this prior art divides a color image into planes of each color, stores compressed data compressed based on a difference value for each pixel adjacent in the scanning direction for each plane, and stores the data in a compressed data buffer. Display data is restored from the compressed value.

  However, in the prior art described in the above publication, a compressed image is obtained by dividing a color image into planes of each color and compressing compressed data based on a difference value for each pixel adjacent in the scanning direction for each plane. Since the display data is only restored from the compressed value, for example, the image data of a format having a plane in which the number of samples in the sub-scanning direction is different, such as a Cb plane and a Cr plane of YCbCr. In the case of output after converting the format, the cost of using a line buffer is high, and for planes with a small number of lines, the bus bandwidth between the memory side by accessing more memory than other planes Such a load problem cannot be solved.

  In view of this, the present invention provides conversion source image data of a predetermined format composed of a plurality of planes including a small line plane of a small number of lines with a small number of lines. It is intended to convert to the destination image data.

  In order to achieve the above object, the image output apparatus according to claim 1, wherein a plurality of planes in which one line in the main scanning direction is a line and the line data is arranged in a sub-scanning direction orthogonal to the main scanning direction are a predetermined number of lines. Conversion source image data of a predetermined format including a small line plane consisting of small line data with a small number of lines at a predetermined magnification in the sub-scanning direction is subjected to conversion processing for each corresponding line data of each plane Format conversion means for converting the image data into the conversion destination image data, compression means for compressing the line data of the small line plane from the conversion source image data line by line by a predetermined compression method, and compression by the compression means A storage unit having a predetermined capacity for storing compressed data for one line, and the compressed data stored in the storage unit A decompression unit that decompresses the conversion source image data from the outside, and the line data of any one of the line data of the small line plane and the line data decompressed by the decompression unit of the conversion source image data And a data control means for inputting the data to the format conversion means in accordance with the line data corresponding to the plane other than the small line plane.

  According to the present invention, conversion source image data of a predetermined format composed of a plurality of planes including a small line plane of a small number of lines and a small number of lines can be converted into a predetermined format at a low cost while suppressing the amount of captured data of the conversion source image data. Can be converted into the destination image data.

1 is a block configuration diagram of an image display device to which an embodiment of the present invention is applied. The detailed block block diagram of the principal part for image processing. The flowchart which shows an image display control process. The flowchart which shows a compression process. 10 is a flowchart showing decompression processing.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all the configurations described in the present embodiment are essential constituent elements of the present invention.

  1 to 5 are diagrams showing an embodiment of an image output apparatus, an image processing apparatus, an image output control method, and an image output control program according to the present invention. FIG. 1 shows an image output apparatus and image processing according to the present invention. 1 is a block configuration diagram of an image output apparatus 1 to which an embodiment of an apparatus, an image output control method, and an image output control program are applied.

  In FIG. 1, an image output apparatus 1 is applied as a display unit of an image processing apparatus such as a printer apparatus, a copying apparatus, a composite apparatus, or a scanner apparatus, and includes an image processing section 10 and a display 20. Note that the output destination of the image is not limited to the display 20, but may be an external device such as an external computer or another image processing device.

  The image processing unit 10 reads out plane data in YCbCr format (hereinafter also referred to as image data as appropriate) from a system memory (external) 30 such as an image processing apparatus to which the image output apparatus 1 is applied, and performs RGB processing. The data is converted into line data in the format, converted into a video signal line by line, and output to the display 20 to display an image.

  The display 20 uses an LCD (Liquid Crystal Display) having a predetermined display size, and displays and outputs an image based on RGB video signals sent from the image processing unit 10.

  The image processing unit 10 includes a display control signal generation unit 11, a compression processing unit 12, a storage unit 13, an expansion processing unit 14, a control unit 15, and the like. The image processing unit 10 reads from the system memory 30 that is external. The line data in the YCbCr format is input to the compression processing unit 12, the expansion processing unit 14, and the display control signal generation unit 11.

  Under the control of the control unit 15, the compression processing unit (compression unit) 12 performs reversible compression processing by the static Huffman coding method on the Cb line data and the Cr line data among the YCbCr line data, and stores them. Stored in the unit 13.

  The storage unit (storage unit) 13 is configured by a memory having a predetermined capacity such as a RAM (Random Access Memory), and stores the compressed image data compressed by the compression processing unit 12 for one line.

  As will be described later, the decompression processing unit (decompression unit) 14 selects Cb line data and Cr line data from the system memory 30 as they are and outputs them to the display control signal generation unit 1 under the control of the control unit 15. And a process of decompressing the compressed Cb line data and Cr line data stored in the storage unit 13 and outputting them to the display control signal generation unit 11 is selectively performed.

  The control unit (data control means) 15 controls the operations of the benthic fish signal generation unit 11, the compression processing unit 12, the storage unit 13 and the expansion processing unit 14 based on the image output control program of the present invention stored in advance. An image that is converted into RGB image data at a low cost and output while suppressing the amount of YCbCr image data that is converted into RGB image data and output at a low cost while suppressing the amount of data taken in the YCbCr image data. Execute output control processing.

  The display control signal generation unit (format conversion means, video signal generation means) 11 includes a data buffer 16 (FIG. 2) for the Y plane line data among the YCbCr image data from the system memory (external, external storage means) 30. The Cb plane line data and the Cr plane line data are selected by the decompression processing unit 14 and stored as they are or after being compressed by the compression processing unit 12. After being stored in the unit 13, it is expanded by the expansion processing unit 14 and is input one line at a time. The system memory 30 as external and external storage means is a non-volatile memory such as NVRAM (Non-Volatile Random Access Memory) or a volatile memory such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory). is there.

  The display control signal generation unit 11 converts the input Y plane line data, Cb plane line data, and Cr plane line data into R, G, and B for each line based on a predetermined clock from a clock generation unit (not shown). The image data is converted to line data, and a video signal for displaying an image (video) on the display 20 is generated from the RGB data. The video signal is output to the display 20 and displayed on a line basis.

  The main part of the image processing unit 10 is configured as shown in FIG. 2 and includes a Y data buffer 16, and the compression processing unit 12 includes a Cb line compression unit 12b and a Cr line compression unit. 12r, the storage unit 13 includes a Cb data buffer 13b and a Cr data buffer 13r each having overflow flags 13bf and 13rf, and the expansion processing unit 14 includes a Cb line expansion unit 14b, a Cr line expansion unit 14r, and a Cb data selector 14bs. And a Cr data selector 14rs.

  As described above, the Y data buffer 16 receives the Y plane line data from the system memory 30, adjusts the timing, and then outputs the Y plane line data to the display control signal generation unit 11.

  In the compression unit 12, the Cb plane line data from the system memory 30 is input to the Cb line compression unit 12b, and the Cr plane line data from the system memory 30 is input to the Cr line compression unit 12r.

  Under the control of the control unit 15, the Cb line compression unit 12 b performs lossless compression on the Cb plane line data by a static Huffman coding method using a predetermined Huffman table, and stores the Cb data in the storage unit 13. Stored in the buffer 13b, the Cr line compression unit 12r performs lossless compression by static Huffman coding using a predetermined Huffman table on the Cr plane line data under the control of the control unit 15, and stores the data. The data is stored in the Cr data buffer 13r of the unit 13.

  As will be described later, the Cb data buffer overflow flag 13bf of the Cb data buffer 13b and the Cr data buffer overflow flag 13rf of the Cr data buffer 13r are controlled to be cleared and set by the control unit 14, as will be described later. It is used to store data in 13r and control reading of data from the Cb data buffer 13b and Cr data buffer 13r.

  The Cb data buffer 13b and the Cr data buffer 13r each store the line data for one line of the Cb plane and the line data for one line of the Cr plane compressed by the Cb line compression unit 12b and the Cr line compression unit 12r, respectively. Under the control of the control unit 15, Cb plane line data and Cr plane line data for one line are stored and read.

  The decompression processing unit 14 sequentially inputs the Cb plane line data for one line compressed from the Cb data buffer 13b to the Cb line decompression unit 14b, and compresses the Cr line decompression unit 14r from the Cr data buffer 13r. One line of Cr plane line data is sequentially input.

  The Cb line decompression unit 14b decompresses the line data of the Cb plane that has been reversibly compressed by static Huffman coding using the same Huffman table as that used for compression, and sends it to the Cb data selector 14bs via the bus b (1). The Cr line decompression unit 14r decompresses the Cr plane line data reversibly compressed by static Huffman coding using the same Huffman table as that used for compression, and the Cr data is transmitted via the bus r (1). Output to the selector 14rs.

  Two buses b (0) and b (1) are connected to the Cb data selector 14bs, and line data of the Cb plane from the system memory 30 is directly input to the bus b (0). The line data of the Cb plane expanded by the Cb line expansion unit 14b is input to b (1). Under the control of the control unit 15, the Cb data selector 14bs selects either the line data of the Cb plane from the bus b (0) or the line data of the Cb plane from the bus b (1) for each line and displays it. Output to the control signal generator 11.

  Two buses r (0) and r (1) are connected to the Cr data selector 14rs, and line data of the Cr plane from the system memory 30 is directly input to the bus r (0). In r (1), the line data of the Cr plane expanded by the Cr line expansion unit 14r is input. Under the control of the control unit 15, the Cr data selector 14rs selects and displays either the Cr plane line data from the bus r (0) or the Cr plane line data from the bus r (1) for each line. Output to the control signal generator 11.

  The image display device 1 includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), a CD-RW (Compact Disc Rewritable), a DVD. An image output control program for executing the image output control method of the present invention recorded on a computer-readable recording medium such as a (Digital Versatile Disk), an SD (Secure Digital) card, or an MO (Magneto-Optical Disc) is read. The image display device that executes the image output control method for reducing the capacity of the data buffers 13b and 13r while reducing the data transfer amount described later by introducing the image processing unit 10 into a non-illustrated nonvolatile memory such as a ROM. Is built as. This image output control program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark) or an object-oriented programming language, and is stored in the recording medium. And can be distributed.

  Further, although not shown in the figure, the display control signal generation unit 11 generates a video signal for displaying an image on the display 20 based on the RGB image data, based on the predetermined clock, and this display control signal. The generation unit 11, the compression processing unit 12, the expansion processing unit 14, and the control unit 15 perform operation processing in synchronization with the same clock as the display control signal generation unit 11.

  Next, the operation of this embodiment will be described. The image display apparatus 1 according to the present embodiment converts RGB image data at low cost and outputs it while suppressing the amount of YCbCr image data taken in.

  In the image display device 1, the image processing unit 10 converts the YCbCr image data stored in the system memory 30 into RGB image data line by line and causes the display 20 to display and output the image data.

  However, as described above, since the number of samples in the sub-scanning direction of the Cb plane and the Cr plane is 1/2 of the Y plane, the image data that is a frame in which the YCbCr planes are overlapped is 2 in the Y plane. While the lines are converted into RGB image data, it is necessary to prepare two identical lines for the Cb plane and the Cr plane. When image data is read from the system memory 30 each time, the system memory 30 Bus traffic will increase. On the other hand, if the image processing unit 10 is provided with a memory for one line for each of the Cb plane and the Cr plane, the cost increases.

  Therefore, in the image display apparatus 1 according to the present embodiment, the image processing unit 10 uses the bus b (0) and the bus that pass the Cb plane line data and the Cr plane line data from the system memory 30 to the data selectors 14bs and 14rs. The line data of the Cb plane and the line of the Cr plane that are compressed by the r (0) and the compression units 12b and 12r, stored in the data buffers 13b and 13r, and then expanded by the expansion units 14b and 14r at the next line conversion timing A bus b (1) and a bus r (1) for passing data to the data selectors 14bs and 14rs are provided, the number of accesses to the system memory 30 is reduced, and line data of the Cb plane and line data of the Cr plane are stored. The capacity is reduced by reducing the capacity of the data buffers 13b and 13r.

  When the image processing unit 10 performs display processing for displaying the YCbCr image data on the display 30 from the data at the head of the plane, the Cb plane data processing is performed as shown in FIG. The compression, storage, and decompression processes are performed to reduce access to the system memory 30, and the capacity of the data buffers 13b and 13r is reduced to reduce costs.

  That is, when the controller 15 first enters the head of the plane, the control unit 15 causes the Cb data selector 14bs to select the bus b (0) and the Cr data selector 14rs to select the bus r (0) (step S101). The control signal generator 11 is supplied with the Y data of the first line via the Y data buffer 16, and the Cb data from the bus b (0) and the Cr data from the bus r (0) are input. The YCbCr image data of the eye is converted into RGB data, and a video signal based on the RGB data is output to the display 20 to display the first line.

  During this time, the control unit 15 inputs the line data of the first Cr plane and the line data of the Cd plane read from the system memory 30 to the Cb line compression unit 12b and the Cr line compression unit 12r, respectively. The line compression unit 12b and the Cr line compression unit 12r each perform lossless compression by a static Huffman coding method using a predetermined Huffman table, and store them in the Cd data buffer 13b and the Cr data buffer 13r of the storage unit 13. (Step S102).

  When the compression for one line is completed, the control unit 15 checks whether the data buffer overflow flags 13bf and 13rf of the data buffers 13b and 13r are raised (step S103), and when the data buffer overflow flags 13bf and 13rf are not raised. (When NO in step S103), the Cb data selector 14bs selects the bus b (1), the Cr data selector 14rs selects the bus r (1) (step S104), and the decompression processing unit 14 The compressed data in the storage unit 13 is expanded, and the expanded Cb plane line data and Cr plane line data from the bus b (1) and the bus r (1) are input to the display control signal generation unit 11.

  That is, when the buffer overflow flag is not raised, the control unit 15 determines that the compressed Cb line data and Cr line data for one line are stored in the Cb data buffer 13b and the Cr data buffer 13r. The Cb data selector 14bs selects the bus b (1), the Cr data selector 14rs selects the bus r (1), and the Cb line expansion unit 14b compresses one line of the Cb data buffer 13b. The Cb line data is expanded by the static Huffman coding by using the same Huffman table as that used for compression in the Cr line decompression unit 14r and the compressed Cr line data corresponding to one line of the Cr data buffer 13r. Cb data selectors 14bs and C via bus b (1) and bus r (1) It is output to the data selector 14Rs (step S105).

  The Cb data selector 14bs outputs the Cb line data expanded from the Cb line expansion unit 14b and input from the bus b (1) to the display control signal generation unit 11, and the Cr data selector 14rs includes the Cr line expansion unit. The Cr line data expanded at 14r and input from the bus r (1) is output to the display control signal generator 11.

  The display control signal generation unit 11 converts the Y-line data of the Y line of the same line, the line data of the Cb plane of the same line that has been compressed and expanded, and the line data of the Cr plane, which are input after being adjusted in timing by the Y data buffer 16. Based on this, RGB data is generated, a video signal is generated from the RGB data, and displayed on the display 20.

  When converting the YCbCr for one line into RGB and displaying it on the display 20, the control unit 15 checks whether each plane is the last line of the frame constituting the superimposed image (step S106). If it is not the last line, the process returns to step S101, and the next line is processed in the same manner as above (steps S101 to S106).

  When the process for the last line of the frame is completed in step S106, the image output control process ends.

  Then, the image processing unit 10 executes the compression process as shown in FIG. FIG. 4 shows the Cb line data compression process, but the same applies to the Cr line data compression process. That is, when starting the compression process, the control unit 15 first clears the buffer overflow flags 13bf and 13rf (step S201), as shown in FIG. 4, and sets the Cb line compression unit 12b and the Cr line compression unit 12r to Cb. Data and Cr data are taken in (step S202), and lossless compression is performed by static Huffman coding using a predetermined Huffman table (step S203).

  In this lossless compression by static Huffman coding, Cb data and Cr data tend to take biased values in natural images, so in many data by static Huffman coding, rather than the input data size, Although the encoded data size is small, the data size may be large because it is lossless compression.

  Therefore, the control unit 15 checks whether the Cb data buffer 13b and the Cr data buffer 13r have enough free space for storing the Cb data and the Cr data compressed by the Cb line compression unit 12b and the Cr line compression unit 12r (Step S15). When there is free space (YES in step S204), the compressed Cb data and Cr data are stored in the Cb data buffer 13b and the Cr data buffer 13r, respectively (step S205).

  When storing the compressed Cb data and Cr data in the Cb data buffer 13b and the Cr data buffer 13r, respectively, the control unit 15 checks whether the data is the last line (step S206), and is not the data of the last line. When (NO in step S206), the process returns to step S202 to acquire the Cb data and Cr data of the next line, and pass them to the Cb line compression unit 12b and the Cr line compression unit 12r for compression. To the same processing as described above (steps S202 to S206).

  When there is no free space in either or both of the Cb data buffer 13b and the Cr data buffer 13r in step S204 (NO in step S204), the control unit 15 selects the Cb data buffer 13b and the Cr data buffer. It is checked whether one or both of 13r has overflowed (step S207), and if not, if the line is the last line of the plane, the compression process can be terminated as it is, so the step is continued. The process proceeds to S206 to check if it is the last line of the plane (step S206).

  In step S207, the control unit 15 determines that one plane of compressed data cannot be stored when one or both of the Cb data buffer 13b and the Cr data buffer 13r overflow, and overflows. The buffer overflow flags 13bf and 13rf of either the Cb data buffer 13b and the Cr data buffer 13r, or both, are raised, and the process proceeds to step S206 to check whether it is the last line (step S206).

  If it is not the last line, the control unit 15 returns to step S202 and performs the same processing as above (steps S202 to S208). If it is the last line in step S206 (YES in step S206), compression is performed. The process ends.

  In the compression process, the control unit 15 may end the process as it is when both the Cb data buffer 13b and the Cr data buffer 13r overflow in step S208.

  Then, the image processing unit 10 executes the expansion process as shown in FIG. 5 shows the Cb line data expansion process, the same applies to the Cr line data expansion process. That is, when starting the decompression process, the control unit 15 first acquires Cb data and Cr data for one line compressed from the Cb data buffer 13b and the Cr data buffer 13r, respectively, as shown in FIG. The data is transferred to the line decompression unit 14b and the Cr line decompression unit 14r (step S301), and the Cb line decompression unit 14b and the Cr line decompression unit 14r are caused to perform decompression processing (restoration processing) of Cb data and Cr data, respectively (step S302).

  As described above, the Cb line decompression unit 14b and the Cr line decompression unit 14r perform the decompression process on the Cb data and Cr data that are compressed by static Huffman coding using the same Huffman table as that used for compression. Stretch.

  When the decompression process for one line is performed, the control unit 15 checks whether it is the last line data of the plane (step S303). If it is not the last line data, the control unit 15 returns to step S301 and performs the same processing as described above. (Steps S301 to S303).

  In step S303, the control unit 15 ends the decompression process when it is the last line of the plane.

  In the above description, the case where an image is displayed and output on the display 20 has been described. However, the present invention is not limited to the case where an image is displayed and output, and the number of samples in the sub-scanning direction is, for example, YCbCr format image data. An image output device that converts image data composed of a plurality of different image data into image data of a format in which the number of samples in the sub-scanning direction is the same or the number of samples is different from that of the original image data, such as image data in RGB format Applicable in general.

  As described above, the image display apparatus 1 according to the present exemplary embodiment includes a plurality of planes in which one line in the main scanning direction is a line and the line data is arranged in the sub-scanning direction orthogonal to the main scanning direction. Conversion source image data in a predetermined format (in this embodiment, YCbCr format) including a small line plane consisting of small line data with a small number of lines at a predetermined magnification in the sub-scanning direction is converted for each line data corresponding to each plane. A display control signal generation unit (format conversion means) 11 that performs processing to convert the image data into conversion destination image data in a predetermined format (in this embodiment, RGB format), and the lines of the small line planes in the conversion source image data A compression processing unit (compression unit) 12 for compressing data line by line in a predetermined compression method; A storage unit (storage unit) 13 having a predetermined capacity for storing compressed data for one line compressed by the unit 12, and a decompression processing unit (decompression unit) 14 for expanding the compressed data stored in the storage unit 13 to original data. The conversion source image data is fetched from the system memory (external / external storage means) 30 and either the line data of the small line plane or the line data expanded by the expansion processing unit 14 is selected from the conversion source image data. A control unit (data control means) 15 for inputting the line data to the display control signal generation unit 11 in accordance with the corresponding line data of the plane other than the small line plane.

  Therefore, the line data of a small line plane with a small number of lines can be compressed and stored in the storage unit 13, and the compressed data in the storage unit 13 can be decompressed and used for format conversion. It is possible to convert the conversion source image data of a predetermined format composed of a plane into conversion destination image data of a predetermined format at a low cost while suppressing the amount of data taken in the conversion source image data.

  The image display apparatus 1 according to the present embodiment includes a plurality of planes in which one row in the main scanning direction is a line and the line data is arranged in the sub scanning direction orthogonal to the main scanning direction. Conversion source image data of a predetermined format including a small line plane composed of a small number of line data with a small number of lines in a direction at a predetermined magnification is converted for each line data corresponding to each plane, and the conversion destination image data of a predetermined format A format conversion processing step for converting the data into a line, and compressing the line data of the small line plane one line at a time by a predetermined compression method in the conversion source image data, and storing the compressed data for one line in a predetermined capacity 13 and a decompression processing step for decompressing the compressed data stored in the storage unit 13 into original data. And the conversion source image data from outside, and the line data of the small line plane and the line data decompressed in the decompression processing step of the transformation source image data are And a data control processing step for inputting to the format conversion processing step in accordance with the corresponding line data of the plane other than the few line planes.

  Therefore, the line data of a small line plane with a small number of lines can be compressed and stored in the storage unit 13, and the compressed data in the storage unit 13 can be decompressed and used for format conversion. It is possible to convert the conversion source image data of a predetermined format composed of a plane into conversion destination image data of a predetermined format at a low cost while suppressing the amount of data taken in the conversion source image data.

  Furthermore, the image display apparatus 1 according to the present embodiment has a computer with a plurality of planes in which one line in the main scanning direction is a line and the line data is arranged in the sub-scanning direction orthogonal to the main scanning direction. The conversion source image data of a predetermined format including a small line plane composed of a small number of line data having a small number of lines at a predetermined magnification in the sub-scanning direction is converted for each line data corresponding to each plane, thereby converting the predetermined format. Format conversion processing for converting to pre-image data, and among the conversion source image data, the line data of the small line plane is compressed line by line by a predetermined compression method, and the compressed data for one line is stored in a predetermined capacity A compression process stored in the storage unit 13, and a decompression process for expanding the compressed data stored in the storage unit 13 into original data. The conversion source image data is captured from the outside, and the line data of the small line plane and the line data decompressed by the decompression process of the conversion source image data other than the small line plane And an image output control program for executing data control processing to be input to the format conversion processing in accordance with the corresponding line data of the plane.

  Therefore, the line data of a small line plane with a small number of lines can be compressed and stored in the storage unit 13, and the compressed data in the storage unit 13 can be decompressed and used for format conversion. It is possible to convert the conversion source image data of a predetermined format composed of a plane into conversion destination image data of a predetermined format at a low cost while suppressing the amount of data taken in the conversion source image data.

  Further, in the image display device 1 according to the present embodiment, the control unit 15 stores the compressed data in the storage unit 13 only when the compressed data for one line compressed by the compression processing unit 12 can be stored in the storage unit 13. The decompression processing unit 14 decompresses the compressed data and inputs the compressed data to the display control signal generation unit 11 only when the compressed data is stored in the storage unit 13, and the compressed data is stored in the storage unit 13. When it is not stored, the line data corresponding to the conversion source image data is fetched from the external system memory 30 and input to the display control signal generator 11.

  Therefore, it is possible to compress and decompress line data using the small-capacity storage unit 13 while appropriately managing it, and to convert conversion source image data in a predetermined format including a plurality of planes including a small number of line planes. While suppressing the amount of image data taken in, it can be converted into conversion destination image data of a predetermined format at a low cost and appropriately.

  Furthermore, in the image display device 1 of the present embodiment, the compression processing unit 12 reversibly compresses the line data of the small line planes one line at a time using the static Huffman coding method, and the expansion processing unit 14 includes the static Huffman. The compressed data compressed by the encoding method is expanded.

  Therefore, the line data of a small line plane of the conversion source image data can be efficiently compressed and expanded by reversibly compressing by the static Huffman coding method, and the conversion source image data is captured from the system memory 30. While appropriately suppressing the data amount, it is possible to reduce the capacity of the storage unit 13 and to convert it into conversion destination image data inexpensively and appropriately.

  Further, in the image display device 1 according to the present embodiment, the display control signal generation unit 11 uses the image data including YCbCr planes as the conversion source image data, and the image data including RGB planes as the conversion destination image data. As a conversion.

  That is, the Cb plane compression unit 12b and the Cr line compression unit 12r compress each line data of the Cb plane and the Cr plane, which is ½ the number of lines with respect to the Y plane, into the Cb data buffer 13b, The data is stored in the Cr data buffer 13r, expanded by the Cb line expansion unit 14b and the Cr line expansion unit 14r, and the uncompressed line data and the compressed / expanded line data are alternately converted into the Cb data selector 14bs and the Cr data selector for each line. The signal is selected at 14 rs and input to the display control signal generator 11.

  Therefore, the image data in the YCbCr format can be converted into RGB image data inexpensively and appropriately by reducing the capacity of the storage unit 13 while appropriately suppressing the amount of data captured from the system memory 30.

  Furthermore, the image display apparatus 1 of the present embodiment generates a display control signal generation unit (based on a predetermined clock) that generates a video signal that causes the display (display unit) 20 to display and output the YCbCr data that is the conversion destination image data. Video signal generating means) 11, and the control signal generating unit 11 itself, the compression processing unit 12, the decompression processing unit 14, and the control unit 15 perform operation processing in synchronization with the same clock as the display control signal generating unit 11. Yes.

  Therefore, it is possible to generate a video signal inexpensively and appropriately by reducing the capacity of the storage unit 13 while appropriately suppressing the amount of data captured from the system memory 30 of the original image data.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

DESCRIPTION OF SYMBOLS 1 Image output device 10 Image processing part 20 Display 30 System memory 11 Display control signal production | generation part 12 Compression processing part 12b Cb line compression part 12r Cr line compression part 13 Memory | storage part 13bf, 13rf Overflow flag 13b Cb data buffer 13r Cr data buffer 14 Decompression processing unit 14b Cb line expansion unit 14r Cr line expansion unit 14bs Cb data selector 14rs Cr data selector 15 Control unit 16 Y data buffer

JP 2010-136264 A

Claims (8)

A small number of lines in which one line in the main scanning direction is a line and the line data is arranged in a predetermined number of lines in the sub scanning direction orthogonal to the main scanning direction, and the number of lines is small in the sub scanning direction at a predetermined magnification. Format conversion means for converting conversion source image data of a predetermined format including a small line plane of data into conversion destination image data of a predetermined format by performing conversion processing for each corresponding line data of each plane;
Compression means for compressing line data of the small line planes of the conversion source image data line by line by a predetermined compression method;
A storage unit having a predetermined capacity for storing compressed data for one line compressed by the compression unit;
Decompression means for decompressing the compressed data stored in the storage means into original data;
The conversion source image data is taken in from the outside, and the line data of the small line plane and the line data expanded by the decompression unit of the conversion source image data other than the small line plane Data control means for inputting to the format conversion means in accordance with the corresponding line data of the plane;
An image output apparatus comprising: The data control means includes
The compressed data is stored in the storage means only when one line of the compressed data compressed by the compression means can be stored in the storage means, and only when the compressed data is stored in the storage means. The decompression unit decompresses the compressed data and inputs the compressed data to the format conversion unit. When the compressed data is not stored in the storage unit, the line data corresponding to the conversion source image data is fetched from the outside and the format data is stored. The image output apparatus according to claim 1, wherein the image output apparatus is input to a conversion unit. The compression means includes
The line data of the small line plane is reversibly compressed line by line by a static Huffman coding method,
The extension means includes
3. The image output apparatus according to claim 1, wherein the compressed data compressed by the static Huffman coding method is decompressed. The format conversion means includes
4. The frame image data composed of YCbCr planes is converted as the conversion source image data, and the frame image data composed of RGB planes is converted as the conversion destination image data. The image output device described in 1. The image output device includes:
Video signal generating means for generating a video signal for causing the display means to display and output the conversion destination image data based on a predetermined clock;
The format conversion means, the compression means, the decompression means, and the data control means are:
5. The image output apparatus according to claim 1, wherein operation processing is performed in synchronization with the same clock as the video signal generation means. A plane in which line data is arranged in a sub-scanning direction orthogonal to the main scanning direction by using one row in the main scanning direction as a line, which is subjected to various image processing on the image data and stored in the external storage means A plurality of lines, and conversion source image data of a predetermined format including a small line plane composed of small line data having a small number of lines at a predetermined magnification in the sub-scanning direction, for each line data corresponding to each plane An image processing apparatus that performs conversion processing to convert the image data into conversion destination image data in a predetermined format and outputs the converted image data,
An image processing apparatus comprising the image output apparatus according to claim 1 as the image output unit. A small number of lines in which one line in the main scanning direction is a line and the line data is arranged in a predetermined number of lines in the sub scanning direction orthogonal to the main scanning direction, and the number of lines is small in the sub scanning direction at a predetermined magnification. A format conversion processing step for converting conversion source image data of a predetermined format including a small line plane made of data into conversion destination image data of a predetermined format by performing conversion processing for each corresponding line data of each plane;
A compression processing step of compressing line data of the small line planes of the conversion source image data line by line by a predetermined compression method and storing the compressed data for one line in a storage unit having a predetermined capacity;
A decompression process step of decompressing the compressed data stored in the storage unit into original data;
The conversion source image data is captured from outside, and the line data of the small line plane and the line data expanded in the expansion processing step are converted into the small line plane. A data control processing step for inputting to the format conversion processing step according to the corresponding line data of the plane other than
An image output control method characterized by comprising: On the computer,
A small number of lines in which one line in the main scanning direction is a line and the line data is arranged in a predetermined number of lines in the sub scanning direction orthogonal to the main scanning direction, and the number of lines is small in the sub scanning direction at a predetermined magnification. A format conversion process for converting conversion source image data of a predetermined format including a small line plane made of data into conversion destination image data of a predetermined format by performing conversion processing for each corresponding line data of each plane;
A compression process for compressing line data of the small line planes of the conversion source image data line by line with a predetermined compression method, and storing the compressed data for one line in a storage unit having a predetermined capacity;
Decompression processing for decompressing the compressed data stored in the storage means into original data;
The conversion source image data is captured from the outside, and the line data of the small line plane and the line data decompressed by the decompression process of the conversion source image data other than the small line plane Data control processing to be input to the format conversion processing according to the corresponding line data of the plane,
An image output control program for executing

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