JPH10154223A - Data convertion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use only one RAM memory even in the case where plural different conversions are successively performed at the time of using a lookup table and to speed up its conversion processing speed. SOLUTION: In the case where plural different conversions are successively performed on one input data using the RAM 11 as a lookup table, synthesized conversion data in which all these conversions are synthesized are written in the RAM 11 as a lookup table, so that even in the case where the plural different conversions are successively performed, the conversion processing is performed in the single one RAM 11 without following a memory for each conversion processing by using the synthesized conversion data in which these conversion processing are synthesized. Then, since plural lookup tables in which all the synthesized conversion data necessary for once conversion are written are stored in the single RAM 11, all the conversion processing is completed only by once conversion by the single RAM 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a digital copying machine, a printer, an image scanner, etc. having a function of converting image data such as an index color conversion function, a color .gamma. Conversion, and a filter function. The present invention relates to a data conversion device that can be applied to processing of image data and audio data on a computer or a workstation.

[0002]

2. Description of the Related Art Conventionally, as this kind of data conversion device,
It is known to use a look-up table (LUT = Look Up Table) storing conversion data corresponding to input data.

Here, when performing a plurality of different conversion processes on one image data, a plurality of lookup tables 1, 2, 3 are connected in series as shown in FIG. Conversion f is performed by up-table 1,
Next, there is a configuration in which conversion g is performed by the lookup table 2 and then conversion h is performed by the lookup table 3. That is, one conversion process is performed sequentially by using one look-up table.

For example, index color data of 256 colors is used as input image data, which is converted f (converts a color number into actual color data), converted g (γ conversion for each color), and converted h (corresponding to an output device). Considering an example in which output image data is created by performing dither conversion for each character / photo data set, the configuration is as shown in FIG. That is, the lookup table 1 is used for index color conversion (conversion f
Lookup table 2 for γ conversion (conversion g
Lookup table 3 is for dither conversion (conversion h
) And are connected in series, lookup tables 1 and
Latches 4 and 5 are interposed between 2 and 2 and 3, respectively. These look-up tables 1, 2, and 3 are, for example, based on a RAM, and conversion data relating to items shown in FIG. 6, for example, are set in each of them.

However, in such a configuration, a memory must be provided corresponding to the number of lookup tables depending on the type of conversion processing, miniaturization of the device is limited, and required hardware is required. Volume and cost increase.

In consideration of such points, for example, Japanese Patent Laid-Open No.
According to JP-A-70165, two rewritable look-up tables are used, and when a data conversion operation is performed by one look-up table, conversion data for a conversion process to be executed next is written to the other look-up table. In other words, an alternative is disclosed that is used alternately. Further, according to Japanese Patent Application Laid-Open No. Hei 7-262081,
Many lookup tables can be stored in one memory element (RO).
M), and the conversion processing until the end of one conversion processing is performed by passing through one ROM a plurality of times.

[0007]

However, in the case of the former Japanese Patent Laid-Open Publication No. Hei 6-70165, the use of two memories is still insufficient to reduce the mounting area and wiring area on a printed circuit board. .

In the latter method disclosed in Japanese Patent Application Laid-Open No. Hei 7-26281, although only one memory (ROM) is required, it is necessary to perform processing through the ROM many times, which hinders speeding up the processing. .

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a data conversion device which requires only one memory, even if a plurality of different conversions are continuously performed when a lookup table is used. It is a second object of the present invention to provide a data conversion device capable of improving the conversion processing speed.

[0010]

According to the first aspect of the present invention,
In a data conversion apparatus for converting input data using conversion data of a lookup table, a RAM is used as a lookup table, and all of these conversions are performed when a plurality of different conversions are continuously performed on one input data. Is written as a look-up table in the RAM. Therefore, even when a plurality of different conversions are continuously performed, the conversion processing in one RAM can be performed by using the synthesized conversion data obtained by summing the conversion processing without tracing the memory for each conversion processing. Only needs to be done. As a result, only one RAM is required, and the mounting area and wiring area on the printed circuit board can be reduced.

According to a second aspect of the present invention, there is provided the data conversion apparatus according to the first aspect, wherein a plurality of lookup tables in which all the combined conversion data required for one conversion are written in one RAM. doing. Therefore, all the conversion processes are completed only by one conversion in one RAM, so that the look-up table does not need to be rewritten during the conversion and the processing can be speeded up.

In these inventions, a RAM in which a plurality of conversion data required as a conversion table can be written is stored in one RAM.
And prepares it as a look-up table for input data on the input data processing step.
It may be connected so that it can also be performed from a control device such as the above. Then, at the time of actual use, all the combined conversion data used in the conversion may be calculated on software and written in a predetermined position of the lookup table.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. In the present embodiment, for example, when the conversions f, g, h shown in FIG. 4 are assumed, as shown in FIG.
The point is that the input data is converted into the output data by using a single RAM 11 in which conversion data, which is a synthesis conversion F obtained by synthesizing the above, is calculated and written on software in advance, as a look-up table. That is, by subjecting each element of one input data to the processing of the combined conversion F through one RAM 11 once, output data having the same result as the case of sequentially performing the conversion processing of the conversions f, g, and h is obtained. It is what is converted.

Here, as described above, for example, 256
Color index color data as input image data,
This is converted f (the color number is converted to actual color data),
Assuming that output image data is created by performing conversion g (γ conversion for each color) and conversion h (dither conversion for each character / photograph data according to the output device), the RAM 11 is configured as shown in FIG. It is configured as shown. That is, as the address input, in addition to the input image data (color number), the table No. , Color, dither counter, character / photo, and the like, which have been input for each of the conversions f, g, and h, are collectively input to one RAM 11.

Compared with the specific items shown in FIG. 6, in the RAM 11 of the present embodiment, the items of the composite conversion F of the conversions f, g, and h are shown in FIG.
Are set as a look-up table. For example, the address 0 _H (subscript "H" denotes a hexamethylene = hexadecimal ... hereinafter the same) from to 99 _H is yellow data table 1 Yellow gamma-character counter (0,0) for the address 100 from _H to 199 _H is a yellow data table 2 yellow gamma-character counter (0,0) for the following, the same address 3
F00 _H to 33FFF Are used for the black color data table 2, black γ, character counter (1, 1), and have a plurality of lookup tables in which all the combined conversion data necessary for one conversion are written. .

A description will be given of an example of actual conversion data in such a configuration. For example, as an example, input data; color number 10 _H , gradation data, gamma correction, dither character ((0,0) (0,1) (1,0) (1,1)), photograph ((0,0) (0 , 1) (1,0) (1,1)) Yellow 37 _H 3A _H (10 _H , 10 _H , 10 _H , 0C _H ) (20 _H , 00 _H , 1C _H , 00 _H ) Magenta 73 _H 77 _H (20 _H , 1C _H , 20 _H , 1C _H ) (34 _H , 08 _H , 34 _H , 08 _H ) Cyan 12 _H 0F _H (04 _H , 04 _H , 04 _H , 04 _H ) (04 _H , 00 _H a 04 _H, 00 _H) black _{41 H 3C H (10 H,} 10 H, 10 H, 0C H) (20 H, 00 H, 10 H, 00 when the converted data example as _H). That is, the color number of the input data is 10 _H , the data of the table number 1 is 256 gradation data of each color, and yellow is 3
7 _H, magenta 73 _H, cyan 12 _H, black and a 3C _H.

[0017] For such conversion data example, incidentally, if the conventional method shown in FIG. 4 or the like, as shown in FIG. 7 (a), the look-up table 1 address 10 _H
37 _H, addresses 210 _H 73 _H as the conversion data, address 410 12 _H as _H conversion data, 41 as the conversion data of the address 610 _{H H} as converted data
Is set. Next, the yellow gradation data 37 _H is converted into 3A _H by γ conversion, and as shown in FIG.
The address 37 _H would 3A _H is set as γ conversion data. Furthermore, according to the output device,
Further, the data undergoes dither conversion in two rows and two columns depending on the distinction between characters and photographs. In this transformation h, 0C in 110 _H, 2 rows and 2 columns in 3A _H becomes data 1-by-1
_{In the} case of conversion into _H , as shown in FIG. 7C, 10 _H is set as the dither conversion data of the address 3A _H in the lookup table 3 and 0C _H is set as the dither conversion data of the address 33A _H. Become. Traditionally,
Through these three look-up tables 1, 2 and 3 sequentially, regarding data of the color numbers 10 _H, in the case the dither converted a yellow data using the color conversion table number 1 is the first row and first column eventually it will be converted into 10 _H.

In this regard, in the present embodiment, the data of the conversion processing sequentially passing through these look-up tables 1, 2 and 3 is calculated as composite conversion data under an operation by software, and FIG. Is written at a predetermined address in the RAM 11 as combined conversion data as shown in FIG. For example, the address 10 _H indicates that the combined conversion data for the yellow color data table 1, yellow γ, character counter (0, 0) relating to the data of the color number 10 _H is 10 _H. Therefore, in addition to the input image data, the table No. , Color, dither counter, etc., one R
Necessary conversion is completed only by receiving the conversion process through the AM 11 once. Therefore, both the miniaturization of the configuration around the memory (mounting area, wiring area) and the increase in processing speed can be achieved.

By the way, in realizing this embodiment,
In practice, prior to the input data conversion process, it is necessary to create the composite conversion data of the look-up table and write it in the RAM 11, so that the data conversion device needs to The control unit, for example, the CPU 12 is configured to read and write data. That is, the latch 13 for inputting image input data to the RAM 11 in synchronization with the pixel synchronization clock
And a latch 14 for inputting address data such as color, table number, dither, etc. to the RAM 11 in response to a register write signal, and connected to the output side of the RAM 11 to convert the converted image output data in synchronization with the pixel synchronization clock. The CPU 12 is connected to the input / output side of the RAM 11 and provided in addition to the original input / output circuit for the data converter by the latch 15 for outputting to the output device. Therefore, CPU1
The synthetic conversion data based on the conversion calculation on the software in 2 can input the bidirectional buffer 16 into the write mode and input it to the RAM 11 via the gate circuit 16 to create a look-up table in the RAM 11.

Although the above description is an example of a case where image data is output to an output device, conversely, the RAM 11 is also used when inputting image data and when inputting and outputting image data.
Are arranged on the processing path of the input data, the contents of the RAM 11 (composite conversion data of the look-up table) are rewritten, so that one RAM 1
1 can be realized. For example, in the configuration shown in FIG.
11, the data subjected to the synthesis conversion process can be taken.

[0021]

According to the first aspect of the present invention, in a data conversion device for converting input data using conversion data of a look-up table, a RAM is used as a look-up table, and a plurality of Is written as a look-up table in the RAM when all of these conversions are continuously performed when different conversions are continuously performed. Therefore, even when a plurality of different conversions are continuously performed. The conversion process in one RAM can be completed by using the combined conversion data that summarizes the conversion processes without tracing the memory for each conversion process. The mounting area and the wiring area on the substrate can be reduced and the size can be reduced.

According to the second aspect of the present invention, one RA
Since there are a plurality of lookup tables in which all the combined conversion data necessary for one conversion are written in M,
All the conversion processes can be completed only by one conversion in one RAM, so that the look-up table does not need to be rewritten during the conversion and the processing can be sped up.

[Brief description of the drawings]

1A and 1B show an embodiment of the present invention, in which FIG. 1A is a conceptual block diagram of a look-up table, FIG. 1B is a conceptual block diagram showing the look-up table more specifically, and FIG. FIG. 4 is a conceptual diagram of a RAM map for explaining a target item of the combined conversion data.

FIG. 2 is a RAM map showing a specific example of combined conversion data constituting a lookup table.

FIG. 3 is a block diagram illustrating a configuration of a data conversion device.

FIG. 4 is a conceptual block diagram of a lookup table showing a conventional example.

FIG. 5 is a conceptual block diagram more specifically showing the lookup table.

FIG. 6 is a conceptual diagram of a RAM map for explaining target items of the converted data.

FIG. 7 is a RAM map showing a specific example of conversion data.

[Explanation of symbols]

 11 RAM

Claims (2)

[Claims] 1. A data conversion apparatus for converting input data using conversion data of a lookup table, wherein a RAM is used as a lookup table and a plurality of different conversions are continuously performed on one input data. The combined conversion data obtained by combining all of these conversions is referred to as the RA.
A data conversion apparatus characterized in that a look-up table is written in M. 2. The data conversion apparatus according to claim 1, further comprising a plurality of look-up tables in which all combined conversion data necessary for one conversion are written in one RAM.