JPS63185168A - Picture output device - Google Patents

Abstract

PURPOSE:To reduce deterioration in a picture quality by extending and outputting a compressed monochrome picture by neglecting a color information component even in picture data in which color picture data and monochrome picture data are mixed. CONSTITUTION:When the output of a mode switch is '0', namely, when the block information of a black and white picture is inputted, a selector 11 outputs input picture data to a ROM 13. The ROM 13 defines the block information of the black and white picture to be the address of a memory and pulses and outputs a compressed result. Since only the brightness of color information is inputted to the ROM 13, compression data outputted from the ROM 13 is the compression data of the brightness of color. In such a way, since mono chrome picture compression data has no information relating to a color, a monochromaticity is completely reserved and it is reproduced and outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image output device that outputs image data in which a color image and a monochrome image are mixed while preserving the image quality of the original image.

[Prior Art] Conventionally, when color image data is stored in an image memory or the like, the brightness and chromaticity of the color image data are separated and the data obtained by compressing them is stored. At this time, even if the color image data document contains a monochrome document (for example, a black and white document), it is compressed and stored as a color image.

[Problem that the invention attempts to solve] Originally, monochromatic image data includes only brightness information.

For example, in a black and white image, only the brightness of black changes, but there is no information about chromaticity. However, when such monochromatic image data is compressed as a color image, there is a drawback that compressed data of unnecessary chromaticity information is stored in the image memory, reducing the usage efficiency of the image memory.

Furthermore, compression of color image data often involves some loss of information, so when monochromatic image data is compressed as color image data, its monochromaticity is lost, and when it is decompressed, unnecessary color information is lost. There was a problem in that the original monochromatic image was altered.

The present invention was proposed in view of the above-mentioned problems of the conventional example, and its purpose is to provide a single-color image when compressed image data is decoded and recorded, even if the image data includes a mixture of color image data and monochrome image data. An object of the present invention is to provide an image output device that outputs images with well-preserved characteristics.

[Means for Solving the Problems] The configuration of the present invention for achieving the above object is based on whether the compressed image data input in blocks is color image compression data or monochrome image compression data. information for instructing, color image data decompression means for decompressing the manually compressed image data in block units as color image data according to the instruction information, and monochrome data decompressing means for decompressing the input compressed image data in block units as monochrome image data. It has an image data decompression means and an output means for outputting the decompressed color image data and monochromatic image data.

[Operation] In the above configuration, for each block, according to the instruction information,
Compressed color image data or compressed monochrome image data is expanded. In particular, since monochromatic image compressed data does not have color information, monochromaticity is well preserved when it is reproduced and output.

[Examples] Examples according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 shows compressed and stored image data. In FIG. 2, 1 indicates each pixel. In this embodiment, a 4×4 pixel block surrounded by a thick line 2 is used as a unit of compression. When each pixel is a color pixel, it is generally represented by three primary colors such as red (R), green (G), and blue (B). On the other hand, monochromatic image data is often referred to as a black and white image. In the case of black and white, it is expressed not by the color white but by high or low density black, and only lightness information exists. Since there is only brightness information, a monochromatic image of red, for example, is also possible. In other words, whether color or monochromatic image data is divided into brightness information and color information, it comes down to whether or not the color information exists equally for each pixel.For example, in a black and white image In this case, the values of R, G, and B are all approximately equal. Therefore, in the embodiments described below, for the sake of simplicity, a monochromatic image will be described as a black and white image.

Color information can be easily separated into brightness information and chromaticity information of the pixel. Generally, in color television, Y, I, and Q are obtained by linearly converting R, G, and B.
information (Y represents luminance, I, Q represent color difference), or CIE
CIE1976L'u''v8 space defined in
There is information such as CIE1976L"a"b"b" spatially transformed information. Here, Ll is lightness, u'', v'' or a
", b", etc. represent chromaticity.

FIG. 1 is a block diagram of this embodiment. In the device of the example, R, G, and 8 image data are once separated into brightness information and chromaticity information, and these image information are inputted from a terminal 3 from an image input device (not shown). 4 is color/black and white
5 is a compressor. In the compressor 5, the mode switch outputs "1" when reading a color image, and "0" when reading a monochrome image. “1” of 4 outputs.

The input data compression method is switched by "0'", the input data is compressed, and the result is output. 6 is an image memory that stores compressed data. 7 is an expander that reproduces compressed data. The decompressor 7 changes the decompression method by changing the mode switch 4 between "1" and "O", decompresses the input compressed data, and outputs the result from the terminal 8. Ahead of terminal 8 are various color image output devices (for example, Y yellow, M magenta, C cyan).

(a printing device that uses ink such as K black).

Compression> FIG. 3 is a circuit diagram of the compressor 5. From terminal 9,
Color image data separated into brightness information and chromaticity information for each block is input. The selector 11 selects the output light of this input color image data according to the output signal of the mode switch 4 inputted from the terminal 10. When the output of the mode switch 4 is "1", that is, when block information of a color image is input, the selector 11 outputs the input color image data to the read-only memory (hereinafter abbreviated as ROM) 12. The ROM 12 inputs the block information of the input color image data as a memory address, and outputs the compression result as an output. Further, when the mode switch 4 output is "O", that is, when monochrome image block information is input, the selector 11 outputs input image data to the ROM 13. The ROM 13 inputs the block information of the input monochrome image as a memory address and outputs the compression result.

Since only the brightness information is entered manually in ROM13, the ROM
The compressed data output from 13 is lightness compressed data in the sense of color image data compression.
The output information amount of the OM 13 is smaller than the output information amount of the ROM 12 by the amount of color information.The 0 combiner 14 combines and outputs such brightness information every two blocks (32 pixels).

The data compressed in this way is transferred to the mode switch 4.
When is 1'', the data includes brightness information and chromaticity information as color image data as shown in FIG. 4(a).
When the mode switch 4 is "0", data in the format of brightness information 1 of the first block and brightness information 2 of the next block is output from the terminal 15 as monochrome data as shown in FIG. 4(b). .

The data compressed by the compressor 5 is stored in the image memory 6. Block information of a color image is stored as shown in FIG. 5(a). That is, in the figure, a solid black portion 17 indicates compressed data of a block of one color image. X,
The Y direction represents the position of block information within the image, and the Z direction represents the depth direction of each block information, that is, the amount of information in one block. Further, block information of a monochrome image is stored as shown in FIG. 5(b). Solid black portions 18 and 19 each indicate one block of compressed data of a monochrome image. That is, the sum of the information amounts of the block information of the black solid portions ta and t9 is the black solid portion 17 in FIG. 5(a).
is equal to the amount of block information.

In this way, in the compressor of this embodiment, since color information does not exist in a monochromatic image, that amount can be assigned to the brightness information of the next block.

Also, the image memory can be shared for color image data and monochrome image data.

Modified example of compression> Fig. 3(b) shows an example of a modified circuit for the above compression. That's true. Examples of compression by this compressor are shown in FIGS. 6(a) and 6(b). ROM12
and ROM16 have the same number of output bits, or ROM1
3 is slightly smaller than that of ROM12. If it is this small, add filler bits to cover the missing amount. Therefore, for this filler pit,
Although the efficiency is lower than that of the compressor shown in FIG. 3(a), the same effects can be obtained in other respects.

<Expansion Output> FIG. 7(a) is a block diagram of the decompressor 7 corresponding to the compressor of FIG. 3(a). Compressed data read from the image memory 6 is input from the terminal 20. This human power is terminal 21
22 according to the signal of the mode switch 4 inputted from
The selector selects the output light. When the mode switch 4 is "1", the selector 22 outputs manual data to the ROM 23. The ROM 23 inputs one block of color compressed data as a memory address, and outputs the decompression result from a terminal 26. Further, when the mode switch 4 is "0", the selector 22 outputs input data to the separator 24. The separator 24 separates the input two blocks of monochrome (brightness) compressed data into blocks, and outputs one block of compressed data in the order of compression. The ROM 25 inputs this output as a memory address and outputs the expansion result from the terminal 26.

Note that the ROM 23 and ROM 25 each store data that is an inverse conversion of the ROM 12 and 14 in FIG. 3(a).

The decompressor shown in FIG. 7(b) corresponds to the compressor shown in FIG. 3(b).

Modified Embodiment> Figure 1A is a block diagram of a partially modified version of the embodiment. Switches 30 to 32 are color selection switches. This is the switch 3 when outputting and playing the input monochrome image.
This is forcibly converted to a desired color specified by a combination of 0 to 32.

Each output of the color selection switches 30 to 32 is input to the expansion@7io along with the output of the mode switch 4.

In decompressor 40, the outputs of switches 30-32 are activated only when mode switch 44 indicates a black and white image. When the outputs of the switches 30 to 32 are activated and are other than 0, color information corresponding to the combination of values is output to RO.
It is added to the brightness information from M25 or ROM2. In this way, the desired color can be easily changed.

Next, regarding the modification, the possibility of modification in detail will be discussed. That is, in the modified example, the unit of compression may be not a 4×4 block but a block size of another size, or may be a pixel unit.

In the above embodiment, the determination of whether the image is color or black and white was made using the mode button 4, but it may also be determined automatically based on data input from the imager or the blade device. It can be determined by - and that is uniform among many blocks.

Although the compressor and decompressor are constructed of ROM in this embodiment, they may of course be constructed of other electronic circuits such as logic circuits.In addition, in this embodiment, the amount of information for one block of color image is is equal to the amount of information for two blocks of black and white; however, the amount of information for one block of a color image may be equal to the amount of information for multiple (three or more) blocks of black and white. Further, the amount of information for one block of a color image does not have to be an integral multiple of the amount of information for multiple black and white blocks.

Avoid referencing the excess memory area at this time.

When the brightness information and color information separated from the color information are compressed separately, it is also possible to compress the monochrome information using only the brightness information compressor.

<Effects of Examples> Effects obtained from the embodiments described above and their modifications are as follows. In other words, without changing the image memory configuration or input/output timing,
This has the effect of increasing image memory usage efficiency.

Also, when outputting images, yellow (Y), magenta (M)
, cyan (C), black (K), etc. When printing in color using black and white inks, you can reproduce a purer black by printing only black if it is a monochrome image, and you can reproduce a purer black color without using other inks. By omitting this, there is an effect of eliminating wasteful consumption of ink.

[Effects of the Invention] As explained above, according to the present invention, even if the image data is a mixture of color image data and monochrome image data, the color information component of the compressed monochrome image is ignored. Since the output is expanded, the monochromaticity of the current image is well preserved and there is little deterioration in image quality.

[Brief explanation of the drawing]

Figure 1 is a block diagram of an embodiment according to the present invention, Figure 2 is a pixel and block configuration diagram of an image, Figure 3 (a) is a configuration diagram of a compressor, and Figure 3 (b) is a modification of the compressor. Example configuration diagram, Figure 4(a)
(b) is a configuration diagram of compressed data according to the embodiment shown in FIG. 3 (a), FIGS. Figure 7(b) is a configuration diagram of compressed data according to the embodiment; Figure 7(a) is a configuration diagram of an decompressor corresponding to the compressor in Figure 3(a); FIG. 8 is a block diagram of a modification of this embodiment. In the figure, 1... pixel, 2... pixel block, 4...
Color/monochrome mode switch, 5... Compressor, 6...
・Image memory, 7...Extender, 11.22...Selector, 12.13.16, 23.25...ROM, 1
4...Synthesizer, 24...Separator, 30-32...
Color selection switch, 40... is an expander. Patent applicant: Canon Corporation Figure 4 (0) Figure 4 (b) Figure 6 (0) Figure 6 (b) Figure 7 (0)

Claims (3)

[Claims] (1) Information indicating whether the compressed image data input in block units is color image compression data or monochrome image compression data, and color processing of the input compressed image data according to the instruction information. a color image data decompression means for decompressing the input compressed image data in blocks as monochrome image data; a monochrome image data decompression means for decompressing the input compressed image data in block units as monochrome image data; An image output device having an output means for outputting. (2) Image output according to claim 1, wherein the color image compressed data is composed of brightness information and chromaticity information, and the monochrome image compressed data is composed of brightness information. Device. (3) Further, it includes an instruction means for instructing color addition and an addition means for adding color information, and when the instruction information indicates monochrome image compressed data and the instruction means instructs color addition, the addition means The image output device according to claim 2, characterized in that color information is added to the expanded monochrome image data.