JPH04115776A - Picture reader - Google Patents

Abstract

PURPOSE:To select a pattern from a storage circuit and to output monochromatic display by separating a picture into plural colors and calculating a pattern to be selected based on a read value corresponding to each color. CONSTITUTION:A color density pattern selection calculation circuit 1 receiving R, G, B signals separated by plural color filters of a color picture reader outputs a color density pattern selection signal depending on each value of RGB signals and gives the signal to a color density pattern storage circuit 2. The circuit 2 (color density pattern ROM 2) to allocate a number to each of plural patterns by each of color and density generated in advance and to store the result selects a color density pattern in response to the pattern selection signal and outputs a color density pattern. The color density pattern storage circuit 2 receives a color density pattern address signal as an address signal to change a column address and a row address of a color pattern. Thus, monochromatic information including color and density information is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention uses color filters to convert images into three colors of R, G, and B.
The present invention relates to an image reading device for separating into primary colors and displaying monochrome images.

(Prior art and problems to be solved by the invention) Conventionally,
In a color image reading device that separates and reads an image into the three primary colors of R, G, and B, when outputting a read image on a monochrome CRT, monochrome print, etc. that cannot display color, one pixel ( (indicates the unit of color pixels expressed by a pair of RGB) is calculated from the input values of each RGB, and the output density is changed as a halftone expression using the dither method, error diffusion method, etc. In other words, the output image has shading. It was expressed by adding .

However, according to the above method, the results calculated from each value of RGB are the same value (for example, the values of R=2, G=10, and B=10 are obtained as input values of R, G, and B. and when we obtain the values of R=10, G=2, and B=10,
The picture element value (Ga) (=R0G0B) is Ga in both cases.
-22), the display density will be the same gradation expression, but the color expression will also be the same expression. However, in the above case, one color is a red-based color and the other is a green-based color. In addition, it is possible to distinguish colors based on past knowledge, such as face photographs and landscape photographs, but it is impossible to distinguish colors in the case of images for which there is no past knowledge, such as data classification. be. Therefore, when reading an image for data classification, etc. and outputting it on a monochrome CRT, monochrome print, etc., even if the image is read as a color image, the color cannot be identified as color information.
The drawback was that the amount of information read was largely lost.

Also, white, red, green, blue, yellow, cyan, magenta, and black are 8
A method of displaying using gradations of light and shade has been known for some time (Japanese Patent Publication No. 13912/1982), but it is not possible to express many colors with only such density gradation expression, As with the above method, this results in a loss of information.

The present invention has been made to eliminate the above drawbacks,
An object of the present invention is to provide an image reading device that can read color image information and output it as monochrome information without causing loss of information amount.

(Means and Effects for Solving the Problems) In order to achieve the above object, the present invention provides an image reading device for color-separating an image into a plurality of colors using a plurality of color filters and performing monochrome display. an arithmetic circuit for performing calculations from read values corresponding to each color separated into colors;
It has a memory circuit that stores a plurality of patterns, and outputs both color and density information as monochrome information by selecting and outputting a pattern from the memory circuit based on the calculation result of the calculation circuit. This is how it was done.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a main part of an image reading apparatus according to an embodiment of the present invention. In the figure, l is a color density pattern selection arithmetic circuit, and R signals color-separated by a plurality of color filters of a color image reading device;
When G signal and B signal are input, as shown in Fig. 2 (, RG
A color density pattern selection signal is output according to each value of B and is supplied to the color density pattern storage circuit 2. As shown in FIG. 3, the color density pattern storage circuit 2 is a circuit (color density pattern ROM) for assigning and storing numbers to each of a plurality of patterns for each color and density created in advance. The circuit selects a color density pattern according to the pattern selection signal and outputs the color density pattern.The color density pattern storage circuit 2 includes a fourth
As shown in the figure, a color density pattern address signal is supplied as an address signal for changing the column address and row address of the color pattern. Regarding the color density pattern address signal, when outputting an image, an address signal in the main scanning direction is input to the column address of the color pattern, and an address signal in the sub-scanning direction is input to the row address of the color pattern.

Figure 2 shows the case classification and color density of each value of the R signal, G signal, and B signal when each of the R signal value, G signal value, and B signal value is expressed with a resolution of 4 gradations. It is a figure which shows the relationship with a pattern Yuzawa number. In the embodiment, the R signal value, G signal value, and B signal value each have a resolution of 4 gradations, and the color patterns are 64 types. Note that it is possible to further increase the resolution of the R signal value, G signal value, and B signal value, and in that case, the types of color density patterns may be increased.

FIG. 3 shows an example of a color pattern. The R signal pattern is represented by diagonal lines upward to the right (R1, R3), the pattern by the G signal is represented by diagonal lines downward to the right (G1, G3), and the pattern by the B signal is represented by horizontal lines (B1, B3). . The higher the density of each pattern (the number of lines per unit area), the higher the density.

In addition, by overlapping the pattern of the R signal and the pattern of the G (sign), a purple-based color (RG2) is created, and by overlapping the pattern of the G signal and the pattern of the B signal, a red-based color (GB2) is created, and the R signal By overlapping the pattern by the 5R signal, the pattern by the G signal, and the pattern by the B signal, a greenish color (BH3) is created by overlapping the pattern by the 5R signal, the pattern by the G signal, and the pattern by the B signal, and the color expressed by each value and the achromatic color. (RG
B2).

4. As described above, according to this embodiment, monochrome information including color and density information corresponding to each RGB signal value is output, so monochrome display can be performed without omitting color image signal information. It becomes possible.

In the embodiment, the circuit is composed of two blocks: a color pattern selection calculation circuit and a color density pattern storage circuit, but it may be configured to directly select the type of color density pattern. In this case, A color density pattern selection arithmetic circuit is not required, and the color density pattern selection calculation circuit can be configured with one color density pattern ROM.

(Effects of the Invention) As detailed above, according to the image reading device of the present invention, since both color and density information are output as monochrome information, monochrome display is possible without missing the amount of color image information. It becomes possible to do so.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of an image reading device according to an embodiment of the present invention, FIG. 2 is a diagram showing the correspondence between RGB signal values and color density pattern selection numbers, and FIG. 3 is a diagram showing the color density pattern selection number. FIG. 4, which is a diagram showing an example of a pattern, is a diagram for explaining a color density pattern address signal. 1... Color density pattern selection calculation circuit, 2... Color density pattern storage circuit. Applicant: Canon Inc.

Claims (1)

[Claims] 1. Using multiple color filters to separate an image into multiple colors, an image reading device for monochrome display performs calculations based on the read values corresponding to each color separated into multiple colors. What is claimed is: 1. An image reading device comprising: an arithmetic circuit for storing a plurality of patterns; and a memory circuit for storing a plurality of patterns, and selecting and outputting a pattern from the memory circuit based on the arithmetic result of the arithmetic circuit.