JPH045306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color conversion device for use in color facsimile.

Various color facsimile recording methods have been proposed in the past, one of which is an inkjet method. In this method, ink droplets of three primary colors, ie, yellow, magenta, and cyan, are sprayed onto a recording paper through subtractive mixing, and a color image is obtained by combining the three colors.

By the way, color facsimile machines are designed to record in color faithfully to the original document, which is natural considering its original function.
For example, even if the background color of a manuscript is red, and this background color itself has little meaning, and only the characters and figures written on it are important, the background color of the calligraphy and paintings reproduced on the receiving side will be red. becomes. This is not desirable in terms of the clarity of the reproduced calligraphy and paintings, and
Especially for those that perform inkjet recording as mentioned above,
Ink will be wasted, and the recording paper will become sticky with ink, making it difficult to handle.

Therefore, in consideration of this point, the present invention enables transmission by replacing a specific color that appears most frequently, such as the ground color, in a document with white.The details will be explained below with reference to the drawings. explain.

FIG. 1 shows a schematic configuration of a color conversion device according to the present invention. In the figure, Y, M, and C are the components of a color image signal derived from the document reading means, separated into the three primary colors of yellow, magenta, and cyan, and then binarized. On the other hand, M and C are stored in a magnetic memory device 2 via a control circuit 1 such as a microprocessor for one document.

On the other hand, the color image signals Y, M, and C are sequentially introduced into a color detection circuit 3, and the color represented by the combination of these signals is detected for each pixel. That is, since the above signals Y, M, and C are all binarized, if Y=M=C=0, it is white, and Y=M=C.
If = 1, black, if Y = M = 1, if C = 0, red. represents the
Each color is detected for each pixel. Each time a certain color is detected, the detection circuit 3 activates counters 4 ₀ , 4 _{1 .} . . 4 ₇ provided for each of the eight colors.
The counter corresponding to the detected color is incremented by one. Therefore, at the time when color image signals for one original document have been stored in the memory device 2, the total number of pixels of each color in the original document has been counted by the counters ₄₀ to ₄₇ . .

When the color image signal for one document is completely stored in the memory device 2, the control circuit 1 activates the size discrimination circuit 5.
By giving a command to the circuit 5, the counting results of the counters ₄₀ to ₄₇ are taken into the circuit 5. Then, this size discrimination circuit 5 detects the counter exhibiting the maximum count value among the respective counting results, and outputs a color signal representing the color corresponding to this counter to the output terminals (TY) (TM) (TC). do. That is,
Now, counter 4 ₁ is cyan (Y=M=0, C=1)
If the count value of this counter ₄₁ is the maximum, the color signals appearing at each output terminal (TY) (TM) (TC) of the discrimination circuit 5 are TY=TM=0, TC. = 1, and each signal is held continuously from now on.

Here, the size discrimination circuit 5 can be constructed by a microprocessor or the like, but in this case, it should be set so that the parallel 3-bit signals representing the aforementioned eight colors represent the respective corresponding counter numbers. It's convenient. That is, since the aforementioned counter ₄₁ corresponds to cyan, the 3-bit signal (001) (in YMC order) representing cyan represents the counter number "1". Therefore, counter bar “2”, that is, the third counter 4 ₂ from the top, is 2
That is, since it is 010, magenta (Y=C=0, M
=1).

On the other hand, when reading from the memory device 2 is started by the control circuit 1, the color image signals Y, M, C sequentially derived from the memory device are passed through the control circuit 1 to the coincidence detection circuits 6Y, 6M. , 6C. At this time, the color signals TY, TM, and TC from the size discrimination circuit 5 are introduced as the other input of each of the coincidence detection circuits. Therefore, if it is assumed that the color signal is TY=TM=0 and TC=1 as described above, the color image signal derived from the memory device 2 via the control circuit 1 is Y. =M=0,=1
(that is, cyan), a coincidence output "1" is generated from all of the coincidence detection circuits 6Y, 6M, and 6C.

When coincidence outputs are generated from all of the coincidence detection circuits 6Y, 6M, and 6C, at this time, the NAND gate 7
The output of is "0", and the output of this NAND gate is given as an input to each of AND gates 8Y, 8M, and 8C. Therefore, each output of this AND gate is the color image signal Y, M, C (at this time, Y=M=0, C
= 1), it becomes 0 and represents white. That is, the cyan of the color image signal read out from the memory device 2 is replaced with white, which is then outputted from the AND gates 8Y, 8M, and 8C.

Further, when the color image signal from the memory device 2 is a color other than cyan, a mismatch output "0" is always generated from any one of the match detection circuits 6Y, 6M, and 6C. Therefore, the output of NAND gate 7 is "1" and AND gate 8Y,
8M and 8C are all open. Therefore, at this time,
The introduced color image signals Y, M, and C are derived as they are from each of the AND gates, and therefore no color conversion is performed.

In this way, the above AND gates 8Y, 8M,
The color image signal derived from 8C is introduced into a transmission processing circuit (not shown), and the parallel 3-bit simultaneous signal type signal is converted into an appropriate signal type, such as a sequential type, and transmitted. Since it is not directly related to the gist of the present invention, the explanation will be omitted.

In the illustrated embodiment, the color image signal is a binary signal, since it is intended for color recording with a total of 8 colors, including 7 colors not including halftones shown in FIG. 2, and black. It can also be applied to analog image signals or multivalued digital image signals.

The color detection circuit 3 shown in FIG. 1 can also be configured by a combination of registers set for each color, logic circuits, etc., but it can be easily realized by using a microprocessor, etc. It is also possible to configure the entire circuit except for the magnetic memory device 2 with a microcomputer.

Since the color conversion device of the present invention is configured as described above, it is possible to detect the color that appears most frequently, such as the ground color, in the document and automatically replace this color with white. , is suitable for transmitting originals with a background color other than white, and is highly effective when implemented in a color facsimile device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a color conversion device according to the present invention, and FIG. 2 is a diagram showing a color combination relationship for explaining the same. Y, M, C...color image signal, 1...control circuit, 2...magnetic memory device, 3...color detection circuit,
4 ₀ , 4 ₁ to 4 ₇ ... Counter, 5 ... Size discrimination circuit, 6Y, 6M, 6C ... Coincidence detection circuit.

Claims (1)

[Claims] 1 means for detecting the color of each pixel of a color image signal obtained from a document; means for counting the number of pixels of each color detected by the means over one document; memory means for storing data for each color; means for checking the counting results of each color by the counting means and creating and holding a color signal of the color corresponding to the maximum counted value; A color facsimile comprising means for sequentially detecting color matching with a color image signal read from a memory means, and means for obtaining a matching output from the means and replacing the color image signal with a white signal. conversion device.