JPH05169694A - Printer - Google Patents

Abstract

PURPOSE:To reduce a scale of a circuit by a construction wherein memory means for storing YC signals and a matrix operating means are provided. CONSTITUTION:A printer is constructed by providing frame memories 20(a)-20(c) for storing YC signals and a matrix operating circuit 21. The matrix operating circuit 21 has both a function of conducting a matrix operation of YC signals to RGB signals and a function of conducting a color masking of the RGB signals. Therefore, the circuit can be reduced in scale.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer which stores a video signal of a TV, VCR, camcorder or the like for one screen and makes a hard copy of the stored screen on paper or the like.

[0002]

2. Description of the Related Art Thermal printing converts an electric signal corresponding to image information into heat energy by a heating resistance element,
This is a recording method in which a visible image is formed on paper by using this thermal energy, roughly classified into a direct thermal method in which thermal energy is directly applied to thermal paper, and thermal energy is applied to an external color source such as an ink ribbon. There is a transfer type heat-sensitive method in which ink is transferred to paper.

In the transfer type heat-sensitive system, it is easy to obtain a multi-recorded color image by switching a plurality of color ink ribbons, and recently, a full-color video printer that gives each recording dot itself a gradation of density has appeared. Then
It is expected as a hard copy device such as a video receiver, an image processing device, and a personal computer.

In this density gradation method, generally, a constant voltage is applied to each heating resistor element of the thermal head to control the energization time to give gradation to the generated heat energy,
A gradation is given to the transfer amount of ink and thus to the density of the image.

FIG. 5 shows an energization time / density characteristic curve used in the density gradation method. Unit of energization time for heating resistance element Δ
The density of the gradation level d1 is obtained by energizing for the energization time t1 corresponding to t, and the density of the gradation level d2 is obtained by energizing for the energization time t2 corresponding to twice the unit energization time Δt. ing. In this example, the maximum gradation level d64 near the saturation density can be obtained by energizing for the energizing time t64 corresponding to 64 times the unit energizing time Δt.

FIG. 4 schematically shows the structure of a conventional video printer. An NTSC video signal VS is input to the input terminal 10 from an external device such as a TV or VTR. The video signal VS is decoded by the NTSC decoder 12 into red, green and blue primary color video signals. Those primary color signals are A
It is supplied to the / D converter 14, where it is converted into, for example, an 8-bit digital video signal, that is, pixel data R, G, B, and input to the frame memory 20.

Each row of the frame memory 20 corresponds to a horizontal scanning line of a television image, and pixel data is written in an order corresponding to raster scanning. Next, the first of the frame memory 20
Starting from the column, pixel data a1j, a2j, ... A512j for one line is read out for each column (j) and supplied to the color process circuit 22, where inverse gamma correction, brightness / density is performed. After being subjected to image processing such as conversion, it is supplied to the matrix calculation circuit 21 and subjected to color correction processing to obtain 6-bit density data b1j, b2j ,.
Converted to 2j. Each of these density data bij is
It has a value (gradation level) corresponding to the density of the corresponding pixel within the range of << 0 >> (minimum density) to << 64 >> (maximum density).

1 output from the matrix operation circuit 21
Density data for printing lines b1j, b2j, ...
b512j is once taken into the line buffer 26 and then given to one input terminal of the data comparison circuit 28. DM for writing / reading of the line buffer 26
It is performed under the control of the A controller 30.

The other input terminal of the data comparison circuit 28 is supplied with a 6-bit comparison reference value DN which is incremented by 1 at a constant period from the gradation counter 31 during the energization interval TE. The data comparison circuit 28 uses the comparison reference value DN.
Is compared with each density data, and if the latter is equal to or larger than the former, a bit of "1" is generated, and if not (smaller), a bit of "0" is generated as a gradation bit.

For example, energization time data B1j, B2j, ...
..... The values of B512j are << 10 >>, << 2 >>, ...
・ ・ It is << 1 >>. In this case, the comparison reference value DN is << 1 >> in the first comparison, and the first gradation data [C1 P1j, C1 P2j, ...
512j] becomes [1, 1, ... 1]. In the second comparison, the comparison reference value DN is << 2 >>, and the second gradation data [C2P1j, C2P2j, ...
12j] becomes [1, 1, ... 0]. In the third comparison, the comparison reference value DN is << 3 >>, and the third gradation data [C3 P1j, C3 P2j, ...
・ C3 P512j] becomes [1, 0, ... 0].

In this way, the energization interval TE
Medium and density data b1j, b2j, ...
Are compared with each other, and gradation data [C1 P1j, C1 P2j, ... C1 P512 corresponding to each comparison result is obtained.
j], [C2 P1j, C2 P2j, ... C2 P512j], ...
... are sequentially sent to the shift register 52 of the thermal head 50 in a fixed cycle.

[0012]

In a video printer which carries out the color masking as described above, the R, not the YC signal is used.
GB signal is required. Therefore, a matrix operation circuit for generating RGB signals from YC signals and a matrix operation circuit for performing color masking are required, and the circuit scale is increased.

The present invention has been made in view of the above problems, and provides a video printer for color masking, which realizes a reduction in circuit scale.

A video printer that performs color masking as described above requires RGB signals instead of YC signals. Therefore, a matrix operation circuit for generating an RGB signal from the YC signal and another matrix operation circuit for performing color masking are required, and the circuit scale is increased.

The present invention has been made in view of the above problems, and provides a video printer for color masking, which realizes a reduction in circuit scale.

[0016]

In order to achieve the above object, the printer of the present invention comprises a memory means for recording YC signals; a function for matrix-calculating YC signals into RGB signals and a function for color masking RGB signals. It is configured to include an arithmetic unit having both.

[0017]

In the present invention, the YC signal is converted to RG in the calculation means.
The B signal is provided with the function of matrix calculation and the function of color masking the RGB signal.

Therefore, the circuit scale can be reduced.

[0019]

FIG. 1 shows a circuit configuration of a printer according to an embodiment of the present invention.

The input terminal 10 receives an NTSC video signal VS from an external device such as a TV or VTR. The video signal VS is separated into a Y signal and a C signal by the YC separation circuit 16 and supplied to the A / D converter 14, where, for example, 8
The bit digital luminance signal Yd and the digital color difference signals (R-Yd) and (B-Yd) are converted and input to the frame memory 20.

Each row of the frame memory 20 corresponds to a horizontal scanning line of a television image, and digital YC signals are written in an order corresponding to raster scanning. Next, the frame memory 2
Starting from the first column of 0s, the digital YC signals for one line are read out for each column (j), and the matrix operation circuit 2
1 and is subjected to matrix calculation to receive pixel data a1
j, a2 j ... a512 j is converted into R, G, B.
Pixel data a1j, a2j ...
The image data is supplied to the process circuit 22 where it is subjected to image processing such as inverse gamma correction and luminance / density conversion, and then supplied to the matrix operation circuit 21 where color correction processing is performed and 6-bit density data b1j, b2j ... ... Converted to b512j.

The density data b1j, b2j for one printing line output from the color process circuit 22 ...
B512j is once taken into the line buffer 26 and then given to one input terminal of the data comparison circuit 28. DM for writing / reading of the line buffer 26
It is performed under the control of the A controller 30.

The other input terminal of the data comparison circuit 28 is supplied with a 6-bit comparison reference value DN which is incremented by 1 at a constant period from the gradation counter 32 during the energization interval TE. The data comparison circuit 28 uses the comparison reference value DN.
Is compared with each density data, and if the latter is equal to or larger than the former, a "1" bit is generated, and if not (smaller), a "0" bit is generated as a gradation bit.

In this way, the energization interval TE
Medium and density data b1j, b2j, ...
Are compared with each other, and gradation data [C1 P1j, C1 P2j, ... C1 P512 corresponding to each comparison result is obtained.
j], [C2 P1j, C2 P2j, ... C2 P512j], ...
Are sequentially sent to the shift register 14 of the thermal head 10 in a fixed cycle.

FIG. 2 shows a concrete example of the matrix operation circuit 21. The matrix operation circuit 21 converts the YC signal into RGB
A method of calculating a signal and a method of performing color masking will be described.

The 8-bit digital luminance signal Yd and the digital color difference signals (R-Yd) and (B-Yd) output from the frame memory 20 pass from the selector 61 to the selector 63 and are latched from the latch 67, respectively. It is latched by 69 and supplied from the multiplier 71 to the multiplier 73. The matrix coefficients m11, m12, and m13 are input from the matrix coefficient circuit 70 to the other input terminals of the multipliers 71 to 73, respectively, and the digital luminance signal Yd and the digital color difference signals (R-Yd), (B- Y
Multiply with d). This coefficient ... 11, ... 1
2, ... 13 are coefficients of calculation generally performed by VTR technology or the like.

The outputs of the multiplier 71 to the multiplier 73 are supplied to the adder circuit 74, and are input to the selector 60 through the limiter circuit 75. When input to the selector 60, the YC signal is calculated as the R signal of the RGB signal. The R signal output from the selector 60 is latched by the latch 64.

The same calculation as above is performed, and the selector 60
The G signal output from is latched in the latch 65.

The same calculation is performed, and the matrix coefficient is m.
B signal is generated as 31, m32, m33. Selector 6
The B signal output from 0 is latched by the latch 66.

After the B signal is latched by the latch 66, the selector 61 to the selector 63 and the select signal of the decoder 60 select the opposite side.

The R, G and B signals are supplied to the color process circuit 2
The image data is supplied to No. 2, where it is subjected to image processing such as inverse gamma correction and luminance / density conversion, converted into Dr, Dg, Db, and latched by the latch 67 to the latch 69, respectively. The signals are supplied from the latch 67 to the latch 69 to one input terminal of the multiplier 71 to the multiplier 73. Multiplier 71 to multiplier 7
The other input terminal of 3 has a matrix coefficient circuit 70
Then, matrix coefficients ni1, ni2, ni3 are respectively inputted and are multiplied by Dr, Dg, Db. This coefficient is CP
It is changed according to the color to be printed by the signals indicating Y, M and C from U40.

The output of the multiplier 71 to the multiplier 73 is supplied to the adder circuit 74, passes through the limiter circuit 75, and reaches the sector 6
Input to 0. When input to the sector 60, it becomes the density data bij. That is, the R signal, the G signal, and the B signal are color-processed, and the signals are color-masked corresponding to Y, M, and C.

[0033]

The present invention has the following effects by having the above-mentioned structure.

Matrix calculation means is provided to convert the YC signal to R
Since the function of performing matrix calculation on the GB signal and the function of performing color masking on the matrix-calculated signal are provided together, the circuit scale can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a printer according to a position embodiment of the present invention.

FIG. 2 is a block diagram showing a matrix operation circuit configuration in the printer of FIG.

FIG. 3 is a block diagram showing a circuit configuration of a conventional printer.

FIG. 4 is a diagram showing a Tsudada time-density characteristic curve used in the density gradation method.

[Explanation of symbols]

 14 Separation Means (A / D Converter) 16 Separation Means (A / D Separation Circuit) 22 Arithmetic Circuit (Color Process Circuit) 50 Thermal Printhead 70 Coefficient Circuit (Matrix Coefficient Circuit) 71 Arithmetic Circuit (Multiplier) 72 Arithmetic Circuit (multiplier) 73 Operation circuit (multiplier) 74 Operation circuit (addition circuit) 100 Conversion means

Claims (1)

[Claims] 1. A separating means for separating an input image signal into a luminance signal and a color difference signal, a converting means for converting a separated video signal from the separating means into a color density signal, and a color density signal from the converting means. A printer having a thermal head for sublimation printing, wherein the conversion means performs a matrix operation on a coefficient circuit for outputting an arbitrary operation coefficient group and the separated video signal by the first group of coefficients from the coefficient circuit. And an arithmetic circuit for forming the three primary color signals and masking the three primary color signals by the second group of coefficients from the coefficient circuit to convert the three primary color signals into color density signals for sublimation printing. Characteristic printer.