JPH05305709A - Video printer - Google Patents

Abstract

PURPOSE:To adjust saturation so as to be suitable for the characteristics of an ink or of the image receiving layer of photographic paper. CONSTITUTION:An analog processing circuit 1 decodes an input image signal into a brightness signal (Y) and color difference signals (R-Y, B-Y). All the image data of an image memory 3 read on a memory control by the control signal from a circuit 8 is supplied to a saturation adjusting circuit 4 to produce a color difference signal (G-Y). The correction factors set by a correction factor setting means 10 against the color difference signal (G-Y) and the other color difference signals (R-Y, B-Y) are supplied to a saturation adjusting circuit 4 through a control circuit 9, thereby effecting the optimum saturation adjustment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video printer, and more particularly, it is used in a color thermal transfer printer and processes a color difference signal with a certain correction coefficient to adjust saturation around a luminance signal level. Related to the video printer.

[0002]

2. Description of the Related Art Generally, a video printer is composed of an image memory unit for fixedly holding an image during a recording operation, a gradation control unit, a mechanism for conveying image receiving paper and the like, a recording medium and the like. .. Since the recorded image is a natural image, it is characterized by expressing analog gradation and is different from a printer whose main purpose is simply to draw characters and figures. The image memory unit stores a field image, a frame image, etc. as a still image, and reads out a part of the image signal according to the recording speed ("Handbook of Television and Image Information Engineering", The Institute of Television Engineers of Japan,
1990-11-30, P285-287).

FIG. 4 is a block diagram of a conventional video printer. In the figure, 11 is an analog processing circuit, 12 is an A / D converter, 13 is an image memory, 14 is a control circuit, and 15 is RGB.
A conversion circuit, 16 is a print processing circuit, 17 is a thermal head, and 18 is a memory control circuit. The input video signal is decoded into a luminance signal (Y) and a color difference signal (RY, BY) by the analog processing circuit 11, and a sync signal is separated. Each of the luminance signal (Y) and the color difference signals (RY, BY) is synchronized with the clock output from the memory control circuit 18 and A / D converted by the A / D converter 12 to generate an image. It is stored in the memory 13. The image data read from the image memory 13 by the memory control signal from the memory control circuit 18 is converted into each data of the primary color signals (R, G, B) by the RGB conversion circuit 15, and the print processing circuit 1
6, color correction is performed based on the R, G, B data, and the corrected R, G, B data is converted into complementary color data. Based on the complementary color data, the control circuit 14 controls the energization of the thermal head 17 for printing.

[0004]

As described above, in the saturation adjusting method in the conventional video printer, the primary color signal (R, G, B) data is created from the luminance signal and the color difference signal,
For each of the R, G, and B data, corrections are made according to the characteristics of the ink and the characteristics of the image receiving layer of the printing paper.
Since the saturation is adjusted according to the characteristics of the ink and the characteristics of the image receiving layer of the photographic paper by performing it on the B data, it is possible to roughly correct each of the R, G, and B primary colors. However, there is a problem in that the brightness and the hue change with respect to the intermediate color and the like.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a video printer capable of adjusting the saturation suitable for the characteristics of the ink and the characteristics of the image receiving layer of the printing paper. ..

[0006]

In order to achieve the above object, the present invention stores an analog processing means for creating a luminance signal and a color difference signal from an input video signal, and a signal created by the analog processing means. Storage means, RGB conversion means for converting the image data stored in the storage means into each data of primary color signals, print processing means for performing color correction based on the data of the RGB conversion means, and complementary colors of the print processing means In a video printer comprising a control means for controlling energization of a thermal head based on data, a means for adjusting saturation at printing by using a predetermined correction coefficient for the color difference signal is further provided. , Inputting the image data stored in the storage means, determining the saturation adjusting means for adjusting the saturation by the correction coefficient from the control means, and the setting condition of the correction coefficient. Is provided with a correction coefficient setting means for inputting to the control means Te.

[0007]

The luminance signal (Y) and the color difference signals (RY, BY) are generated from the input video signal, and the luminance signal (R, G, B) is generated before the respective data of the primary color signals (R, G, B) are generated. Y) and color difference signals (RY, BY) to create a color difference signal (G-Y), and for the obtained color difference signals (RY, G-Y, BY), By changing the primary color signal (R, G, B) data centering on the luminance signal level and changing the luminance and hue by processing each data with a certain correction coefficient suitable for the characteristics and the characteristics of the image receiving layer of the printing paper. The saturation is adjusted without any adjustment, and after the saturation adjustment, each data of the primary color signals (R, G, B) is created and printed out.

[0008]

Embodiments will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining an embodiment of a video printer according to the present invention, in which 1 is an analog processing circuit, 2 is an A / D converter, 3 is an image memory, and 4 is a saturation adjustment circuit. 5 is an RGB conversion circuit, 6 is a print processing circuit, 7 is a thermal head, 8 is a memory control circuit, 9 is a control circuit, and 10 is a correction coefficient setting means.

The analog processing circuit 1 performs predetermined signal processing such as decoding an input video signal into a luminance signal (Y) and color difference signals (RY, BY) and separating a sync signal. .. The A / D converter 2 performs A / D conversion on the luminance signal (Y) and the color difference signals (RY, BY) in synchronization with a clock. The image memory 3 stores each image data A / D converted by the A / D converter 3. The image memory 3 read by the memory control signal from the memory control circuit 8.
Each image data of is input to the saturation adjustment circuit 4, and color difference signal (GY) data is created. Further, in the saturation adjusting circuit 4, the created color difference signal (GY) data,
For the other color difference signal (RY, BY) data, the setting condition from the correction coefficient setting means 10, that is, the correction coefficient (α, β, γ) is input via the control circuit 9, and the ink characteristics are set. Also, the optimum saturation adjustment is performed according to the characteristics of the image receiving layer of the printing paper.

For example, a voltage that is changed by an external volume or the like is A / D converted, and the A / D converted data and the like is input to the control circuit 9. Assuming that the setting condition of the correction coefficient (α, β, γ) created by the correction coefficient setting means 10 is a curve A of data as shown in FIG. 2, a color difference signal (R−
The Y, G-Y, B-Y) data is subjected to saturation adjustment by the saturation adjustment circuit 4, and the color difference signal (RY ', G as shown in FIG. 3 is obtained.
-Y ', BY') data is created, and the RGB conversion circuit 5
Entered in. At this time, in FIG. 2, the correction is performed such that the saturation is high when the curve is A and the saturation is low when the curve is B. In the RGB conversion circuit 5, each color difference signal (R-Y ', G-Y', B-Y ') data and luminance signal (Y) data is converted into primary color signal (R, G, B) signal data. To create. The respective signal data of the primary color signals (R, G, B) are supplied to the print processing circuit 6 at Ye (yellow),
After being converted into complementary color data of Mg (magenta) and Cy (cyan), the print processing circuit 6 controls the energization of the thermal head 7 by the control of the control circuit 9 based on the complementary color data.
In this way, it is possible to perform high-quality printing that is optimal for the characteristics of the ink and the characteristics of the image receiving layer of the printing paper.

In the present invention, the thermal transfer system is adopted. In this thermal transfer method, a printing paper and a transfer paper consisting of a base film coated with ink are appropriately pressed between the printing drum and the thermal head,
The electric energy applied to the thermal head while rotating the printing drum is controlled according to the amplitude of the image signal to express gradation. A line head is used as the thermal head.

[0012]

Since the present invention is constructed as described above, it has the following effects. Since the saturation adjustment circuit is provided and the correction coefficient by the correction coefficient setting means is input to the saturation adjustment circuit via the control circuit to adjust the saturation, there is no need to change the brightness and the saturation especially for the intermediate color. In addition, it is possible to adjust the saturation suitable for the characteristics of the ink and the characteristics of the image receiving layer of the printing paper, and it is possible to perform high-quality printing.
Further, the circuit is simplified because the adjustment is not performed after conversion to R, G, B.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a video printer according to the present invention.

FIG. 2 is a diagram showing a correction coefficient setting condition created from data of a correction coefficient setting means according to the present invention.

FIG. 3 is a diagram showing data subjected to saturation adjustment by a saturation adjustment circuit according to the present invention.

FIG. 4 is a diagram showing a conventional video printer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Analog processing circuit, 2 ... A / D converter, 3 ... Image memory, 4 ... Saturation adjustment circuit, 5 ... RGB conversion circuit, 6 ... Print processing circuit, 7 ... Thermal head, 8 ... Memory control circuit, 9 ... control circuit, 10 ... correction coefficient setting means.

Claims (2)

[Claims] 1. An analog processing means for creating a luminance signal and a color difference signal from an input video signal, a storage means for storing the signal created by the analog processing means, and a primary color signal from the image data stored in the storage means. Of the RGB conversion means, the print processing means for performing color correction based on the data of the RGB conversion means, and the control means for controlling the energization of the thermal head based on the complementary color data of the print processing means. The video printer according to claim 1, further comprising means for adjusting the saturation at the time of printing by using a predetermined correction coefficient for the color difference signal. 2. Saturation adjusting means for inputting image data stored in said storage means and adjusting saturation with a correction coefficient from said control means, and setting conditions for said correction coefficient to determine said control means. 2. The video printer according to claim 1, further comprising correction coefficient setting means for inputting.