JPS59123392A - Video printer - Google Patents

Abstract

PURPOSE:To attain ease of change and to reduce processing time by using lookup table so as to decide the imaging amount of cyan, magenta, yellow and black. CONSTITUTION:Data with the corrections such as inverse gamma correction for cathode ray tube, the correction of color distortion due to incomplete spectral characteristic of each color member by a masking matrix, the determination of black print from a neutral color component, the elimination of background color of each color member, and the correction of a picture density characteristic to the modulation of an input signal are stored in a lookup tables 2. The imaging amount of each ink for a full-color print mechanism 4 is controlled by using the data 3 of the imaging amount of cyan, magenta, yellow and black print decided by the table 2. Thus, the printer can cope instantly with the change in the color member, an imaging system, and the change in an object picture, to obtain an optimum color balance at all times and a high speed imaging.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to signal processing means in a video printer for obtaining full-color hard copies of color television video signals.

In recent years, video decks have become widespread, and video discs have appeared, making it easier to obtain still image signals from color television. A magnetic recording camera was also announced, intended to be used in the same way as conventional silver halide photography, and this also outputs color television still image signals.

In this way, when it became possible to easily obtain high-quality color still images, people wanted to obtain the still images as hard copies.
Demand will increase. Conventionally, instant photography was used to meet this demand. However, instant photography had high running costs, and it was easy for ordinary users to accurately install the front f-camera of a television set. It can be said that it is a tedious task.

Additionally, video printers that combine a dedicated flat CRT and instant photos have less graphic distortion and good color balance, but are currently too expensive for general home use and are limited to special uses. .

However, recently, the development of printing principles that enable color printing, such as inkjet, thermal transfer, and electrical transfer, has progressed, and the environment has become such that the above-mentioned demand can be met.

By the way, in the above-mentioned printing principles, when performing full-color printing, three-second color materials of cyan, magenta, and yellow, and even a black plate are used, but the YIQ signal, which is the video signal of color television, is used. Or RG
In order to determine the printing amount of each color material from B (F), it is essential to carry out various types of A/I processing. First, the video signal is
If it is a Q signal, it must be converted to an RGB signal and then gamma-corrected for use with the tube.

Furthermore, since the spectral characteristics of the cyan, magenta, and yellow coloring materials used are not ideal, it is necessary to balance each hue using a masking matrix. When using a black plate, a neutral color component is extracted by 1,000 yen, and if necessary, an undercolor removal process of the three coloring materials is performed.

Furthermore, it is necessary to correct the characteristic of the modulation degree of the input signal versus the image density, which is determined by the printing principle.

The above signal processing has conventionally been performed using hardware such as a gamma correction circuit or a matrix circuit. However, hardware processing is inconvenient for immediately responding to changes in color materials, printing methods, and even changes in target images.

Furthermore, if software processing using a CPU were to be executed for all 260,000 pixels, it would take more than an hour, making it very impractical.

The present invention eliminates the above-mentioned disadvantages, provides a signal processing means that is easy to change, and has a short processing time.
This will be explained in detail below.

In the present invention, a look-up table is used to determine the printing amount of cyan, magenta, yellow, and the substrate. Lookup tables are used in some large-scale image processing devices.

Figure 1 shows the concept of a lookup table.

The three types of video signals of color television are digitized to create a three-dimensional address space R, G, B, and one address is assigned to each combination of signal strengths r2g,b. . Each address contains C, M, Y, and EK as a result of the signal processing for the signal strength.
Automatically memorizes the colors of cyan, magenta, and yellow.

In addition, you can read out the inno and quantity of the black version.

FIG. 2 conceptually shows the overall configuration of a video printer according to the present invention. 1 accesses the lookup table of pl 2 with color television video (i number).

The printing Z of the cyan, magenta, yellow, and black plates determined by lookup table 2, ``FC determined data is 3, and the Sandoku color paulownia of cyan, magenta, and yellow of 4, and the black plate is It is sent to a structure that performs digital printing, and forms a video printer 5 as a whole.

This will be explained below using examples.

As video signal 1 of a color television, a signal obtained by converting an RGB signal to 4 bits using an A/D converter was used. The lookup table 2 has an address space having 4096 addresses, and is a ROM in which each address stores four types of data: cyan, magenta, yellow, and black, 4 bits each, totaling 11.6 bits. . Summary of lookup tables 1. The capacity is about 8.2
It is a kilobyte.

The data stored in the lookup table is based on the inverse correction of gamma correction for the tube tube and the masking matrix. Correction of color distortion caused by incomplete spectral characteristics of each color A2, printing determination of A-plate from neutral color components, removal of undercolor of each hue, variation of input signals, adjustment of image density characteristics per degree This is the result of correction. The time required to determine data using a look-up table was almost the same as the ROM access time, and was sufficiently small compared to the printing speed of the coloring material, so it did not pose a problem. Determined cyan, magenta, yellow, and black printing amount data 3
By controlling the printing amount of valley ink in the inkjet method, it can immediately respond to changes in color material, printing method, and target image, always achieving the optimal color balance, and printing at high speed. A video printer capable of printing has been realized.

As another embodiment, an example will be shown in which a full-color printing mechanism uses a thermal transfer sheet for cyan, magenta, yellow, and black and a thermal head.

Color television video (as Fj No. 1, a signal digitized to 5 bits was used. Lookup table 2i1'; 11..32768 addresses, cyan, magenta, yellow, color). board four 1
This is a ROM that stores 5 bits each and 20 pits. Using the data 3f of the printing amount of each electric printing plate and printing plate determined by the above lookup table,
By controlling the power input to the thermal head in the thermal transfer method, it was possible to print hard copies with good recovery at high speed.

As described above, according to the present invention, very flexible and
By exchanging the look-up table, it is possible to obtain a signal processing means that can handle any printing amount F'l''.

[Brief explanation of the drawing]

FIG. 1 shows the concept of a lookup table in the present invention. 21) Figure 2 conceptually shows the configuration of a video printer according to the present invention. 1:Color television video signal 2Niltsukup double 3N, magenta, yellow and Hi! Signal indicating the printing amount of the i version 4: Full-color printing mechanism using at least three types of color materials: cyan, magenta, and yellow 5: The entire video printer according to the present invention or more Applicant Suwa Chiko Co., Ltd. Joint Agent Patent Attorney Sai Up ? Attack'1 Procedural Amendment IF (Voluntary) December 9, 1982 H ('I'Y, Ir Ii Director D? Ji 1, Incident Display Showa 57 + 1 Born, γ5' ``Claim No. 234452 Bow 2 Third Title of Invention Video printer; Supplement 4.4"Relationship with 1+11'l Applicant 2-4-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo (236) Suwa Sei Co., Ltd. 1 Sha Representative Director Kouya Nakamura 4 Agent No. 5 The number of inventions in the sleeve H- increases by 1 = λ Drawing Figure 2 is amended and attached as a separate sheet. Figure 2

Claims (1)

[Claims] 111 A video printer that produces a hard copy of a color television image using at least three different coloring materials: cyan, magenta, and yellow, in one-to-one correspondence with a signal obtained by digitizing a color television video signal. do,
A video printer characterized in that it has a look-up table for determining the amount of printing of the three color materials of cyan, magenta, and yellow. (2) From the color television video signal! , 3. The video printer according to claim 1, further comprising a look-up table for determining the amount of printing for the third edition.