JPS58145948A - Photoengraver for picture image of television - Google Patents

Abstract

PURPOSE:To prevent formation of mosaiclike picture images by neutralizing the differences in the levels among the respective scanning lines and time differences of television signals and converting the abruptly changing signals to gradually changing signals. CONSTITUTION:The pulses synchronized with the rotation of an exposure cylinder 12 are inputted to the synchronizing circuit 11 of a signal processing unit 2 from the rotation control circuit 15 of a photoengraving scanner 3 and the reading out from a frame memory 6 is controlled by a memory controlling circuit 16. When a magnification for photoengraving is set in the circuit 16, the clock frequency for the readout is determined from said magnification and the timing for the readout is controlled. The image signal read out from the memory 6 is inputted to an arithmetic circuit 17, the operation whereof is controlled with the circuit 16. The abrupt change of the signal is thus prevented, and the appearance of mosaiclike unnaturality in the picture image is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a color television image plate-making device that produces printing plates for color television images, which alleviates sharp differences in level between each scanning line of television signals and creates a mosaic pattern on the printed image. This prevents any unnatural appearance from appearing.

Since there has been a need to record desired images from television images as photographs or prints, and to reproduce them in large quantities, the applicant has already applied for an invention relating to a television image plate-making apparatus. The invention reads an image signal corresponding to one desired frame from a videotape on which a television image is recorded, converts this signal into three primary color signals, and supplies the three primary color signals to an electronic plate making device such as a color scanner. , relates to a device for producing color separation plates, etc., which selects and extracts a necessary one-frame image and directly finishes the image into a printing plate. Therefore, this invention eliminates the intermediate steps and directly makes a printing plate from a television image without degrading its original resolution, hue, or gradation, and allows the rotation of the plate-making scanner to It also controls and synchronizes signal readout.

FIG. 1 shows a basic configuration diagram of such a conventional television image plate making apparatus. As long as it consists of a television signal source (LI), a signal processing device (2), and a plate making scanner (3), for example, it can be a received broadcast signal, a video disc output, etc., but the most common one is a VTR output. The NTSC composite signal is transmitted from the VTR (4) to the signal processing device (
2) and input R (red) with the NTSC decoder (5).
It is decomposed into three primary color signals of G (green) and -B (blue) and supplied to the frame memory (6). The frame memory (6) is composed of, for example, six digital memories using semiconductors, and can store a predetermined image automatically or manually in response to a frame freeze signal from the frame specifying circuit (7). Images of input signals to the signal processing device (2) and stored signals can be viewed on a color monitor (8).

The signal processing device (2) separates the input moving image into three primary colors, and stores a predetermined image from among the three primary colors as a still image.

This stored image is read out in accordance with the synchronization signal from the scanner (3) and becomes a signal suitable for exposing the film in the color computer (9), which modulates the intensity of the light and exposes the film 01. .

The signal processing device (2) has a synchronization circuit 011 and can set the platemaking magnification. This is to input the dimensions of the image to be exposed on the film 01, and this setting controls the reading of signals from the frame memory (6).

A specific example of this will be described.

When the rotation speed (main scanning) of the exposure cylinder 021 in the plate-making scanner f31 is 600 revolutions per minute, and the lateral movement density (sub-scanning) of the exposure light source α3 is 500 lines/inch (20 lines/1oI), -scanning of the television signal If there is a one-to-one correspondence between the line and the line of the plate-making scanner, 52
One image can be formed with 5 lines, and the size of the image is approximately 2
It becomes 6.7mX 55.6■.

The frame memo 17-(6) of the signal processing device (2) is a digital memory using a semiconductor, and the sampling frequency is 10.7 MH2.

From this value, the size of the picture element of the above image is 50×52 μm.

A picture element of 50 x 52 μm in a size of 26.7 x 55.6 m cannot be distinguished, and a plate-making film with a clear image without raster can be obtained.

(141 is a drive unit, 09 is a rotation control circuit.

The plate-making magnification when one scanning line of the television signal and one line of the plate-making scanner correspond one-to-one is called 1x.

By the way, if this magnification is increased, for example 8 times, that is, 1:8, the image size to be made will be 214X.
2B5m+11, and the size of the picture elements in this image is Q, 4 x Q, 42 fi, and can be sufficiently identified. Since this looks like a mosaic, the printed image is not a normal image with smooth gradations (it becomes a mosaic-like rough image. This is because the amount of information in the television signal is small, and the memory This is because analog signals such as video signals are stored as digital signals in FtAM using an A/D converter when being stored.
/A converter to restore the original analog signal, but normally it passes through a low pass filter (LPF) to remove the sampling frequency component.

However, in the plate making circuit, the plate making magnification is set arbitrarily depending on the image, and the clock frequency when reading the image signal from the memory changes depending on the plate making magnification.
If an LPF is to be used, its cutoff frequency must also be variable and must be linked to the platemaking magnification setting.

Ordinary plate-making scanners do not use LPF, and as a result, as mentioned above, when the plate-making magnification increases and the picture elements become larger, they stand out in a mosaic-like manner, resulting in an unusual appearance.

As a means to solve this problem, that is, to prevent a mosaic pattern, the applicant has proposed a "television image plate-making apparatus 1" (Patent Application 1982-1983) which is equipped with an LPF with a variable cut-off frequency that is linked to the setting of the plate-making magnification. 184481) has been filed.

The mosaic has a rectangular shape, and in order to erase it, it must be processed both horizontally and vertically. The aforementioned Japanese Patent Application No. 55'-184481 relates to a device for solving this problem in the horizontal direction, and the present invention relates to a device for solving the problem in the vertical direction.

FIG. 2 shows an embodiment of the apparatus of the present invention. The difference from the conventional technology is that a memory control circuit (161 and arithmetic circuit 07) is newly added, and the arithmetic circuit 07) is controlled by a memory control circuit Q61.

Since the basic signal flow is the same as that explained in FIG. 1, only the parts of the present invention will be described in detail below.

A pulse synchronized with the rotation of the exposure cylinder 02 is sent from the rotation control circuit a9 of the plate making scanner (3) to the signal processing device (2).
), and the memory control circuit +161K controls reading from the frame memory (6). When the prepress magnification is set in the memory control circuit 061, the reading clock frequency is determined from the magnification, and the reading timing is also controlled. The feature of the present invention is that the image (video) read out from the frame memo IJ-(6)
The signal is input to the arithmetic circuit 0η, and the arithmetic operation is controlled by the memory control circuit 061.

FIG. 3 shows an example of a video signal and its handling.

FIG. 3(1) shows an example of a video signal, FIG. 6(2) shows the signal level in the prior art, and FIG. 3(3) shows the signal calculation result in the present invention.

FIG. 6(1) shows the N-th and N+1-th video signals among the 525 television scanning lines. In order to explain the technology of the present invention in detail, specific points (IIN and aN+1 are taken as examples).

When the plate-making magnification is 8 times, k=8, and the number of TV scan lines to scanner lines is 1 to 8, that is, the same TV scan line is printed on the film 8 times! Shine.

The prior art is illustrated in FIG. 3 (2). aN signal 8 times,
Exposure is repeated with aN+1 8 times... In the case of 12N\aN+1, because of the difference X, a boundary line will appear in the same way as a television scanning line.

In the present invention, in order to prevent this boundary line from appearing, the signals (IN and aN+1) are calculated by the arithmetic circuit αη as shown below, and nl represents the exposure time in the scanner.

In the first exposure scan of the ON signal, m =
1, by substituting k==6 into the above formula, Y1=aN,
In the second foggy light scan, Y, = 4 Q N +
1 +4Q N, and in the 8th exposure scan, Y a =Q N +1+B ON. Soshi-
This ninth line becomes the first line of the next line aN+1.

The result of this calculation is shown in Fig. 3 (3), and aI+
No boundary line appears at the boundary between and aN+1, that is, it is possible to eliminate the mosaic-like boundary line in the vertical direction.

As described above, when there is a difference in level between each scanning line of a television signal, the present invention calculates between adjacent scanning lines, neutralizes the level difference and time difference, and eliminates sudden By converting the changes into signals that gradually change, unnatural mosaic-like effects do not appear in the image even in high-magnification platemaking.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional television image plate making apparatus, FIG. 2 is a block diagram of a television image plate making apparatus of the present invention, and FIG. 3 is an explanatory diagram of an example of a television signal. fil...Television signal source (21 signal processing device (3)...Prepress scanner (4)...VTR+
51...NTSC decoder (6)...Frame memory (91...Color computer OI/
...Film au...Synchronization circuit (121...Exposure cylinder a3...Exposure light source Q4)...Drive unit 09...Rotation control circuit Cl61...Memory control circuit 0η...Arithmetic circuit patent Applicant Toppan Printing Co., Ltd. Representative Kazuo Suzuki

Claims (1)

[Claims] (11) In a television image plate-making device that creates printing plates by directly inputting television signals to a plate-making scanner, if there is a difference in level between each run of the television signal, the formula described in the main text is used. According to the above, there is provided a television image plate-making apparatus comprising an arithmetic circuit that performs arithmetic operations between adjacent scanning lines and obtains an interpolation signal according to an output magnification.