JPH0226836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gradation correction device that performs gradation correction suitable for printing plate making in a device that handles video signals, such as a video image plate making device.

Due to the remarkable development and spread of video technology in recent years and changes in publishing trends due to the diversification of printed matter, it would be possible to use a predetermined screen from the continuous video information recorded on video tapes for photographs, printed manuscripts, etc. The information is becoming more and more advantageous. In other words, compared to the conventional method in which photographers shoot film using still cameras,
While being freed from constraints such as shutter speed, shutter sound, flash lights, and low brightness, it is also expected to meet a variety of needs. For example, photographs or printing plate materials can be created directly from video information recorded on video tapes, or NTSC signals or
It becomes possible to create RGB signals and directly create plate-making materials for printing, making it possible to publish at a lower cost than with conventional methods.

However, in the method of selecting a predetermined screen from continuous video footage and photographing it with a still camera, the color temperature of the color CRT is adjusted to improve the quality of the image.
Due to the mismatch between the coloring characteristics and density range of the RGB phosphor and the color temperature, coloring material characteristics and density range of the color film, a special color temperature conversion filter is inserted in the front of the camera, and the hue and contrast of the color monitor is There are problems such as the need for adjustment. However, these corrections alone do not necessarily provide a satisfactory color tone. Also,
Conventional gradation correction functions for video images are only limited to contrast adjustment, so when creating printing films or printing separation plates from video images, it is not possible to perform overall or partial gradation correction suitable for printing plate making. Ta. Furthermore, with conventional gradation correction devices, it is not possible to set the level and gradation of the video image signal in advance for a video image output device such as a scanner or color film output device, and then perform optimal adjustment thereof. Nakatsuta.

The purpose of the present invention is to solve the above-mentioned problems, and to provide a system that after converting a color TV signal into three RGB signals, performs parallel translation, contrast adjustment, middle tone adjustment, highlight adjustment, and shadow adjustment for three colors simultaneously or independently by manual operation. It is possible to make gradation corrections such as partial adjustment, and the correction status can be displayed on the display device at any time.
To provide a gradation correction device that can be viewed and display the video level at any point in a still image as a comparison value with respect to a video white signal reference value.

The present invention is a video image plate-making apparatus that creates a printing film or a printing separation plate from a television image, and after converting still image information of a color television signal into R, G, and B signals, three signals are simultaneously or individually converted depending on the image. The present invention is characterized in that it is provided with means capable of performing gradation correction such as parallel movement, contrast adjustment, highlight part adjustment, middle tone adjustment, and shadow part adjustment on the signal alone.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a videotape editing section in a video image plate making apparatus of the present invention. Currently, the video tapes provided by customers are generally 3/4 inch wide U-MATIC video cassette tapes, and after loading the original cassette tape provided into a 3/4 inch video recorder, the monitor screen It is also possible to select the screen to be used by repeatedly operating the automatic electronic editing unit's slow playback and stop playback knobs while observing the screen. However, it is a very difficult operation to accurately select the screen desired by the customer from among the actual continuous images. In particular, repeating slow playback, stop playback, etc. of a video tape recorder in order to capture a single screen shot like a shot will shorten the life of the video tape recorder, and furthermore, the friction caused by the playback head of the video tape recorder will damage the valuable strength of the video tape recorder. It may also damage the previous videotape. In order to solve the above-mentioned problems, in the present invention, as shown in FIG. It is rerecorded via a time record generator/reader 4 onto a 1-inch wide video tape 8 preset in a 1-inch helical scan type video tape recorder 5. In addition to a video track for recording video information and an audio track for recording audio information, a 1-inch wide videotape has a time code track for recording time code. By re-recording onto a 1-inch wide video tape 8 via the time code generator/reader 4, the time code generated from the time code generator/reader 4 is converted into one frame of video information on the 1-inch video tape. Correspondingly, it is recorded continuously. Using this time code,
Since customers can specify the screen they want to use for printing, screen extraction can be done accurately and in a short time. Also, when re-recording, automatic electronic editing unit 3 can be used to record 3/4
We perform playback stop control for inch and 1 inch helical scan video tape recorders.
The re-recording situation can be observed on the display monitor 7 via the video switcher 6. Therefore,
If it is not necessary to re-record the entire 3/4-inch wide video tape provided by the customer, it is possible to re-record only the necessary portion while viewing the image on the display monitor 7.

The 1-inch wide videotape 8 re-recorded as described above is once rewound on the 1-inch helical scan type video tape recorder 5 and then played back. Reproduction is performed by operating the slow reproduction and stop reproduction knobs of the automatic electronic editing unit 3, and the video information can be observed on the display monitor 7 via the video switcher 6.
This display monitor has a built-in Y/C separation decoder and uses a high-resolution cathode ray tube, so it can provide better image quality than ordinary monitors. Therefore, while re-recording images are being played back on the display monitor 7, a desired screen can be selected at any time based on the customer's instructions for printing screens or in the customer's presence, and at the same time the screen selection instruction operation console 10 can be used. By pressing the frame designation switch, the time code of the selection screen read by the time code generator/reader 4 is registered in the memory section of the time code reading section 9. After completing the frame registration for all the necessary screens of the re-recorded 1-inch wide videotape 8 in this way, the frame registration completion switch on the screen selection instruction console 10 is pressed. As a result, the registered time code information is sequentially read out from the time code reading section 9, encoded, and outputted to the paper tape 12 from the paper tape puncher 11. Note that this part of the system is controlled by a microcomputer.

In addition, the 1-inch helical scan video tape recorder 5 is used to re-record video cassette tapes provided by customers without deteriorating the image quality as much as possible, but if it is necessary to reduce costs, re-recording is possible. If you are willing to accept some loss of image quality over time, you can choose a 3/4 inch video tape recorder. However, in this case, since the 3/4 inch wide video cassette tape does not have a time code track, an audio track will be used instead. Furthermore, in this example, a 1-inch videotape was used for re-recording, but this can be changed to a video desk, 3/4-inch VTR, etc., and the paper tape on which the time code is recorded can also be used as a magnetic tape, cassette, etc. Can be changed to tape, disk, floppy disk, etc.

FIG. 2 is a block diagram showing an embodiment of the signal conversion processing section and output section in the video image plate making apparatus of the present invention. The tone correction device is a part of this signal conversion processing section. This signal conversion processing section automatically searches and extracts a desired screen from the re-recorded 1-inch wide videotape 8 and the paper tape 12 on which time code information corresponding to the desired screen is recorded, and further, Performs image quality improvement processing such as time jitter correction, noise removal, edge enhancement, gradation correction, and scanning line interpolation. In addition, in this example, the input device was one manufactured by the videotape editing department mentioned above.
Although an inch VTR tape was used, it is also possible to directly input the output of a telecine or TV receiver without using a videotape editing section. Further, in the above example, the color television signal is of the NTSC format, but it may be a signal of other formats.

In FIG. 2, first, a re-recorded 1-inch wide videotape 8 and a paper tape 12 on which time code information corresponding to a desired screen has been recorded are
Each is set in a 1-inch helical scan type video tape recorder 21 and a paper tape reader 24. Next, by pressing the frame extraction switch located on the operation console 25, one frame of information on the paper tape 12 is read into the frame search unit 23, and the re-recording information set in the 1-inch helical scan video tape recorder 21 is read. Playback of the finished 1-inch wide videotape begins. At the same time as playback starts, the time code information recorded in advance corresponding to each frame is sequentially read by the time code reader 22, inputted to the frame search section 23, and first from the paper tape 12 to the paper tape reader 2.
It is compared with the frame code read through 4. When the information from the time code reader 22 and the information read from the paper tape 12 by the frame search unit 23 match, the frame search unit 23 outputs a freeze command for the corresponding image signal to the noise reducer 27, and the desired one screen worth of information is output. It is recorded in the built-in frame memory by the noise reducer 27. At the same time, the frame search unit 23
A playback stop signal is output to the inch helical scan type video tape recorder 21, and this tape recorder 21 is stopped. Note that until the information from the time code reader 22 and the information read from the paper tape 12 by the frame search unit 23 match, the reproduced image signal of the video tape is transmitted via the time base collector 26 and the noise reducer 27. The contents of the built-in frame memory are sequentially compared and noise components are removed. Further, this content can be observed on the display monitor 29. The time base corrector 26 and the noise reducer 27 are part of image quality improvement processing in the signal conversion processing section. The time base corrector 26 is for correcting the temporal deviation of the video image signal, which is usually called jitter, and if it is recorded in the frame memory with temporal jitter, the sample starting point of each scanning line and To prevent differences in the number of sample pixels. The noise reducer 27 is designed to improve image quality by suppressing various noises and emphasizing contours, and it improves the image quality recorded on the original 3/4 inch wide videotape 1 provided by the customer. The detail collector 28 prevents the image quality from deteriorating due to noise, or from noise occurring in the video editing section or the signal conversion system during playback of the re-recorded videotape 8. Then, contour enhancement processing is performed to emphasize the changing points of the image and make them fit together with the image.

FIG. 3 is a block diagram showing one embodiment of the tone correction device of the present invention. In Figure 3, the still image signal recorded in advance in the frame memory is
After converting to an RGB signal, the level adjustment circuit 101 converts the signal level to suit the signal level value of each gradation correction circuit. The level-converted RGB video image signal is subjected to tone correction by tone correction circuits such as a parallel movement adjustment circuit 102, a contrast adjustment circuit 103, a middle tone adjustment circuit 104, a highlight adjustment circuit 105, and a shadow adjustment circuit 106. is performed and input to the video signal distribution circuit 107.
Furthermore, the video signal distribution circuit 107 separates the
The RGB image signal is displayed on the RGB display monitor 113 at any time. At the same time, as shown in Figure 3, this RGB image signal is converted from an analog signal to a digital signal by an A/D converter connected to each signal, and then converted to a digital signal corresponding to each signal. It is recorded in the frame memory at any time. Each adjustment circuit includes a parallel movement adjustment volume group 108 and a contrast adjustment volume group 1.
09, a middle tone adjustment polygon group 110, a highlight area adjustment volume group 111, and a shadow area adjustment volume group 112 are connected, and each volume group can simultaneously or simultaneously output RGB signals.
It consists of four volumes, T, R, G, and B, each of which can be adjusted separately. The amount of change in each volume is displayed on the displays 122 to 12 via the selector 115, A/D converter 116, and decoders 117 to 121.
In addition to displaying numerical values in 6, the results corresponding to the amount of change in each volume of each adjustment volume group are displayed.
It can be observed on the RGB display monitor 113.
The method of switching each adjustment item in the selector 115 is to apply a vertical deflection voltage V _D to the selector 115 and use this V _D to switch and display parallel movement, contrast, middle tone, highlight, and shadow. At this time, the display frequency is 60 times per second, and each item is displayed 12 times per second. In addition, the display device 12
The displays 2 to 126 display scales with the center of the adjustment volume for each adjustment item as 0, the left end as -100, and the right end as +100. The display on the display devices 122 to 126 is displayed on the MPU 128.
If you print it out on the printer 129 via the printer 129, when you subsequently try to make a film or print separation of the same image, you can set each volume at the position printed on the print 130 and the same image output as last time will be produced. can get. The video image, to which gradation has been corrected as necessary as described above, is displayed on the RGB display monitor 113. When inputted to the signal generation circuit 140, the clock pulse, blanking pulse, and cursor position signal are inputted from the cursor signal generation circuit 140 to the video signal distribution circuit 107, and a cursor is inserted into the display image of the RGB monitor 113. Note that the video signal distribution circuit 10
7 is displayed with a cursor inserted into the display image, but has a circuit configuration that does not output the cursor to the output signal. Further, this cursor can be moved to any position in the displayed image by a cursor position signal obtained by operating the joy stick.

Note that in the gradation correction device of the present invention described above, parallel movement adjustment means brightness adjustment, where brightness refers to brightness, and brightness adjustment refers to the adjustment of the video signal from the highlight area to the entire shadow area. It means to change the level by the same amount.

In the sampling hold circuit 132,
The video voltage at the cursor position is sampled and held, and this voltage is sent to the A/D converter 133 and the decoder 1.
34 to 136, a display 1 corresponding to each of the RGB signals as a percentage value with respect to the video white level signal;
Numerical values are displayed from 37 to 139. Display unit 137~
139 display, each level of R, G, and B included in the video white signal standard value is set to 100.
The black level, that is, the 0 level, is displayed as 0, and is displayed as a two-digit number. Further, as described above, the selector 115 selects between the signal from the adjustment volume group corresponding to each adjustment circuit and the signal from the RGB volume changeover switch 131, and the MPU 128 automatically selects a timing signal for data transfer to the printer. This is a circuit that generates The selector 127 selects the A/D converter 1
This circuit selects digital values from 16 and prints them out from printer 129 under the control of MPU 128. Furthermore, the test signal generation circuit 114
This circuit generates the TV standard color bar and 12-level gray scale, and is used for basic adjustment of each adjustment circuit.

FIGS. 4a to 4e are diagrams showing the gradation correction state of each gradation correction circuit. FIGS. 4a, b, c, d, and e show the relationships between input signals and output signals for parallel movement adjustment, contrast adjustment, shadow adjustment, highlight adjustment, and middle tone adjustment, respectively. In the figure, the solid lines represent the unmodified state, and the dotted lines represent the state after each gradation correction is performed.

As is clear from the detailed explanation above, according to the present invention, the gradation can be corrected in advance using the display device, so there is no need to observe the output result, examine the gradation correction, and re-output. Since it has the function of printing out the gradation correction amount as a numerical value, it is possible to easily reset it without relying on intuition when re-outputting under the same conditions occurs at a later date.

[Brief explanation of drawings]

1 and 2 are block diagrams showing an embodiment of the gradation correction device of the present invention used in a video image plate-making device, and FIG. 3 is a block diagram showing an embodiment of the gradation correction device of the present invention. FIG. 4 is a diagram showing the gradation correction state of each gradation correction circuit. 101... Level adjustment circuit, 102... Parallel movement circuit, 103... Contrast adjustment circuit, 104... Middle tone adjustment circuit, 105... Highlight part adjustment circuit, 106... Shadow part adjustment circuit, 107... Video signal distribution circuit, 108, 109 ,110,1
11, 112...adjustment volume group, 113...
RGB display monitor, 114...Test signal generation circuit, 115, 127...Selector, 11
6,133...A/D converter, 117,118,1
19, 120, 121, 134, 135, 136
...Decoder, 122, 123, 124, 125,
126, 137, 138, 139...Indicator, 12
8...MPU, 129...Printer, 132...Sampling hold circuit, 140...Cursor signal generation circuit.

Claims (1)

[Claims] 1. In a video image plate-making device that creates a printing film or printing separation plate from a television image, still image information of a color television signal is converted into R,
After converting to G and B signals, parallel shift, contrast adjustment,
A gradation correction device characterized by being provided with means capable of gradation correction such as highlight part adjustment, middle tone adjustment, and shadow part adjustment. 2. The status of the gradation correction knob can be detected numerically.
Claim 1 characterized in that it has a function of printing out the numerical value from a printer.
The gradation correction device described in Section 1. 3. The video voltage of each of R, G, and B at a point displayed by a movable cursor on the image is displayed numerically as a percentage value with respect to the white level signal on the display corresponding to each of the RGB signals. A gradation correction device according to claim 1.