JPH0214687A - Characteristic correction device - Google Patents

Abstract

PURPOSE:To attain accurate level correction even in a signal recorder without a time base collector device by using a reproduction reference pulse having a pulse width. CONSTITUTION:A reference data generating means 3 generating a reference data comprising reference pulses having plural kinds of levels corresponding from a black level to a white level of a video signal and comprising a pulse height data being data to identify the reference pulse, a reference data insertion means 7 inserting one set of reference data consisting of one or plural reference pulses and their pulse height data into a blanking period of a recording video signal and a level correction means 11 using a reference pulse and a pulse height data obtained from the reproduction video signal to correct the level of the reproduction video signal are provided to the title device. Then each of plural kinds of pulses with different height are made correspondent accurately at the recording and reproduction. Thus, even with a signal recorder having no time base collector device, the level is corrected correctly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention automatically corrects distortion caused by nonlinearity of a signal processing system during recording and playback and corrects the playback signal level in a signal recording device. The present invention relates to a characteristic correction device for correcting characteristics.

[Conventional technology]

In signal recording devices such as VTRs, channel division recording is a method for recording wideband signals by dividing one signal into multiple channels to reduce the bandwidth required for each channel. There is a method.

In such a method, if the signal to be recorded is a television signal, the signal is divided into multiple horizontal scanning periods, distributed to multiple channels, and the distributed signals are time-extended and recorded. is used.

An example of this method is shown in FIG. 10, in which the input video signal is distributed to two channels (A, B). In the same figure (al indicates an input signal, and Hl indicates a number in time order for each horizontal scanning period.

They are labeled as H2, H3,... The human input signal is divided into channel A and channel B for each horizontal scanning line, and is subjected to time axis expansion and converted into the recording signal format shown in FIG. 10(b).

When the time axis of the signal is expanded by channel division in this way, the bandwidth for each channel decreases, but
Since one signal is recorded and reproduced in two systems, if there is a difference in characteristics between the channels, this will lead to deterioration of the reproduced image quality, such as the scanning lines becoming conspicuous in the above example. Therefore, a device that automatically corrects the characteristic difference between channels is required.

V that performs channel division and records and plays back as described above.
An example of the configuration of a characteristic correction device used in a TR is ``Kiyoshi Sasaki et al.
National Technical Report Vo1.32 No.
4 J. FIG. 12 is a block diagram showing the configuration of this device. In the figure, 13 is a memory for storing the reproduced lamp signal, 14 is an averaging and checking circuit for averaging and checking the reproduced lamp signal, and 15 is a level correction circuit. 1 is a table memory; 16 is a reference lamp signal data memory; 17 is a data processing circuit; 18 is a switch for switching the address of the level correction table memory 15;
9 is a reproduction signal input terminal, 20 is a reproduction lamp signal input terminal, 21 is a time axis data terminal, and 22 is a correction output terminal.

The conventional characteristic correction device is configured as described above, and records the ramp signal that changes from the black level to the white level within the vertical blanking period of the video signal, and reproduces this to adjust the recording level and playback level. I'm trying to take care of this. When the ramp waveform shown in FIG. 11(a) is recorded, if a distorted waveform as shown in FIG. By correcting the time axis and matching the timing with the ramp signal during recording, the input signal level and reproduction output level are made to correspond.

To explain this operation in detail, the reproduced ramp signal is first input to the averaging and checking circuit 14, where a plurality of reproduced ramp signals are added together to improve the S/N ratio, and the averaged reproduced ramp signal is Check the shape of
Eliminate effects such as dropout. The reproduced lamp signal subjected to the averaging and shape checking is stored in the reproduced lamp data memory 13 using the time axis data as an address.

Next, the data and address of the reproduction lamp data memory 13 are reversed and stored in the level correction table memory 15. The reference ramp signal data memory 16 stores the shape of the ramp signal at the time of recording, and if reproduced video signal data is given as the address of the level correction table memory 15 via the switch 18, the address of the reference ramp signal data memory 16 is stored. is determined, and the level-corrected video signal data is obtained as the output of the reference lamp signal data memory 16.

[Problem to be solved by the invention]

Since the conventional characteristic correction device is configured as described above, the timing of the ramp signal during recording and the ramp signal during playback must be perfectly matched, so a very high precision time base collector device is required. In addition, if there is a time axis fluctuation within one horizontal period called velocity error, the timing cannot be completely matched between recording and playback in the second half of one horizontal period, and the recording level There was a drawback that the correspondence between the data and the playback level could not be established correctly.

Additionally, if the video signal level is at the same level for a short period of time, such as the lamp signal used in conventional equipment, incorrect reproduced lamp data will be captured if the sampling position shifts, making it impossible to perform correct level correction operations. There was a problem.

This invention was made to solve the above-mentioned problems with the conventional ones, and its purpose is to provide a characteristic correction device that can correctly perform level correction operations even in a signal recording device that does not have a time base collector device. do.

[Means to solve the problem]

The characteristic correction device according to the present invention includes a reference pulse that is a plurality of types of pulses with different heights corresponding to at least the black level to the white level of a video signal, and pulse height data that is data for identifying the reference pulse. and reference data for inserting a set of reference data consisting of one or more reference pulses and their pulse height data into a blanking period of a recorded video signal. The apparatus is provided with an insertion means and a level correction means for level-correcting the reproduced video signal using a reference pulse and pulse height data obtained from the reproduced video signal.

[Effect]

In this invention, since the reference pulse has a time width, even if the reproduced video signal includes time axis fluctuations, by sampling and holding the vicinity of the center of the reference pulse, the pulse height at the time of reproduction can be determined. .

Further, since the pulse height data is quantized data, its value does not change even if it is subjected to distortion.

Therefore, it is possible to accurately associate the plurality of pulses of different heights corresponding to the range from the black level to the white level inserted during recording during recording and during playback.
Even in a signal recording device that does not have a time base corrector device, level correction can be performed correctly.

〔Example〕

FIGS. 1 and 2 are diagrams showing a characteristic correction device according to an embodiment of the present invention. Here, the recorded video signal is 8 b
It is quantized by IT to generate 256 height reference pulses corresponding to the number of quantization levels and serial format pulse height data corresponding to the reference pulses. An example will be explained in which a set of pulse height data corresponding to one pulse height data (hereinafter, this set is referred to as reference data) is inserted one set at a time during the vertical blanking period.

FIG. 1 shows a recording system block of this embodiment, and in the figure, 1 is a gate pulse generating means for separating vertical and horizontal synchronizing signals from a recorded video signal and generating a gate pulse;
Reference numeral 3 indicates a read address generation means for generating an address for reading reference data according to the output of the gate pulse generation means 1, and reference data generation means 3 for producing a plurality of reference pulses and pulse height data. using a computer. 4 is a microcomputer (
RAM (hereinafter referred to as microcomputer) temporarily stores reference data created by microcomputer 3;
Address switching means for switching the address of M4 to the reading side or the writing side; 6 is a reference data creation start signal generating means for generating a signal for the microcomputer 3 to start creating reference data according to the output of the gate pulse generating means 1; 7 is a reference This is a reference data insertion means for inserting data into a vertical blanking period of a recorded video signal.

FIG. 2 shows a playback system block of this embodiment. In the figure, 8 is a playback A/D converter that A/D converts the playback video signal, and 9 is a playback A/D converter that converts the output data of the playback A/'D converter 8. Reference pulse selection means selects the data of the reference pulse inserted at the time of recording; 10 is a pulse height data selection means for selecting pulse height data from the reproduced video signal; 11 is the output data and pulse height of the reference pulse selection means 9; Data selection means 1
12 is a reproduction D/A converter that performs D/A conversion of the level-corrected video signal.

It should be noted that the gate pulse generating means 1 can also be used for the recording system, and it is of course possible to use another circuit that operates in exactly the same way.

Next, the operation will be explained using FIGS. 1 to 6. In FIG. 1, gate pulse generating means 1 during recording
separates the vertical and horizontal synchronization signals from the recorded video signal (see FIG. 3(a)). Then, the vertical synchronization signal (Figure 3 (
A gate pulse (see FIG. 3(0)) that becomes high in one horizontal period after three horizontal periods from (see (0) in FIG. 3) is generated.

The reference data creation start signal generating means 6 generates a reference data creation start signal (see FIG. 4(b)) when the gate pulse (see FIG. 4(a)) changes from high to low. When the reference data creation start signal is input, the microcomputer 3 starts creating the reference data. The microcomputer 3 switches the address switching means 5 to the writing side. After that, first, a reference pulse with a quantization level of O/255 and O/2
Serial format pulse height data indicating the height of the 55 quantization levels is created, stored in the RAM 4, and the address is switched to the read side. Thereafter, each time the reference data creation start signal is input, the reference pulse (8/255.16/255°..., 248/25
5) Create. Thereafter, each time the reference pulse exceeds the highest value (255/255) of the 8-bit quantization level, the reference pulse is changed to 4/255 so as to have less deviation from the already created reference pulse. 2/255.6/255.・
..., 7/255, and increase the quantization level by 8 quantization levels from those reference pulses to create reference pulses. 4/255.12/255. ..., 25
2/255.2/255.10/255. ....

255/255) to create reference pulses corresponding to all quantization levels. Then, pulse height data corresponding to the reference pulse is added to create reference data, and R
Store in AM4. When reading the reference data, when the gate pulse changes from low to high, a read address is generated, and the reference data (see FIG. 4(e)) in the RAM 4 is read out and sent to the reference data insertion means 7. The reference data insertion means 7 inserts the reference data into the vertical blanking period of the recorded video signal, resulting in an output signal as shown in FIG.

During playback, a playback A/D converter 8 A/D converts the playback video signal whose level has changed due to distortion.

At the same time, the gate pulse generating means 1 generates a reproduction gate pulse (see FIG.
a)). In accordance with this reproduction gate pulse, the reference pulse selection means 9 selects a reproduction reference pulse (see FIG. 6 (bl)) whose height has changed due to distortion from the output data of the reproduction A/D converter 8, The data selection means 10 obtains pulse height data (see FIG. 6(C)) that allows identification of the pulse height at the time of recording from the reproduced video signal.

Next, the level correction means 11 will be explained. First of all, O/255.8/255. . . , a reference pulse at the time of recording with a quantization level height of 248/255 is recorded, and pulse height data corresponding to the reproduced reference pulse is obtained. Then, each quantization level of the reproduced video signal other than the obtained reproduction reference data is interpolated from the pulse height data corresponding to the obtained reproduction reference pulse to determine the quantization level of the corresponding recorded video signal. Using each quantization level of the signal as an address, the quantization level of the corresponding recorded video signal is written into the memory as data to create a level correction table. During the normal video period, the playback A/D converter 8
Level correction operations such as reading out values from the level correction table using the output data of the address are performed, the reference pulse and pulse height data inserted during recording are removed, and then the reproduction D/A converter 12 performs D/A After conversion, a level-corrected playback video signal is obtained.

Thereafter, every time pulse height data corresponding to the reproduction reference pulse is obtained, interpolation is performed to create a new level correction table. Once the quantization level of the recorded video signal corresponding to the quantization level of all the reproduced video signals is obtained, the interpolation operation is not performed every time the pulse height data corresponding to the reproduction reference pulse is obtained. Only the portion corresponding to the reproduction reference pulse and pulse height data that have been set is changed.

In the above embodiment, the reference pulse is increased by 8 quantization levels, and finally, one set of pulse height data corresponding to the reference pulse of all quantization levels is inserted into the vertical blanking period. However, in addition to this, the reference pulse may be inserted after reducing it by 8 quantization levels. Further, the increase/decrease width of the reference pulse is not limited to eight quantization levels. The reference pulse may vary based on certain rules. In addition, as shown in Fig. 7, ■ pulse height data corresponding to two or more reference pulses and one reference pulse among them within the vertical blanking period, and corresponding to an uncorresponding reference pulse; It is also possible to insert reference data such that pulse height data can be obtained, or, as shown in FIG. Pulse height data may be inserted into the horizontal period. Alternatively, as shown in FIG. 9, the pulse height data may be inserted first and one or more reference pulses may be inserted later. In this way, any pattern may be used as long as one or more reference pulses and pulse height data corresponding to one of them are inserted within the blanking period. It has the same effect as.

Further, in the above embodiment, the quantization level of the recorded video signal corresponding to each quantization level of the reproduced video signal is determined by interpolation from the pulse height data corresponding to the reproduction reference pulse obtained so far, and the reproduced video signal is Using each quantization level of the signal as an address, the corresponding quantization level of the recorded video signal is written to the memory as data, and during normal video periods, playback A/
Although we have described an example using the level correction method in which the output data of the D converter 8 is used as an address and a corrected value is read out, there are other methods as well. The difference between the quantization level of the recorded video signal and the quantization level is written into the memory as correction data, and during a normal video period, the correction data is read out using the output data of the reproduction A/D converter 8 as an address, and the output of the reproduction A/D converter 8 is read out. It is also possible to correct the level by adding it to the data. In the above example, once the reproduction reference pulse of the height of the quantization level of all the reproduction video signals is obtained, the address corresponding to the reproduction reference pulse will be used. You may rewrite only

Further, in the above embodiment, an example was explained in which binary pulse height data of high or low was used, but quantized data such as ternary data may also be used.

In addition, in the above embodiment, an example was explained in which the data of the reproduction reference pulse obtained during reproduction is used as is. Further effects can be expected by combining measures such as not using reproduction reference pulse data.

〔Effect of the invention〕

As described above, according to the present invention, since the reproduction reference pulse has a pulse width, the level correction operation can be performed accurately even in a signal recording device that does not have a time base collector device. Since the level correction data is created from the reproduced reference pulse and the pulse height data, it is possible to obtain a characteristic correction device that can quickly create the level correction data.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a recording system of a characteristic correction device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a reproduction system of a characteristic correction device according to an embodiment of the present invention, and FIG. 4, 5, and 6 are operation explanatory diagrams of an embodiment of the present invention, and FIG. 7. FIGS. 8 and 9 are operation explanatory diagrams of other embodiments of the present invention,
FIG. 10 is a diagram for explaining a channel division recording method in a signal recording device, FIG. 11 is a diagram for explaining the operation of a conventional example, and FIG. 12 is a block diagram showing the configuration of a conventional characteristic correction device. In the figure, 3 is a reference data creation means (microcomputer);
Reference numeral 8 indicates a reference data insertion means, 8 a reproduction A/D converter, and 11 a level correction means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A characteristics correction device for correcting the characteristics of a signal processing system when recording and reproducing video signals, the device comprising multiple types of reference pulses of different heights corresponding to at least the black level to the white level of the recorded video signal. One or more are created for each blanking period of the recorded video signal with a predetermined increase/decrease width, and the reference pulse for each blanking period is quantized data for identifying the height of the reference pulse. Reference data generating means for generating reference data together with certain pulse height data; reference data inserting means for inserting the reference data into a blanking period of the recorded video signal; and reference data obtained from the reproduced video signal. 1. A characteristic correction device comprising: level correction means for level-correcting the reproduced video signal by interpolating reference data other than the reference data.