JPS62176380A - Digital recording and reproducing device for color picture - Google Patents

Abstract

PURPOSE:To improve the reproducibility without increasing the capacity of a memory medium by recording a part of a blanking area and representing all signals during a blanking period of a reproducing video signal by it. CONSTITUTION:A recording video signal is clamped in a clamp circuit 12, and converted into a digital signal by an AD converter 14. An effective picture area of the recording video signal is written in a main digital memory 15, and in the blanking area, only an optional one sample value is written in a sub-digital memory 27. During the reproduction, in an effective picture period, the information of the effective picture area is read from the main memory 15 and the sub-memory 27 continues to output the information of the one sample value of the blanking area during the blanking period. The output data from the memories 15, 27 is changed over by a selector 28 during the effective picture period and during the blanking period and time division multiplexed, converted into an analog signal by a DA converter 16 to obtain the succeeding reproducing video signal.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color image digital recording and reproducing device that encodes color image information and records and reproduces it on a recording medium such as a magnetic tape, an optical disk, and a semiconductor memory. be.

[Conventional technology]

FIG. 4 shows a conventional example of a color image digital recording and reproducing device that records and reproduces only information in an effective screen area and time-division multiplexes the information with information in a separately set blanking area to record and reproduce continuous image information. It is a block diagram.

In FIG. 4, 11 is a video signal input terminal, 12 is a clamp circuit, 13 is a clamp voltage, 14 is an analog/digital converter (hereinafter referred to as AD converter), 15 is a digital memory, and 16 is a digital/analog converter (hereinafter referred to as DA converter). 17 and 18 are the first and second reference voltages, respectively, 19 is the offset voltage, 20 is the analog switch, 21 is the memory control circuit, and 22, 23, 24, and 25 are the AD voltages from the memory control circuit 21, respectively. Converter 14. Digital memory 15
．． The first signal output to the DA converter 16 and analog switch 20. Second. third and fourth control signals, 26
is the video signal output terminal.

Next, the operation will be explained. A baseband video signal is input to the input terminal 11 . In the clamp circuit 12, the manually inputted video signal is clamped according to the value of the clamp voltage 13. The first and second reference voltages 17 and 18 set the dynamic range of the input signal of the AD converter 14 and the output signal of the DA converter 16. Therefore, in the clamp circuit 12, the input video signal is between the reference voltages 17 and 18. The clamp voltage 13 is set so as to fall within the range of .

The clamped video signal is converted into a digital signal by the AD converter 14, and only the effective screen area is written into the digital memory 15. Next, digital memory 1
The video signal of only the effective screen area read from 5 is DA.
The converter 16 converts it into an analog signal. D.A.
Since the video signal output from the converter 16 is only for the effective screen area and the blanking area is missing, the video signal from the DA converter 16 is time-division multiplexed with a separately set offset voltage 19. A continuous video signal is reproduced. This time division multiplexing is performed by switching the analog switch 20 at predetermined timing.

The above operations are performed by the first and second signals generated by the memory control circuit 21.
．． Third and fourth control signals 22, 23° 24 and 2
It is carried out based on 5.

[Problems that the invention will solve]

Conventional color image digital recording and reproducing devices are configured as described above, and record and reproduce information only in the effective screen area, and time-division multiplex this with information in a separately set blanking area to create continuous image information. In this case, the clamp voltage 13 and the offset voltage 19 had to be set separately, and the balance between them was lost due to power supply voltage fluctuations and temperature changes.
As a result, there were drawbacks such as easy deterioration of signal reproducibility.

This invention has been made in order to eliminate the above-mentioned drawbacks, and provides a color image digital recording and reproducing device that prevents the influence of drift caused by power supply voltage fluctuations and temperature changes and improves signal reproducibility. With the goal.

[Means for solving problems]

A color image digital recording and reproducing apparatus according to the present invention includes a writing means for encoding an effective screen area and a part of a blanking area in image information and writing it on a recording medium; The apparatus is provided with a reading means for reading a part of the image information of the blanking area, and a reproducing means for reproducing continuous image information by representing all of the blanking area with the information of the part.

[Effect]

In this invention, during recording, information on the effective screen period and a small part of the information on the blanking period are recorded, and during playback, these are read out and the information on a part of the blanking period represents the information on all the blanking periods. The information on the blanking period of the recorded color image information is constant, so that the continuous image information is reproduced accurately.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a color image digital recording and reproducing apparatus according to an embodiment of the present invention. In Figure 1, 1
1 is a video signal input terminal, 12 is a clamp circuit, 13 is a clamp voltage, 14 is an AD converter, 15 is a main digital memory for recording information on the effective screen area, and 16 is a DA
converters, 17 and 18 are first and second reference voltages, respectively; 21 is a memory control circuit; 22; 23 and 25;
are from the memory control circuit 21 to the AD converter 14, respectively.
, main digital memory 15 and DA converter 16
The first . 2nd and 3rd control signals, 26 is a video signal output terminal, 27 is a sub-digital memory for recording blanking area information, 28 is a selector for selecting 2 memory outputs, 29 and 30 are memory controls, respectively. These are the fourth and fifth control signals output from the circuit 21 to the sub-digital memory 27 and the selector 28.

In the above configuration, the clamp circuit 1
2. The AD converter 14 and the memory control circuit 21 constitute a writing means that encodes the effective screen area and a part of the blanking area in the image information and writes it to the recording medium, and the main digital memory 15 and the sub-digital memory 27 is a recording medium, and the selector 2B, the DA converter 16, and the memory control circuit 21 serve as a reading means for reading image information of the effective screen area and information of a part of the blanking area from the recording medium, and a reading means of the reading means. The output receiver constitutes a reproducing means for reproducing continuous image information by using part of the information in the blanking area as the entire information.

Next, the operation will be explained. A baseband video signal is input to the input terminal 11 . The clamp circuit 12 clamps the input video signal based on the value of a clamp voltage 13. The first and second reference voltages 17 and 18 are used to set the wide range of the input signal of the AD converter 14 and the output signal of the DA converter 16, and in the clamp circuit 12, the input video signal is The clamp voltage 13 is set to fall between 18 and 18.

Now, if a recorded video signal as shown in FIG. 2(a) is clamped and input to the AD converter 14, the recorded video signal is converted into a digital signal.Next, as shown in FIG. 2(b), Memory control is performed, and the effective screen area in the recorded video signal is written into the main digital memory 15, and the blanking area is written into the sub-digital memory 27 using only one arbitrary sample value, taking advantage of the fact that there is no change in the signal during that time. written.

Next, during playback, memory control as shown in FIG. 2(e) is performed, and the information of the effective screen area is read out from the main digital memory 15 during the effective screen period, and the information is read out during the blanking period. Not possible. Further, the sub-digital memory 27 continues to output information of one sample value of the blanking area during the blanking period. Therefore, the output data from the main memory 15 and the sub memory 27 are as shown in FIG. 2(C) and (dl), respectively.Therefore, the output data from these two memories 15. The signals are switched by the selector 28 and time-division multiplexed, and further converted into an analog signal by the DA converter 16, thereby obtaining a continuous reproduced video signal as shown in FIG. 2(f).

The above operations are performed by the first and second signals generated by the memory control circuit 21.
．． Third, fourth and fifth control signals 22°23.24,2
It will be held on the basis of 9.30.

The apparatus of this embodiment as described above takes advantage of the fact that the information on the blanking period of the recorded color image information is constant, records information on a part of the blanking period, and uses this part of information to change the blanking period. Since we made it possible to reproduce continuous image information by representing all the information in
Between the recorded video signal and the reproduced video signal, the relative DC level relationship between the effective screen area and the blanking area does not change due to power supply voltage fluctuations, temperature changes, etc.
Signal reproducibility can be greatly improved.

In addition, since this device records information on the effective screen period and part of the blanking period, there is no need to increase the memory capacity much compared to conventional devices that record only information on the effective screen period. do not have.

In the above embodiment, the sub-digital memory 27 was provided to record one sample value of the blanking area, but this may be done using the main digital memory 1501 portion.

For example, if the main digital memory 15 is a memory with a capacity of 256 pixels in the horizontal direction and 256 pixels in the pixel direction as shown in FIG. Write to the range of addresses, and write to the last column address 255 of each row.
Write an arbitrary sample value of the blanking area immediately after the valid screen area written in that line. When reading data from this memory, the effective screen period is column address O.
Read the data in the effective screen area up to address -254, and at the same time as entering the blanking period immediately after that, read out one sample value of the blanking area at column address 255, and continue until the blanking period ends. Make the value continue to be output. By writing the video signal into the main digital memory 15 and reading it out as described above, the same effects as in the previous embodiment can be obtained without using the sub-digital memory 27.

〔Effect of the invention〕

As described above, according to the present invention, by taking advantage of the fact that the signal in the blanking area does not change, a small part of the information in the blanking area is recorded during recording, and during playback, the reproduced image is recorded using that part of the information. Since all the signals during the signal blanking period are made representative, signal reproducibility can be improved without significantly increasing the capacity of the recording medium.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a color image digital recording and reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating the operation of the above embodiment, including recorded video signals, memory control during recording, and main memory output. A diagram showing a timing chart of data, sub-memory output data, memory control during reproduction, and reproduction video signal, FIG. 3 is a diagram for explaining another embodiment of the present invention, and FIG. 4 is a diagram showing conventional color image digital recording. FIG. 2 is a configuration diagram showing a playback device. 12... Clamp circuit, 14... AD converter,
15... Main digital memory, 16... DA converter, 21... Memory control circuit, 27... Sub digital memory, 28... Selector. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claim] A color image digital recording and reproducing device for recording and reproducing color image information on a recording medium, comprising: a writing means for encoding an effective screen area and a part of a blanking area in the image information and writing it on the recording medium; reading means for reading the image information of the effective screen area and a part of the image information of the blanking area from the recording medium; and upon receiving the output of the reading means, the information of the part of the blanking area is used as the information of the entire area. 1. A color image digital recording and reproducing apparatus, comprising: reproducing means for reproducing continuous image information.