JPH0340680A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and reproduce a video signal with high resolution by using a solid-state image pickup element picking up a picture subject to line interleave in a field in the unit of a horizontal scanning period on a pickup plane in which a vertical picture element number is less than that of a conventional solid-state image pickup element. CONSTITUTION:When a signal in the vertical direction is interleaved by a half, a picked-up picture is a picture interleaved at an interval of one line. Then a readout clock generating circuit 14 outputs a video signal subject to time axis expansion by a double. A modulation circuit 16 applies modulation to the inputted video signal suitable for the recording and reproducing system. A reproducing head 20 reads a video signal at reproduction, the signal is demodulated into the original signal at a demodulation circuit 21 applying opposite processing to the modulation, subject to time axis compression into 1/2 at a time axis compression circuit 22 and becomes a video signal of each line. Furthermore, an interpolation circuit 23 interpolates the interleaved line to obtain a substantial video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video signal recording and reproducing apparatus for photographing, recording and reproducing video signals.

Conventional technology In recent years, imaging devices have been using solid-state imaging devices with a high number of pixels (
Products using CCD, MOS, etc.) are beginning to be developed. High-resolution video signals such as high-visibility signals are conventional NTSC signals and PAL signals in both horizontal and vertical frequency bands.

Compared to the SECAM signal, the band is about twice as wide. These video signals are photographed, recorded and played back.

As a result of necessity, solid-state imaging devices with double the number of vertical and horizontal pixels and video signal recording and reproducing devices with four times the bandwidth of conventional devices have been developed.

A conventional video signal recording and reproducing device will be described below, but for the sake of simplicity, it is assumed that the video signal recording and reproducing device is an imaging device that takes a black and white image and records and reproduces only a luminance signal. FIG. 4 shows a block diagram of a conventional video signal recording and reproducing apparatus. In FIG. 4, l represents a lens system, usually several lenses are used in combination. 2 performs photoelectric conversion with a solid-state image sensor, 3 is a readout clock generation circuit, 4 is a synchronization signal addition circuit, 5 is a modulation circuit, 6i is a recording head, 7 is a recording medium, 8 is a recording/reproducing system, 9 is a reproduction The head, IO is a demodulation circuit, and 11 is an output terminal. The operation of the video signal recording and reproducing apparatus configured as described above will be explained below.

The lens system l forms an image on the solid-state image sensor 2.

The solid-state image sensor 2 receives a clock from the read clock generation circuit 3 and outputs a video signal.

A synchronization signal is added to the video signal by a synchronization addition circuit 4, and the video signal is input to a modulation circuit 5. In the modulation circuit 5, the input signal is modulated into a signal suitable for recording and reproduction, and is recorded on a recording medium using a recording head 6. At the time of reproduction, the video signal reproduced by the reproduction head 9 is processed in the demodulation circuit 10 in the opposite manner to that at the time of recording, and the original signal is reproduced. Then, it is output from the output terminal 11 as a reproduction signal.

Problems to be Solved by the Invention However, with the above-mentioned conventional configuration, when shooting, recording and playing back very high-resolution video, such as in high-definition television shooting, high-pixel processing technology is required, which requires fine processing technology. A high-density solid-state image sensor is used, and such an image sensor is difficult to process. Furthermore, since the obtained high-resolution signal has a wide frequency band, it has the disadvantage that high-density recording is required if the same recording time as the conventional method is to be secured.

The present invention solves the above-mentioned conventional problems, and aims to provide a video signal recording and reproducing device that can record and reproduce high-resolution video signals using a solid-state image sensor with a low number of pixels. .

Means for Solving the Problems To achieve this object, the video signal recording and reproducing device of the present invention has fewer pixels in the vertical direction than conventional solid-state image sensors, and has a horizontal scanning period as a unit on the imaging surface within the field. A solid-state image sensor that captures an image with line thinning performed is used, and the solid-state image sensor outputs a video signal whose time axis has been expanded for a time corresponding to the thinning ratio of the line-thinned image. A modulation circuit that converts the axial extension signal into a signal suitable for recording and reproducing using a tape head system, and a tape head system that records and reproduces the output signal of the modulation circuit.
a head system, a demodulation circuit that demodulates the signal reproduced from the tape head system, a time-base compression circuit that returns the output signal of the demodulation circuit to the original time base, and interpolation from the output signal of the time-base compression circuit. It consists of an interpolation circuit that obtains signals and interpolates lines thinned out during imaging.

Function: With this configuration, it is possible to provide a video signal recording and reproducing device that can capture high-resolution signals using a solid-state image sensor with a low number of pixels, converts a video signal with a wide frequency band into a video signal with a narrow frequency band, and records and reproduces the video signal.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a video signal recording and reproducing apparatus in one embodiment of the present invention. In FIG. 1, 12 is a lens system, which is usually used in combination with several lenses. A solid-state image sensor 13 performs photoelectric conversion. 1
4 is a read clock generation circuit, 15 is a synchronization signal addition circuit, 1σ is a modulation circuit, 17 is a recording head, 18 is a recording medium, 19 is a recording/reproduction system, 20 is a reproduction head, 21 is a demodulation circuit, 22 is a time axis A compression circuit, 23 an interpolation circuit, and 24 an output terminal.

The operation of the video signal recording and reproducing apparatus configured as described above will be described below.

The lens system 12 forms an image on the solid-state image sensor 13. now,
If the vertical direction is thinned out to 1/2, the solid-state image sensor 13
The number of pixels in the vertical direction is 1/2 that of the conventional one, and the captured image is an image thinned out every other line. Upon receiving the supply, a video signal (FIG. 2A) whose time axis has been expanded twice is output. A synchronization signal is added to the video signal by a synchronization addition circuit 15 and input to a modulation circuit 16 . The modulation circuit 16 modulates the input video signal in a manner suitable for the recording/reproducing system. When a magnetic tape is used as a recording medium, FM modulation is often used, but other modulation methods may also be used.

During playback, the video signal recorded on the recording medium 18 is
After being read out by the playback head 20, it is demodulated into the previous signal (FIG. 2A) by the demodulation circuit 21, which performs the opposite process to the modulation process, and the time axis is compressed to 1/2 by the time axis compression circuit 22. This results in a video signal for each line (FIG. 2B). Furthermore, the interpolation circuit 23 interpolates the lines that have been thinned out to obtain the original video signal (C in Figure 2). If axis fluctuations have an adverse effect, a time axis correction circuit (not shown, a so-called TBC circuit) is connected from the demodulation circuit 21 to the interpolation circuit 2.
It may be inserted between 3.

For example, as shown in FIG. 3, the time axis compression circuit 22 includes an input terminal 26, a first switch 27, a first line memory 28, a second switch 29, an output terminal 30. Write clock generation circuit 31, read clock generation circuit 32
, and a second line memory 33. The first line memory 28 has an input terminal 34, an output terminal 35, a write clock input terminal 36, and a read clock input terminal 37, and the second line memory also has an input terminal 28, an output terminal 39, and a write clock input terminal. 40, has a read clock input terminal 41.

1st line memory 2 days and 2nd line memo IJ3
3 is CCD, AD converter, digital memory,
It consists of memory such as DA converter. switch 2
7 and 29 are turned to opposite terminal sides every 2H (H: horizontal scanning period).For example, while the movable piece of switch 27 is turned to the Sl side, the movable piece of the switch 29 is turned to the S4 side. While the movable piece of the switch 27 is pushed to the Sl side, the line memory 28 performs a write operation and receives the clock from the write clock generation circuit 31. For example, the signal in FIG. 2B Load YE into the line memory 28. If the movable piece of the switch 27 is pushed to the S2 side after 2H time has passed, the movable piece of the switch 29 is pushed to the S3 side. The signal WE shown in FIG. The line memory 33 receives and receives the clock from the write clock 31.The frequencies of the write clock and read clock are determined by the compression ratio, and here, 1
:Has a frequency relationship of 2.

In this way, the output terminal 30 of the time axis compression circuit 23 outputs a time axis compressed signal as shown in FIG. 2B.

The interpolation circuit 23 is, for example, a circuit that performs the calculation of Z-(X+Y)/2 on the signal X and the signal Y shown in FIG. 2B, and includes a memory, an adder, and a 1/2 attenuator (all not shown). Any device that outputs the signal Z shown in FIG. 2C may be used. Alternatively, the signal Z may be generated by interpolating from a signal before one field, after one field, one frame before or after one frame, using a field or frame memory (not shown) as a memory.

In this way, the original video signal is reproduced at the output terminal 24.

As described above, according to this embodiment, a solid-state image sensor is used that captures an image in which lines are thinned out within a field in units of horizontal scanning periods on the imaging surface, and the solid-state image sensor captures the line-thinned image. a modulation circuit that outputs a video signal whose time axis has been expanded by a time corresponding to the thinning ratio and converts the time axis expanded signal into a signal suitable for recording and reproducing using a tape head system; A tape head system that records and plays back the output signal of the modulation circuit, and the above tape head system.
A demodulation circuit demodulates the signal reproduced from the head system, a time-base compression circuit that returns the output signal of the demodulation circuit to the original time base, and an interpolated signal is obtained from the output signal of the time-base compression circuit and used during imaging. By providing an interpolation circuit for interpolating the thinned out lines, it is possible to provide a video signal recording and reproducing device that uses a solid-state image pickup device with a small number of pixels and does not require high-density recording as conventionally required.

Effects of the Invention As described above, the present invention uses a solid-state image sensor that captures an image in which lines are thinned out within a field in units of horizontal scanning periods on an imaging surface, and uses the solid-state image sensor to capture the line-thinned image. a modulation circuit that outputs a video signal whose time axis has been expanded by a time corresponding to the thinning ratio and converts the time axis expanded signal into a signal suitable for recording and reproducing using a tape head system; a tape head system for recording and reproducing the output signal of the circuit; a demodulation circuit for demodulating the signal reproduced from the tape head system; and a time axis compression circuit for returning the output signal of the demodulation circuit to the original time axis; By providing an interpolation circuit that obtains an interpolation signal from the output signal of the time axis compression circuit and interpolates the lines thinned out during imaging, high-density recording is possible using a solid-state image sensor with a low pixel count. Therefore, it is possible to provide an excellent video signal recording and reproducing device that is not limited to the above.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a video signal recording/reproducing device according to an embodiment of the present invention, Fig. 2 is a waveform diagram, Fig. 3 is a block diagram of a time axis compression circuit, and Fig. 4 is a block diagram of a conventional magnetic recording/reproducing device. It is a diagram. 1.12... Lens system, 2. 】３・・・・・・
Solid-state image sensor, 3.14...readout clock generation circuit, 4.15...synchronization addition circuit, 5,1
6... Modulation circuit, 6, 17... Recording head, 7... Recording medium, 9.20...
Reproduction head, 10.21... Demodulation circuit, 22.
...Time axis compression circuit, 23...Interpolation circuit.

Claims (2)

[Claims] (1) Using a solid-state image sensor that captures an image in which lines are thinned out within a field in units of horizontal scanning periods on the imaging surface, the rate of thinning of the above-mentioned line-thinned image is equivalent to that of the solid-state image sensor. A modulation circuit that outputs a time-axis expanded video signal and converts the time-axis expanded signal into a signal suitable for recording and reproducing using a tape head system, and recording and reproducing the output signal of the modulation circuit. the tape head system mentioned above, the tape head system mentioned above, and the tape head system mentioned above.
A demodulation circuit demodulates the signal reproduced from the head system, a time-base compression circuit that returns the output signal of the demodulation circuit to the original time base, and an interpolated signal is obtained from the output signal of the time-base compression circuit and used during imaging. A video signal recording and reproducing device comprising: an interpolation circuit that interpolates thinned out lines. (2) From the video signal recording and reproducing device according to claim (1),
A demodulation circuit demodulates the playback signal from the tape head system, a time-base compression circuit that returns the output signal of the demodulation circuit to its original time, and an interpolated signal is obtained from the output signal of the time-base compression circuit and thinned out during imaging. A video signal recording device characterized in that an interpolation circuit for interpolating drawn lines is removed.