JPH04157885A - Still image recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a still image recording device.

[Conventional technology]

2-inch magnetic disk (hereinafter referred to as Sv floppy)
S as a system for recording still images in the NTSC format.
v (still video) system.

And recently, this S floppy has 1000 pixels (vertical)
Enables recording of image quality of approximately 1300 x 1300 pixels,
In addition, as a method that is compatible with the conventional Sv system, the CH3V method (Compatible High
Definit, ion SV) has been proposed.

Since the details of the CHSV method have already been published in literature, etc., the outline thereof will be explained here to the extent necessary for understanding the present invention.

The CH3V method uses a technique called sample value analog transmission. This is HDTV (High Definition)
The MUSE method (Multiple Subsample) proposed by NHK as a transmission method for
This technique is also used in NG Encoding, and attempts to correctly transmit a sample value sequence (time interval T) using an analog transmission path with a predetermined band limit.

There are the following two conditions for realizing this sample value analog transmission.

a. The frequency characteristics of the analog transmission line are linear phase, and (
It has a point-symmetric roll-off characteristic centered on the frequency 1f). . . . "Nyquist condition" b. On the receiving side (during playback), resample the correct sample point.

In the CH3V system, after satisfying the above two conditions, the sample value sequence of the video signal is recorded on the Sv floppy according to the conventional S system recording format and played back, as shown in Figure 2. shall be.

FIG. 3 shows sample points of a Y (luminance) signal and CI, C2 (color difference) signals when recording on an sv floppy in the CHSV method. Here, the color difference signals CI and C2 indicate the (RY) signal and the (B-Y) signal.
is displayed. Therefore, if C1= (RY), then C2= (B-Y)"t', and conversely, C1= (B
-Y), then C2=(RY). and,
In the CH3V system, the Y, CI, and C2 signals of the sample pattern shown in FIG. 3 are divided into four types and recorded on four tracks of the Sv floppy.

The division method is different for the Y signal, CI signal, and C2 signal.

In the recording format of the conventional Sv system, as shown in FIG. 4, an FM-modulated Y signal and an FM-modulated C1/C2 (color difference line sequential) signal are frequency-multiplexed and recorded.

In the CH3V system, C2A/C is used for YA to YD signals.
IC, C2A NC2D signal is F in the combination shown below.
The signal after M modulation is frequency multiplexed.

■ YA, C2A/CIC o YB, C2A/CIC @) YC, C2B/CID [Phase] YD, C2B/CID Figure 5 shows the recording pattern when recording the signals from ■ to [stock] above on the Sv floppy. shows.

Therefore, when an Sv floppy recorded in the CHSV format is played back by a conventional SV playback device, at least field playback is completely compatible, and the 2. Frame playback compatibility can also be achieved when playing back frames of the third track.

Furthermore, during CHSV playback, the original sample values are completely restored by resampling the sample value strings recorded on the four tracks at the correct sample points. They are stored in memory during playback, and then by interpolating pixels other than the sample points shown in Figure 3, ~1000x~130
A still image of approximately 0 pixels is reproduced.

The above is an overview of the CHSV method.

(Problem to be solved by the invention) According to this method, still images with excellent characteristics can be recorded and reproduced, but in reality, the frequency characteristics of the reproduced video signal are slightly deteriorated. .

The present invention was made in order to solve the problems in devices that handle such wideband signals, and an object of the present invention is to provide a still image recording device that can supply a recorded recording medium that can reproduce video signals without deteriorating frequency characteristics. That is.

(Means for solving 8 problems) The deterioration of the frequency characteristics will be discussed.

As described above, the CH8V system and the like use a technique for correctly transmitting a sequence of sample values of a video signal through an analog transmission path.

Here, the sample value sequence of the video signal is, in principle, a narrow impulse sequence shown in FIG. However, in reality, in order to secure the energy of each sample value and ensure compatibility with the conventional S system, as shown in Fig. 6,
It is necessary to manually input the pulse train to the transmission line (recording/reproducing system) as a pulse train having a finite width t.

In the case of FIG. 6, the width of each pulse and the interval between pulses are the same, so the aperture is 100%.

In such a case, the frequency characteristics required for the transmission path (recording/reproduction system) are Nyquist characteristics as shown in Figure 7(a).
Being a filter is not enough.

This is because, as described above, since each sample value in the video signal sample value sequence has a finite width, the frequency characteristics of the video signal sample sequence itself are no longer flat due to the aperture effect.

FIG. 7(b) shows the aperture effect when the aperture is 100%.

Therefore, in this case, it is necessary to add an aperture correction filter as shown in FIG. 7(C) somewhere on the transmission path.

By the way, in order to compensate for the reproduction characteristics, it is conceivable to add this aperture correction filter to the signal processing circuit of the reproduction system.

However, as shown in Figure 7 (C), the aperture correction filter has the characteristic of emphasizing high frequencies, and as a result, noise components generated in the electromagnetic conversion system, etc., are also emphasized, and the reproduced image This results in a significant deterioration of the S/N ratio.

Therefore, the present invention solves the above problem by adding this aperture correction filter (compensation means) to the signal processing system before the electromagnetic conversion system in the transmission path, that is, before recording.

That is, in the present invention, a still image recording device is configured as shown in (1) below.

(1) A still image recording device that records a sample value sequence of a video signal of a still image in analog on a recording medium, the frequency characteristics of the video signal occurring because each sample value of the video signal has a finite width. A still image recording device including a compensation means for compensating for deterioration.

[Effect]

According to configuration (1) above, the compensating means records on the recording medium in a state in which deterioration in the frequency characteristics of the video signal caused by each sample value of the video signal having a finite width is compensated for.

〔Example〕

The present invention will be explained below with reference to Examples.

FIG. 1 is a block diagram of a "still image recording apparatus" which is an embodiment of the present invention.

In FIG. 1, the output signal from the image sensor 101 is C
In the HSV camera signal processing circuit 102, the signal undergoes predetermined signal processing and is output as a video signal sample value sequence.

This video signal sample value sequence is subjected to aperture correction (video 4
No. 3 (compensation for frequency characteristic deterioration of the video signal caused by each sample value having a finite width), processing such as emphasis and FM modulation in the recording signal processing circuit 104, and Sv (not shown) Recorded to floppy.

Note that although the above embodiments have been described using the CH3V system as an example, the present invention is not limited to this. Furthermore, although the embodiments perform recording magnetically, the present invention is not limited to this, but can also be implemented by optical or other suitable recording.

〔Effect of the invention〕

As explained above, according to the present invention, aperture correction is performed in the recording device, that is, in the signal processing device before the electromagnetic conversion system, etc., so there is no S/N deterioration due to aperture correction, and the aperture correction It is possible to provide a recorded recording medium that can reproduce video signals without deterioration of frequency characteristics due to effects.

[Brief explanation of drawings]

Figure 1 is a block diagram of one embodiment of the present invention, Figure 2 is a conceptual diagram of analog transmission of sampling values, and Figure 3 is Y, C1
, C2 signal sample pattern, Figure 4 is Sv
FIG. 5 is a diagram showing a recording pattern of the CHSV method, FIG. 6 is a diagram showing a sample value sequence of a video signal, and FIG. 7 is an explanatory diagram of the present invention.

Claims (1)

[Claims] A still image recording device that records a sample value sequence of a video signal of a still image in analog on a recording medium, and is capable of recording frequency characteristic deterioration of the video signal caused by each sample value of the video signal having a finite width. A still image recording device characterized by comprising compensation means for compensation.