JPH0523112B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is an NTSC television signal that displays video signals of odd and even fields on a screen in an interlaced relationship. The present invention relates to a technique for displaying an image on a non-interlaced receiver using a video signal that displays two images.

BACKGROUND TECHNOLOGY AND PROBLEMS Currently, television signals such as the NTSC system used as television broadcasting signals display images by interlacing odd and even field signals to achieve relatively low resolution. I'm trying to raise it. For this reason, for example, when trying to obtain a still image by repeatedly displaying one frame's worth of signals on a receiver as an image, the signals of odd and even fields are displayed alternately, resulting in a flicker in the field period. stands out. This causes the screen to flicker, making it extremely difficult for viewers to view.

In order to prevent flickering on the screen when viewing still images, a receiver that displays one frame of the screen without interlacing has been considered. In this case, for example, an NTSC television signal that arrives in interlaced mode cannot be directly supplied to this receiver.
Conventionally, one image is formed in a figurative manner as follows.

That is, when an odd field signal is supplied to this receiver, the signals of two horizontal lines are averaged and the average value is used as information for the even field horizontal line. As shown in Fig. 1, the line L ₂₆₃ of the even field is located between the lines L ₁ , L ₂ ...L ₂₆₂ of the odd field.
It utilizes the fact that the information of L ₂₆₄ ,...L ₅₂₅ is located and that the video signal has vertical correlation.

However, this method is equivalent to a beam spot having a vertically elongated diameter, and has the disadvantage that the resolution in the vertical direction is degraded.

Purpose of the Invention The present invention provides an interlaced mode television signal such as the NTSC system to a non-interlaced receiver without deteriorating the vertical resolution as described above, thereby facilitating the production of still images with less noticeable flickering. The purpose of the present invention is to provide a device that allows the user to obtain the following information.

Summary of the Invention This invention uses a video disc playback device as a video signal supply source, uses a special type of disc playback device, and supplies its output to a non-interlaced receiver to eliminate flickering. Moreover, it is possible to obtain still images without loss of resolution.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a system diagram showing an overview of an example of the apparatus of the present invention. In the diagram, numeral 1 is a video disc on which, for example, an NTSC television signal is optically recorded in interlaced mode. This video disk 1 is designed to record one frame of video signals per revolution, and therefore, the odd field video signal is recorded for half the revolution, and the even field video signal is recorded for the remaining half revolution. For example, video signals of odd-numbered fields and even-numbered fields are recorded in a spiral pattern from the inner periphery toward the outer periphery. The playback signal from this video disk 1 is obtained optically by scanning the recording track of the disk 1 with one playback optical head, but when obtaining a still image, this one The same signal for one frame is repeatedly retrieved by repeatedly scanning the same scanning track for one rotation of the reproducing optical head. This is then supplied after the image is received, and the still surface is displayed.

Normally, the video disk reproducing apparatus has one reproducing optical head as described above, but in the present invention, two optical heads are provided. And in this example the second
As shown in the figure, the reproduction heads H ₁ and H ₂ are spaced apart by one field period, or 180°.
Then, the video signals are simultaneously reproduced by these two reproduction heads _H1 and _H2 . Therefore, when one head is reproducing an odd field signal, the other head is in a state where it is reproducing an even field signal.

Here, when the direction of rotation is the direction shown by arrow 2 in the figure, the head _H1 is positioned in advance of the head _H2 .

Therefore, when the head _H1 starts to reproduce the video signal of the odd field, for example, the head _H2 starts to reproduce the video signal of the even field. The video signals of odd and even fields thus obtained simultaneously are supplied to A/D conversion circuits 4A and 4B through head amplifiers 3A and 3B, respectively, and converted into digital signals. This digital signal is supplied to line memories 5A ₁ , 5A ₂ and 5B ₁ , 5B ₂ each having a capacity to store information for one horizontal line, and is stored line by line.

Signal extracted from head _H1 (Figure 3A)
are stored alternately in line memories 5A ₁ and 5A ₂ for each line (see C in the same figure). Further, the signal obtained from head _H2 (FIG. 2B) is stored alternately in line memories _5B1 and _5B2 line by line (see FIG. 2D). and each line memory 5
The information stored in A ₁ , 5A ₂ and 5B ₁ , 5B ₂ is 2
Reads out twice as fast.

That is, as shown in FIG. 3C and D, the head
When the signal extracted from head H ₁ is an odd field signal and the signal extracted from head H ₂ is an even field signal, first, a certain horizontal period TH ₁
At the same time as the first line signal is written into the line memory 5A ₁ , the 263rd line signal is written into the line memory 5B ₁ . next horizontal period
At TH ₂ , the signal on the second line is written into the line memory 5A ₂ and at the same time the signal on the 264th line is written into the line memory 5B ₂ . In this horizontal period TH ₂ , the information on the first line is read out from the line memory 5A ₁ at twice the writing speed (by a clock signal with twice the frequency) during the first half period, and during this period The information of the 263rd line written in the line memory _5B1 during the 1/2 horizontal period in the latter half of TH ₂ is read out at twice the speed. Thereafter, this process is repeated sequentially, and a signal is obtained at the output end of the adder circuit 6, as shown in FIG. .
This signal is supplied to a D/A converter 7 and returned to an analog signal, which is demodulated in a demodulation circuit 8 for reproduced video signals, and the demodulated video signal is displayed on a receiver 9 where an image is displayed without interlacing. is supplied to Therefore, after the receiver 9 displays the signal of the odd field, the signal that arrives one field later is displayed in the originally interlaced mode of the even field. In this way, the odd field and even field signals are displayed on the screen for each horizontal line to form one frame. Therefore, flickering of one field period does not occur at all. Furthermore, since the signals of the odd field and even field are combined to form a correct image of one frame, the resolution in the vertical direction does not deteriorate at all as in the conventional example.

The frequency of the write clock when writing to line memory is, for example, 14.3MHz, and when reading, it is 14.3MHz.
It is said to be 28.6MHz.

The above example is an example where the video signal is recorded on the disk as an analog signal, such as an FM signal, but when the video signal is converted to a PCM digital signal and recorded. , A/D conversion circuits 4A and 4B, and D/A conversion circuit 7 are not necessary. However, it is easy to understand that in this case, a PCM signal decoder is naturally provided between the receiver 9 and the adder 6.

It should be noted that it is easy to understand that the present invention is applicable not only to NTSC signals but also to PAL signals. In short, the present invention is very effective for video signals whose images are displayed in interlaced mode.

Effects of the Invention As described above, according to the present invention, a device having two heads is used as a device for reproducing a video disk in which video signals are recorded in interlaced mode, and these two heads are used to play odd fields. and even field signals at the same time, the read signals are once written to the buffer memory, and the written signals are read out at twice the speed, and the odd field lines and the even field lines are read out alternately. Since the image can be displayed by supplying the image to a receiver without interlacing, a beautiful image can be obtained as a still screen without any flickering in the field period. Moreover, 1
Since the still image for each frame is a correct combination of the original odd field signal and even field signal, there is no deterioration in vertical resolution as in the conventional method.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the state of interlacing, FIG. 2 is a system diagram of an example of the apparatus of this invention, and FIG. 3 is a diagram for explaining the same. 1 is a video disk, H ₁ and H ₂ are playback heads, 5A ₁ , 5A ₂ , 5B ₁ , and 5B ₂ are line memories each serving as a buffer memory, and 9 is a receiver that displays images without interlacing.

Claims (1)

[Claims] 1. Plays back a disc on which an NTSC video signal is recorded at a rate of one frame per revolution, in which signals from odd and even fields are displayed in an interlaced relationship on the screen to form a single image. and a receiver capable of displaying one frame of a video signal consisting of the same number of lines as the video signal without interlacing as one image at twice the speed, and the playback device includes a playback head. Two playback heads are installed spaced 180 degrees apart, and these two playback heads simultaneously play back the video signals of the odd and even fields, and the playback output is sent to a buffer memory that can store the video signal for one horizontal line. The written video signals are written to the buffer memory at twice the writing speed, and
One horizontal line of the odd field and one horizontal line of the even field are read out alternately, and the read signals are sequentially supplied to the receiver to produce a non-interlaced image at twice the speed. An image display device characterized in that it is adapted to be displayed.