JPH0683488B2 - Video signal recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal recording / reproducing apparatus, and more specifically, it is preferably implemented in a video tape recorder or a video disc player having a still image function and has little flicker. The present invention relates to a video signal recording / reproducing device that realizes a still image.

2. Description of the Related Art In a typical prior art video tape recorder having a still image function, one frame of video is stored in a memory and played back. In such a conventional technique, when a fast-moving image is reproduced, the 1-frame image is formed.
Since the images in the two fields are displaced from each other, the reproduced still image may flicker.

In another prior art video tape recorder which solves this problem, an image of one field is stored in a memory, and the stored image of one field is repeatedly read out to obtain 1
It made up the video of the frame. In such a conventional technique, since the image information is halved, there is a problem that the vertical resolution is significantly reduced.

Problems to be Solved by the Invention The object of the present invention is to solve the problem of
It is possible to obtain a still image with little flicker by repeatedly reading out the field image to form one frame image, and for a relatively little moving image, by reading out the one frame image, It is an object of the present invention to provide a video signal recording / reproducing device capable of obtaining a still image with good resolution.

Means for Solving the Problems In the present invention, (a) one frame includes a video signal composed of a first field and a second field following the first field, and a luminance signal Y and first and second color difference signals R. A decoder 2 for obtaining -Y, BY, (b) a field discriminating circuit 44 for discriminating the first and second fields of the video signal, and (c) storing a luminance signal Y for each of the first and second fields. First and second memories 4 and 5, and (d) third and fourth memories 3a and 3b for the first color difference signal which store the first color difference signal RY for each of the first and second fields. (E) fifth and sixth memories 6a and 6b for the second color difference signal, which store the second color difference signal BY for each of the first and second fields, and (f) read from the first memory 4. Of the predetermined nth line line memory 51 for storing n video information (n), (g) nth video information (n) read from the line memory 51, and (n + 1) th line read from the first memory 4. (N + 1) video information (n + 1) is calculated to obtain an average value F (n), And (h) the output representing the average value F (n) from the arithmetic unit 52 and the image information g (n) of the n-th line read from the second memory 5 are compared. A comparator 53 for determining whether they match, (i) a first changeover switch 21 for switching and outputting the signals stored in the first and second memories 4 and 5, and (j) a third And a second changeover switch 11 for switching and outputting the signals stored in the fourth memories 3a, 3b, and (k) a third for switching and outputting the signals stored in the fifth and sixth memories 6a, 6b. The changeover switch 31 and (l) the first, second and third changeover switches 21, 11, 31
Signal deriving means 47 for deriving a signal for switching to derive the outputs of the first, third and fifth memories 4, 3a, 6a respectively.
(M) in response to the output of the comparator 53, and when it is determined that they match, the output from the field determination circuit 44 is changed to the first output.
-Third changeover switches 21, 11, 31 are provided with the luminance signal Y and the first and second, third and fourth and fifth and sixth for each of the first and second color difference signals RY and BY. Memory 4,
The outputs from 5; 3a, 3b; 6a, 6b are alternately switched and derived for each field, and when it is determined that they do not match, the output of the signal deriving means 47 is changed to the first to third changeover switches 2
The video signal recording / reproducing apparatus is characterized in that it includes a control changeover switch 45 to be provided to 1, 11, and 31.

Operation According to the present invention, the luminance signal Y and the first and second color difference signals RY and BY are provided in the first to sixth memories 4,5 and 3a for each of the first and second fields. , 3b; 6a, 6b, respectively. Of the signals stored in this way,
The average value F of the luminance signal Y of the nth video information (n) of the nth line read from the first memory 4 and the (n + 1) th video information (n + 1) of the (n + 1) th line.
(N) is obtained by the calculator 52, and this average value (n)
And the video signal g (n) of the n-th line read from the second memory 5 are compared, and when they match, that is, when the video has relatively little motion, the video signals of two fields are compared. Is the first to sixth memories 4,5; 3a, 3b; 6a, 6b
Are read out alternately from each other, so that a still image with good resolution can be obtained. In the case of disagreement, that is, in the case of a relatively fast-moving video, the video signal of the field preceding in time is repeatedly read from the first, third, and fifth memories 4, 3a, 6a, respectively, and therefore flicker occurs. You can get no still images.

Embodiment FIG. 1 is a block diagram showing an electrical configuration of a video signal recording / reproducing apparatus according to an embodiment of the present invention. This video signal recording / reproducing apparatus is used for a video tape recorder having a still image function. The analog video signal input to the input terminal 1 is demodulated by the decoder 2 into the luminance signal Y and the color difference signals RY and BY, and then analog / digital (A / D) converted.

The color difference signal RY demodulated and A / D converted by the decoder 2 is
The odd number field memory 3a and the even field memory 3b (collectively referred to as "3"), which are storage means, are supplied to the memory 3a.
And the even-numbered field memory 5 and the color difference signal B
-Y is given to the memory 6a for odd fields and the memory 6b for even fields (collectively 6).

The output terminal of the odd field memory 3a is connected to the individual contact 12 of the changeover switch 11 which is the reading means, and the output terminal of the even field memory 3b is connected to the individual contact 13. The switching mode of the change-over switch 11 is changed by the change-over control signal from the line 14, so that the video information from the odd field memory 3a and the even field memory 3b is selectively read from the common contact 15. Digital / analog (D / A) converter 16 performs analog conversion and leads to output terminal 17. Similarly, the output terminal of the memory 4 for odd fields is the individual contact 22 of the changeover switch 21.
, The output terminal of the even field memory 5 is connected to the individual contact 23, and the video signal from the common contact 25 is led to the output terminal 27 via the digital / analog converter 26. The output terminal of the odd field memory 6a is connected to the individual contact 32 of the changeover switch 31, and the even field memory is
The output terminal of 6b is connected to the individual contact 33, and the video signal from the common contact 35 is led to the output terminal 37 via the digital / analog converter 36.

The video signal from the input terminal 1 is also given to the sync separation circuit 41. The sync separation circuit 41 derives a horizontal sync signal from the line 42 and a vertical sync signal shown in FIG. 2 (1) from the line 43, and supplies the vertical sync signal to the field discrimination circuit 44. The field discriminating circuit 44 is composed of, for example, a flip-flop and, as shown in FIG. 2B, derives a low level output to the line 49 in the case of an odd field and a high level output in the case of an even field. Derive. Field discrimination circuit 44
The field discrimination signals from are supplied to the memories 3 to 6, respectively, and the writing and reading operations of the memories 3 to 6 are synchronized.

The field discrimination signal is also sent to the individual contact 46 of the changeover switch 45.
The individual contact 47 of the changeover switch 45 is grounded, and the common contact 48 is connected to the line 14. Therefore, when the common contact 48 of the changeover switch 45 is electrically connected to the individual contact 46, the changeover control signal led to the line 14 is the field discrimination signal shown in FIG. During the period when the signal is low level, the common contacts 15, 25, 35 of the changeover switches 11, 21, 31 conduct to the individual contacts 12, 22, 32, respectively, and are stored in the odd field memories 3a, 4, 6a. The image information thus read is read. During the period when the field discrimination signal is at high level, the common contacts 15, 25, 35 of the changeover switches 11, 21, 31 are set to the individual contact 1 respectively.
The video information stored in the even field memories 3b, 5, 6b is read out. Further, when the common contact 48 of the changeover switch 45 is conducted to the individual contact 47, the changeover control signal remains at the low level, and therefore, as in the case where the above-mentioned field discrimination signal is at the low level,
Common contact 15, 25, 35 of changeover switch 11, 21, 31 is individual contact 1
The video information stored in the odd-numbered field memories 3a, 4 and 6a is read out by being electrically connected to the terminals 22, 22 and 32.

The movement of the subject on the video signal input from the input terminal 1,
That is, a line memory 51, a calculator 52, and a comparator 53, which are comparison means, are provided in order to discriminate the shift between the video of the odd field and the video of the even field which are adjacent to each other. The line memory 51 includes an odd field memory 4
The video information (n) of the specific nth line is given from the line 54 to the line 54. Odd field memory 4
The output terminal of is also connected to one input terminal of the computing unit 52 via the line 55, and the other input terminal of this computing unit 52 is provided with the output from the line memory 51 via the line 56. To be In this way, the video signal (n) of the nth line delayed by one line by the line memory 51 is input to the other input terminal of the calculator 52 via the line 56, To one of the input terminals, the video information (n +
1) is input.

The computing unit 52 computes the average value F (n) of the two pieces of video information (n) and (n + 1) based on the following equation, and supplies it to one input terminal of the comparator 53 via the line 57.

The image information g (n) of the nth line in the even field is input to the other input terminal of the comparator 53 via the even field memory 5 filtering line 57. The comparator 53 determines whether or not these two pieces of input information match, that is, whether or not there is a shift between the image of the odd field and the image of the even field. , The common contact 48 of the changeover switch 45 is conducted to the individual contact 46, and when there is a deviation, the line 59 is brought to a high level and the common contact 48 of the changeover switch 45 is conducted to the individual contact 47.

Therefore, as described above, when there is a discrepancy between the video of the odd field and the video of the even field, the line 59 becomes high level, whereby the changeover control signal of the line 14 becomes low level, and the changeover switches 11, 21, The common contacts 15, 25, 35 of 31 are electrically connected to the individual contacts 12, 22, 32, respectively, and the video signal of the odd field preceding in time is repeatedly read out, and a still image without flicker can be obtained. Further, when there is no deviation between the video of the odd field and the video of the even field, the line 59 becomes low level, whereby the field discrimination signal is derived as the switching control signal of the line 14, and the changeover switches 11, 21, 31
The common contacts 15, 25, 35 of are alternately conducted to the individual contacts 12, 22, 32 and the individual contacts 13, 23, 33, respectively, and the video signal of the odd field and the video signal of the even field are read alternately.
A still image with good resolution can be obtained.

As described above, according to the present invention, in the case of a video with relatively little motion, the signals of the two fields are alternately read from the first to sixth memories 4,5; 3a, 3b; 6a, 6b, Therefore, a still image with good resolution can be obtained. In the case of a relatively fast-moving video, the video signal of the first field temporally preceding is repeatedly read out, so that a still image without flicker can be obtained.

Further, according to the present invention, the line memory 51 enables the first
The nth video information (n) of the nth line of the first field read from the memory 4 is stored, and the arithmetic unit 52 stores the (n + 1) th video information (n + 1) of the (n + 1) th line. Then, the average value F (n) is calculated based on
Video information G of the nth line from the second memory 5
Since it is compared with (n), the excellent effect of preventing malfunction due to noise is also achieved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the electrical configuration of a video signal recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining the operation. 2 ... Decoder, 3a, 4, 6a ... Odd field memory, 3b, 5, 6b ... Even field memory, 11, 21, 31, 45
...... Changeover switch, 16,26,36 ...... Digital / analog converter, 41 ...... Synchronous separation circuit, 44 …… Field discrimination circuit, 51 …… Line memory, 52 …… Calculator, 53 …… Comparator

Claims (1)

[Claims] 1. A luminance signal Y and first and second color difference signals RY and BY from a video signal in which one frame is composed of a first field and a second field following the first field. A decoder 2 for obtaining, (b) a field discriminating circuit 44 for discriminating first and second fields of a video signal, and (c) first and second memories for storing a luminance signal Y for each first and second field. 4 and 5, (d) third and fourth memories 3a and 3b for the first color difference signal that store the first color difference signal RY for each of the first and second fields, and (e) the second color difference. Fifth and sixth memories 6a and 6b for the second color difference signal for respectively storing the signal BY for each of the first and second fields, and (f) a predetermined nth memory read from the first memory 4. Strike the nth video information (n) of the line Line memory 51, (g) nth video information (n) read from the line memory 51, and (n + 1) th video information (n + 1) of the (n + 1) th line read from the first memory 4. And the mean value F (n), And (h) the output representing the average value F (n) from the arithmetic unit 52 and the image information g (n) of the n-th line read from the second memory 5 are compared. A comparator 53 for determining whether they match, (i) a first changeover switch 21 for switching and outputting the signals stored in the first and second memories 4 and 5, and (j) a third And a second changeover switch 11 for switching and outputting the signals stored in the fourth memories 3a, 3b, and (k) a third for switching and outputting the signals stored in the fifth and sixth memories 6a, 6b. The changeover switch 31 and (l) the first, second and third changeover switches 21, 11, 31
Signal deriving means 47 for deriving a signal for switching to derive the outputs of the first, third and fifth memories 4, 3a, 6a respectively.
(M) in response to the output of the comparator 53, and when it is determined that they match, the output from the field determination circuit 44 is changed to the first output.
-Third changeover switches 21, 11, 31 are provided with the luminance signal Y and the first and second, third and fourth and fifth and sixth for each of the first and second color difference signals RY and BY. Memory 4
The outputs from 5; 3a, 3b; 6a, 6b are alternately switched and derived for each field, and when it is determined that they do not match, the output of the signal deriving means 47 is changed to the first to third changeover switches 2
A video signal recording / reproducing apparatus including a control changeover switch 45 provided to 1,11,31.