JPH0683487B2 - 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 less flicker by repeatedly reading out the field image to form one frame image, and for the image with relatively little motion, 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 first field and a second field subsequent to the first field. , R, B, (b) a field discriminating circuit 44 for discriminating the first and second fields of the video signal, and (c) storing the first color signal G for each of the first and second fields. First and second memories for a first color signal
4, 5 and (d) third and fourth memories for the second color signal which store the second color signal R for each of the first and second fields.
3a, 3b, and (e) fifth and sixth memories for the third color signal which store the third color signal B for each of the first and second fields.
6a, 6b, (f) a line memory 51 for storing the nth video information (n) of the predetermined nth line read from the first memory 4, and (g) a line memory 51 The n video information (n) and the (n + 1) th video information (n + 1) of the (n + 1) th line read from the first memory 4 are calculated to calculate 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 to the first and second, third and fourth and fifth and sixth memories 4,5 for each of the first to third color signals G, R, B; The outputs from 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 21, 11 The video signal recording / reproducing apparatus is characterized in that it includes a control changeover switch 45 to be provided to the terminals 31 and 31.

Operation According to the present invention, the signals separated into the first to third color signals G, R and B of the three primary colors are the first to sixth memories 4 and 4 for each of the first and second fields. Stored in 5; 3a, 3b; 6a, 6b respectively. Of the signals thus stored, the nth video information (n) of the nth line of the first color signal G read from the first memory 4 and the (n + 1) th line of the (n) th video information (n). n + 1) Average value F with video information (n + 1)
(N) is obtained by the calculator 52, and this average value F
(N) is compared with the video signal g (n) of the n-th line read from the second memory 5, and when they match each other, that is, when the video has a relatively small motion, 2
Video signals of one field are stored in the first to sixth memories 4,5; 3a, 3
b; 6a and 6b are alternately read out, so that a still image with good resolution can be obtained. Further, when the first color signal G between the two fields does not match, that is, when the image has a relatively fast motion, the image signal of the field preceding in time is stored in the first, third, and fifth memories 4, 3, 4.
It is possible to obtain a flicker-free still image that is repeatedly read from a and 6a, respectively.

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 supplied to the decoder 2 by the color signals R, G, B of the three primary colors.
After being demodulated, the analog / digital (A / D) conversion is performed.

The red color signal R demodulated and A / D converted by the decoder 2 is
The memory 3a for odd fields and the memory 3b for even fields (collectively referred to as 3), which are storage means, are respectively supplied, and similarly, the green color signal G is supplied to the memory 4 for odd fields and the memory 5 for even fields. The blue color signal B is given to the odd field memory 6a and the even field memory 6b (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.

To the other input terminal of the comparator 53, the image information g (n) of the n-th line in the even field is input from the even field memory 5 via the 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.

In the above-described embodiment, whether or not the motion of the subject on the video signal is large is determined by the green color signal G, but other color signals may be used as another embodiment of the present invention.

As described above, according to the present invention, in the case of a video in which the motion is relatively small, the video signals of the two fields are read out alternately, so that 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 preceding in time is repeatedly read,
Therefore, 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. 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 decoder for obtaining first to third color signals G, R, B of three primary colors from a video signal in which one frame comprises a first field and a second field following the first field. 2, (b) a field discriminating circuit 44 for discriminating the first and second fields of the video signal, and (c) a first color signal for storing the first color signal G for each of the first and second fields. First and second memories
4, 5 and (d) third and fourth memories for the second color signal which store the second color signal R for each of the first and second fields.
3a, 3b, and (e) fifth and sixth memories for the third color signal which store the third color signal B for each of the first and second fields.
6a, 6b, (f) a line memory 51 for storing the nth video information (n) of the predetermined nth line read from the first memory 4, and (g) a line memory 51 The n video information (n) and the (n + 1) th video information (n + 1) of the (n + 1) th line read from the first memory 4 are calculated to calculate 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 to the first and second, third and fourth and fifth and sixth memories 4,5 for each of the first to third color signals G, R, B; The outputs from 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 21, 11 A video signal recording / reproducing apparatus including: