JPH05304657A - Reducing method for number of scanning lines - Google Patents

Abstract

PURPOSE:To suppress the deterioration of a resolution, and to obtain a reduced screen in which the movement of an animationis smooth by operating and averaging processing by basically leaving the scanning lines positioned up-and- down adjacent to processing line in one frame, and operating the averaging processing to the scanning lines in the same field. CONSTITUTION:One frame is cnstituted of the scanning lines (contineous lines) in an odd field of an inputted video signal, and the scanning lines (broken lines) in an even field, just like (a). Here, at the time of reducing the scanning line to half, a line obtained by averaging the first and third scanning lines is outptted so that the scanning line in the odd field can be prepared just like (b), and the second scanning line interposed between them is thrown away. Then, the fourth scanning line is outputted to an odd field as it is just like (c). Then, an operation from the first scanning line to the fourth scanning line is repeated int he same way by every four scanning lines. And also, the first scanning line can outputted to the odd field as it is, and a line obtained by averaging the second and fourth scanning lines can be outputted to the even field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing the number of scanning lines of a component video signal or the like to an integer fraction, by fitting another reduced screen to the screen of one video monitor, or 1 Digital processing of video signals in case of dividing one screen into multiple parts and allocating separate reduced screens to each other for simultaneous display, or combining with an image enlarging device provided on the receiving side of the image transmission system The present invention can be applied to digital signal processing of a video signal in a device for reducing an image when a narrow band line is used or a device for reducing a plurality of images when efficiently transmitting a plurality of images simultaneously.

[0002]

2. Description of the Related Art In the case of so-called picture-in-picture in which another reduced screen is fitted in one screen, or in the case where a plurality of video screens such as television broadcasts are reduced in size and displayed simultaneously on one screen. , The original screen must be reduced according to the size of the screen to be reduced.

Since the amount of information in the horizontal direction is large in the signal components constituting the screen, the screen of the reduction ratio obtained even if data is appropriately thinned out is a reduced screen in a relatively unnatural form. Can be obtained. In contrast,
In the vertical direction, the number of scanning lines is very small, for example, 525 in the case of the NTSC system, which is a standard television system of Japan, and the amount of information is very small. The image quality will be greatly affected by the reduction processing.

Conventionally, as a method of reducing the number of scanning lines, there is a method by an in-field operation shown in FIGS. 4 to 7. That is, in the case of the NTSC system, one screen is composed of an odd field and an even field which are interlaced every 60 Hz, and the number of scanning lines is reduced in each of the odd field and the even field. ..

In FIG. 4, the number of scanning lines is halved, and in FIG.
A method of multiplying by 3 is schematically shown. In each field, if 1/2 times, only one in every two scanning lines is output as it is, and if it is 1/3 times, three scanning lines are output. In this method, only one line is output as it is and the remaining scanning lines are discarded.

In contrast to the first method, FIG. 6 schematically shows a second method for halving the number of scanning lines, and FIG. It shows a method of averaging three scanning lines and outputting them. In the case of 1/2 times, two scanning lines are paired, and one scanning line is output by simple averaging, and in the case of 1/3 times, three scanning lines are simply averaged or a figure. 1/4 and 1/2 as shown in 7
Is multiplied by the weight and output is added.

In contrast to the first and second methods for reducing the number of scanning lines by the intra-field operation for each field as described above, the third method shown in FIGS. 8 and 9 uses only one field. Then, it is a method of allocating this to an odd field and an even field, that is, a method of completely discarding one of the odd field and the even field.

FIG. 8 schematically shows a method of halving the number of scanning lines by the third method, and FIG. 9 schematically shows a method of halving the number of scanning lines. For example, only odd fields are used. If the scan lines of the odd field are 1/2 times, they are distributed to the odd field and the even field in order from the top, and if they are 1/3 times, one is output as it is to the odd field and the other two are averaged. It outputs to an even field. In the case of ⅓ times as large as that in FIG. 9, the order of allocating to the odd field and the even field may be opposite to that shown.

[0009]

By the way, in the above three reduction methods of the number of scanning lines, in the first and second methods, the reduction processing is performed by the same method for the odd field and the even field. When such reduction processing is performed on a raced video signal, jitter that shakes in the vertical direction is generated, the vertical resolution is extremely deteriorated, and the center of brightness moves on a moving screen, which is always a little confusing. It will be a movement. Further, in the first method, since the number of scan lines to be discarded is large, the screen is always rough.

On the other hand, in the third method, the processing in the memory in the hardware becomes simple, but since only one field is used, the movement of the image is halved, and a smooth screen cannot be obtained. ..

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of reducing the number of scanning lines capable of obtaining a reduced screen with smooth motion in a moving image while suppressing deterioration of resolution to a minimum. And

[0012]

For the above object, according to the present invention, interlaced scan lines of odd fields and even fields are taken into a memory to form one non-interlaced frame in the memory. When the number of scanning lines forming one frame is multiplied by 1 / N (N is an integer), the scanning lines are divided into groups of 2N from the top, and the odd number from the top in each group. Of the first sub-group and the remaining odd second sub-groups, and the odd-numbered scan lines in the first sub-group are averaged to form the scan lines of the odd-numbered field. The method for reducing the number of scanning lines is provided by averaging the odd-numbered scanning lines to obtain even-numbered scanning lines.

[0013]

According to the above means, when considering one frame and discarding one of the scanning lines, it is always necessary to average the scanning lines on both sides thereof, that is, on both the upper and lower sides.
By performing the averaging on the scanning lines of the same field, the motion does not move to other fields, so that the motion of the moving image is smooth.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the method of reducing the number of scanning lines according to the present invention illustrated in FIGS. 1 to 3 will be described in detail below.

FIG. 1 schematically shows a method of reducing the number of scanning lines to 1/2. FIG. 1A shows scanning lines (shown by solid lines) in odd fields of an input video signal. One frame composed of scan lines of even fields (shown by broken lines) is shown. The scanning lines taken in the memory are not arranged as shown in (a), but for convenience of explanation, it is assumed that the scanning lines of the odd field and the even field are arranged alternately, and these scanning lines are coded in order from the top. ,, ... are attached.

Here, in the case of forming the scanning lines of the odd field, the average of the first scanning line and the third scanning line is output as shown in FIG. 1B, and in the meantime. The second scan line sandwiched is discarded. Then, the next fourth scanning line is directly output to the even field as shown in FIG. The operations from the top to the fourth are repeated in the same manner for every four scanning lines thereafter. It should be noted that the first scanning line may be output as it is to the odd field, and the average of the second and fourth scanning lines may be output to the even field. In addition, this reduction processing is performed for three RGB signals in the case of component signals. Also, the brightness signal,
The same applies to the case of color difference signals.

FIG. 2 shows a method of reducing the number of scanning lines to ⅓. The averaged scanning lines of the first and third scanning lines are output to an odd field and the fourth and sixth scanning lines are output. The averaged scan lines are output to the even field, and the second and fifth scan lines between them are discarded. The operations from the top to the sixth are similarly repeated for every six scanning lines from this point onward.

FIG. 3 shows a method of reducing the number of scanning lines to 1/4. Averaged scanning lines of the first and third scanning lines are output to an odd field to output the fourth, sixth and fourth scanning lines. 8
The averaged scan lines are output to the even field, and the second, fifth and seventh scan lines between them are discarded. The operations from the top to the eighth are repeated for every eight scanning lines after that in the same manner. The averaging process for the 3rd, 5th, and 7th scan lines in which the scan lines of the even field are formed is to emphasize the information of the scan line located in the middle, that is, the 6th scan line. , The weight applied to the scanning line is heavier than the other two.

In the embodiment shown in FIG. 3, the scan lines of the odd field are formed from the first and third scan lines of the frame, and the scan lines of the even frame are the fourth, sixth and eighth scan lines.
Although the scan lines are formed from the first scan line, the scan lines in the odd field may be formed from the first, third and fifth lines, and the scan lines in the even field may be formed from the sixth and eighth lines.

In summary, the method for reducing the number of scanning lines according to the present invention considers that two fields of input interlaces are stored in a memory and scanning lines are arranged in one non-interlaced frame. When it is desired to multiply the number of scanning lines by 1 / N (N is an integer), the scanning lines are divided into 2N lines in order from the top, and the 2N lines are divided into odd lines by 2 to divide the first half into odd lines. The averaged odd-numbered scanning line is output as the odd-numbered scanning line, and the averaged odd-numbered scanning line in the latter half of the odd-numbered scanning line is output as the even-field scanning line. ing.

[0021]

As described above, according to the present invention, the scanning lines of the odd fields of the input that form a frame are averaged to form the scanning lines of the odd fields of the output, and the scanning of the even fields of the input is performed. Since the lines averaged by each other become the scanning lines of the even field of the output, the movement does not move to the other field at the time of averaging, and therefore, the movement of the reduced screen is averaged and becomes smooth. When a certain scanning line in a frame is discarded, the scanning lines on both sides of the scanning line are always left and the averaged processing is performed for them, so that the input screen can be reduced to a similar shape. In addition, since the center of brightness does not move and there is no processing that spans between fields, it is possible to obtain a reduced screen with high resolution and no unnaturalness of moving images.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a method of reducing an image by half in a vertical direction in a method of reducing the number of scanning lines according to the present invention.

FIG. 2 is an explanatory diagram showing a method of reducing an image to 1/3 in the vertical direction in the method of reducing the number of scanning lines according to the present invention.

FIG. 3 is an explanatory diagram showing a method of reducing an image to 1/4 in the vertical direction in the method of reducing the number of scanning lines according to the present invention.

FIG. 4 is an explanatory diagram showing a conventional method of reducing the number of scanning lines by a factor of 1/2 in the vertical direction.

FIG. 5 is an explanatory diagram showing a conventional method of reducing the number of scanning lines by reducing the image by a factor of 1/3 in the vertical direction.

FIG. 6 is an explanatory diagram showing a method of halving an image in the vertical direction by a second method of reducing the number of scanning lines in the related art.

FIG. 7 is an explanatory diagram showing a method of reducing an image to ⅓ in the vertical direction in a second method of reducing the number of scanning lines in the related art.

FIG. 8 is an explanatory diagram showing a method of reducing an image by a factor of 1/2 in a vertical direction in a third conventional method of reducing the number of scanning lines.

FIG. 9 is an explanatory diagram showing a method for reducing an image by a factor of 1/3 in the vertical direction in a third method for reducing the number of scanning lines in the related art.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 5/66 D 9068-5C // H04N 1/393 4226-5C

Claims (2)

[Claims] 1. It is assumed that interlaced odd-field and even-field scan lines are taken into a memory to form one non-interlaced frame in the memory, and the number of scan lines forming this one frame. 1 / N times (N is an integer), the scanning lines are divided into groups of 2N in order from the top, and within each group, the odd first subgroup and the remaining odd second subgroup are arranged. Divided into
In the first sub-group, odd-numbered scan lines are averaged into odd-field scan lines, and in the second sub-group odd-numbered scan lines are averaged into even-field scan lines. A method for reducing the number of scanning lines characterized in that 2. The method of claim 1, wherein when averaging the odd scan lines, the odd scan lines are equal to three.
A method of reducing the number of scanning lines in which, when there are more than one line, the heavier weight is applied to the scanning line located in the central part of them.