JP2881436B2 - Television signal format converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention converts the format of a high-definition television signal having an aspect ratio different from that of a standard color television signal, and converts the high-definition television signal with a current standard color television receiver. The present invention relates to a television signal format converter that can receive a television signal.

(Prior Art) The standard system of color television is configured such that the aspect ratio, which is the ratio of the screen length and width, is 4: 3.
The number of scanning lines is 525 for the NTSC system, and 625 for the PAL and SECAM systems. In contrast, high-definition television broadcasting, the next-generation television broadcasting system, requires approximately twice the number of scanning lines as the current color television system. Also has a long screen configuration.

For example, in the HDTV developed by NHK, the number of scanning lines is 1
It has a value of 125 lines and an aspect ratio of 16: 9.

However, since this high-definition television broadcast cannot be received by a television receiver for the current broadcasting system as it is, the high-definition television signal is converted into a standard format signal by scanning lines and received by the current television receiver. A method conversion device that enables this is required. At that time, a problem is a difference in aspect ratio between a high definition television signal and a standard television signal. Therefore, the following three methods have been considered as screen processing when a high-definition television signal is projected on a current television receiver. The first method is a method of cutting and removing both ends of a horizontally long high-definition television image to make the aspect ratio 4: 3, as shown in FIG. 3A. 3 Figure B
As shown in FIG. 3, a high-definition television image is compressed in the horizontal direction to make the aspect ratio 4: 3, and the third method is not only for the horizontal direction, as shown in FIG. In this method, the image is also compressed in the vertical direction and fitted into a 4: 3 screen while maintaining the aspect ratio of the original high-definition television image. At this time, no image exists above and below the screen.

Here, the first method among the above three methods will be described. FIG. 4 is a block diagram when a high-definition television signal is projected on a current standard television receiver.

The high-definition television signal is input to the high-definition television signal input terminal 7, and the number of scanning lines is made the same as the current television signal by the scanning line conversion circuit 8. Then, the scanning line-converted signal is taken into the memory circuit 9, written by the address generation circuit 10, and read addresses are appropriately given to obtain an image having both ends cut as shown in FIG. 3A. it can.

(Problems to be Solved by the Invention) However, the above three methods have the following problems, respectively. First, the method of FIG. 3A has a problem that information at both ends in the horizontal direction of the screen is lost. Although there is not much effect because it is at both ends of the screen, for example, a display such as a score, the number of times, and an out-count may be displayed at both ends in a baseball broadcast. In such a case, inconvenience occurs. In the method of FIG. 3B, the information is not lost as in the method of FIG. 3A, but the image is vertically long and unnatural. In addition, in the method of FIG. 3C, all information on the screen can be displayed while maintaining the feeling of the original image, but since there is no image at both the upper and lower ends, such usage has been performed for a long time. Then, there is a possibility that the mold may remain on a display device such as a cathode ray tube.

In view of the above problems, the present invention compensates for a lack of image information due to a difference in aspect ratio when a high-definition television signal is converted to a scanning line and projected on a current standard television receiver by a simple method. It is intended to provide a television signal format conversion device capable of performing the above-mentioned operations.

(Means for Solving the Problems) In order to solve the above-described problems, the present invention relates to a method of scanning a standard television signal by changing the number of scanning lines of a high-definition television signal input to a high-definition television signal input terminal. A scanning line conversion circuit for converting the number of lines, a memory circuit for storing an image signal subjected to the scanning line conversion in the scanning line conversion circuit, and outputting an image signal in an addressed projection range from a conversion signal output terminal; An address control circuit for arbitrarily setting a horizontal projection range with respect to the image signal stored in the memory circuit; and an address control circuit for assigning an address to the image signal stored in the memory circuit. An address generation circuit for specifying an address of a horizontal projection range, the horizontal projection range being addressed by the address generation circuit. The surrounding image signal is compressed in the horizontal direction and projected on the screen of a standard television.

(Operation) According to the above configuration, when projecting a high-definition television signal having an aspect ratio different from that of the standard television system to a standard television receiver, the position where the screen of the high-definition television is captured can be arbitrarily set. You can select, compress horizontally and project it on a standard television, and see all necessary information on the screen.

(Embodiment) Hereinafter, a television signal format converter according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram of a television signal format converter according to one embodiment of the present invention. In FIG.
1 is a high-definition television signal input terminal, 2 is a scanning line conversion circuit for converting a high-definition television signal into the number of scanning lines of a standard television signal, 3 is a memory circuit for storing signals converted by scanning lines, and 4 is An address generation circuit for controlling the memory circuit, 5 is an address control circuit for controlling the address generation circuit, and 6 is a conversion signal output terminal.

The television signal format converter configured as described above will be briefly described.

The signal converted by the scanning line conversion circuit 2 is taken into the memory circuit, and the address generation circuit 4 is controlled by the control signal of the address control circuit 5 so as not to be compressed in the horizontal direction. The output range is as shown in FIG. 2A. This projection range is the same as the conventional one. Further, as shown in FIG. 2B, in order to project only a necessary portion, the address generation circuit 4 is controlled by a control signal of the address control circuit 5 so as to compress the above portion in the horizontal direction. The required portion is compressed in the horizontal direction by the control signal of No. 4 and projected on a standard television. Also, the entire screen of high-definition television,
As described above, the image is compressed in the horizontal direction and projected on a standard television. As described above, it is possible to freely compress a required portion of a high-definition television screen in the horizontal direction and project the screen. Although FIG. 2A is usually sufficient, the present invention can also display the necessary part with the missing information in the horizontal direction, and can display with the minimum horizontal compression. is there.

As described above, according to the present embodiment, the projection range of the image of the high-definition television can be freely switched easily simply by controlling the address circuit.

(Effects of the Invention) As described above, according to the present invention, the horizontal projection range of the image signal stored in the memory circuit is equivalent to the screen of a high-definition television at maximum by the address control circuit, and is minimized by the address control circuit. It can be set arbitrarily within the range equivalent to the screen of a standard television, and the information projected simultaneously on the left and right ends of the screen of a high-definition television minimizes the horizontal image compression as much as possible. , While minimizing the unnaturalness of the image projected on the standard television screen,
It has the effect of being able to see it.

[Brief description of the drawings]

FIG. 1 is a block diagram of a television signal format converter according to an embodiment of the present invention, FIG. 2 is an example of a display screen thereof,
FIG. 3 is an example of a conventional display screen, and FIG. 4 is a block diagram of a conventional television signal format converter. 1,7 high-definition television signal input terminal, 2,8 scanning line conversion circuit, 3,9 memory circuit, 4,10 address generation circuit, 5 address control circuit, 6,11 …… Conversion signal output terminal.

Claims (1)

(57) [Claims] A scanning line conversion circuit for converting the number of scanning lines of a high-definition television signal input to a high-definition television signal input terminal into the number of scanning lines of a standard television signal, and a scanning line in the scanning line conversion circuit. A memory circuit for storing the converted image signal and outputting the image signal in an addressable projection range from a conversion signal output terminal; and a horizontal image display for the image signal stored in the memory circuit. An address control circuit for arbitrarily setting an output range; and an address generator for assigning an address to the image signal stored in the memory circuit and specifying an address of a horizontal projection range set by the address control circuit. Circuit for horizontally compressing the image signal in the horizontal projection range addressed by the address generation circuit, and A television signal format converter, which is displayed on a screen of a revision.