JPS611186A - Television receiver - Google Patents

Abstract

PURPOSE:To display a picture with high resolution by detecting a signal with low and high correlativity without gradation and controlling whether the same data is read n times or a pseudo signal between scanning lines is generated in the operating processing of a signal converting circuit. CONSTITUTION:A composite picture signal subject to scanning line conversion is fed to a gradation detecting circuit 4, a scanning line converting circuit 3 and a synchronism processing circuit 2. The circuit 4 discriminates whether the signal is a signal (a) with no gradation or a signal (b) with gradation to obtain absolute values (d), (e) of a differentiating signal and the result is fed to a control circuit 5 as a gradation signal. Further, the circuit 2 separates a horizontal and vertical synchronizing signal, a signal N times the horizontal synchronizing signal for scanning line number conversion and a control signal of line memories 9, 10 are fed to the control circuit 5. The gradation signal discriminated by the circuit is fed to an operation circuit 11 of the converting circuit 3 via a switching circuit 12 and the line memories 9, 10. Then the operating processing in the circuit 11 is controlled as to whether the same data is read N times or the pseudo signal between scanning lines is generated to display a picture with high resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a television receiver that uses a storage element to convert a standard television signal into a signal having a horizontal scanning frequency n times higher for display.

Conventional configuration and problems The current standard television system is NTSCPA-compliant.
Although there are methods such as L and S ECAM, the resolution of either method cannot necessarily be said to be sufficient. Especially today, when there is a demand for larger screens, higher resolution broadcasting is required. Therefore, in the near future, it is thought that high-definition broadcasting will be implemented in which the number of scanning lines is about 2 to 3 times that of the current standard system and the bandwidth is about 5 to 10 times. In fact, NHK has 1125 scanning lines, 2 QMHz in the luminance signal band,
K.I.A. (Kloctronic Industry)
The number of scanning lines is 1023, and the frequency of 21.1 MHz in the luminance signal band is specified by the Electronic Industries Association of America.
, B B C have proposed systems with 1501 scanning lines and a luminance signal band of 6 oMHz. During the transitional period of practical application of these new television systems,
It is thought that if a television receiver capable of receiving signals of these systems can also receive standard television signals, it would become more widespread if a television receiver that is so-called compatible could be realized.

Furthermore, in the information age of recent years, there has been an increasing demand for character displays that display alphanumeric characters and characters, and graph ink displays that display diagrams, patterns, etc. as computer terminals. In order to improve the amount of information, these devices have come to be used in which the resolution and number of scanning lines have been increased and the scanning frequency has been set to about twice that of the standard television system. If these display devices are configured to receive standard television signals, they will also be able to receive signals from VTRs and cameras, which will expand the range of applications of the display devices, and is expected to be realized.

In order to create a compatible television receiver, both the standard system and the new system must share circuits, not only for the signal circuit, but also for the deflection circuit, due to the large difference in horizontal scanning frequency. It was difficult to operate the circuit, and it was necessary to switch the circuit using a switching inch, relay, etc. This not only made the circuit more complex, but also caused problems in terms of reliability since parts with high potential were switched. -1 Conventionally, the converters used as converters between systems with different scanning frequencies used a conversion method that matched exactly the scanning frequency to be converted. The configuration was extremely complex, requiring operations such as dropping or adding additional signals.

For this reason, the standard television signal is close to the horizontal scanning frequency of the new television system.

However, in the same application, when a standard format television signal is converted into a signal having a horizontal scanning frequency nearly n times as high using a storage element, the same data is converted from the standard format television signal at n times the speed. Read n times. Therefore, for signals with low correlation or no gradation, such as character signals, image quality can be improved by increasing the number of scanning lines, but compared to standard television signals with gradation, With highly correlated signals, there is a drawback that when the same data is read out n times, the image quality deteriorates at the edges of movement for diagonal images and images with movement.

Purpose of the Invention Therefore, in view of the above points, the present invention improves the arithmetic processing of a signal conversion circuit by reading out the same data n times by detecting a low correlation signal with no gradation and a relatively high correlation signal. It is an object of the present invention to provide a television receiver that can display images with high resolution by controlling whether a pseudo signal is created from data between scanning lines or data between scanning lines.

Structure of the Invention The present invention is a television receiver equipped with a gradation detection circuit for a composite image signal, a scanning line number conversion circuit, and a control circuit. A high-quality image can be projected by sending out the calculated signal if there is a gradation, or the same data if there is not, using the calculation of the number conversion circuit or the output signal of the same data by the control circuit. It is something that can be done.

DESCRIPTION OF THE EMBODIMENTS FIGS. 1, 2, and 3 show a partial configuration of a television receiver according to a first embodiment of the present invention.

In FIG. 1, 1 is a composite image signal input terminal, 2 is a synchronization signal processing circuit, 3 is a scanning line number conversion circuit, 4 is a gradation detection circuit, and 5 is a control circuit. FIG. 2 is a block diagram of the gradation detection circuit 4, in which 6 is a differential circuit, 7 is an absolute value circuit, and 8 is a comparator. FIG. 3 is a block diagram of the scanning line number conversion circuit 3.
9 is a line memory 1, 10 is a line memory 2, and 11 calculation circuits; 12 is a switching circuit 1; 13 is a switching circuit 2; and 14 is a switching circuit 3.

The operation of the first embodiment configured as above will be explained using the waveform diagrams of FIGS. 4 and 5.

First, a composite image signal subjected to scanning line number conversion is supplied to an input terminal 1, and is applied to a gradation detection circuit 4, a scanning line number conversion circuit 3, and a synchronization signal processing circuit 2. The gradation detection circuit 4 determines whether the composite image signal is a signal with gradation. The operation will be explained using FIG. 4. In Fig. 4, A indicates an image signal without gradation, and ^ indicates an image signal with gradation. 7 shows a signal waveform converted into an absolute value. 2 indicates that there is a gradation, and BO indicates that there is no gradation, and the comparator 8 applies it to the control circuit 5 as a gradation detection signal. Here, the comparator 8 determines whether there is a gradation or not based on a predetermined level signal C. Therefore, if a plurality of predetermined level signals C are provided, they are sent to the control circuit 5 as a plurality of gradation detection signals, and scanning line conversion can be performed as a plurality of calculation signals depending on the degree of gradation.

Next, the synchronization signal conversion circuit 2 separates the horizontal and vertical synchronization signals, and also converts the number of scanning lines by N times the horizontal synchronization signal, and further controls the read and write of the line memory 1, and the switching circuits 1 and 2.
．． -3 control signals are sent.

The scanning line number conversion circuit 3 is a signal processing circuit for increasing the number of scanning lines by N times (in this case, it is doubled), and its operation will be explained with reference to FIGS. 3 and 5.

In FIG. 5, A is a composite image signal and indicates a signal every H periods. B and D are line memory 1.9 and line memory 2.
It indicates a write period of 1o and is controlled by the switching circuit 12. C and E indicate the reading period which is twice the writing time, and the OF which performs reading three times for the writing of 1H sequentially reads the line memory 1.2 and is controlled by the switching circuit 13, and the scanning line Indicates that the numerical conversion is processed using the same signal as the previous line, resulting in a converted signal with no gradation. (It is called twice writing) G is the calculation circuit 1 which converts the number of scanning lines.
1, the signal is processed from the upper and lower lines and becomes a converted signal when there is a gradation, and is applied to the control circuit 5. The control circuit 5 controls the F and G signals from the scanning line number conversion circuit 3 when there is no gradation or when there is a gradation, by the detection signal of the gradation detection circuit 4, and converts them into double writing or calculations like the H signal. The mixed signals are mixed and sent out, and supplied to a CRT driving circuit (not shown).
It will be projected. Although only the switching of the H period is illustrated here, it goes without saying that mixing during the H period is also possible.

As described above, according to the present invention, the gradation of the input composite image signal is detected by the gradation detection circuit, the scanning line number conversion circuit and the control circuit are controlled by the detection signal, and the gradation is written twice or calculated. By transmitting the signal as a high-quality video signal without deterioration in image quality, the number of scanning lines can be converted.

The second embodiment of the present invention will be described below with reference to FIG.

This will be explained with reference to FIG. The second embodiment serves as the gradation detection circuit of the first embodiment, and determines whether the input image signal is a binary signal such as a character. For example, it is written twice, and if not, it is calculated and sent from the upper and lower lines. The 24-value detection circuit will be explained below. In FIG. 6, 15 is a binarization circuit, 16 is a difference calculation circuit, and 17
is determined by a binary discrimination circuit. The operation will be explained using the waveform diagram in FIG. The image signal I with the input amplitude E is converted into a binary code by the binarization circuit 15 at a predetermined level 1 (approximately E/2).
In addition to the difference calculation circuit 16, the difference (l I - T I ) between the image signal processing and the binary code (■) is detected and becomes a K signal. Even if the character part is binarized, it is almost the same as the input, so the difference is 0 and is added to the binary discrimination circuit 17. The binary discrimination circuit 17 discriminates the signal as a binary signal if it is smaller than a predetermined level (a value close to ◯) (FIG. 7L). As described above, by using the binary detection circuit of the present invention, the first
Effects similar to those of the embodiment can be obtained.

Effects of the Invention As described above, according to the present invention, it is possible to display high-quality images without deteriorating the sharpness of character signals and the like, and with little image deterioration of signals with gradations.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the main parts of a television receiver according to an embodiment of the present invention, Fig. 2 is a block diagram of a gradation detection circuit of the same receiver, and Fig. 3 is a scanning line number conversion of the same receiver. The block diagram of the circuit, Figures 4 and 5 are waveform diagrams for explaining the receiver, Figure 6 is a block diagram of the binary detection circuit in the gradation detection circuit of the receiver, and Figure 7 is the binary detection circuit of the receiver. FIG. 3 is a waveform diagram illustrating the operation of the extraction circuit. 3...Scanning line number conversion circuit, 4...Gradation detection circuit, 6...Control circuit, 6...Differential circuit, 9...
... 10 line memory, 11 ... Arithmetic circuit, 15
-... Binarization circuit, 16... Difference calculation circuit, 17... Binary discrimination circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3-nb- Figure 4 Figure 5 4 d,, CC,....

Claims (4)

[Claims] (1) A gradation detecting means for determining the gradation of an image signal and a scanning line number converting means for multiplying the number of scanning lines of the image signal by N are provided, and an area or pixel that substantially includes a gradation is 1. A television receiver comprising a control means that performs calculations from pixels and otherwise controls a scanning line number conversion means using the same information as the pixels of the previous scanning line. (2) The television receiver according to claim 1, wherein the gradation detection means differentiates the image signal and determines whether gradation is included or not based on its absolute value. (3) The television receiver according to claim 2, wherein the gradation detection means discriminates between a plurality of gradation levels. (4) The television receiver according to claim 1, wherein the gradation detection means discriminates between binary signals.