JPH02288693A - High definition/standard television converter - Google Patents

Abstract

PURPOSE:To reduce the scale of the circuit and to facilitate large scale circuit integration by reducing the interpolation processing to the constitution required for converting a MUSE signal into a standard television signal in the case of decoding the sent MUSE signal and adopting such a configuration that a filter processing in common use of the scanning line conversion is in use. CONSTITUTION:A MUSE signal subjected to MUSE signal encoding and sent at the sender side is converted into a digital signal at an A/D converter 1 and subjected to de-emphasis processing at a de-emphasis filter 2. In the case of decoding the signal, the constitution is reduced to that required for converting the signal into a standard television signal (NTSC signal) in the interpolation processing and an interpolation filter 4 is formed for aiming at the filter processing used for a vertical direction low pass filter applying in-field interpolation processing to the MUSE signal and the vertical direction low pass filter for converting the scanning line in common. Thus, the scale of the circuit is reduced and large scale circuit integration is facilitated.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a conversion device for converting a high-definition television signal into a standard television signal, and particularly to a conversion device that simplifies the interpolation process used at that time. The present invention relates to a conversion device with a dimensional low-pass filter.

(Summary of the Invention) The present invention relates to a conversion device for converting a high-definition television signal, such as a MUSE signal, into a standard television signal, such as an NTSC signal. The structure is devised so that the hardware can be easily converted to convert the number of scanning lines from a book to 525 lines.

In this way, the converter can be made small and simple, and the L
SI becomes easier.

(Prior art) A MUSE signal (Multiple Sub-Ny
When attempting to convert a high-definition television signal, typically represented by quistSampling(coding), to a standard television signal, represented by an NTSC signal,
The first method is to completely decode the MUSE signal encoded on the transmitting side for band compression on the receiving side.
It is conceivable to restore the high-definition television signal of 125 lines/30 frames and convert it to a standard television signal.

In addition, since the above-mentioned decoder originally has a complicated configuration, the inventors of the present application have proposed a second method that is simplified for the purpose of converting the device, as described in the separate literature, Izumi et al., MUSE method reception standard method adapter, television John Society Technical Report, TEBS 99-5. pp, 21-26, Showa 5
It was announced on September 20, 2009. In the second method, intra-field interpolation processing is performed using only a two-dimensional filter, followed by scanning speed conversion for scanning line number conversion, and motion detection signals are used to turn interframe interpolation on and off. We are currently converting the configuration. For details, please refer to the above-mentioned television technical report.

Furthermore, regarding the encoding and decoding of MUSE signals, see the literature, Ninomiya et al. Development of MUSE method, NHK Technical Research, Vol. 39, N002, pp. 18-53.19
See 87.

(Problems to be Solved by the Invention) Now, in the first method described above, the transmitted MUSE signal is once decoded into a high-definition television signal with a number of scanning lines of 1125, and then the number of scanning lines is converted. In this case, the circuit scale for interpolation processing for decoding before conversion is too large, and there are parts that can be considerably simplified as a conversion system device. Furthermore, the conversion device described in the above-mentioned television technical report also requires a frame memory and a motion detection circuit, and the circuit size is L.
Considering the problem of SI, there is still a need for simplification.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an economically useful high-quality/standard television conversion device by simplifying the circuit scale when implementing such a conversion device into an LSI.

(Means for Solving the Problem) In order to achieve this object, the high-definition/standard television conversion device of the present invention receives a high-definition television signal transmitted after being compressed in a motion-compensated multiplex subsampling band. In a conversion device that converts into a standard television signal,
A two-dimensional interpolation low-pass filter used for conversion resamples the transmitted high-definition television signal and then holds the resampled value at its previous value to make it a carrier null. a vertical low pass that doubles as a horizontal low pass filter and a vertical filter used for scan line thinning to convert the number of scan lines of the high definition television signal to the number of scan lines of the standard television signal; The device is characterized by comprising a filter.

(Function) As described above, according to the present invention, the transmitted MUSE
When decoding the signal, the interpolation processing circuit is narrowed down to only the configuration necessary to convert it into a standard television signal (NTSC signal), and a vertical low-pass filter that performs intra-field interpolation processing on the MUSE signal. Since the configuration incorporates filter processing that can also be used as a vertical low-pass filter for converting the number of scanning lines, the circuit scale can be reduced and it can be easily integrated into an LSI.

(Examples) The present invention will be described in detail below by way of examples with reference to the accompanying drawings. FIG. 1 shows the overall configuration of an embodiment of the conversion device of the present invention.

The MUSE signal encoded and transmitted on the transmission side
If the transmission system is a group transmission system, the USE signal is pre-emphasized and transmitted, so the received MUSE signal is
After being converted into a digital signal by a /D converter 1, it is subjected to de-emphasis processing by a de-emphasis filter 2.

The technology up to this point is similar to the technology disclosed in the ordinary MUSE decoder and the aforementioned Television Society technical report, and this part is not an essential part of the present invention.

FIG. 2 shows the configuration of this de-emphasis filter 2. After passing through the inverse non-linear processing circuit 21, the digital llzMUsE signal is subjected to transversal filter processing and de-emphasis processing in the following stages. In this figure, each small block of block 22 is a one clock delay circuit and is equal to (DQ). The numbers written in the small blocks indicate the coefficients to be multiplied after each signal is delayed by one clock, and the signals to which the coefficients have been added are outputted downward in each small block. It is also assumed that the addition coder in FIG. 2 also includes an operation in which the addition is divided by two. Also, A in the same figure? 1. The purpose of FM switching is to switch between pre-emphasis processing, since only FM transmission is pre-emphasized and static transmission is not emphasized.

Now, returning to FIG. 1, the digital signal processed by the de-emphasis filter 2 is then subjected to two-dimensional filter processing for signal interpolation by the interpolation filter 4, but before that, in this example, the digital signal is processed by the speed converter 3. It undergoes preprocessing for scanning line number conversion. That is, in this speed converter 3, the sampling frequency of 16.2 Hz for MUSE is converted to 5.67 MHz for NTSC. However, in this converter 3, the state of 1125 scanning lines/frame remains unchanged.

The conversion of the number of scanning lines from 1,125 lines to 525 lines is performed by the following processing by the interpolation filter 4.

A more detailed block diagram of the interpolation filter 4 is shown in FIG. FIG. 3 shows an example in which the input signal is converted into two phases by a serial-to-parallel converter 41 in advance and guided to the speed converter 3 in order to reduce the speed of this processing and separate the two color signals that have been multiplexed and transmitted line-sequentially. The outputs of the illustrated circuit are a luminance signal Y and two color signals R-Y and B-Y, respectively.

In the subsample shifter 42 of the third illustrated interpolation filter, the signal is resampled again and the resampled value is held as the previous value. When the previous value is held, it becomes a horizontal low-pass filter with a carrier null characteristic for 5inx as shown in FIG. 4(d). In this case, the carrier is 16.2Mtlz before speed conversion and 5.67MHz after speed conversion.

The vertical low-pass filter of this interpolation filter 4 is a carrier-null filter like the horizontal low-pass filter, and the sample point uses the subsample shift value of the current line, and the non-sample point uses the subsample of the upper and lower lines. It can be configured by switching and using the shift value (switch 44).
(See the top circuit in Figure 3). Here, the carrier is not made completely null, but a coefficient that is also used for the scanning line number conversion shown in FIG. 5 is used. This will be understood by comparing the coefficients calculated by the circuit shown in FIG. 3 with the coefficients shown in FIG. Note that in FIG. 3, the addition coder also includes an operation that is divided by 2 after addition, and block 43 is a one-line delay device.

The signal processed by the interpolation filter 4 has also undergone scanning line number conversion. A schematic diagram showing this situation and each coefficient to be multiplied is shown in FIG. The luminance signal Y is converted by interlaced scanning using three lines (scanning lines) above and below (see Figure 5 (a)), and the color signal C is converted by interlaced scanning using two lines (scanning lines) above and below (see Figure 5 (b)). ), B-Y performs interpolation using three upper and lower lines (see FIG. 5(C)).

Note that in this diagram, it is stated that 1125 lines are converted to 525 lines, but in order to match the number of lines, 105 lines are converted.
It is necessary to change the number from 0 lines to 525 lines, and if necessary, the speed converter 3 may output 1050 lines/frame.

There is no need to particularly explain the other blocks 6 to 10 shown in the first figure, so they will be omitted.

(Effects of the Invention) As described in detail above, according to the conversion device of the present invention, a high-definition television signal transmitted by band compression multiplexed subsampling value type, represented by the transmitted MUSE signal, can be converted into an NTSC signal. When converting to a typical standard television signal, the interpolation process is reduced to only the configuration necessary for converting to the standard television signal, and the configuration also incorporates filter processing that can also be used for scanning line number conversion. Therefore, the circuit scale can be reduced and it can be easily integrated into an LSI.

[Brief explanation of drawings]

FIG. 1 shows an overall configuration block diagram of an embodiment of the conversion device of the present invention, FIG. 2 shows the configuration of a de-emphasis filter, and FIG. 3 shows a two-dimensional low-pass filter for the interpolation filter of the present invention. 4 shows the filter characteristics due to subsampling thick, and FIG. 5 shows an example of the coefficients of the line number conversion filter of the present invention. 1...-A/D converter 2... De-emphasis filter 3... Speed converter 4... Interpolation filter 5...
...D/A converter 6...Inverse matrix circuit 7
... PLL circuit 8 ... Control signal decoder 9 ... Audio decoder 21 ... Inverse nonlinear processing circuit 22 ... Delay and coefficient multiplication circuit 41 ... Serial-to-parallel converter 42 ... Subsampling shifter 43 ...1 line delay device

Claims (1)

[Scope of Claims] 1. A conversion device that receives a high-definition television signal that has been transmitted through motion compensation multiplex subsampling band compression and converts it into a standard television signal, comprising: a horizontal low-pass filter in which the interpolated two-dimensional low-pass filter resamples the transmitted high-definition television signal and then holds the resampled value as a carrier null; It is characterized by comprising a vertical low-pass filter that also serves as a vertical filter used for scanning line thinning to convert the number of scanning lines of the high-definition television signal to the number of scanning lines of the standard television signal. High definition/standard television conversion equipment. 2. The apparatus according to claim 1, characterized in that a speed converter serving as a preprocessing role for converting the number of scanning lines is placed in front of the two-dimensional low-pass filter to reduce processing speed. High definition/standard television conversion equipment. 3. In the apparatus according to claim 1 or 2, a two-phase converting means is provided in front of the two-dimensional low-pass filter in order to reduce the processing speed and simultaneously separate the color signals that have been multiplexed and transmitted line-sequentially. A high-definition/standard television conversion device featuring: