JPH0482483A - Ghost elimination device - Google Patents

Abstract

PURPOSE:To discriminate a GCR signal without use of a vertical synchronizing signal and to reduce malfunction at ghost elimination by fetching a video signal for a specific horizontal period to a memory so as to discriminate whether or not the fetched signal is the GCR signal. CONSTITUTION:An inputted video signal from a terminal GR is A/D-converted by an A/D converter 1, inputted to a transversal filter 2 and a waveform memory 4 respectively and an output of the filter 2 is inputted to a CPU 5 via a 1H memory 6. The CPU 5 detects a GCR signal while controlling a set signal of a timing generating circuit 7 so as to move a fetched position by one H each. When the GCR signal is discriminated, the GCR signal is fetched and ghost is eliminated. Thus, even in the case of out of synchronism or unstable synchronization due to at strong ghost, an irregular data is not fetched but the GCR signal is stably fetched thereby preventing malfunction.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ghost removal device that performs ghost removal using a GCR signal.

Conventional Technology The first generation of EDTV broadcasting, which aims to improve picture quality while maintaining compatibility with current television systems, is about to begin, and ghost removal is attracting a lot of attention. Among the requirements for ghost removal performance are image quality evaluation after improvement and removal time. In other words, this means how quickly ghosts can be removed and the amount of ghosts remaining after removal can be reduced.

An example of a conventional ghost canceling device is a ghost canceller reported in "Television Society of Japan Technical Report RE80-6.pp, 9-14, February 1980 J." Ghost detection is performed using the differential signal at the leading edge of the signal as a reference waveform, and the detected ghost signal is used to perform correlation calculations on the time axis and sequentially modify the tap coefficients of the transversal filter. Remove ghosts.

In addition, as a ghost removal device using GCR signals, [
Television Society Technical Report ROF T896, pp, 3
There is a ghost canceller reported in "T~36". This uses a transversal filter in the ghost canceller like the ghost canceller described above, but inputs and outputs of the transversal filter are input to the CPU through memory, and synchronous addition is performed on the field according to the transmission sequence. Performs all ghost removal calculations, including processing in between.

An example of a conventional ghost removal device will be described below with reference to the drawings. FIG. 3 is a schematic block diagram showing the configuration of a conventional ghost removal device. In Figure 3, 5
is CPU, 2 is transversal filter, ■ is A/D
Converter, 3 is a D/A converter, and 4 is a waveform memory.

The operation of the ghost removal device configured as above will be explained. The input video signal is sent to A/D converter 1
The signals are A/D converted and input to a transversal filter 2 and a waveform memory 4, respectively. The input and output of the transversal filter 2 are connected to C through the waveform memory 4.
It is input to PU5. In the first generation HDTV broadcast, Figure 4(a).

The WRB signal and 0 pedestal signal shown in (b) are the same in the sequence of 8 fields of WRB signal → 0 pedestal signal middle WRB signal 0 pedestal signal → 0 pedestal signal → W'RB signal - +0 pedestal signal → WRB signal Sent during the horizontal period. By performing the calculation shown in the first equation below on the signals of these eight fields, the fourth
The signal shown in Figure (C) can be obtained. However, Fn
(n=1 to 8) represents the signal of the nth field. Hereinafter, processing between fields according to the transmission sequence as shown in the first equation will be referred to as field sequence processing.

F=1/4 ((Fl-F5)+ (F6-F2)+
(F3-F7)+ (F8-F4)l・・・・・・(
1) In reality, the signal in Figure 4 (d) is differentiated from the signal in Figure 4 (C).
) is used as a reference signal for ghost detection to perform the following ghost removal calculation. MSE (Mea
n 5quare Error) method or ZF (Z
ero forcing) method, etc., which sequentially correct on the time axis according to a certain algorithm to finally find the optimal tap coefficient. The output signal of the transversal filter is (Ykl, the reference signal is (Rkl)
,) If the difference signal between the output signal of the transversal filter and the reference signal is (Ekl, and the total number of stamps is M+N+1, then the nth disturbance coefficient C(
+)! ``l'' is modified based on the following equation 2 in the MSE method and equation 3 in the ZF method. However, αβ is a coefficient for determining the amount of correction.

((41(11411= (C1l (R) −
α・Z Yk-ilk...(2) k=-N (C4) +PI-11= (Ci) (fi
+ -β·Ei (3) The CPU 5 performs the synchronous addition and field sequence processing shown in the first equation, and then performs the calculation of the second or third equation to repeatedly correct the tap coefficients.

A series of these processes is performed by software, and the processes are repeated until the amount of residual ghost becomes sufficiently small in ghost detection.

In the conventional configuration, data is loaded into the waveform memory 4 using G.
It is fixed to each horizontal synchronization period of 18H and 281H in which the CR signal is inserted.

Problems to be Solved by the Invention However, in the above configuration, data is loaded into the waveform memory using 18H and 18H into which the GCR signal is inserted.
Since it is fixed to each horizontal synchronization period of 281H, if the vertical synchronization shifts or becomes unstable due to strong ghosting, the extraction of the GCR signal will also become unstable, making it impossible to capture the regular GCR signal, resulting in malfunction. There was a problem with this.

In view of the above problems, the present invention provides GC control without using a vertical synchronization signal.
The present invention provides a ghost removal device that can discriminate an R signal and reduce malfunctions during ghost removal.

Means for Solving the Problems In order to solve the above problems, the ghost removal device of the present invention includes a circuit for capturing a video signal of one specific horizontal period into a memory, and a means for determining whether or not the captured signal is a GCR signal. It is equipped with the following.

Effect The present invention has the above-described configuration, so that the G
When data for one horizontal period other than the CR signal is captured, that captured signal is not used for ghost removal, and by searching for a new extraction position of the GCR signal,
Malfunctions during ghost removal can be reduced.

Embodiment Hereinafter, a ghost removal device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a circuit configuration of a ghost removal device in an embodiment of the present invention. In Fig. 1, 1 is an A/D converter for digitally converting the input video signal, 2 is a transversal filter for removing ghosts, 3 is a D/A' converter for analog converting the output video signal, and 4 is a transformer. A waveform memory provided on the input side of the universal filter 2, 5 a CPU, and 6 an IH provided on the output side of the transversal filter 2.
Memory 7 is a timing generation circuit.

The operation of the ghost removal device configured as described above will be described below. The input video signal from the GR terminal is A/D converted by an A/D converter 1 and input to a transversal filter 2 and a waveform memory 4, respectively. The output of the transversal filter 2 is input to the CPU 5 via the IH memory 6. The CPU 5 determines whether the input data is a GCR signal and causes the timing generation circuit 7 to generate a set signal. Timing generation circuit 7
generates extraction pulses of 18H and 281H to the IH memory 6. Thereafter, field sequence processing is performed according to the first equation to calculate the signal shown in FIG. 4(d). The CPU 5 performs a difference with a reference signal held within the preparatory unit to obtain a ghost detection component. Thereafter, the calculations shown in the second and third equations are performed to control the transversal filter.

The operation of the ghost removal device configured as described above will be explained below using FIG. 2.

First, in the first step 8, a search for a GCR signal is performed. By controlling the set signal of the timing generation circuit 7, the GCR signal is detected without moving the capture position by IH.

In step 9, it is determined in each IH whether the signal is a GCR signal or not. Here, the determination is made based on the shape of the WRB and whether it is an 8-field sequence. If it is determined that the signal is a GCR signal, the GCR signal is captured in step 10 and ghost removal is performed. If no GCR signal is detected in step 9, the process returns to step 8 and the capture position is moved by IH.

Effects of the Invention As described above, according to the present invention, there is provided a circuit that captures a video signal of one specific horizontal period into a memory, and a circuit that captures a video signal of one specific horizontal period into a memory, and
By providing a means to determine whether the signal is a CR signal or not, it is possible to stably import the GCR signal without importing irregular data even when synchronization is lost or unstable due to strong ghosting, and malfunctions can be prevented. It can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a ghost removal device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the process flow of the ghost removal device of the present invention, and FIG. 3 is a block diagram of a conventional ghost removal device. , filter, 3...
・D/A converter, 4... Waveform memory, 5...
...CPU, 6...IH memory, 7...
...Timing generation circuit. Name of agent: Patent attorney Shigetaka Awano This is a signal waveform diagram obtained by differentiating one person. 1...A/D converter, 2...Transversal diagram

Claims (1)

[Claims] In a device that performs ghost removal using a GCR signal,
A ghost removal device comprising: a circuit for capturing a video signal of one specific horizontal period into a memory; and means for determining whether the captured signal is a GCR signal.