JPS59132293A - Color field discriminating circuit in pal video system - Google Patents

Abstract

PURPOSE:To attain the discrimination of color field of the PAL video system by sampling the presence or absence of the synchronizing signal waveform and a color burst signal around a vertical synchronizing signal. CONSTITUTION:The color burst signal (c), the synchronizing signal (d), the vertical synchronizing signal (e), the sampling pulse (f) and a horizontal synchronizing signal interval measuring data (h) are formed respectively from a video signal (a) and applied to a microcomputer CPU15. Then, the CPU15 checks at first whether or not the vertical synchronizing signal is detected and when it is detected, the CPU15 fetches the pulse signal (c), the synchronizing signal (d), and the measuring data (h) in synchronizing with the sampling pulse (f). Further, the data are compared with the prescribed pattern data of the color field stored in a memory 16. Thus, the color field of the PAL video system is discriminated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color field discrimination circuit in a PAL video system.

Conventional configuration and its problems VTRs are used to record video signals, but
Nowadays, multiple VTRs are often used for editing to create a single program. In the PAL video system, since the signal is in PAL format, it is better to edit by matching the color fields during editing for a more beautiful result. In order to match the color fields, a circuit for determining the color field is first required, but such a circuit did not exist in the past.

OBJECTS OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a circuit for determining color fields in a PAL video system.

Structure of the Invention In order to achieve the above object, the color field discrimination circuit in the PAL video system of the present invention includes sampling means for sampling the presence or absence of a synchronization signal waveform near the vertical synchronization signal and a color burst signal near the vertical synchronization signal;
The configuration includes a microcomputer that determines the color field by taking in the signal sampled by the sampling means and comparing it with fixed pattern data of the color field already stored in the memory.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to drawing C1.

FIG. 1 shows a color field waveform of a PAL video system, which is repeated in sequence from the 4th field, the 8th field, the 2nd field, and the 1st field. Here, arrows (1) and (2) are color burst signals, with phases of +185 degrees and -185 degrees, respectively. A in Figure 1
The period is the vertical synchronization signal part, and the 82μ
There are equivalent pulses at intervals of

Figure 2 is a circuit block diagram of a color field discrimination circuit for discriminating the four types of waveforms shown in Figure 1. ) is the 5YNC separation circuit, (6) is the V-
8YNC separation circuit, (7) is 5YNC falling detection circuit,
(8) is a delay circuit, (9) is a pulse shaping circuit, α is a delay circuit, H is a clock pulse generation circuit, 0 is a digital counter, a is a reference value generation circuit, Q barrel is a digital comparator, 09 is a microcomputer, (11 is a memo)
), <at is a video signal, tb) is a color burst signal signal, (C) is a color burst pulse, (d) is a synchronization signal,
(e) is the vertical synchronization signal, (f) is the sample pulse, (g
) is a counter reset pulse, (h) is H-5YNC interval measurement data, and (i) is color field discrimination data.

The PAL video signal (a) containing the synchronization signal is input to the color burst signal separation circuit (3) and the 5YNC separation circuit (5), and the color burst signal (b) and the synchronization signal @ (d
) is obtained. The color burst signal (b) is waveform-shaped by a color burst waveform shaping circuit (4) to obtain a color burst pulse (C). The synchronization signal (d) is V-
9YNC separation circuit (6) Ni addition error, vertical synchronization signal (e
) is obtained.The 5YNC falling detection circuit (7) detects the falling edge of the synchronizing signal (d), and the pulse () is added to the microcomputer α0 and is added to the delay circuit (IQ, This becomes the counter reset pulse (g). This No. 18 is applied to the reset terminal of the digital counter Q to reset the digital counter (2). The digital counter (2) is always generated by the clock pulse generation circuit (II). The clock pulses counted up are counted up until the reset pulse (g) is input, and the data being counted is outputted to the digital comparator 04.
The output data of the reference value generating circuit OI is compared with the reference value from the reference value generation circuit OI, and if it is smaller than the reference value, it outputs a "low" level, and if it is larger, it outputs a "high" level. digital counter 0
1 continues counting up until it is reset as described above, so measure the number of clock pulses from the previous reset to the next reset, that is, the interval from the falling edge of the synchronizing signal (d) to the next falling edge. become. And H
-5 Output YNC interval measurement data (h). The microcomputer 0Q has a color burst pulse (C), a synchronization signal (d), a vertical synchronization signal (e), and a sample pulse (
f), 11-8YNC interval measurement data (h) are input, and four types of color field discrimination data (D) are outputted by the algorithm shown in FIG.

The microcomputer 01 operates according to the algorithm shown in Fig. 8. First, the V-5YNC (vertical synchronization signal)
If V-5YNC is detected, the color burst pulse (C), synchronization signal (d), and H-9YNC are synchronized with the sample pulse (f).
1 [I import the l-plane measurement data (h).

Next, the operation of field discrimination will be explained with reference to the timing waveform diagram shown in FIG. FIG. 4 is a timing waveform diagram of the color field discrimination circuit, and shows the case of the fourth field. The video signal (a) includes a synchronization signal and a color burst signal in addition to the video signal, and the arrow represents the color burst signal. Also H-5Y
The NC is made up of a 64μ% portion and an 82μth equivalent pulse portion. The circuit shown in FIG. 2 generates a video signal (a
) to color burst pulse (c), synchronization signal (d),
Vertical synchronization signal (e), sample pulse (f), H-8Y
Create NC interval measurement data (1)) and add it to the microcomputer at 9 o'clock. Here, the H-5YNC interval measurement data (h) is the output obtained by comparing the value counted by the digital counter (b) with the reference value, so the reference value should be set between 82μs and 64μ%. By selecting H-5YNCU) 11 as shown in Figure 4 (h)
A pulse is always generated in the long part of the 11th interval. After detecting the vertical synchronizing signal, the microcomputer takes in the data at the point marked Q in synchronization with the sample pulse (f) using the algorithm shown in FIG. FIG. 5(a) shows the collected data, and FIG. 5(b) shows the rearranged data. By the way, since the vertical synchronization signal (e) is generated by integrating the synchronization signal (d), the sample point of one shot moves back and forth due to variations in the integral constant. In order to eliminate the effect of this movement, pay attention to the data obtained by sampling the synchronization signal (d) (see the collected data in Figure 6 (a)), from 0 to 1.
When the change occurs, the data is shifted by °C using the reference point (point A), rearranged (assumed to be 8 samples in this example), and rearranged, resulting in the rearranged data shown in FIG. 6(b).

In PAL, there are four types of patterns from the first to the fourth, and this data is determined by comparing the four types of fixed patterns shown in FIG. The color fields up to this point are determined and output as field discrimination data (i).

As described in detail, according to the present invention, it is possible to discriminate the color field of a PAL video system, and its industrial utility value is extremely large.

[Brief explanation of drawings]

Fig. 1 is a color field waveform diagram of a PAL system, Fig. 2 is a block diagram of a cod field discrimination circuit in an embodiment of the present invention, Fig. 8 is an explanatory diagram of a color field discrimination algorithm, and Fig. 4 is a color field discrimination circuit diagram. FIG. 5 is an explanatory diagram of collected data, and FIG. 6 is an explanatory diagram of a color field fixed pattern. (3)...Color burst signal separation circuit, (4)...
・Color burst waveform shaping circuit, 04e...5YNC
Separation circuit, (6)...V-5YNC separation circuit, (7)
...5YNC falling detection circuit, (8) -...delay circuit, (9)...pulse shaping circuit, Oft...delay circuit,
αυ...Clock pulse generation circuit, 01 River digital counter, O8)...Reference generation circuit, u4...Digital comparator, Cao...Microcomputer, 01
...Memory Agent Yoshihiro Morimoto

Claims (1)

[Claims] l. A sampling means for sampling the synchronization signal waveform near the vertical synchronization signal and the presence or absence of a color burst signal near the vertical synchronization signal, and a signal sampled by the sampling means is taken in and already stored in the memory. A color field discrimination circuit in a PAL video system comprising a microcomputer 6 that discriminates a color field by comparing it with fixed pattern data of the color field.