JPS5928113B2 - solid color television camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to moire prevention in solid state color television devices.

If the checkered pattern filter shown in Figure 1 is attached to the front and the subject is photographed using a solid-state image pickup plate, then when scanning the n number, Figure 2 a
, the green 0 signal and red [F] signal shown in b are obtained, and (n+l
)-th scan, the blue (B) signal and G signal shown in FIG. 2c and d are obtained.

The signal obtained in the nth scan is delayed by one horizontal scanning time using a delay line and added to the signal obtained in the n+1st scan, or the nth and (n+l)th lines are read out simultaneously. When the signals shown in FIG. 2 a and d are added by a method such as adding the signals shown in FIG. 2, the signal shown in FIG. 2 e is obtained. The signal in Figure 2e has a waveform sampled at a higher frequency than the signals in Figures a and d. As is well known, a sampling waveform has a low-frequency component of the signal and a sideband component that folds around the sampling frequency, and when the low-frequency signal is extracted with a low-pass filter, the sideband component becomes moiré and gets mixed in. do. Therefore, moiré can be reduced if the sampling frequency is high. For the reasons mentioned above, Figure 2 e (7
) The G signal has less moiré than the a and d signals, and can provide a high resolution signal. Now, when creating an NTSC composite color signal using the three primary color signals shown in Figure 2 b, c, and e, the luminance signal of the NTSC system is G3R, B 0.59:0.
．． Since it is mixed at a ratio of 30■011, ■)■O, 59
G (wo) + O, 30R (wo) + O, IIB (wo)...
...(1).

However, Y (the) is a luminance signal, G (the), R (the), B(
) are G, R, and B signals. In equation (1), G(
) is a signal with little moiré as mentioned above, but R(
) and B(a) have a lower sampling frequency than G(a) and contain more moiré.

Therefore, Y is also a signal with a lot of moiré, which deteriorates the resolution of the reproduced image. However, R
B (a) are in an inverted phase relationship with each other as shown in Figure 2 b and c. When V, R (a), and B (a) exist at the same time, n
By adding both the signals on the th and (n+1)th scanning lines, it is possible to reduce moiré as in the case of the G signal shown in FIG. 2e.

The present invention has been made in view of this point, and its purpose is to provide a solid-state color television camera with extremely little moiré.The main points thereof are as follows.

That is, in the present invention, when synthesizing a volatility signal from the output signal of a solid-state image pickup plate equipped with a checkered pattern filter as shown in FIG.
For example, Y(t)-0.60G(t)+0.20R(t)
+0.20B(t) ・・・・・・(2) Add the three color signals at the ratio shown, that is, R(t) of the nth scanning line and B(t) of the n+1th scanning line with the same weight. However, it is an attempt to reduce the moiré component of the luminance signal.

A typical subject is an image that most likely contains R, G, and B at the same time! ). There are almost no objects in nature that have only R or only B, and in many cases the R and B components are approximately equal to Y.

For this reason, most subjects' R(t) and B(t
) is approximately equal to Y. On the other hand, in the filter arrangement shown in FIG. 1, the phases of the output signals R(t) on the n-th scanning line and BB(t) on the n+1-th scanning line are out of phase by half a period, so the output level is low! If the weights related to equal R(t) and 8t are made equal to 7 and added, it will be as if the sampling frequency were doubled. Therefore, the effect of reducing moiré is produced. However, since the present invention only changes the weight of the matrix circuit in the conventional configuration circuit of the NTSC system, the circuit configuration is not particularly illustrated.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams for explaining the present invention.

Claims (1)

[Claims] 1. When adding the R signal, G signal, and B signal on two scanning lines from a solid-state image pickup plate with a checkered pattern filter disposed in front thereof to obtain a luminance signal, the above R signal on the nth scanning line and the n+1th A solid-state color television camera characterized in that the weights of the B signals on the scanning line are the same.