JPS5945777A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To reduce the noise generated at a correcting circuit and to increase the S/N ratio of a video signal, by amplifying a video signal including a missing part obtained from a solid-state image pickup device of a color VT camera at the front stage correcting the missing part and attenuating it at the rear stage. CONSTITUTION:The video signal including the missing part obtained from a solid-state image pickup device 11 is amplified into a prescribed level at an amplifier 31. The amplified video signal is corrected for the missing part of the video signal at a correcting circuit 12. The corrected video signal is attenuated to a prescribed level at an attenuator 32 and applied to a signal processing circuit 29 to be a video signal of the prescribed system. The noise generated at the correcting circuit 12 is reduced by amplifying the video signal at the front stage of the correcting circuit 12 and attenuating the video signal at the rear stage. Thus, the S/N ratio of the video signal corrected for the failure is improved and the picture quality is improved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a solid-state image pickup device (1) which is used in, for example, a color television camera, and in particular, to
Correcting the defects in the No. 1 C;

[Technical background of the invention and the interim period (one point)]

In general, a color television camera using a solid-state image sensor (2A) is a photosensitive area of the solid-state image sensor; one image collection called a C smear, white scratch, or black scratch in the video signal corresponding to the defect that occurs. A defect occurs. This defect in the video signal degrades the image quality, so it is corrected. FIG. 1 shows an example of this correction circuit.
C11ar, Llavice), and the photosensitive portion C2 of this solid-state image sensor 11 is provided with a color filter (not shown). From this solid-state image sensor 'tt, a video im signal is output horizontally in accordance with the arrangement order of the color filters, and is supplied to the correction circuit 12.

One line of the video signal output from the solid-state image sensor 11 is shown as the second factor (a), for example.

It is assumed that one pixel (-) not indicated by an arrow has a defect. However, W, 0 corresponds to green (2) within the color filter element of the color filter. The position of the defective portion is the solid-state image sensor 1117J.
This corresponds to the position of the defect that occurred in the photosensitive part, and the video signal always includes the defective part at the same position and is outputted at 0.degree. The signal is supplied to a sample bold circuit 17, which is a high input impedance amplifier. The switch circuit 14 outputs i!(l (
No. 8 (shown in Figure 452 (b)). Therefore, as shown in Ph21(C), the amplifier 16 outputs two pixels in the defective area.
It is output as E number W of the same color.

This output signal is directly connected to the switch circuit 19.20 and the capacitor 21. where it is supplied to a sample and hold circuit (signal removal and synthesis circuit) 23 consisting of a high input impedance amplifier 22;

1) The switch circuit 2θ of No. 11 is connected to R (not shown in the figure)
The switch circuit 19 is switched by the switch 1 (not shown), which is output from the 1 (not shown).
(shown in el) is switched □This switch circuit No. 9 has a
◎Therefore, from the Ail amplifier 22, f'is
The two-color signals W are combined and output. This signal is transmitted to the switch circuit 25. Capacitor 26. Consists of high input impedance amplifier 22→No-pull hold circuit 28ζ
Two supplied. The miJ switch circuit 25 is supplied with a control signal 26 shown in FIG. 2(g) from R (not shown) and is switched by this signal. is shown in Figure 2(b) l
- As shown, an almost normal video No. 4M is output. This signal is supplied to a signal processing circuit 294 and is converted into a video signal corresponding to, for example, N'18C or PAL.

In addition, the control 4J number of the switch circuit (/4179, 20, 25) is preliminarily stored in R (J By the way, in the above configuration, the image output from the solid-state imaging device ii (6
No. 1) R is 8°, noise 1 is N, ・Correction circuit 1
The noise component generated by sampling 2 is N2
, if the noise of the signal processing circuit 29 is Ns, then the output of the solid-state sensor 1 is expressed as S+. Also, the output signal of correction circuit No. 2 is 5→
, N, +N, I) The output of the signal processing circuit 29 becomes 8+, +N2+, and therefore the correction circuit ゛Il! A noise component N of 1°512 is added to the video signal by 10()
% is added (Yunatama), and by supplementing the video signal with the correction circuit 12 (114), it has the disadvantage that the S/N ratio increases. [Purpose]] This was made after the 1st generation of 41'10, a self-width'1 blue entry ('I' is based on the 'I' generated by the circuit that corrects the image signal phase). , J-line is reduced by 1, and the image (Th is the S/N conversion of the bow), L is an attempt to provide the most solid image device portrait. [Calyx] The present invention amplifies a video signal output from a solid-state imaging device to a predetermined level C2 and supplies the amplified signal to a correction circuit.

This correction circuit reduces the noise generated in the correction circuit by attenuating the output video signal to a predetermined level.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention (two examples will be explained with reference to the drawings. The same parts as the first meat are denoted by the same reference numerals and the explanation will be omitted). The video signal containing the defective portion outputted from the circuit 12C is supplied to the amplifier 3) and amplified to a predetermined level (2). This corrected video signal is supplied to an attenuator 32, and after being attenuated by a predetermined level C2, it is supplied to a signal processing circuit 29 (2) to produce a predetermined type of video signal.

Here, the signal components and noise components of the video signal output from the solid-state image sensor 11 are calculated as described in 8. N, Toshi',
The amplification degree of the amplifier 3] is A, and the noise component of the sleeve positive circuit 12 is N.
1. The attenuator of the attenuator 32 is l/A, (; The noise component of the i-th processing circuit 29 is N3. However, it is assumed that there are no noise components of the amplifier 31 and attenuator 32.

Under the above conditions, the video signal output from the solid-state image sensor +II is expressed as 8+, and the output signal of the amplifier 31 is A(8+N,)=AX8+AXN. Also,
The output of the correction circuit 12 (No. 8 is A
A X N H + N 1.

The output signal of the attenuator 32 to which this signal is supplied is (A
S + A X N, + N, ) I X
l/A = 8 + N.

+Ni/A. The output signals of the signal processing circuit 29 to which this signal is supplied are 8 + N, + N, /A + N
.

becomes. As is clear from this, the noise generated by the correction circuit 12 can be reduced by amplifying the video signal at the stage before the correction circuit 12 and attenuating the video signal at the stage after the correction circuit 12. Therefore, the defect-corrected video signal (7J S/N ratio can be 1)
Same as above for image quality.
amplifier,? By applying gamma correction to l and degamma correction to attenuation @:, 32, the dynamic range of the correction circuit 12 can be reduced.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a solid-state imaging device that can reduce the noise generated by the circuit for correcting defects in the video signal and increase the φ ratio of the video signal.

[Brief explanation of the drawing]

In order to explain the correction of a video signal including a defective part outputted from a one-dimensional image sensor, FIG. 1 shows circuit components shown as C1;
II... Solid-state image sensor, 12... Correction circuit, 29.
...Signal processing circuit, si...Amplifier, 32...Attenuator. Applicant's attorney Takehiko Tsuzue

Claims (1)

[Claims] A ti'j single body imaging device that outputs a video converter, and this converter 1
a predetermined level C of the input video signal; a means for amplifying the amplified video No. 46; a circuit for correcting the defective part in the dark; A solid-state imaging device 0 characterized by comprising means for attenuating a corrected video signal to a predetermined level.