JPS6285591A - Image pickup device - Google Patents

Abstract

PURPOSE:To completely remove a partial noise such as a crystal defective noise by separating a time series read signal into the prescribed color at the time of picking up the image of an object and correcting the defect of a chrominance signal with the aid of its right before chrominance signal in the same color. CONSTITUTION:A color sepating optical system with the prescribed color pattern photographs on a CCD7. The picked-up image is read as a clock pulse from a generator 8 as an accumulation information signal SC and supplied to a sample holding circuit 10. For a means which separates signals read by an image pickup means in time series at every prescribed color, a memory 9 which discriminates the positions of crystal defects in the CCD7 in terms of hue such as R-G-B and Te-G-Cy and stores them is used. The defect of the separated and stored chrominance signal is corrected by the right before chrominance component. In this case, a sampling pulse is stopped at a noise position in the signal SC, and a noise signal is pulled out with a signal one bit before held.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a color solid-state imaging device (hereinafter referred to as COD).
The present invention relates to an imaging device having means for compensating both a luminance signal and a chroma signal for noise caused by crystal defects.

[Conventional technology]

The image capturing means uses a color separation optical system having a predetermined color pattern to optically project an image onto the COD.
Charges are accumulated in a portion under each electrode of the semiconductor substrate constituting the D element, and are sequentially transferred and read out by clock pulses applied to the electrodes. In this case, if crystal defects occur locally in the semiconductor substrate, dark current will increase due to thermal causes, and if the dark current is large when an image is projected and a signal is read out, noise will occur. . In order to remove this noise, conventional methods have been used.

FIG. 3 is a block diagram of a conventional imaging device, in which 1 is a COD, 2 is a sample and hold circuit, 3 is an EE amplifier circuit, 4 is a clock pulse generator,
5 is a scratch memory that stores crystal defects in advance, 6
is a gate circuit, and SQ is a storage information signal.

41M(a) and (b) are waveform diagrams showing the relationship between the sample and hold circuit and the gate circuit for crystal defects; 3 is a diagram showing an output waveform of circuit 6. FIG.

The conventional imaging device is configured as described above, and the position of the crystal defect on the CCD 1 is stored in advance in the memory circuit 5, and the signal read out by the clock pulse from the clock pulse generator 4 is sent to the sample hold circuit 2. However, as shown in Figure 4, in the case of a crystal defect, the gate is not opened and the previous signal of one bit is held and replaced with the signal of that part. be.

[Problem that the invention seeks to solve]

In conventional imaging devices such as those mentioned above, when composing a luminance signal using R, G, B stripe filters, mosaic filters, etc., there is a strong correlation between the signal one bit before and the signal at the defect location. However, when composing a chroma signal, replacing the previous signal with a signal of a different hue means replacing it with a signal of a different hue, so this is a good method for removing defective noise for chroma signals. The problem was that there was no.

The present invention has been made to solve these problems, and aims to provide an imaging device that can completely remove local noise such as crystal defect noise.

[Means for solving problems]

The imaging device according to the present invention includes a means for imaging a subject image through a color separation optical system having a predetermined color pattern, and a separation means for separating signals read out in time series by the imaging means for each predetermined color. and a correction means for correcting defects in the separated color signals using the immediately preceding same color signal.

[For production]

In this invention, a subject image is captured through a color separation optical system having a predetermined color pattern, and signals read out in time series during this imaging are separated for each predetermined color. Defects in the color signal are corrected using the same previous color signal.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention,
FIG. 2 is a waveform diagram showing the relationship between the sample hold circuit and the gate circuit for crystal defects. In the figure, Y is a luminance signal, R, G, and B are each chroma signal, 7 is a CCD, 8 is a clock pulse generator, 9 is a memory that discriminates the position of crystal defects by color discrimination, and 10 is a luminance signal system. 11 is a low-pass filter, 12 is a gate circuit, 13, 14, and 15 are sample and hold circuits provided in the chroma signal system, and the rest are the same as in FIG. 3.

In the imaging device configured as described above, an image is captured on the CCD 7 using a color separation optical system having a predetermined color pattern. This captured image is read out as a stored information signal So using a clock pulse from a clock pulse generator 8. Then, as shown in FIG. 2, the read accumulated information signal So is supplied to the sample and hold circuit 10. Accumulated information signal S.

The part indicated by NG in the middle is noise due to local crystal defects of the C0D7, and the level is particularly high at the charge accumulation point taken out from this part because the dark current is abnormally large. On the other hand, clock pulses from the clock pulse generator 8 are supplied to the gate circuit 12 . As an example of a storage means for separating and storing signals read out in time series by the imaging means for each predetermined color, the positions of crystal defects of C0D7 are stored in advance in R-GB, YeG-
There is a memory 9 that stores images discriminated based on hue, such as CY.

Further, as an example of means for correcting defects in separately stored color signals using the same color signal immediately before, there is the following method. That is, upon receiving the information command pulse from the memory 9, the gate circuit 12 determines from the information and the clock pulse that each sample and hold circuit 13, 14, 15
Supply sampling pulse to. In addition, a sampling pulse as shown in FIG. Stop the sampling pulse, hold the previous signal one bit, and extract the noise signal NG.After removing the noise signal NG, one of the signals is used as a low-pass signal for configuring the luminance signal. One is supplied to a filter 11 and the other is R for color signal composition.
Alternatively, it is supplied to the Ye multiplied signal sample and hold circuit 13, the G signal sample and hold circuit 14, and the B or CM multiplied signal sample and hold circuit 15. Sample and hold circuits 13, 14 and 15 for configuring color signals are connected to gate circuits 12, respectively, as shown in FIG. 2(e).

The sampling pulses shown in (f) and (g) are supplied, and only the R signal is taken out by the sampling pulse corresponding to the R signal to the R signal sample and hold circuit 13.

Regarding the B signal, only the B signal is similarly extracted as shown in FIG. 2(g). For a G signal in which a defective scratch has occurred, the previous state of the same color G signal is maintained at the position of the scratch, as shown in FIG. 2(f). In this way R,G.

Each color signal of B is constructed.

〔Effect of the invention〕

As explained above, the present invention includes an imaging means for capturing an object image through a color separation optical system having a predetermined color pattern, and a signal that is read out in time series by the imaging means and is separated for each predetermined color. Since the groove bottom is equipped with a separation means and a correction means for correcting defects in the separated color signal using the same color signal immediately before, C is applied to each of the Y, R, G, and H signals.
This has the advantage that it can be constructed without noise caused by local crystal defects in the OD.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram showing the relationship between each sample hold circuit and each gate circuit in FIG. 1, and FIG. 3 is a block diagram showing a conventional example.
FIG. 4 is a waveform diagram showing the relationship between the sample hold circuit and gate circuit in FIG. 3. In the figure, 7 is a CCD, 8 is a clock pulse generator,
9 is a memory, 10 is a sample and hold circuit, 11 is a low-pass filter, 12 is a gate circuit, and 13, 14, and 15 are sample and hold circuits. Agent Patent Attorney 1) Haru Kitatake Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] an imaging means for imaging a subject image via a color separation optical system having a predetermined color pattern; a separation means for separating signals read out in time series by the imaging means for each predetermined color;
An imaging apparatus comprising: a correction means for correcting a defect in the separated color signal using the immediately preceding same color signal.