JPH0324892A - Image pickup device - Google Patents

Abstract

PURPOSE:To perform the correction of a defective picture element so as not to make a defective flaw prominent by performing the correction of the defective picture element by separating a signal outputted in the color dot sequential system of a solid-state image pickup element to a chrominance signal, and generating a luminance signal and a color difference signal, respectively via a switching circuit. CONSTITUTION:When signal output including defective picture element output as shown in oblique line part in figure (a) is obtained, a sample-and-hold pulse at a corresponding part is eliminated in advance as shown in figure (b), and interpolation(preceding value interpolation) is performed with the output value of a preceding pic ture element with an ordinary interpolation means(a signal obtained with the above operation is a signal S1). Simultaneously, the sampling is performed on even the sample-and-hold pulse shown in figure (d) (the signal obtained with the above operation is a signal S2). Two obtained signals S1 and S2 are inputted to the switching circuit 24, and switching is performed with a switching pulse shown in figure (f), then, the luminance signal Y shown in figure (g) can be obtained. In such a way, the interpolation of the defective picture element can be performed so as not to make the flaw prominent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to an imaging device using a solid-state imaging device such as a CCD. [Prior Art] FIG. 3 is a block diagram showing a schematic configuration of the main parts of a conventional imaging device provided with a COD. As an imaging device for processing CCD signals from a CCD color camera, a structure as shown in FIG. 3, for example, has been proposed. That is, a signal scco from a CCD (not shown) is input to an input terminal 1, sampled by a sample hold circuit 2, and inverted and amplified to become a luminance signal Y. On the other hand, the signal obtained at the same time is also input to the sample and hold circuit 3.4 and sampled to become a color signal, which is then sent to the difference circuit 5 as a color difference signal CR/-C. is obtained. The luminance signal and color difference signal thus obtained are output as a video signal through a matrix circuit, a white balance circuit, and a gamma circuit (not shown). [Problem B to be solved by the invention] In the case of an imaging device having the structure described above, when there is a pixel defect (so-called scratch) on the solid-state image sensor, it is difficult to correct this scratch as it is. there were. In general, pixel defect correction uses previous value interpolation that uses the value of a pixel preceding a defective pixel. However, if a signal output including a defective pixel output as shown in Figure 4A is obtained, the sample and hold pulses at the corresponding location should be removed in advance as shown in Figure 4B, and the output of the previous pixel should be removed. If you try to interpolate using values, you will end up with an output signal like that shown in Figure 4 (c), which means that you will end up interpolating with different color signal output values. Also, if you try to correct the same color using a sample and hold pulse as shown in Figure 4 (2), three consecutive pixels will have the same signal value as shown in Figure 4 (E), which will be very noticeable. There was a problem. The present invention has been made to solve such conventional problems, and it is an object of the present invention to provide an imaging device that can interpolate pixel defects so that scratches are not noticeable. [Means for Solving the Problems] In order to achieve the above object, the imaging device of the present invention includes means for correcting defective pixels by separating the signals sequentially output from the solid-state imaging device into color signals. The apparatus is equipped with a means for generating a slope signal and a color difference signal from each signal after passing through the separation and correction means through a switch circuit. [Function] The imaging device according to the present invention performs color separation on each color signal of the point sequential signal in the output signal of the solid-state imaging device, performs defective pixel correction, and then generates a new luminance signal, and
Since it generates color difference signals, defects are not noticeable. [Example] Hereinafter, an example of the present invention will be described in detail based on FIGS. 1 and 2.

FIG. 1 is a block diagram showing the circuit configuration of one embodiment of the imaging apparatus of the present invention, which uses a complementary color mosaic type CCD. Figure 1. In FIG. 2, reference numeral 20 is an input terminal to which a CCD signal Sccn (FIG. 2A) is supplied from a CCD color camera (not shown), and this input terminal 20 is connected to sample and hold circuits 21 and 22. Sample and hold circuits 21 and 22 are sampling pulse SHPI
(Fig. 2 B) and SHP2 (Fig. 2 2), respectively.
The signal output part of the signal scco is sampled and inverted and amplified. The two signals obtained by sampling by the sample and hold circuits 21 and 22 are turned into a luminance signal Y by the switch circuit 24. On the other hand, the two color signals are simultaneously input to the difference circuit 23, and a color difference signal Cm/-Cts is obtained. The luminance signal and color difference signal obtained in this way are processed by a matrix circuit (not shown).
White balance circuit. It passes through a gamma circuit, becomes a video signal, and is output. Next, the operation of this embodiment will be explained. : When a signal output including a defective pixel output as shown in the shaded area in Figure 52A is obtained, the sample and hold pulses in the corresponding area are removed in advance as shown in Figure 2B, and the normal interrogation method is used. interpolates with the output value of the previous pixel (previous value interpolation) (the signal obtained thereby is S1). At the same time, sampling is also performed using a sample hold pulse as shown in Figure 2 (the resulting signal is S2). Then, the obtained two signals Sl and S2 are input to a switch circuit, and switching is performed using the switch pulse shown in FIG. 2 to obtain the decoration level signal Y shown in FIG. 2, G.

In addition to this embodiment, the sample hold circuit can also be used as a CDS.
(Correlated double sampling) circuit may also be used. In that case, please use the sample and hold circuit shown in Figure 1 21.22.
You can use the S configuration.

[Effects of the Invention] According to the present invention, defective pixels can be corrected without unnecessarily increasing the scale of the circuit and without making the existence of defective scratches obvious.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the imaging device of the present invention, FIG. 2 is a waveform diagram explaining the operation of the device shown in FIG. 1, and FIG. 3 is a conventional imaging device equipped with a CCD. FIG. 4 is a block diagram schematically showing MIi commands of the main parts of the device, and FIG. 4 is a waveform diagram illustrating the operation of the device shown in FIG. 3. In the figure. 20: Input terminal 21.22: Sample hold circuit 23: Differential circuit 24: Switch circuit

Claims (1)

[Claims] A means for correcting defective pixels by separating the signals sequentially output from the solid-state image sensor into color signals, and a means for correcting defective pixels by separating the signals sequentially output from the solid-state image sensor into color signals, and converting each signal after passing through these separation/correction means into a luminance signal and a color difference signal through a switch circuit. An imaging device characterized by comprising means for generating a signal.