JPS61128685A - Picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a reasonable picture without enlarging a circuit even if an image pick up element including a failure picture element is used by recording a picture element failure position information on a recording medium and using a drop out compensating circuit to compensate at a side of a reproduction. CONSTITUTION:When an image pick up element 101 contains a failure of an image pick up element, a position information of a failure picture element obtained in a failure detecting circuit 102 is stored in a failure memory circuit 103 before a normal photographing. During a normal photographing, an output signal of the element 101 is processed in a video signal processing circuit 104 and recorded in a recording medium 108 by a recording circuit 106. The failure picture element position information herein is already stored in the circuit 103 and recorded together with the video signal in the recording medium 108. At a reproduction side, when in a drop out compensating circuit 112, a lost section of a video signal is detected and a compensation control signal to the failure picture element position information of the element 101 is outputted from a compensation control circuit 107, a gate circuit 115 is controlled. Thereby, a horizontal scanning signal including the failure picture element signal of the element 101 is replaced by a horizontal scanning signal having no failure picture element signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to pixel defect compensation of an image sensor in an image recording and reproducing apparatus.

Conventional technology For example, 4 Japanese Unexamined Patent Application Publication No. 6
0-128414.

FIG. 3 shows a block diagram of this conventional scratch compensation. In the figure, 301 is an image sensor, 302 is a pixel defect detection circuit of the image sensor, 303 is a storage circuit that stores the output signal of the pixel defect detection circuit 302, 304 is a drive circuit that drives the image sensor and the memory circuit; 305 is a delay circuit that delays the output signal of the image sensor 301; and 306 is the image sensor 30.
1 and the output signal of the delay circuit 305.

The operation of the conventional example configured as above will be explained below. Currently, it is extremely difficult to completely manufacture a solid-state image sensor, and defects occurring in a portion of the image sensor result in scratches on the screen.

Conventionally, in defect compensation, a defective pixel is first detected by a defect detection circuit 302 from an output signal of an image sensor 301 and stored in a defect storage circuit 303. Next, when the subject is imaged during regular photography, the defect position information of the image sensor has already been stored, so when the signal of the defective pixel is output from the image sensor, the gate circuit 306 receives the output signal of the storage circuit 303.
is controlled to replace the defective pixel signal with a normal pixel signal, which is the output signal of the delay circuit 305, thereby performing scratch compensation.

At this time, the normal pixel signal to be replaced with the defective pixel signal is:
The signal must have a high correlation with the defective pixel signal, so a signal 1H period ago is optimal, but this requires a high-bandwidth 1H delay circuit, making the circuit expensive and large. The method shown in 4 is often used.

The method will be explained below. In the same figure, 401~
404 is the same as in FIG. 405 is a sample hold circuit, 406 is a sampling pulse generation circuit, and 407 is a gate circuit that switches and controls the sampling pulse.

Next, its operation will be explained. This method controls the sampling operation of a sample and hold circuit without using a delay circuit. When sampling defective pixel signals,
The gate circuit 407 is activated by the output signal of the defect memory circuit 403.
Sample and hold circuit 4 controls the sampling pulse.
Sampling operation is not performed without supplying the signal to 05. Therefore, as for the defective pixel signal, the previous image sensor output is held as it is, the defective pixel signal is removed, and scratch compensation is performed.

Problems to be Solved by the Invention However, in the above configuration, the defective pixel signal is replaced with a pixel signal on the same horizontal scan, so when the defective pixel is located at the vertical edge of the subject, an image faithful to the subject cannot be obtained. Therefore, if a 1H delay circuit is used to replace the defective pixel signal with a signal that does not include the defective pixel before the 1H scanning period, the circuit will be expensive and large. This was an obstacle to miniaturization of cameras.

In view of the above, an object of the present invention is to provide an image recording and reproducing device that can obtain faithful images without increasing the cost and size of the circuit even when using an image sensor including defective pixels. .

Means for Solving the Problems In order to solve the above problems, the present invention provides a color image sensor,
means for storing pixel defects of a color image sensor; means for recording the stored surface element defect information on a recording medium; and means for reproducing the pixel defect information recorded on the recording medium;
The image recording and reproducing apparatus includes means for replacing a defective pixel signal with a non-defective pixel signal based on the reproduced pixel defect information.

Effect of the Invention According to the above-described configuration, when an image is captured using an image sensor having a pixel defect, the pixel defect information of the image sensor is stored in the defect storage circuit, so this pixel defect information is recorded on the recording medium. However, the recorded pixel defect information can be reproduced on the reproduction side, and the reproduced pixel defect information can be used to convert the defective image signal into a normal image signal using a reproduction circuit.

Embodiment FIG. 1 shows a block diagram of an image recording and reproducing apparatus in a first embodiment of the present invention. In Figure 1, 1
01 is an image sensor, 102 is a defect detection circuit, 103 is a defect storage circuit, 104 is a video signal processing circuit that processes the output signal of the image sensor 101, 105 is an FM modulation circuit, 106 is a recording circuit that records signals, and 107 is a Compensation control circuit, 10
B is a recording medium, 109 is a reproduction circuit, and 110 is a recording circuit 1
06 and a drive circuit for the reproduction circuit 109, 111 an FM demodulation circuit that demodulates the reproduction circuit output signal into a video signal, 112 a dropout compensation circuit, and 113 a 1H delay circuit 114.
is a dropout detector that detects signal loss, 115
is the output signal of the FM demodulation circuit 111 and the 1H delay circuit 113
116 is a reproduction signal processing circuit 117 is an encoder.

The operation of the image recording and reproducing apparatus of the first embodiment configured as described above will be explained below. When the image sensor 1o1 includes a pixel defect, the defect detection circuit 102
The position information of the defective pixel obtained in step 1 is stored in the defect storage circuit 103.

Next, during regular photographing, the output signal of the image sensor 101 is processed by a video signal processing circuit 104, modulated by an FM modulation circuit 105, and then recorded on a recording medium 108 by a recording circuit 106. Here, the defective pixel position information has already been stored in the defect storage circuit 103, and this defective pixel position information is recorded on the recording medium 208 together with the video signal.

On the other hand, on the reproduction side, defective pixel information recorded on the recording medium is read out by the reproduction circuit and inputted to the readout compensation control circuit 107 . By the way, on the playback side, it is a matter of course to provide a dropout compensation circuit to compensate for missing portions caused by scratches on the tape magnetic layer or dust between the tape and the head. Here, the dropout compensation circuit 11
2 will be explained. In the dropout compensation circuit, when the dropout detection circuit 114 detects a missing part of the video signal, it controls the gate circuit 115 to convert the horizontal scanning signal including the missing part to the output signal of the 1H delay circuit 113, which is a signal not including the missing part. is replaced with

By adopting a configuration that controls the gate circuit when this dropout compensation circuit detects a missing portion of the video signal and when the compensation control circuit outputs a compensation control signal corresponding to defective pixel position information of the image sensor. , a horizontal scanning signal including a defective pixel signal of an image sensor can be replaced with a horizontal scanning signal without a defective pixel signal.

As described above, according to this embodiment, the dropout compensation circuit required on the reproduction side can be operated using the defective pixel position information recorded on the recording medium.
A horizontal scanning signal that includes a defective pixel signal can be replaced with a horizontal scanning signal that does not include an adjacent defective pixel signal with a high correlation without providing a special 1H delay circuit for defective pixel compensation.

FIG. 2 is a block diagram of an image recording and reproducing apparatus according to a second embodiment of the present invention. In the same figure, 201 to 206.208
-217 are the same as in FIG. The difference from FIG. 1 is the recording control circuit 207.

The operation of the image recording and reproducing apparatus of the second embodiment configured as described above will be explained below.

First, before regular photographing, pixel defects in the image sensor are detected and defective pixel information is stored.

Next, during normal photography, the defective pixel position information is already stored in the storage circuit, so when recording the horizontal scanning signal including the defective pixel signal on the recording medium, the output signal of the defective storage circuit 203 is used to control the recording. A circuit 207 controls the recording circuit 206 so that no signal is recorded on the recording medium during the horizontal scanning period that includes the defective pixel signal.

On the other hand, on the reproduction side, a dropout compensation circuit is provided as shown in the first embodiment, and a signal reproduced by the reproduction circuit 209 and demodulated by the FM double temperature control circuit 211 is input. In this dropout compensation circuit 212, horizontal scanning including defective pixel signals not recorded on the recording medium is performed by controlling the recording circuit described above, as well as missing portions caused by scratches on the tape magnetic layer or dust between the tape head and the like. - The period is also detected and the same operation as when dropout occurs is performed, and the defective pixel signal of 1H period before is replaced with a horizontal scanning signal that does not include the defective pixel signal.

As described above, according to the second embodiment, the horizontal scanning signal including the defective pixel signal is not recorded on the recording medium using the defective pixel position information, so that the defective pixel signal is detected by the dropout compensation circuit on the playback side. Since the horizontal scanning signal containing the defective pixel signal can be replaced with a horizontal scanning blue signal that does not include the defective pixel signal, it is not necessary to specially record the defective pixel position information on the recording medium or to provide a special 1H delay circuit to compensate for the defective pixel. Without,
A horizontal scanning signal that includes a defective pixel signal can be replaced with a horizontal scanning signal that does not include adjacent defective pixel signals that have a high correlation.

In the above embodiment, dropout compensation was performed after FM modulation, but it goes without saying that it may be performed before FM modulation.
It goes without saying that the method of dropout compensation is not limited to the method of this embodiment.

Furthermore, although the above embodiment has a configuration that includes a defect detection circuit, the configuration is such that a jig and a measuring device are used to detect defective pixels of the image sensor, obtain defective pixel position information, and store this information. Needless to say, it is okay to do so.

Further, in the above embodiment, the defective pixel position information is stored before the regular photographing, but it goes without saying that the defective pixel position information may be obtained and stored during the regular photographing.

As described in detail, according to the present invention, pixel defect position information of an image sensor is recorded on a recording medium, the pixel defect position information is obtained on the playback side, and the playback side performs the necessary dropout. Since a compensation circuit is used, a horizontal scanning signal containing a defective pixel signal can be replaced with a horizontal scanning signal not containing a highly correlated defective pixel signal without the need to provide a special delay circuit for defective pixel compensation. It is possible to obtain images that are faithful to the subject without increasing the size or price of the camera, and its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, and FIGS. 3 and 4 are block diagrams of a conventional example. 101... Image sensor, 102... Defect detection circuit, 103... Defect storage circuit, 104...
...Video signal processing circuit, 105...FM
Modulation circuit, 106... Recording circuit, 107...
... Compensation control circuit, 108 ... Recording medium, 1
09...Reproduction circuit, 111...-FM demodulation circuit, 112...Dropout compensation circuit,
207... Recording control circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person
3 Figure 30f jρ2 4th
figure

Claims (4)

[Claims] (1) A color image sensor, means for storing pixel defects of the color image sensor, means for recording the stored pixel defect information on a recording medium, and reproducing the pixel defect information recorded on the recording medium. and means for converting a defective pixel signal into a normal pixel signal using the reproduced pixel defect information. (2) The means for recording pixel defect information on the recording medium is configured to include a recording control signal generation circuit that uses the pixel defect information to control recording of a signal including the pixel defect on the recording medium. An image recording and reproducing apparatus according to claim 1. (3) The means for converting the defective pixel signal into a normal pixel signal is comprised of means for replacing the horizontal scanning signal containing the defective pixel signal with an adjacent horizontal scanning signal not containing the defective pixel signal. An image recording and reproducing apparatus according to claim 1. (4) means for replacing a horizontal scanning signal containing a defective pixel signal with a horizontal scanning signal not containing an adjacent defective pixel signal;
Claim 3, characterized in that the apparatus is configured to include means for compensating for missing portions of a reproduced video signal reproduced from a recording medium, and compensation control signal generating means for controlling compensation for the missing portions. Image recording and playback device.