JPH0686206A - Electronic still camera - Google Patents

Abstract

PURPOSE:To obtain an image with high quality even when a defect exists in a CCD image sensor picture element when a still picture is obtained by an electronic still camera. CONSTITUTION:The still picture with high quality can be obtained by recording a defective picture element address, etc., at every CCD image sensor 5 on a ROM individually in advance, reading out the defective picture element address, etc., when IC card memory 16 is loaded on the electronic still camera, and performing correction at a defect correction processing circuit 15F based on the defective picture element address read out from the IC card memory 16 in reproduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an electronic still camera which records a still image picked up by a solid-state image pickup device such as a CCD on a recording medium such as an IC card.

[0002]

2. Description of the Related Art A so-called electronic still camera of the type in which an image pickup signal output from a solid-state image pickup device is converted into a digital signal and recorded in a semiconductor memory, a magnetic disk or the like is known, for example, US Pat. No. 4,131,919. Is disclosed in.

FIG. 6 shows an example of such a conventional digital electronic still camera. In FIG. 6, 101 is a lens, 102 is a diaphragm, 103 is a half mirror for guiding an image to a finder, 104 is an optical low-pass filter, 105 is a CCD image sensor, and 106.
Is a drive circuit of the CCD image sensor 105. 10
Reference numeral 7 is a processing circuit for performing video signal processing on the image pickup output signal obtained by the CCD image sensor 105, and 108 is a sample hold circuit for sampling and holding the image pickup output signal subjected to the video signal processing by the processing circuit 107.
An AD converter 9 digitizes the image pickup output signal sample-held by the sample-hold circuit 108. Reference numeral 110 is a latch circuit 111 for latching the image information digitized by the AD converter 109, and reference numeral 111 is a digital memory for storing the image information latched by the latch circuit 110. Reference numeral 112 denotes a magnetic disk for storing still image information stored in the digital memory 111, 1
Reference numeral 13 is a release switch for taking a still image by the CCD image sensor 105, and 114 is a timing control circuit for controlling the operation of these circuits.

[0004]

In the conventional electronic still camera, the main purpose is to display a photographed image on a home television receiver, and the CCD image sensor 105 has about 400,000 pixels. Therefore, it was incomparable to compare it with a photograph taken by a conventional silver halide camera. Further, the magnetic recording disk may have a recording density corresponding to the pixels of the CCD image sensor 105, and the recording capacity is extremely limited due to the necessity of downsizing the disk. However, the recent development of the image sensor is remarkable, and the number of pixels of the CCD image sensor 105 is 2 to 30 million.
With the advent of IC cards and the like, which have reached the capacity of 0,000 pixels and have a small recording medium and large capacity, it has become possible to obtain image information with high resolution.

When the number of pixels of the CCD image sensor is increased to 2 to 3 million in this way, even if there are some defects in a predetermined pixel of the CCD image sensor due to a problem such as a yield at the time of manufacturing, the CCD image sensor can be used as a CCD image sensor. May be used.

When a CCD image sensor having such defective pixels is used in an image pickup system such as a camera-integrated VTR, the CCD image sensor used in the camera-integrated VTR at the time of factory shipment of the camera-integrated VTR. 5
The pixel defect information of No. 1 is written and stored in the ROM, the information is read out, and the correction operation is performed in real time when a moving image is captured by the camera-integrated VTR.

That is, in a camera-integrated VTR or the like, pixel defects of the CCD image sensor can be corrected by sample hold or the like, but since it is a moving image, these correction processes must be performed in real time at the time of image capturing.
Since complicated and time-consuming interpolation processing and the like cannot be performed, improvement of the image information of the defective pixel portion cannot be expected.

The present invention is intended to provide an electronic still camera which solves the above problems, and an object thereof is to provide a CCD image sensor having a defect when a still image is taken by the electronic still camera. Even if it is used, the defect of the CCD image sensor is not corrected at the time of recording, and the correction process is performed for a sufficient time at the time of reproduction, so that a high quality image can be obtained.

[0009]

As shown in FIG. 1, an electronic still camera according to the present invention converts a picked-up image signal picked up by a solid-state image pickup device 1 into digital data and is a removable recording medium 16. In the electronic still camera that is written in the recording medium, the individual information of the solid-state image sensor 1 is recorded on the recording medium 16
The electronic still camera is characterized in that the recording means 15R for recording the information and the individual information of the solid-state image sensor 1 are reproduced from the recording medium 16 to obtain a high quality image.

[0010]

According to the electronic still camera of the present invention, individual information such as defective data of the CCD image sensor is written in the ROM or the like in advance at the time of factory shipment, and this individual information is stored in a recording medium such as an IC card together with the image information. Since image information and individual information are read from this IC card during recording and reproduction and interpolation processing or the like is performed on defective pixels, a high quality image can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electronic still camera according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an electronic still camera 1 according to the present invention.
It is a systematic diagram which shows the structure of an Example. In FIG. 1, 1 is a lens, 2 is a diaphragm, 3 is a half mirror for guiding an image to a finder, 4 is an optical low-pass filter, 5 is a CCD image sensor of, for example, 2 million pixels, and 6 is a drive of the CCD image sensor 5. Circuit. Reference numeral 7 is a processing circuit for performing video signal processing on the image pickup output signal obtained by the CCD image sensor 5, 8 is a sample hold circuit for sampling and holding the image pickup output signal subjected to the video signal processing by the processing circuit 7, and 9 is a sample. AD for digitizing the imaging output signal sampled and held by the hold circuit 8
It is a converter. As the sample hold circuit 8 and the AD converter 9, general-purpose integrated ones are used. Reference numeral 10 is a latch circuit for latching the image information digitized by the AD converter 9, and 11 is a digital memory for storing the image information latched by the latch circuit 10. An image compression processing circuit 12 performs data compression processing such as block coding on the still image information stored in the digital memory 11. 13 is a CCD
A release switch for taking a still image by the image sensor 5, and a timing control circuit 14 for controlling the operation of these circuits. Reference numeral 15 is an individual information recording circuit.

The individual information recording circuit 15 has a memory such as a ROM that stores individual information. The individual information recording circuit 15 is constructed as shown in FIG. 2 in the recording system. First, Figure 2
The electronic still camera side of the recording system will be described below.

The individual information recording circuit 15 shown in FIG.
The OM 15A is provided, and the output of the ROM 15A is output to the removable IC card memory 16 via the IC card interface 15B. Of course, the IC card interface 15B is supplied with image-processed data from the CCD 5 side in FIG. 1 via the data compression circuit 12 and written in the IC card memory 16.

In the ROM 15A, the address 23A of the defective pixel in the pixels of the CCD image sensor 5 used at the time of factory shipment of this electronic still camera or the address of the pixel having dark noise (fixed scratch) in the pixel is stored. Pixel defect information such as level 22B (hereinafter referred to as individual information) is written. Others A in this ROM as necessary
Additional information such as conversion characteristics of the / D converter 9, presence / absence of compression method of digital image information, gamma characteristics, transfer rate of image information, presence / absence of audio information, characteristics of audio noise reduction circuit, and the like are written as predetermined digital information.

Of course, in the electronic still camera of the present invention, an IC
Instead of the card memory 16, a memory such as a magnetic disk device, an optical disk device, or an optical recording card device can be used.

In the above-mentioned electronic still camera, when the plug of the IC card memory 16 is inserted into the jack of the electronic still camera, the individual information, which is the defect information of the pixel in the ROM 15A, is transferred to the I card via the IC card interface 15B.
It is sent to the C card memory 16. Further, the writing speed or the like to the IC card memory 16 is set based on the additional information. At the same time, additional information as well as individual information is written on the IC card memory 16.

FIG. 3 is a memory map 2 of the IC card memory.
In this example, the individual information from the ROM 15A written in the IC card memory 16 is written as shown in FIG. That is, information such as the recording capacity of the IC card memory itself is recorded in the medium information management area 21 and the address 2 of the defective pixel in the pixels of the CCD 5 is subsequently recorded in the individual information area 23.
Addresses of dark noise in pixels of 2A and CCD 5 and individual information such as level 22B are recorded, and additional information is recorded in additional information area 24 as necessary, and the remaining area 25 is formed as an image information area. .

Of course, the above-mentioned pixel defect address information is used for the IC.
Various methods are conceivable for the format to be written in the card memory 16. For example, the marker and the number of data are recorded before the image data and the address information of the defective pixel is written as a header, or the address information of the defective pixel is assigned to each defect of the CCD in horizontal and vertical 2 bytes.

Next, a case where a still image is taken by the electronic still camera according to the present invention will be described.

When the release 13 is operated, the image pickup charges accumulated in the CCD image sensor 5 at that timing are subjected to predetermined color balance processing by the video signal processing circuit 7, and the sample hold circuit 8 and the AD converter 9 are operated. , Is written to the digital memory 11 via the latch circuit 10. That is, if the recording medium is an optical disk instead of an IC card memory or the like, the image pickup signal is stored in the digital memory 11 for a predetermined time until the recording speed reaches a predetermined recording speed.

During this period, the optical disk or the like is prepared for recording operation. When the optical disk or the IC memory card 16 becomes recordable, the image information of the digital memory 11 is transferred to the image information area 2 of the IC card memory 16 via the compression processing circuit 12.
Written to 5. When recording of image information is completed,
The above-mentioned additional information and individual information may be written in the IC card memory 16.

Next, the still image picked up by the electronic still camera as described above is displayed on the monitor screen or made into a hard copy by the reproducing system as shown in FIG.

FIG. 4 shows a circuit for reproducing individual information. It reproduces a plug of the IC card memory 16 which is a still image taken by an electronic still camera and in which individual information is written and data is stored. System IC card interface 15C jack. The IC card memory 16 is provided at the output end of the IC card memory interface 15C.
Individual information such as image data and defective address data in the medium is read. The image data is the image data processing circuit 15D.
Is supplied to the defect correction processing circuit 15F after being subjected to image data processing.

The CCD defective pixel address or dark noise pixel address and level data from the IC card memory 15C are detected by the CCD defective address detecting circuit 15E,
It is supplied to the defect correction processing circuit 15F at the next stage. Image data processing circuit 15D, CCD defect address detection circuit 15E
Similarly, the defect correction processing circuit 15F is controlled by the CPU 15G, and corrected image data is obtained at the output terminal T.

An example of soft processing in the defect correction processing circuit 15F will be described with reference to the flowchart of FIG. 5A and the correlation diagram of FIG. 5B.

First, in the first step ST1, the CPU 15
The defective portion address is read from the CCD defective address detection circuit by G.

Next, in the second step ST2, correlation check in each direction is performed in the CPU. For example, vertical, horizontal, and diagonal correlation checks are performed on the defective pixel address X in the pixel as shown in the following equation. mn (| a-h |, | c-f |, | b-g |, | d-e |) (1) where | a-h | and | c-f | are defective pixels X. On the other hand, the difference between the diagonal pixel address and | b−g | and | d−e | are the differences between the vertical and horizontal pixel addresses with respect to the defective pixel X.

In the next third step ST3, the defective pixel X is interpolated by the pixel closest to the defective pixel in the direction having the strongest correlation.

In such pixel interpolation, the correlation check is │a
When −h | is minimum, average value interpolation such as a + h / 2 is performed. For example, when | a−h | is minimum, the distance dax from the defective pixel X to the oblique a and the defective pixel X are the same. From the diagonal h to the diagonal h, dax ≦
When dah, interpolation is performed by a, and when dax> dah, interpolation by h can be performed by software. Of course, a correlation circuit may be built in hardware or interpolation may be performed using a DSP or the like.

In the above-described embodiment, the method of interpolating the defective pixel address has been described, but in dark noise or the like, the CPU 15G controls the level and the like based on the address and level value of this portion.

In the present invention, since the electronic still camera is constructed as described above, the defect information of the individual CCD is written in the IC card memory in advance, and the defect information and the captured still image information from the IC card memory when the still image is reproduced. Since the image is taken out and the interpolation is performed, it is possible to obtain a display image obtained as a still image or a printed image with improved quality.

[0033]

According to the electronic still camera of the present invention, an IC
Since an image and an interpolation process can be performed based on the individual information of the CCD image sensor when reproducing the card memory, a high quality image can be obtained.

[Brief description of drawings]

FIG. 1 is a system diagram showing a configuration of an embodiment of an electronic still camera according to the present invention.

FIG. 2 is an individual information recording circuit diagram of a recording system of the electronic still camera according to the present invention.

FIG. 3 is an explanatory diagram of an embodiment of a map of a memory used in the electronic still camera of the present invention.

FIG. 4 is a circuit diagram of an individual information reproducing circuit of a reproducing system of the electronic still camera of the present invention.

FIG. 5 is a flow chart of the defect correction processing used in the electronic still camera of the present invention and a correlation explanatory diagram along with the flow chart.

FIG. 6 is a system diagram of a conventional electronic still camera.

[Explanation of symbols]

 5 CCD image sensor 9 AD converter 11 digital memory 12 data compression circuit 14 timing control circuit 15R individual information recording circuit 15A ROM 16 IC card memory

Claims (4)

[Claims] 1. An electronic still camera in which an image pickup signal picked up by a solid-state image pickup device is converted into digital data and written in a removable recording medium, and individual information of the solid-state image pickup device is recorded in the recording medium. An electronic still camera having a recording means for reproducing the individual information of the solid-state image pickup device from the recording medium to obtain a high-quality image. 2. The electronic still camera according to claim 1, further comprising a correction unit that corrects the image pickup signal based on individual information from the reproduction unit. 3. The electronic still camera according to claim 1, wherein the individual information is a defective address. 4. The electronic still camera, wherein the individual information is a dark address and its level information.