JP3385509B2 - Still video camera - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a still video camera, and an analog image signal output from an image sensor is
The present invention relates to a still video camera configured to record a digital image signal obtained by D / D conversion in a memory.

[0002]

2. Description of the Related Art In recent years, in place of a conventional film camera, a still video having a structure in which an optical image signal from a subject is converted into an electric image signal by an image pickup device and the electric image signal is stored in a memory corresponding to a film. A camera has been developed, and an electric image signal stored in a memory is reproduced on a monitor for viewing and a hard copy is made on a printer.

A magnetic disk is generally used as a memory of such a still video camera. In this case, for example, an optical image signal obtained by passing through an optical lens is photoelectrically converted by an image pickup device such as CCD, An electric image signal obtained by the conversion is subjected to color separation, gamma correction, line-sequentialization, FM modulation and the like by analog processing, and then electromagnetically converted using a magnetic head or the like to be magnetically recorded on a magnetic disk.

During reproduction, a magnetic signal recorded on a magnetic disk is electromagnetically converted and analog-processed and displayed on a monitor.

However, in such a method of magnetically recording an analog signal on a magnetic disk, since signal analog processing and electromagnetic conversion are required, the signal is apt to deteriorate, and both the camera and the regenerator use the magnetic disk. Since a rotary drive mechanism is required, it is inevitable to increase the size and cost, which is a cause of delaying the spread for commercial use as well as commercial use.

In view of this point, the applicant of the present invention has proposed a method in which a digital signal obtained by A / D converting an electric image signal obtained by an image pickup device is stored in a semiconductor memory (Japanese Patent Laid-Open No. 59-59). 183582),
According to this, it is possible to prevent the deterioration of the signal due to the analog processing, and it is possible to reduce the size and weight of the camera and the regenerator and to reduce the cost because a drive mechanism unlike the case of the magnetic disk is not necessary.

[0007]

By the way, in the still video camera configured to record the digital image data in the semiconductor memory as described above, it is possible to record the digital image data in the memory without performing the process processing such as color separation. (Refer to FIG. 9), the circuit configuration is simplified as compared with a still video camera of analog recording type on a magnetic disk (see FIG. 10), and the effect of omitting the drive mechanism of the magnetic disk is further reduced, and the cost is further reduced. Can be down.

However, since the dynamic range of the output signal of the CCD is 70 dB or more, the number of bits at the time of A / D conversion needs to be about 12 bits or more to secure the resolution, which is expensive A / D Since a converter is required, a gamma correction is performed before the A / D conversion to compress the dynamic range of the output signal of the CCD to about 50 dB. It is necessary to be able to use it, and it is better not to omit the gamma correction circuit.

As described above, in the digital recording type still video camera, the circuit processing on the camera side can be simplified by constructing the digital video recording still video recording while omitting the signal processing as much as possible. It is difficult to judge that the shooting conditions such as the type of color filter in the color still video camera are different from only the image recording, so that a large problem does not occur when using a dedicated player with one type of camera. For example, if a common player reproduces a memory in which images captured by a plurality of types of still video cameras having different color filters are recorded, a problem occurs such that desired color separation is not performed.

The present invention has been made in view of the above problems, and in a still video camera for recording a digital image signal, it is possible to perform desired processing during reproduction while omitting the signal processing circuit as much as possible. The purpose is to

[0011]

Therefore, in the invention according to claim 1, the optical image of the subject obtained by the optical lens is converted into an electric image signal by the image pickup device through the filter, and the electric image signal is In a still video camera configured to store a digital image signal obtained by A / D conversion by a D converter in a memory, the digital image signal and the manufacturer name or model number of the filter are stored in different areas of the memory. Configured to record.

[0012]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

FIG. 1 shows the system configuration of the still video camera according to the embodiment.

Here, an optical image signal from the optical system 1 including a lens, a diaphragm, a shutter, an optical low-pass filter, an infrared cut filter, etc. is controlled by the drive circuit 2 and the drive timing generation circuit 7. And MOS
Is converted into an electric image signal by the image pickup device 3, and the analog image signal is processed by the analog processing circuit 4 and then A / D converted by the A / D converter 5 to obtain the converted digital image signal. The data is recorded in the memory 6.

As the memory 6, a semiconductor memory in the form of a card and a memory card detachably attached to a still video camera, a magneto-optical disk, DAT or the like capable of recording digital signals may be used.

Here, in the analog processing circuit 4, C
A sample and hold circuit such as a DS (correlated double sampling) circuit converts the electric image signal output from the image sensor 3 into a baseband signal, and outputs the signal to the A / D converter 5.

When only the sample and hold as described above is performed and no other signal processing is performed, the signal can be converted into a digital signal by using the A / D converter 5 of 12 bits or more. The configuration is simplified.

However, if the 12-bit data is recorded in the memory as it is, there is a problem that the memory capacity required for image recording becomes large. In this case, for example, gamma correction is performed before or after the A / D converter 5. The amount of data may be reduced by performing such a signal compression process.

If gamma correction is applied to the output signal of the image pickup device 3 before the A / D converter 5 in an analog manner, the dynamic range can be compressed from 70 dB or more to about 50 dB. An 8-bit device can be used as the device 5.

Further, as shown in FIG. 3, if an A / D converter having a gamma characteristic in the A / D conversion characteristic is used, the A / D conversion and the gamma correction are performed at the same time. Can be simplified.

The conversion timing by the A / D converter 5 is
Since sampling is performed at the same frequency as the signal read clock of the image sensor or at a frequency that is an integer fraction thereof, all the clocks necessary for the A / D converter 5 are supplied from the drive timing generation circuit 7 of the image sensor 3.

Here, in the still video camera of this embodiment, since the digital image signal is recorded in the memory without performing signal processing such as color separation or line sequentialization, color reproduction is performed on the reproducing device side as shown in FIG. A process circuit 11 for performing signal processing such as separation is provided, and a digital image signal processed by the process circuit 11 is converted into an analog signal by a D / A converter 12 and output as a television signal (or D A / A converted signal is processed by a process circuit).

Therefore, data necessary for performing signal processing such as color separation at the time of reproduction is recorded in FIG.
It is necessary to record them in a predetermined memory area at the same time as shown in FIG.

For example, in the case where the A / D converted value of the output signal of the image pickup device 3 is recorded almost as it is as described above, the number of the pixel in the memory, in other words, the data for one screen is stored. If it is not known which area is recorded at the time of reproduction, it may not be possible to reproduce. Therefore, for example, as shown in FIG. 4, the screen number (shooting order) indicates which address the four corners of one screen are stored. It may be stored in a predetermined area of the memory corresponding to the above, and at the time of reproduction, the data may be read by referring to such an address.

There is also a method in which one screen is sequentially recorded as one pixel row and the addresses of the first pixel and the last pixel are stored in a predetermined area. In this case, only the first address may be stored, and the first pixel of the next screen may come immediately after the last pixel.

With this configuration, even when the recording method is such that a plurality of image data are packed and stored in the order of addresses without dividing the memory area for each image, access for reproduction is easy. Become.

As in the present embodiment, a color filter is provided in order to extract a color signal from the single-chip image pickup device 3. However, if the color arrangement in this color filter is not known, color separation processing is performed during reproduction. Since it cannot be done, you can see the arrangement of the color filters in the still video camera used in Fig. 5 (R, G, B filters).
And the minimum unit of the color filter array (or the code that can refer to the filter array) as shown in FIG. 6 (green, magenta, cyan, and yellow filters) is stored in the memory in association with each screen, and at the time of reproduction The photographed still video camera color filter array is read from the memory 6, and color separation processing is performed according to this array.

If the data indicating the arrangement of the color filters is stored in the memory 6 as described above, even if the images taken by the still video cameras having the different arrangements of the color filters are mixed, the reproducing apparatus is reproduced. Since this can be determined on the side, it becomes possible to use a common player among a plurality of types of still video cameras having different filter arrangements.

In addition, although white balance adjustment is generally performed in a video camera, the still video camera of the present embodiment records in the memory 6 without performing such white balance adjustment. Therefore, the white balance adjustment is performed on the reproducing device side. Need to do.

Therefore, as the information necessary for the adjustment, for example, the color temperature of the object detected by the sensor, or the RGB
If the camera is equipped with a sensor corresponding to the three primary colors
Information such as the signal level of each color B or the deviation from the reference level is recorded in the memory 6 at the same time as the image is taken, and is read into this information on the reproducing device side so that the white balance can be adjusted well.

In addition to the above, the photographing conditions to be stored in the memory 6 together with the photographing include, for example, the spectral characteristics of the color filter, the number of pixels of the image sensor 3 (total number of pixels, number of moving pixels), and the spectrum of the infrared cut filter. The characteristics, the spectral characteristics of the optical system, the shooting time and date, etc. can be mentioned.

Here, the information necessary for the color separation processing,
For the spectral characteristics of infrared cut filters and color filters, do not record the characteristic values directly.
The model number, thickness, etc. may be recorded.

When the spectral characteristics of an optical system such as an optical lens or a crystal plate are stored, the spectral characteristics recorded in the memory are read out and the three primary color signals are corrected based on the spectral characteristics. good.

Further, based on the data of the shooting date / time corresponding to the image recorded in the memory, the predicted shooting environment is reflected in the color reproduction by, for example, strengthening the red of the reproduced image in the evening. In this case, the weather may be estimated from the photographing time and the color temperature recorded for white balance adjustment and reflected in the color reproduction.

Further, information such as a photographing location and weather may be recorded in the memory in association with the image by the operation of the photographer.

On the other hand, the photographing conditions are recorded in the memory together with the image data as described above, and the following measures are taken in recording the image data so that more efficient signal processing or saving of the recording capacity is performed. It is desirable to do.

Normally, when image data is recorded in the memory, it is recorded in pixel order as shown in FIG.
In the case where the G and B color filters are provided, if the pixels of the red R filter, the green G filter, and the blue B filter and the pixels of each of the three primary colors are collectively recorded in the memory, the same color is obtained. The correlation between adjacent pixels appears, and the compression process can be performed more efficiently.

Further, in a normal image pickup device, pixels for optical black (OB), which is a black reference, are 40 × 500 (2
However, it is not necessary to record all of them, so that, for example, only one OB pixel is recorded per scanning line, or only one OB pixel is recorded in one image. Therefore, the memory capacity can be saved.

Here, one OB pixel is set for one scanning line.
In the case of recording only pixels, only one OB pixel is sampled from one scanning line, or the average of OB pixels (about 40 pixels) in one scanning line is calculated and the average value is scanned once. When the OB pixel data for each line is used and only one OB pixel data is recorded per image, the average of the whole is taken and recorded.

Further, it is possible to record one pixel for each scanning line when the variation in the signal level of the OB pixel is large, and record one pixel for each image when the variation is small.

[0042]

According to the present invention, in a still video camera configured to store a digital image signal in a memory, the digital image signal and the maker name or model number of the filter are recorded in different areas of the memory. Therefore, it is possible to perform processing according to the manufacturer name or model number of the filter on the regenerator side. Further, it is possible to perform the processing common to the filter manufacturer and the model number on the regenerator side.

[0043]

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a reproducing device in the embodiment.

FIG. 3 is a diagram showing conversion characteristics of an A / D converter.

FIG. 4 is a diagram showing characteristics when recording a recording location of image data.

FIG. 5 is a color filter distribution diagram showing the minimum unit when recording the type of color filter.

FIG. 6 is a color filter distribution diagram showing the minimum unit when recording the type of color filter.

FIG. 7 is a diagram showing a recording area of shooting conditions in a memory.

FIG. 8 is a recording processing state diagram showing a recording state for each filter color.

FIG. 9 is a block diagram showing a conventional example of a digital recording still video camera.

FIG. 10 is a flock diagram showing a conventional example of an analog recording still video camera.

[Explanation of symbols]

1 ... Optical system 2 ... Drive circuit 3 ... Image sensor 4 ... Analog processing circuit 5 ... A / D converter 6 ... Memory 7 ... Drive timing generation circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H04N 9/79 H04N 9/79 G (72) Inventor Masaaki Tsuchida 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation (72) Invention Katsuya Nagaishi Address 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation (56) Reference JP-A-63-281595 (JP, A) JP-A-59-183592 (JP, A) JP-A-62-140590 (JP) , A) JP-A-60-153283 (JP, A)

Claims (2)

(57) [Claims] 1. A digital image obtained by converting an optical image of a subject obtained by an optical lens into an electric image signal by an image pickup device through a filter and A / D converting the electric image signal by an A / D converter. A still video camera configured to store a signal in a memory, wherein the digital image signal and the maker name or model number of the filter are recorded in different areas of the memory. 2. The still video camera according to claim 1, wherein the digital image signal and the manufacturer's name or model number are recorded for each frame of an image corresponding to the digital image signal.