JPH02248186A - electronic still camera - Google Patents

Abstract

PURPOSE:To change the compression rate of image pickup information written once in a memory card in the presence of the compression mode by providing plural frames of buffer memory prior to signal processing so as to attain high speed consecutive shot. CONSTITUTION:A signal from an image pickup device 1 is subjected to processing such as amplification or white balance at a pre-processing circuit 2, and the information is stored to a buffer memory 5 via an A/D converter 3 and a digital switch 4. The image pickup information by plural frames stored by a digital switch 6 is selected and the information is converted into a luminance signal and two color difference signals at a low speed (the speed is limited by the signal processing speed or the write speed to a memory card) signal processing circuit 7 and recorded on a memory card 8. Since the limit of the signal processing or card write speed is not received at the consecutive shot, high speed consecutive shot is attained. Since the pickup data readout is attained for many times, the compression circuit 9 is provided to vary the compression rate of the pickup information written once and the compression rate of the information in N-preceding frame is revised in the case of the memory 5 by N-frame.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electronic still camera using a memory card for recording still images.

(Prior Art) In recent years, in contrast to electronic still cameras that record analog data, electronic still cameras that record digitally using memory (RAM, etc.) have been considered. This electronic still camera digitally processes the image signal, so it can obtain high-quality still images without image quality deterioration during signal processing, and records DigiMole image data in memory, eliminating the need for a rotating mechanism and reducing power consumption. It is superior to conventional electronic still cameras in many ways, including the ability to make the camera body more compact, and improve reliability.

FIG. 4 shows a basic configuration diagram of an electronic still camera for digital recording currently being considered. A signal obtained from the image sensor 1 is subjected to processing such as amplification, white balance, and gamma correction by a preprocessing circuit 2, and is converted into a digital value by an analog-to-digital converter 3. The image data converted into digital values is converted into a luminance signal and two color difference signals by a signal processing circuit 7, and then recorded in a memory card 8.

Here, when considering continuous shooting, the continuous shooting speed is limited by the signal processing speed and the writing speed to the memory card, and it is not possible to increase the speed of continuous shooting. Further, in a system including the compression circuit 9, there is a problem in that the compression ratio of image data once written to the memory card cannot be changed.

(Problem to be Solved by the Invention) As described above, in conventional electronic still camera systems, signals read out from an image sensor are directly converted into a recording format for a memory card and recorded on the memory card. Therefore, there is a problem in that there is a limit to the signal processing speed and the writing speed to the memory card, which also limits the continuous shooting speed. Furthermore, when compressing the data and writing it to the memory card, there is a problem in that the compression ratio cannot be changed for the data that has been written once.

The present invention was made in response to such problems,
It is an object of the present invention to provide a novel electronic still camera capable of increasing the continuous shooting speed and changing the compression ratio of data written once.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a buffer memory that can store multiple frames of analog-digital converted image data, writes multiple frames of data to the buffer memory at high speed during continuous shooting, and then writes the data at low speed. To provide an electronic still camera characterized in that high-speed continuous shooting is achieved by performing readout signal processing and writing to a memory card.

(Function) By providing buffer memory for multiple frames before signal processing, the speed of continuous shooting can be increased. Furthermore, if there is a compression mode, it is possible to change the compression rate of the imaged data written to the -degree memory card.

(Example) An example of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 is a basic configuration diagram of the present invention.

The signal obtained from the image sensor 1 is processed by a preprocessing circuit 2 such as amplification, white balance, and γ correction, and then converted into a digital value by an analog-to-digital converter 3. After passing through a digital switch 4, the signal is sent to a buffer memory. 5
will be stored once. During continuous shooting, the digital switch 4 is switched, and the captured data is stored in the buffer memory 5 one after another.

- The image data for multiple frames that have been stored are selected by the digital switch 6, and processed into a luminance signal and two color difference signals by the signal processing circuit 7 at low speed (limited by the signal processing speed or writing speed to the memory card). and recorded on the memory card 8. By providing a buffer memory for multiple frames in this way, it is possible to read out data from the image sensor 1 without being limited by the signal processing speed or writing speed to the memory card during continuous shooting, thereby increasing the speed of continuous shooting. .

FIG. 2 is a basic configuration diagram of the present invention including a compression circuit. Since the buffer memory 5 stores the imaged data before signal processing, the imaged data can be read out many times in the case of a system including a compression circuit 9 that can make the compression ratio of the pig variable. Therefore, the data compression rate can be easily changed. Also, for N frames (N
=1°2.3...), it becomes possible to change the compression rate of the imaged data N frames before.

FIG. 3 shows a detailed configuration diagram around the buffer memory in FIG. 1. Here, a case will be explained in which a buffer memory for four frames is provided. The imaging signal converted to digital at the clock rate (CLKI) is transferred to a bidirectional buffer 10.
First, B1 is selected by chip select and written into buffer memory B1.

The next imaged data is stored in buffer memory B2, and the next is stored in buffer memory B3.
It is written alternately with B4. The written imaging data is sequentially selected by the digital switch 6, subjected to signal processing at low speed (clock rate CLK2), and written to the memory card 7. Therefore, during continuous shooting, images can be captured at the clock rate of CLKI, thereby increasing the speed.

By providing buffer memory for a plurality of frames in this way, it is possible to achieve high-speed continuous shooting.

〔Effect of the invention〕

As described in detail above, according to the present invention, by providing a buffer memory for multiple frames, it is possible to achieve high-speed continuous shooting in an electronic still camera, and in a system including a data compression circuit, the image pickup part can be stored in a memory card. Even after writing, it is easy to change the compression ratio of the data.

[Brief explanation of drawings]

1 and 2 are basic configuration diagrams of an electronic still camera according to the present invention, FIG. 3 is a detailed configuration diagram of the buffer memory and its surroundings in FIG. 1, and FIG. 4 is a basic configuration diagram of a conventional electronic still camera. be. 1...Image sensor 2...Pre-processing circuit 3...
N/D converter 5...Buffer memory 7...
・Signal processing circuit 8...Memory card 9...Compression circuit Agent Patent attorney Noriyuki Chika Yudo Mitsuyuki Matsuyama Diagram

Claims (1)

[Claims] An analog-to-digital conversion means for converting imaged data obtained from a solid-state image sensor into a digital signal, a buffer memory means for a plurality of frames for once recording the imaged data converted into digital by this analog-to-digital conversion means, and this buffer. The present invention is characterized by comprising means for reading out one frame of imaging data from a memory and converting it into a luminance signal and two color difference signals, and a semiconductor memory card for recording the luminance signal and two color difference signals obtained by this means. Electronic still camera.