Imaging is the culture which only human beings can make use of freely. Our ancestors had possessed the culture to exchange, communicate, and record information by means of images since primeval age when they had no civilization at all. The camera was invented, and has evolved as a tool to record images easily and accurately. The origin of the camera goes back to Camera Obscura which was a tool to draw a picture, tracing an image which focused on a screen in a dark box through a pin hole or a lens. Cameras had been developed as tools to record images by means of an opto-chemical reaction since Daguerreotype, the first camera, was announced in 1826 until early 2000s. On the other hand, in 1981, an electronic camera also known as the "Floppy Camera", which converts the captured images to electronic signals by an image sensor and records it on an exclusive floppy disc, was developed. This Floppy Camera was the first camera which adapted electronic still pictures recording apart from conventional silver halide cameras. However, the Floppy Camera, which appropriated the technologies employed in existed Video Cam Coders to view images on a TV screen, didn't have enough image quality to replace the silver camera market. At almost the same time, Toshiba announced a prototype to record images digitally for the sake of improved image quality. It indeed made improved image quality possible by means of digital signal processing instead of traditional analog ones, preventing dropout occurring in the recording and reproduction stages. However, it was of no practical use because of the recording media, which was an audio cassette tape, and poor image compression technology. It took long reproduction time with poor image quality which was provided just for image playback on a TV screen. In late 1980s, Flash Memory, which is a non-volatile semiconductor mass storage, was developed and a digital still camera (DSC) which records image signals in the semiconductor memory was announced. But it could not replace the silver halide cameras because of poor image compression efficiency, high expense over 1 million yen, and poor image quality which was not enough for printed images just enough for viewing on a TV screen.

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