The imaging principle of computer photography is briefly described.

IP (imaging board) is composed of a base layer, a phosphor layer and a protective layer, and stores the received X-ray photon energy in the crystal as a latent image after X-ray irradiation. The IP is placed in the cassette of ordinary X-ray photography, and the exposed imaging plate (IP) is sent to the reader. IP is automatically taken out and scanned by laser beam, so that the latent image stored in IP crystal emits fluorescence, which is received by photomultiplier tube and converted into electrical signal. The reader transmits the digital image information to the processor, and the processed image can be stored on a CD or disk or printed into a CR photo by laser.