A NEW AUTOMATIC EXPOSURE SYSTEM FOR DIGITAL STILL CAMERAS

This paper presents a newly developed automatic exposure (AE) system f or digital still cameras (DSC). The through the lens (TTL) system whic h has been employed mainly by conventional camcorders has been applied as an exposure control system for DSCs. However, the TTL system requi res a longer time to obtain an appropriate exposure value, and it is t herefore not a suitable control method for DSCs which demand immediate imaging after the shutter button is pushed. The authors have develope d a high-precision AE capable of controlling the exposure quickly by c onverting the brightness of an object directly using the obtained valu e of an integrated image without using the photometric sensors other t han a charge coupled device (CCD). They have also confirmed that the n ew system enables excellent exposure control without any problem.