A PC digital still camera based on a mega-pixel CCD area array is presented. This camera can be used as an image input device in the applications of multimedia. The system is equipped with a conventional camera lens, and an 1 .5 mega-pixel progressive color CCD area array. A driving circuit is designed to control the focusing and the iris of the lens in order to perform auto/manual focus and auto/manual exposure functions. The CCD image sensor is also used as a sensor for auto focus, auto exposure and auto white balance control. This could eliminate the additional sensors. A shuuer wheel is built for continuos exposure, which allows the host computer to display the entire field ofview for preview without using an additional optical viewfinder. The digital signal processing is implemented in a computer software for interpolation, color reproduction, and edge enhancement, etc. A SCSI interface is used to connect to a host computer for data and command transmission.

The purpose of this paper explains the applications of automatic exposure adjusting apparatus for digital still camera.Supposed one image has 512 X 512 pixels and gray levels of each pixel range from 0 to 255, then it will result in 256512 X 512 kinds of images. The next question comes: how can you differentiate the proper luminance from these images 7The fuzzy c-means algorithm of the fuzzy pattern recognition is used. When the degree of the membership function , representing each element in the 8 orthogonal vector spaces calculated by variance criterion , is equal to 0.5 , it represents neither light images nor dark images and will be the proper luminance. The equation of "the degree of the membership function equal to 0.5" is derived.Applying the third form of the fuzzy control, then-part uses this equation to differentiate proper luminance of images from all images. The experimental data demonstrate satisfied results.