<title>Back-illuminated CCD imagers for high-information-content digital photography</title>

Abstract

The advantages of digital photography are well documented, and digital photography is seeing increased use in demanding photography applications. Of the many implementations of digital cameras, the three-CCD camera provides the optimal resolution, temporal sampling, and color reproduction, which when examined together form the information content of the sensor - a physical measure of the detector's imaging performance. So that uncertainty between the object of interest and the reproduced image is reduced, high quality, precise, color photographic records require sensors with the highest possible information handling capability. Furthermore, high information content images, due to the increases information about the scene, can be compressed to smaller file sizes than can lower fidelity images -thus, allowing reduced transmission data rates. Whereas traditional film is hypersensitive in the blue, conventional CCD imagers have reduced blue response as compared to their red response. A class of CCD called the back-illuminated CCD has uniform spectral response throughout the visible, UV, and NIR spectral regions. By integrating the uniform spectral response of the back-illuminated CCD with ultra-low noise amplifiers, high dynamic range pixels, a high pixel density, a large area detector, and a 3-CCD color prism architecture, a nearly ideal digital camera can be realized. This paper discusses a development effort at PixelVision Inc. to realize a nearly ideal color digital camera. So that a system for evaluating solid state photographic imagers can be established, a methodology of determining the information content of an imager is introduced and the information content of a back-illuminated CCD camera is compared to conventional film and to currently available studio digital cameras.