Showing papers on "High-dynamic-range imaging published in 1998"

High-dynamic-range front end for automatic image processing applications

Abstract: A camera system is described which can be used as a front end to automatic image processing applications,capable of imaging very high dynamic range scenes. We were inspired by the mammalian retina to build a system entirely upon commercially-available components which has the maximum flexibility and minimimum risk and development cost. The result is a system which includes logarithmic photodetectors, together withsimple robust fixed pattern noise correction and high-pass spatial filtering.Keywords: CMOS camera, high dynamic range, fixed pattern noise correction 1. INTRODUCTION There is currently considerable interest in developing affordable, low-power CMOS cameras for imagingapplications, where the detector is coupled directly or indirectly to a display device, for example digital cameras. However, whilst CMOS cameras are developing rapidly,"2 an application domain which has so far received less attention is that of sensors specifically designed for automatic image processing applications,such as "smart" front ends for automatic recognition. In these latter applications, the image itself is notdisplayed directly to a human observer, so the system is not constrained to create a natural-looking scene.Image quality and fidelity are therefore less of an issue than for other applications. Rather, it is moreimportant to extract relevant information and present it in a form which is suitable for subsequent image-processing algorithms. It is therefore vital that all the useful information present in the scene be preservedby the camera. This paper will describe the functionality required for a high-performance imaging system,suitable for use as an input to an automatic image recognition system, and built entirely out of off-the-shelf