<title>TDI camera for industrial applications</title>

Abstract

Time delay and integration (TDI) imaging is an ideal technique for digitizing images of continuous webs and other large, flat objects in motion. It offers vastly improved sensitivity and set-up ease compared to line scan techniques, while retaining the line-scanner's variable- rate capabilities. The light sensitivity is comparable to that of area arrays. TDI cameras require an external horizontal drive signal in synchronization with the motion of the object being scanned. Vertical resolution is critically dependent upon synchronization of the motion of the moving object with the motion of the lines of charge as they move across the CCD sensor. This has been achieved by obtaining a synchronization signal directly from the moving object, utilizing an electro-optical resolver slaved to the object. Operation has been achieved with line rates of less than 500 Hz up to RS170 line rates -- 15,750 Hz. The integration phenomenon is readily seen: Halving the scanning rate will double the video signal for a given light intensity. The full horizontal resolution of the CCD sensor is achieved by careful alignment of the CCD sensor; in our case, in the order of 600 pixels© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.