The VSH (video-scan head) scan engines have been designed for real-time point scanned image capture systems. The contrast produced by a point-scanned system can exceed those produced by CCD systems for objects such as scratches or low-profile edges. Intended applications range from semiconductor inspection to fluorescent microscopy to biological diagnostics. The capabilities spanned by the VSH-4 (4000 lines/second) and VSH-8 (8000 lines/second) engines are frames up to 1024 by 1024 pixels and frame rates to 100 frames per second. Frame size (zooms to 1/10th full-frame), user-defined lines-per-frame, frame rate, and pan moves in the frame scan direction are supported. To assess the performance of these devices an imaging system was built and the outputs i.e., detector or bit-mapped images, were analyzed and compared to specific criteria. This imaging system is described and measurements including image linearity, pixel stability, and system MTF are presented. Discussions of how scanning systems impact overall imaging performance along with some of the practical lessons learned from interfacing the VSH to optics and a commercial frame- grabber are included.
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