Two new scanning type cotton trashmeters are being developed to indicate the amount of trash and foreign matter in lint cotton. These instruments are primarily intended to replace the current visual method of grading cotton for market quality. They both perform a two dimensional surface scan using a black and white television camera. High-speed microprocessors provide an analysis of the TV signal at video scan rates. Only a fraction of a second of time is required to complete all scanning, signal processing, and data analysis for each cotton sample exposure. This article discusses some common problems in TV image analysis and how they relate to cotton scanning. Also discussed are instrument precision and design features and a method of calibrating each instrument.