A simplified television densitometer was developed utilizing a filterhyphen;andhyphen;hold technique. The system circumvents the use of complex digital circuitry by using a fading memory filter which yields an approximate integral of the optical density in a window in the area of interest. The response is linear for features whose optical density changes in the parallel direction to the raster lines, and linear for 40percnt; changes of optical density in the vertical direction.
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