Digital image processing techniques can improve the interpretation and evaluation of radiographic and acoustic image data as well as the time domain waveforms produced by ultrasonic, eddy current, and acoustic emission in two important ways. First, the image or waveform being evaluated can be enhanced to bring out detail not readily apparent to the observer. Second, the properly enhanced image or waveform can be evaluated automatically by computer. The size of defects can be measured and accept/reject decisions made, without relying on the subjective interpretation of an inspector. During the past ten years many new and innovative procedures have been developed for image enhancement and restoration. This presentation describes just one: the spatial filtering technique used to put acoustic and radiographic images in a mode suitable for automatic computer evaluation.