FILMLESS X-RAY EVALUATION OF STRUCTURES MADE OF LIGHT MATERIALS

A filmless X-ray imaging system is described in which an inexpensive C CD-based video camera is used to photograph the image from a simple fl uorescent screen. The image can be displayed on a monitor and stored f or computerized image processing. The formation of differential images by subtraction is a powerful technique for evaluation of structures i n which the important parts are made of light materials such as polyme rs and plastics. It is even possible to obtain good images of light pa rts hidden behind dense materials. Examples presented include X-rays o f adhesive bonds in windmill blades, insulation foam in district heati ng pipes, and foam cores as well as filler joints of sandwich material s. In all of these structures it was possible to detect voids. An exam ple of fracture mapping with the aid of a liquid contrast medium is al so shown.