Diaphanoscopy apparatus

A non-destructive testing technique, particularly suitable for the non-invasive examination of human body tissue, wherein the object of interest is sequentially transilluminated within light having different wavelengths. Apparatus for practicing the technique alternately generates light of different colors and the light which passes through the tissue is detected by a video system synchronized with the source of the different wavelength light. The video system provides information bearing signals to data processing circuitry which determines the transmissivity at each wavelength of each point of the object within the viewing field.