Two-Dimensional Tomographs Using Range Measurements

We demonstrate a method of constructing two-dimensional projection images of objects using reflective tomography. The method consists of detecting reflected light from an object illuminated by short pulses (FWHM ≈ 100 ps) from a laser with high time resolution (FWHM ≈ 250 ps) to produce one-dimensional range-resolved data. Repetition at many aspect angles provides input to a filtered back projection algorithm that produces a 2D projection image of the object. The receiver consists of 1) a lens to image the object to a point, 2) a streak camera to provide time resolution, 3) a tv detector to record the streaked light, and 4) electronics to control the system and to store data. This paper describes the concept on which the receiver is based, the details of the prototype receiver, and the characteristics of images of many objects.