VIDEO-BASED ANALOG TOMOGRAPHY

A high-speed analog tomographic reconstruction device is described. The device uses convolution filtering of the projection data to improve the image quality. This filtering was performed using a tapped analog delay configured as a transversal filter. Filtered back-projections were displayed on a raster, rotated using a dove prism, and integrated using analog techniques. Images of high-contrast objects are presented and are a better approximation to the object than those obtained without filtering and have a spatial resolution of approximately 1 in 300. The electronics used to perform the Radon inversion were analog and provided real-time computations introducing a delay between data input and data output of only 2 ms. The shortest time attained for total data collection and processing was 8 s; however, it is suggested that with new commercially available technologies reconstruction times could be further shortened. The individual components of the device were tested and the final results compared with digital reconstructions.