Abstract: Tomography apparatus is used to irradiate a body cross section and acquire a relatively small amount of data which is mapped into a two dimensional array or sinogram and image enhancement techniques are applied to the sinogram to reveal visible lines representing flaws. An array processor operates on the sinogram to perform edge enhancement and averaging convolutions, a fast Fourier transform, low pass filtering in frequency domain, and an inverse fast Fourier transform to generate the enhanced sinogram.

Abstract: Ultrasonic thickness measurement of layers of paint on a substrate produces pulse echoes indicative of each layer interface. Several ultrasonic waveforms are averaged in a digital oscilloscope and the resultant waveform is analyzed by a computer programmed to recognize wave forms resembling pulse echoes, compare such waveforms to stored reference waveform characteristics, and selecting the waveform having the best fit to the reference. Each selected pulse echo is graded based on amplitude, peak separation, peak symmetry, and spacing from a previous echo to determine the quality of the waveform. Layer thickness is calculated from the spacing between pulse echoes and the velocity of sound in the layer material.

Abstract: Ultrasonic transducers spring biased into seating engagement in a pair of opposed spot welding tips transmit and receive ultrasonic waves and associated circuitry measures the time of flight between the transducers which is a function of tip separation, workpiece temperature and nugget size which are indicators of the progress of a weld. The rate of change of flight time is measured and the weld current is adjusted early in the weld cycle to maintain a preset rate of weld growth. The weld current is terminated later in the cycle if the transit time rate falls below another preset value. Otherwise the weld current and termination time follow a standard schedule.