Electro-optical gaging system having dual cameras on a scanner

Abstract

Computerized electro-optical system gages two orthogonal dimensions of a moving hot bar at various peripheral positions. Dual back-light electronic camera heads mounted 90.degree. apart on a scanner generate high-speed bar shadow pulses which represent the bar dimensions. Bar pulses are processed by way of individual camera electronics and a digital computer. CRT and printing terminals, interacting with the computer, indicate and/or record each cold-size bar diameter measurement, a plot of bar profile deviation from aim gage overlaid on full- and half-commercial tolerance references with a data header, and a gaging system histogram. Each camera head electronics includes camera AGC circuit, a digital type one-axis bidirectional linear sweep, bar pulse edge-detection with an autocorrelator to remove noise and enhance the bar pulse, and a digital accumulator of digital bar size signals and digital bar position-in-field-of-view signals. The digital computer assimilates each bar size and bar position digital signal along with scanner position, bar temperature and other data signals. The computer is programmed to: (a) compensate each bar size signal for field-of-view errors and other optical and electronic nonlinearities, bar temperature and other sources of error; (b) calibrate the gage off-line and automatically recalibrate the gage on-line to correct for drift and slope errors; (c) automatically drive the scanner and implement incremental digital storage of corrected bar size signals for bar profile plotting; (d) perform gaging system histograms; and (e) communicate with the CRT and printing terminals and an exterior control system.