Abstract: A non-contacting optical imaging system for seam or other periodic pattern detection for a web of material such as a strip of fabric is disclosed in which a line scan camera is used to capture a seam or other periodic pattern image and the electrical output from the camera is converted to an alternating current signal and then to a direct current signal which is proportional to the presence or absence of a seam other periodic pattern. The DC signal is integrated and then compared to a preset reference value to produce a signal for driving an alarm, display or machine control devices.

Abstract: An all digital eddy current measurement system is described and illustrated in which an eddy current probe is driven by a driving signal and voltage signals representing the current through and voltage across the probe coil are used to calculate the magnitude and phase angle of a complex probe impedance. Digitization of the voltage signals is controlled by a control logic system which is run separately from but initiated by a microprocessor, the latter of which functions to analyze the acquired data and calculate impedance magnitude and phase angle values therefrom.

Abstract: An automatic watering and gas purging system for batteries and fuel cells utilizing a watering cap which establishes a desired electrolyte level in the cells.