Abstract: A system and method is provided to detect surface anomalies. The detection system and method provides the ability to automatically detect and characterize anomalies on a surface, such as detecting and characterizing pitting corrosion on metal surfaces. The surface anomaly detection system and method uses an image of the surface under evaluation. The image data is passed to a noise filter. The noise filter uses an estimated characterization of the background noise to remove the background noise from the image data. The smoothed pixel intensity is then compared to a threshold to identify significant departures. The detected anomalies are then passed to a contour detector, which determines the contours of anomalies in the surface to provide more precise characterization of the detected anomalies. The detected closed contours of anomalies may then be passed to a defect severity estimator that provides an anomaly factor metric.

Abstract: A micropower apparatus and method for milliohm resistance detection includes a drive circuit and a monitoring circuit. The drive circuit includes a step up current transformer that is driven by a square wave oscillator via a low pass filter and voltage-driven current source. The drive circuit drives a series arranged test coupon and reference coupon, the latter being exposed to the elements. The coupons are Kelvin connected to the monitoring circuit, which includes a pair of low noise, low offset pre-amplifiers, a pair of post amplifiers connected to outputs of the pair of pre-amplifiers, a pair of full wave rectifiers connected to outputs of the pair of post amplifiers, and a pair of low pass filters connected to the outputs of the pair of full-wave rectifiers. Resistance values of the test and reference coupons can accordingly be monitored ratiometrically to determine a state of a selected environment by, for example, detecting changes in electrical resistance due to corrosion of the test coupon.

Abstract: A micropower apparatus and method for milliohm resistance detection includes a drive circuit and a monitoring circuit. The drive circuit includes a step up current transformer that is driven by a square wave oscillator via a low pass filter and voltage-driven current source. The drive circuit drives a series arranged test coupon and reference coupon, the latter being exposed to the elements. The coupons are Kelvin connected to the monitoring circuit, which includes a pair of low noise, low offset pre-amplifiers, a pair of post amplifiers connected to outputs of the pair of pre-amplifiers, a pair of full wave rectifiers connected to outputs of the pair of post amplifiers, and a pair of low pass filters connected to the outputs of the pair of full-wave rectifiers. Resistance values of the test and reference coupons can accordingly be monitored ratiometrically to determine a state of a selected environment by, for example, detecting changes in electrical resistance due to corrosion of the test coupon.

Abstract: A corrosion sensor and method for its use to detect and determine the, type, location, size and growth rate of corrosion of metals and the like in a corrosive environment. The corrosion sensor can distinguish between different types of corrosion such as uniform corrosion, pitting, crevice, and stress corrosion cracking. The sensor detects corrosion conditions of a corrodible metal article in a corrosive environment. It has a metal probe comprised of a metal which is substantially identical to that of the corrodible metal article and a transducer element attached to said probe, which is capable of projecting and receiving ultrasonic or radio frequency signals through the probe. The received signals indicate corrosion of the probe and hence the corrodible metal article.

Abstract: A corrosion sensor and method for its use to detect and determine the, type, location, size and growth rate of corrosion of metals and the like in a corrosive environment. The corrosion sensor can distinguish between different types of corrosion such as uniform corrosion, pitting, crevice, and stress corrosion cracking. The sensor detects corrosion conditions of a corrodible metal article in a corrosive environment. It has a metal probe comprised of a metal which is substantially identical to that of the corrodible metal article and a transducer element attached to said probe, which is capable of projecting and receiving ultrasonic or radio frequency signals through the probe. The received signals indicate corrosion of the probe and hence the corrodible metal article.

Abstract: A sensor for detecting acoustic energy emitted by a target is disclosed. The sensor comprises a housing including a plurality of transducers for receiving acoustic energy. The transducers are randomly deployed within a predetermined area around the housing, forming an array and a self-survey technique is utilized to determine the positions of the sensors. Beamforming techniques are utilized to analyze the acoustic energy detected by the transducers to provide the azimuth of a target and a class estimate of the target. A plurality of sensors may be utilized to provide target location, course and velocity.

Abstract: In combination, intrusion detection apparatus giving a signal when a light vehicle approaches a geophone, and a heavy vehicle discriminator disabling the detection apparatus when the approaching vehicle is a heavy one.

Abstract: Geophone apparatus for receiving seismic signals due to an approaching vehicle, and giving an output when the signals are those characteristic of a heavy vehicle.

Abstract: In combination: a geophone having a resonant frequency in the pressure wave band and a response that decreases with frequency below the resonant frequency; an amplifier connected to the geophone and having a gain which is substantially constant for frequencies above the resonant frequency, and which varies inversely with frequency for frequencies below the resonant frequency; a band-pass filter connected to the amplifier; a single channel rectifier connected to the band-pass filter; apparatus connected to the rectifier for obtaining short term and long term averages of the rectifier output; and apparatus including a comparator connectied to the last named apparatus for giving an output when the short term average exceeds the long term average by more than a predetermined amount.