Abstract: An optical inspection system for using laser-induced luminescence to detect deterioration of a polymer-based material. The inspection system comprises an excitation means for illuminating a specimen of the polymer material to cause it to produce fluorescent radiation. The spectral representation of the fluorescence produced by the specimen is compared to the spectrum of a reference sample of known quality in order to obtain an indication of the physical characteristics of the specimen.

Abstract: A noninvasive optical oximeter for measuring oxygen saturation of arterial blood. A sample of blood is illuminated with light at two different wavelengths. Light reflected by the blood is sensed by a photodetector and an output signal is created in response thereto. The output signal is processed to form a quotient representing the AC components of the reflected light at each wavelength. The oxygen saturation of the blood is calculated by correlating this quotient with an oxygen saturation reference curve uniquely representative of the blood oxygen saturation characteristics of a particular individual. The reference curve used in the preferred embodiment of the invention is calibrated in a two-step process which minimizes the effects of calibration errors. A first oxygen saturation reference curve is calculated which is based on a linear relationship between the ratio of the AC components of the reflected light.

Abstract: A system for determining the thickness of an oxide deposit on a conductive surface by applying a voltage across the deposit while measuring the dielectric breakdown of the layer at various points. An electrode mechanism containing a first electrode can be positioned at any point on the surface of the deposit with a high degree of accuracy. A second electrode is defined by a contact which is electrically coupled to the conductive surface. With the first electrode positioned at a point on the deposit, a ramped voltage is applied across the electrodes. An analog dielectric breakdown detection circuit monitors electrode voltage until dielectric breakdown occurs. At the point in time of dielectric breakdown of a deposit, the voltage across the deposit decreases sharply, approaching a short circuit condition. The dielectric breakdown detection circuit, however, maintains the maximum voltage attained, which is represented as the true breakdown voltage for the point being tested.

Abstract: A method for determining the pulse rate of a person. The method of the present invention is implemented in two phases. The first phase involes the determination of pulse intervals and the second phase provides an indication of the pulse rate based on the data produced during the first phase. The first phase is implemented by an algorithm which produces a pulse distribution profile from an array of pulses obtained from an appropriate transducer. In the second phase of the measurement, the distribution is searched to locate the region of maximum density. The pulse rate within the maximally dense region are then averaged to determine pulse rate. The pulse rate detection method of the present invention eliminates a significant number of erroneous pulse signals before calculation of pulse rate, thus providing a more accurate indication of the true pulse rate.

Abstract: An interference resistant biomedical transducer for monitoring the acoustic output of a patient's cardiac or respiratory system which provides a high degree of rejection of acoustic noise and spurious electromagnetic signals. The transducer comprises a piezoelectric diaphragm assembly having electrodes which produce a differential output signal. The transducer housing includes a massive metal disc and a compliant handle which provide a mechanical filter to remove undesired signals such as those related to motion of the patient and ambient acoustic noise.

Abstract: A method and apparatus for ensuring accurate measurement of blood pressure regardless of the position of the sensing transducer relative to the position of the patient's heart. The method and apparatus provides a hydrostatic balancing system in which a column of fluid is used to offset the hydrostatic pressure created by the corresponding column of blood contained in the blood vessel in the limb upon which the measurement is being taken. A flexible tube is routed along the patient's limb with one end being positioned at heart level and the other end terminating at the occlusion cuff which supports the pressure sensing transducer. The tube is filled with fluid and is connected to a fluid reservoir chamber located at approximately the same level as the patient's heart. The hydrostatic pressure created by the fluid in the tube effectively balances the corresponding hydrostatic pressure created by the blood in the blood vessel.