Abstract: An optical detection sensor detects presence or absence of a product within a fluid delivery medium. An emitter directs radiation into the fluid delivery medium and detectors detect transmitted light at a plurality of wavelengths. The output of each detector and combinations of outputs of multiple detectors are associated with at least one out-of-product threshold. In addition, a color ratio is established. A controller compares the detector outputs and combination outputs with the associated out-of-product threshold(s). If any of the thresholds are satisfied, the controller compares the color ratio with an associated out-of-product threshold to verify an out-of-product event has occurred and reduce errors due to batch-to-batch variation of the product. The sensor is able to determine presence or absence of a variety of products having different color, transparency or turbidity.

Abstract: A method of measuring the level of an impurity in a gas comprises providing a gas detection tube having a internal volume containing a reagent which can react with said impurity to produce a compound capable of producing a color change in said tube such that the extent of the color change is proportional to the concentration of the impurity in said gas. A volume of the gas at least 1×103 times the test volume of the gas detection tube is passed through the tube and the extent of the color change of the detector element is measured.

Abstract: A miniature readhead is provided for photometric color detection using ambient light. The readhead is hand-held, including a superposed plate and tray. The tray receives sample media configured to react and to change color according to an amount of analyte in a sample. The plate is optically transmissive, so that ambient light is transmissible therethrough to the sample media indexed within the tray. An array of light detectors is disposed along the plate, including sets of detectors configured to detect light of at least three mutually distinct wavelengths reflected from the test areas. Light shields superposed with each of the light detectors selectively permit ambient light to pass to the tray, while substantially preventing ambient light from reaching the light detectors prior to reflecting from the test areas. The readhead may be incorporated into a photometric diagnostic instrument configured to analyze the reflections and derive a diagnosis value.

Abstract: An optical detection sensor detects presence or absence of a product within a fluid delivery medium. An emitter directs radiation into the fluid delivery medium. Each of a plurality of detectors detects light within an associated one of a plurality of wavelength ranges transmitted through the fluid delivery medium. The output of each detector is further associated with at least one out-of-product threshold. A controller may further combine detector outputs, such as by multiplication, summation, or other mathematical operation, to produce additional measures of product presence or absence. Each combination output is also associated with at least one out-of-product threshold. The controller compares the output of each detector with the associated out-of-product threshold(s) and compares each combination output with the associated out-of-product threshold(s) to determine presence or absence of product within the fluid delivery medium.

Abstract: A body fluid constituents measurement device, which performs measurement under a setting where light intensity of the light-emitting element is suitably stabilized, is provided.

Abstract: A method for reducing fringe interference of light created in a passive cavity defined by partially reflecting optical surfaces, wherein the optical path length of the cavity is varied with a Gaussian distribution, where the standard deviation is at least one-quarter of the light's wavelength.

Abstract: A portable, scanning and analyzing apparatus that uses an integrated scan probe for the scanning operation is described. The integrated scanning probe is formed with a light emitting diode array light source and a photodiode detector array. After a test sample finishes the reaction in test strip paper, a scanner device scans the test paper to collect the optical signals at variable, consecutive intervals along the scanning path to obtain the test signal accordingly. Then, the scanner device outputs the test signal for amplification. The amplified test signals are sent to an analog/digital converter such that the amplified test signals are converted into digital signals, which are then output to a computing unit for analyzing for subjective analytical results. The computing unit couples with the controller device, wherein the controller device controls a driver device that drives the scanner device to perform the scanning operation on the test paper.

Abstract: A spectrometer (100) includes a light source (102) providing output light (106) to the bundled input ends (108) of multiple light pipes (110). The light pipes (110) branch into sets (118) between their input ends (108) and output ends (114), with each set (118) illuminating a sample detector (126) (via a sample chamber (122)) for measuring light scattered or emitted by a sample, or a reference detector (128) for obtaining a reference/datum measurement of the supplied light, so that comparison of measurements from the sample detector (126) and the reference detector (128) allows compensation of the sample detector measurements for drift. Efficient and accurate measurement is further assured by arraying the multiple light pipes (110) in each set (118) about the input bundle (116) so that each set receives at least substantially the same amount of light from the light source (102).

Abstract: A field test-kit for analyzing arsenic concentration in water samples is provided. The kit includes a portable infrared beam photometer for measuring light absorbance in aqueous specimens. An infrared light emitting diode is configured to direct a beam of light through a specimen. A photodetector diode measures the intensity of light passing through the specimen. The photodetector output voltages relate to the light absorbed in the specimen and are displayed on a liquid crystal display screen. The kit is assembled using off-the-shelf electronic and opto-electronic components that have low power requirements. Dry cell batteries or solar cells power the kit. To test for arsenic, molybdenum based chemistries are used to selectively bind and convert arsenates and phosphates in the specimen into molybdenum-blue color complexes.

Abstract: A device for verifying and reading color, particularly used in reading the color of a liquid, the device comprising: a) a guide tube (10); and (b) at least one pair of liquid detection sensors (20), associated to the guide tube (10), the device comprising pairs of spectral-frequency emitting sensors (30, 31, 32) and spectral-frequency receiving sensors (30?, 31?, 32?), associated to the guide tube (10) and oppositely aligned, the spectral-frequency emitting sensors (30, 31, 32) being activated by detection of the liquid by the detection sensors (20).

Abstract: A double path microdrop optical biometric system comprises a micro container, a corner cube array, a collimator, a beam splitting device, a light source selector, a detector and a signal comparator unit. It utilizes the beam to penetrate a specimen with specific coloring agent twice. Then, the shade of the beam can be detected so that a signal comparator unit can calculate the absorptance. The required volume of the specimen used in the system is small. The precision will be doubled by the double path design. Its entire optic-electronic system is simple and at low cost. By using the LEDs, it can avoid the use of filter and solve the over-heating problem. Plus, it can execute many bio-chemical tests.

Abstract: The invention relates to a transparent or translucent colored cosmetic composition for making up the skin, lips and superficial body growths comprising a transparent or translucent cosmetic base and at least one coloring agent in an amount such that the transmission of a 10 ?m layer of the final composition, measured at the wavelength of the maximum of one of the absorption peaks of the coloring agent, is between 20% and 80%.

Abstract: A means for determining the concentration of a hydrogen-rich fuel in a fuel solution within the anode reservoir of a fuel cell. The fuel concentration is determined using a dye mixture responsive to fuel concentration within a fuel solution. As fuel is consumed, the fuel concentration decreases. As the fuel concentration decreases, the dye changes color. The resulting color changes occur within the anode reservoir of the fuel cell, or within a dye chamber in fluid contact with the anode reservoir, and are made visible by a window. A color strip and fuel scale may be included to facilitate fuel concentration determination based on the color of the fuel solution. Additionally, a valve responsive to dye color may act to control fuel delivery.

Abstract: A method for refining fluid sample data includes obtaining optical density data for a fluid sample in at least two color channels and at least one fluid component channel and determining a color-absorption function from the optical density data for the fluid sample in the at least two color channels. The method also includes calculating a portion of the optical density caused by color absorptions in each of the at least one fluid component channels, and de-coloring the optical density data in each of the at least one fluid component channels by removing the portion of the optical density data caused by color absorption.

Abstract: When a plurality of types of biopolymers on a biochip is to be measured using a fluorescence or colorimetric means, the image of the above biochip is obtained by measuring a plurality of images while moving the above biochip step-wise by an integer multiple of the field-of-view of a one-dimensional or two-dimensional array detector on the sample, then by combining the above-described plurality of images.

Abstract: An apparatus for inspection of fluids having a fluid analysis cell with a cavity therein enclosed by two light transmitting windows and having a spacer member fixedly positioned therebetween which provides a fluid analysis chamber of fixed pathlength where fluid flows by the windows and preferably wherein the flow laminar and at a uniform shear to provide accurate color measurements. Light transmitting and receiving probes are positioned adjacent to the viewing windows and wherein the faces of each probe are contiguous and flush with the viewing windows but are separated from the flow by the viewing windows, so that transmission measurements can be taken orthogonal to the direction of flow. The apparatus is particularly useful in the manufacture of dispersions and tints used in the manufacture of paints, so that the color of material being made can be accurately matched to a standard color in the wet state with confidence that the color will match in the dry state.

Abstract: A measuring device includes an irradiation optical system and a detection optical system. The irradiation optical system includes a light-emitting element and a mixing rod. The detection optical system includes a lens and an imaging element. Light from the light-emitting element enters into the mixing rod, where it is mixed. The light mixed inside the mixing rod is irradiated onto an immunochromatography test piece as measurement light. The light transmitted by the immunochromatography test piece is formed as an image on an acceptance surface of the imaging element, by means of the lens. The imaging element captures the image formed by the lens at the acceptance surface.

Abstract: A method for refining fluid sample data includes obtaining optical density data for a fluid sample in at least two color channels and at least one fluid component channel and determining a color-absorption function from the optical density data for the fluid sample in the at least two color channels. The method also includes calculating a portion of the optical density caused by color absorptions in each of the at least one fluid component channels, and de-coloring the optical density data in each of the at least one fluid component channels by removing the portion of the optical density data caused by color absorption.

Abstract: Methods for determining mixing accuracy are provided. The present invention includes methods for determining mixing accuracy with respect to mixing devices that are employed to mix a number of solutions, such as dialysis solutions. The mixing accuracy is evaluated based on a spectrophotometric analysis of a surrogate ingredient, such as a colorant, in the mixed solution. The colorant can be added to one of the original solutions prior to mixing.

Abstract: A device for determining the concentration of heparin in a fluid sample comprising: a container for holding the fluid sample; a container for holding the dye solution; a mixer for mixing the fluid sample and the dye solution; an illumination source for illuminating a mixture comprising the fluid sample and the dye solution with electromagnetic radiation having a substantially continuous range of wavelengths in the visible range; a detector for detecting the absorption spectrum of the mixture within the substantially continuous range of wavelengths; a recorder for recording the absorption spectrum of the mixture within the substantially continuous range of wavelengths; and a calculator for calculating a spectral parameter.

Abstract: A method for determining the concentration of heparin in a fluid sample comprising: (a) providing a fluid sample containing heparin; (b) adding to the fluid sample a solution of a dye to form a mixture of sample and dye, wherein the dye interacts with the heparin in the sample so that the absorption spectrum of the mixture of sample and dye in the visible range varies as a result of the interaction in a manner quantitatively dependent on the heparin concentration; (c) determining the absorption spectrum in the visible range of the mixture of sample and dye; and (d) calculating a spectral parameter representative of both the reduction in the absorption of the free dye in solution and the increase in the absorption of the dye-heparin complex, the value of the spectral parameter being indicative of the concentration of heparin present in the fluid sample, in order to determine the concentration of heparin present in the fluid sample.

Abstract: A process is provided for measuring the opacity in gases, especially in exhaust gases or in the atmosphere, at or near the maximum of the eye sensitivity in the green wavelength range with a central wavelength lying between 550 and 570 nm. In order, in a simple manner, to separately determine the components which are responsible for clouding in the visible wavelength range, or to make a correction possible by taking into consideration further components that have an effect in the visible range, the opacity in at least one second wavelength range which is located in the spectral between 200 nm and 2&mgr;, and which overlaps at most slightly with the first wavelength range is additionally measured.

Abstract: A multichannel fluorosensor includes an optical module and an electronic module combined in a watertight housing with an underwater connector. The fluorosensor has an integral calibrator for periodical sensitivity validation of the fluorosensor. The optical module has one or several excitation channels and one or several emission channels that use a mutual focusing system. To increase efficiency, the excitation and emission channels each have a micro-collimator made with one or more ball lenses. Each excitation channel has a light emitting diode and an optical filter. Each emission channel has a photodiode with a preamplifier and an optical filter. The electronic module connects directly to the optical module and includes a lock-in amplifier, a power supply and a controller with an A/D converter and a connector. The calibrator provides a response proportional to the excitation intensity, and matches with spectral parameter of fluorescence for the analyzed fluorescent substance.

Abstract: A method for treating an electronic component wherein the value of an optical property associated with a process fluid is measured and compared with a threshold value of an optical property. This comparison is used to determine what modification, if needed, should be made to the process fluid to restore it to its threshold value. Also disclosed is a system for treating electronic components with a process fluid.

Abstract: In one aspect the current invention provides a method for automatic real time monitoring of true color in a liquid. A sample is automatically withdrawn from the liquid in real time and is then automatically filtered in real time. The true color in the filtered sample is automatically detected in real time and the true color is automatically quantified in the filtered sample in real time. In another aspect, the present invention provides an apparatus that automatically monitors true color in a liquid in real time. The apparatus has a pump for automatically withdrawing a sample from the liquid in real time and a filter for automatically filtering the sample in real time. The apparatus also has an absorption spectrophotometer for automatically detecting true color in the filtered sample in real time and a controller for automatically quantifying the true color of the filtered sample in real time.

Abstract: An apparatus for inspection of fluids, particularly dispersions and tints, having a fluid analysis cell with a cavity enclosed by two light transmitting windows and having a spacer member fixedly positioned therebetween which provides a fluid analysis chamber of fixed pathlength where fluid flows by the windows and wherein the flow is laminar and at a uniform shear to provide accurate color measurements. The apparatus is particularly useful in the manufacture of dispersions and tints used in the manufacture of paints, so that the color of material being made can be accurately matched to a standard color in the wet state with confidence that the color will match in the dry state.

Abstract: A rapid diagnosis method for organ specific disease state is based on obtaining an infrared absorbance spectra of a patient's blood at a frequency range from about 400 cm−1 to about 2000 cm−1 and further from about 3000 cm−1 to about 3100 cm−1. Comparing it with the predetermined normal infrared absorbance spectra of known healthy subjects for the presence or absence of predetermined features such as increase or decrease of infrared absorbance, peaks at particular frequencies allows for accurate diagnosis of a disease of an organ, including most major organs such as a heart, lungs, stomach, liver, kidneys, brain, etc.

Abstract: A tracking system is provided for tracking while determining the position of a point relative to a datum and includes a carriage (4) rotatably mounted on a frame (1) and which can rotate around a precision sphere (2). An interferometer (16) is mounted so as to rotate with the carriage (4), such that a mechanical center of rotation of the device and the measurement datum of the interferometer coincide at the same point.

Abstract: A length and velocity measurement apparatus based upon an interference pattern created between the amplitude modulation component of a transmitted signal, generated by an RF/microwave modulated continuous wave (CW) laser, and the amplitude modulation component of a signal reflected back from the target. The distance between the system and the target is measured by counting the periods in the interference pattern created between the amplitude modulation component of the transmitted signal and the amplitude modulation component of the reflected signal while the modulation frequency is swept from a frequency F.sub.1 to a frequency F.sub.2. In order to provide a fine adjustment of the apparatus, the apparatus may be mounted on a movable carriage to adjust the periods in the interference pattern to an integral number. Velocity measurements are made at a single frequency based upon the Doppler effect induced by the moving target.

Abstract: An assembly comprising a 3-D scanner and suitable for capturing at least one of objects, or textures, or documents. The assembly preferably can be developed as a pocket page scanner having dimensions approximately the size of a chalkboard eraser. The assembly preferably utilizes an alignment-insensitive diode laser interferometer. In operation, the assembly enables a user to scan any page-sized area in e.g., a half of second, store a hundred or so of them, then play them back into a PC infrared port for OCR, printing, archival storage, or further processing.

Abstract: A system and method for determining the concentration of an analyte such as oxygen in an unknown gas sample. A Vertical Cavity Surface Emitting Laser (VCSEL) is used as a variable wavelength light source which is "swept" through a wavelength range by varying the drive signal applied thereto. Quantitative spectroscopic analysis of the unknown gas sample is performed without the requirement of feedback circuitry for tuning the light source to the characteristic frequency of an analyte. Instead, the VCSEL is repeatedly "swept" through a range of frequencies determined by the drive signal, and the absorption is measured by the detector. The absorption lines do not always occur at the same place but instead move along around during the sweep based on the temperature and baseline current. The absorption at a particular wavelength may be determined by overlaying the drive signal and its timing information over the detected absorption signal.

Abstract: Apparatus for determining the level of fluid in a vessel comprises a fixed optical emitter for emitting light into the vessel, a light steering means for steering light emitted by the fixed optical emitter, the light steering means for steering the light to reflect from a surface of one of the vessel and a substance within the vessel, a window for receiving the steered light prior to transmission to the vessel, a detector for receiving light from the vessel, and a processing system for determining distance from the vessel or substance in accordance with a predetermined geometric relationship. The apparatus may additionally comprise a level for determining a number of degrees out of plumb of the vessel. Also, the apparatus may comprise an acoustic transmitter and receiver for determining the depths of first and second liquids in the vessel which are immiscible in one another.

Abstract: A colorimeter for measuring colour of process medium comprising two light sources and two detectors both light sources being arranged to emit a beam through the process medium and the windows adjoining the process medium to both detectors. In order to achieve a solution functioning reliably the windows adjoining the process medium at both light sources are formed from a triangular prism, the two surfaces of which being at an angle to each other, are arranged to divide the beam arriving from the light source into two beams travelling in different directions so that both beams proceed to the process medium through the same part of the window surface formed by a third surface of the prism. Mirror surfaces arranged to gather radiation arriving form both light sources to a sensor of the detector are formed at both detectors.

Abstract: An apparatus and method are disclosed for measuring the concentration of gases that are unstable or difficult contain in a sample cell. A frequency modulated laser is tuned to the frequency of a first spectral feature of a gas of interest and a laser beam is projected through a reference cell containing, at a selected pressure, a selected second gas that has a second spectral feature near the first spectral feature of the gas of interest. The laser is line-locked to an outer zero crossing of a third harmonic of the detected laser beam coincident with the first spectral feature. The concentration of the gas of interest is calculated from a second harmonic of a portion of the laser beam projected through a transmission medium containing the gas.

Abstract: An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path.

Abstract: A optical displacement sensor comprises optical output detecting unit for detecting an optical output from the semiconductor laser, which changes in accordance with the phase of return light reflected by the external reflection unit, when an optical distance between the semiconductor laser and the external reflection unit changes at a change rate, optical distance modulation unit for changing the optical distance at predetermined periods by an amount of modulation of the optical distance at a rate higher than the change rate, and a detection circuit system for detecting the amount and direction of change of the optical distance based on an optical output from the optical output detecting unit detected in synchronism with a timing of modulating the optical distance by the optical distance modulation unit.

Abstract: A position detecting apparatus utilizing optical interferometry changes the wavelength of a light beam from the light source. The variation in the wavelength causes an increment and decrement Cx, Co in the number of waves in the measurement and reference lengths Lx, Lo. The position data calculating section calculates the measurement length Lx on the basis of the detected increment and decrement Cx, Co and the reference length Lo according to an equation, Lx=Lo(Cx/Co). The position detecting apparatus can easily detect an absolute position of an object to be detected.

Abstract: The present invention relates to apparatus and methods for the precision measurement and calibration of a body such as a precision rotary table. It consists of at least one, or preferably a polygon of mirrors placed on the body or around a circumference of the precision rotating table and an interferometer instrumentation arranged on an optical path which includes the mirrors. The rotational angle of the body or table is continuously measured with high accuracy without being affected by bearing runout. An optical means for detecting actual positions of the body using a laser and razor blade means provides for simple and easy calibration of the body's position.

Abstract: To test a bottle for contamination, the bottom of the bottle is laterally illuminated with a measuring light beam from a source. This measuring light beam is deflected, as if in a waveguide, in the ring of residual liquids at the bottom of the bottle. Light reemerging from the residual liquid is imaged on a detector by an imaging lens. The detector measures the spectral composition of the deflected light and compares this with theoretical values which should be yielded by the liquid with which the bottle was last filled. If deviations from the theoretical values are excessive, the bottle is rejected. The process described provides a simple way of determining whether a multi-trip bottle has contained an extraneous liquid.

Abstract: An interpolation circuit for a measuring device capable of increasing a resolution and providing a velocity proportional output. Both sin .theta. signal and cos .theta. signal outputted from a sensor is fed to a balanced modulation adding circuit, resulting in providing a sin(.omega.t-.theta.) signal, which is then shaped into a pulse wave in a waveform shaping circuit. Then, a higher harmonic component is extracted by a BPF and then mixed with cos n.omega.t and sin n.omega.t signals in mixers, so that cos n.theta. and sin n.theta. signals are taken out of LPFs, respectively. The signals are subject to interpolation in a voltage comparison interpolation circuit of which the number of dividing is m, resulting in providing an interpolation circuit of which the whole number of dividing is m.multidot.n. Interpolation output A-phase and B-phase thereof each are a velocity proportional output.

Abstract: A method and apparatus for conducting laser absorption spectroscopy uses a frequency tunable laser aligned to pass a laser beam through a sample volume and to an optical detector. A two-step modulation is used to generate frequency components that may be used to both lock the tunable laser to the absorbance signal, and generate an output signal proportional to the absorbance signal. The method includes frequency modulating the tunable laser at a first frequency while further modulating the tunable laser with a triangular waveform having a second frequency, and generating a feedback control signal based upon an antisymmetrical signal demodulated from the optical detector using a first predetermined harmonic of the second frequency. The tunable laser is locked to the absorbance signal with the feedback control signal. An output signal proportional to the absorbance signal is generated using a symmetrical signal demodulated using a second predetermined harmonic of the second or triangular waveform frequency.

Abstract: An optical device and method for sensing a plurality of ambient conditions (e.g., temperature and pressure) may include transmission of an optical flux through a fiber optic cable to a section of the cable that is placed where the ambient conditions are to be sensed. The section of cable includes a plurality of serially aligned sensors for reflecting the optical flux back through the cable, each of the sensors having semi-reflective surfaces at the two ends thereof for partially reflecting the optical flux. The distance between the two ends of each sensor varies primarily as a function of a different one of the ambient conditions. The optical flux is partially transmitted and partially reflected at each of the ends of the sensors and the optical flux reflected back through the cable includes an interference pattern that is a function of each sensor's end-to-end distance. A detector evaluates the interference pattern to determine the ambient conditions.

Abstract: The invention performs coordinate measurement employing multiple-frequency intensity-modulated laser radar. A laser diode source is intensity modulated by variation of its excitation current. Its output beam is directed to a target using scanning mirrors or other opto-mechanical means, and the light returned from the target is detected. The modulation frequency is alternated between two or more values, creating a dataset of several relative phase measurements that uniquely determine the distance to the target without ambiguity.

Abstract: An optical correlator is disclosed which, in combination with an ultrafast optical pulsed source, can be used for estimating distances of objects with submicron precision. The system includes at least one ultrafast pulsed laser source feeding into an amplitude-division device, an entity for launching pulsed radiation at the target along with an entity for collecting the radiation scattered or reflected off the surface of the object, a nonlinear device for timegating the collected signal with the amplitude-divided source, and a detection device for observing the timegated signal.

Abstract: A system for controlling the color of compounded polymer(s) comprises: a compounder for mixing the constituents of the compounded polymer(s) to produce a substantially homogeneous mixture; a sensor for measuring the color of the substantially homogeneous mixture at predetermined intervals; a colorant additive feeder, responsive to a controller, for providing the colorant additive(s) to the mixture at substantially predetermined colorant additive addition rates; and a controller, responsive to the sensor, for controlling the colorant additive addition rate(s) of the feeder.

Abstract: The invention provides a method consisting successively in producing two electromagnetic radiations of the same wavelength that is modulated as a function of time over a range of wavelengths, a "measurement" one of said radiations passing through a gas that presents selective absorption for said radiation in the range, while the other radiation constitutes a "reference" radiation. Each of said radiations is transformed into a respective "measurement" or "reference" electrical signal. The measurement signal is divided by the reference signal to obtain a first quotient electrical signal which is in turn split into two portions: a time-varying AC portion and a DC portion that does not vary with time. The AC portion is divided by said DC portion in order to obtain a second quotient electrical signal representative solely of the electromagnetic radiation absorbed by the gas.

Abstract: An optical correlator is disclosed that, in combination with an ultrafast optical pulsed source, can be used for estimating the differential position of remote objects with submicron precision, as opposed to measuring the absolute distance. The system includes an ultrafast pulsed laser source feeding into an amplitude-division device, with each amplitude component leading to an entity for launching pulsed radiation at the target, along with an entity for collecting the radiation scattered or reflected off the surface of the object, a nonlinear device for time-gating the collected signal with the amplitude-divided source, and a detection device for observing the time-gated signal. The device has remarkable spatial resolution and sensitivity. Applications of the technique to the measurement of torque, angular deformation, and two- and three-dimensional surface profilometry are presented.

Abstract: A photometer readhead is used to measure concentrations within a test sample of preselected color-developed analytes having different characteristic absorption bands. The photometer readhead comprises an artificial light source for illuminating the test sample, a plurality of light-emitting diodes for detecting light transmitted through or reflected from the test sample, and a housing assembly for enclosing and supporting the plurality of light-emitting diodes. The plurality of light-emitting diodes have spectral responses encompassing respective ones of the different characteristic absorption bands of the preselected color-developed analytes.

Abstract: An interferometric gauge for high precision absolute and incremental measurements of distances of up to at least 100 meters. An accuracy of 0.02 Angstrom has been demonstrated, free of the .about.10 Angstrom polarization-leakage errors of conventional gauges. The absolute distance measurement requires no a priori information, and multiple synthetic wavelengths need not be used. The gauge can be used as the sensor for a null servo. There are reduced-cost versions of lower accuracy. The gauge can employ a resonant cavity for greater sensitivity, and can be built with no transmissive elements in the measured path. Without additional hardware, the gauge readout can be in the form of a frequency or an analog electrical signal, in addition to a digital count of an integral number of wavelengths. The gauge employs a high-sensitivity null sensor. Feedback to an optical frequency shifter maintains the null condition; the frequency shift is measured electronically, providing a high sensitivity distance readout.

Abstract: Apparati and methods are disclosed for detecting vibrations, displacements and motions of a remote surface with high sensitivity, high frequency response and high accuracy using a laser beam with optical modulation, optical hetrodyning and phase detection. High speed digital signal processing is used. Shared aperture design is employed for utilization of a flat target, double-pass design for large lateral movement tolerance with high resolution, and dual target design for detection of displacement as well as angular changes in vibrational motion.