Abstract: A method for measuring ash content of food stuff is carried out by 1) preparing, with respect to food stuff samples whose ash content values are known, a calibration curve by a non-linear analysis of absorbance values and the known ash content of each sample, the absorbance values being obtained by irradiating light having particular wavelengths containing at least an ultraviolet ray band wavelength, the particular wavelength being specific to organic ingredients well coupled to inorganic ingredients which result in the ash content, and 2) deriving, with respect to a sample whose ash content value is unknown, an ash content value of the sample from absorbance values obtained by irradiating, on the sample, light having the particular wavelengths containing at least the ultraviolet ray band wavelength and from the calibration curve prepared in advance by the non-linear analysis.

Abstract: An optical filter used in applications involving spectroscopic measurements is fabricated by depositing layers of optical coatings onto a substrate. The layers are deposited so as to have a substantially constant thickness in a first direction along the surface of the substrate, and a gradually increasing thickness along a direction perpendicular to the first direction. The structure of the optical filter allows for large scale production of the filter so that costs in producing the filter are greatly reduced. The filter may be used in a variety of applications including, but not limited to chemical analysis, blood glucose monitoring, and the like.

Abstract: Optical characteristic measuring systems and methods such as for determining the color or other optical characteristics of an object are disclosed. Perimeter receiver fiber optics are spaced apart from a source fiber optic and receive light from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the optical characteristics measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence, gloss and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing prostheses based on measured data also is disclosed.

Abstract: A multispectral sensor device comprises a plurality of optoelectrical conters. Each optoelectrical converter generates wavelength selectively from an optical signal an electrical measurement signal in a respective measurement channel. A processing circuit processes the generated electrical measurement signals to the respective measurement signal values. A fuzzy logic circuit performs a comparison of the generated measurement signal values with reference values and, on the basis of the comparison, assigns the measurement signal values to a number of channels, this number exceeding the number of measurement channels.

Abstract: A multi-spectral two-dimensional imaging spectrometer includes a combination of single or multi-element, achromatic, well-corrected lenses for imaging a two-dimensional scene on an internal field stop. The light emanating from this intermediate image is collimated with another multi-element, achromatic, well-corrected lens. A spectral separation subassembly that divides the incident light into multiple, identical, and independent arms is placed in the collimated space following the collimating lens. The light in each arm is spectrally filtered based on the properties of an interference filter in each arm. An imaging subassembly composed of a single multi-element, achromatic, well-corrected lens system forms contiguous images onto a single two-dimensional detector array. The images are identical copies of the original object with each copy having a different spectral component and can be viewed on a standard monitor or alternatively on a computer employing an analog-to-digital conversion device.

Abstract: In an optical wavelength monitoring apparatus for easily monitoring wavelength deviation, light introduced from a laser source 10 to an optical transmission line 12 is divided by directional couplers 14, 20. Optical output of the directional coupler 14 is converted into an electrical signal by a photodiode 16, and logarithmic-amplified by a logarithmic amplifier 18. Optical output of the directional coupler 20 is introduced to a photodiode 26 via an optical filter 24. The optical filter 24 is an optical element whose transmittance decreases as the incident light deviates from a specific wavelength .lambda.a. Optical output from the optical filter 24 is converted into an electrical signal by a photodiode 26, and logarithmic-amplified by a logarithmic amplifier 28. A differential amplifier 30 outputs a difference between outputs of the amplifiers 18, 28.

Abstract: Color measuring systems and methods are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: Optical characteristic measuring systems and methods such as for determining the color or other optical characteristics of teeth are disclosed. Perimeter receiver fiber optics are spaced apart from a source fiber optic and receive light from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the optical characteristics measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence, gloss and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed.

Abstract: A method and system is disclosed in which the local variation of an extended radiation source is monitored with single-element detector. The chromatic aberration of the imaging optics induces the different transmittance curves for different wavelengths, and the different shape in the transmittance curve is used as a spatial filter which is multiplied to the chromatic intensity profile of the extended radiation source to detect the local variation in the intensity profile of the extended radiation source. The signal processing of the chromatic signals is implemented to detect the size variation and the environmental effects on the extended radiation source. A fiber is also used for remote operation.

Abstract: A description is given of a photoelectric measuring device by means of which the light reflected from a measuring point on a printed product is detected, and the corresponding measured signals are processed for the purpose of indicating quality data. A measuring instrument of this type, having at least one illumination device and measuring channels, is an improvement over the prior art in order to expand its possible uses, with a construction which is cost-effective and stable when handled. In accordance with the invention, this is achieved with an illumination device which has a spectral intensity distribution which corresponds to the number of spectral ranges provided for the irradiation of the measuring point. The light from the sequentially drivable illumination devices irradiates the measuring point. The light reflected from the measuring point is detected and converted into a reflective signal which is processed to determine ink density values.

Abstract: A wavelength monitor detects wavelength drifts of component channel signals within multi-wavelength light signals. Multiwavelength light incident on the wavelength monitor is cascaded along a multipoint travel path. Within the travel path, the component channel signals are incident on a series of wavelength discriminators arranged on an optically transmissive member. Each wavelength discriminator is selectively transmissive to a predetermined one of the channel signals and is reflective to the remaining component channel signals of the multi-wavelength light signal. According to a first preferred embodiment of the present invention, the optical transmission through each wavelength discriminator varies monotonically according to variations in the wavelength of the predetermined channel signal. Each selectively transmitted channel signal is intercepted by a detector which produces an output current that is mapped to corresponding signal wavelengths.

Abstract: A photometer for measuring electromagnetic radiation absorption of a sample utilizing a source of the electromagnetic radiation. Electromagnetic radiation is conducted from the source, to a sample sensor or sensors, and is passed through or scattered from, the sample utilizing a sample cell. The electromagnetic radiation is then directed to a detection system which determines absorbance of electromagnetic radiation by the sample at the sample cell. The detection system includes a beam splitter which receives the electromagnetic radiation and outputs first and second beams. A first detector having a first wavelength filter and a second detector having a second wavelength filter receives the two beams from the splitters. One detector may be employed to produce a reference signal. The remaining detector or detectors produce an output signal which is a representation of a characteristic, such as absorbance of the sample.

Abstract: For detecting the material properties of a moved material web (10) this web is illuminated along bands and the illuminated strip is imaged onto a two-dimensional camera (20) via an infrared optics (16) and a infrared filter device (18) consisting of individual strips with said camera being preferably an infrared camera. The pixels produced by the filter strips are translated into according absorption profiles within a computer (22).

Abstract: A spectroscopic system for measuring content of a constituent in a sample of a natural product is provided. The spectroscopic system includes a source for electromagnetic (EM) radiation and an absorbance filter for filtering EM radiation received from the source, where the absorbance filter transmits EM radiation of predetermined wavelengths solely by the absorbance characteristics of the filter material.

Abstract: Semiconductor chips for use in a chip array assembly for scanning of hard-copy images include rows of photosensors, each row of photosensors having a polyimide filter layer for passing one primary color. In addition to the photosensors, a reflective area is provided on the chip, with filter portions provided on the reflective area. The filter portions are created at the same time as the filter layers placed on the photosensors. The filter layers disposed on the reflective area can be used as test sites for determining the light transmissivity of the filter layers on the photosensors.

Abstract: A multi-wavelength optical filter for a portabe gas analyzer includes a filter assembly having a first opening and multiple additional openings. The first opening has a linearly variable filter disposed therein, while the additional openings have discrete filters disposed therein. The filters are linearly aligned, such that filter selection is facilitated by using the filter assembly with a linear positioning mechanism.

Abstract: A color separation prism in which are arranged, in the order according to the direction in which the light from the objective travels: a first prism which extracts a predetermined wavelength component; a first air gap; a second prism which extracts a predetermined wavelength component; a second air gap; and third and fourth prisms that are joined to each other, wherein, in particular, a light reflected by the joint plane is totally reflected by a surface adjacent the second air gap and guided to an image pickup device.

Abstract: An optical filter used in applications involving spectroscopic measurements is fabricated by depositing layers of optical coatings onto a substrate. The layers are deposited so as to have a substantially constant thickness in a first direction along the surface of the substrate, and a gradually increasing thickness along a direction perpendicular to the first direction. The structure of the optical filter allows for large scale production of the filter so that costs in producing the filter are greatly reduced. The filter may be used in a variety of applications including, but not limited to chemical analysis, blood glucose monitoring, and the like.

Abstract: A color classification system and method for classifying, judging and/or identifying objects by color. An optical system utilizes light from an object to form an image on an imaging device. A plurality of optical band-pass filters each having a different pass band are provided between the object and the imaging device. The optical band-pass filters include a plurality of measurement filters for use in measuring a color of the object and a test filter for use in judging which one of the measurement filters should be applied to the object. A changeover section changes between the optical band-pass filters. A computing circuit performs at least one of a color classification and a color judgment based on a spectral characteristic of the imaged object through a statistical approach, and a control section causes the changeover section to select an effective one of the measurement filters based on a judgment by the computing circuit of a result sensed by the test filter.

Abstract: A photometer for measuring electromagnetic radiation absorption of a sample utilizing a source of the electromagnetic radiation. Electromagnetic radiation is conducted from the source, to a sample sensor, and is passed through the sample utilizing a sample cell. The electromagnetic radiation is then directed to a detection system which determines absorbance of electromagnetic radiation by the sample at the sample cell. The detection system includes a beam splitter which receives the electromagnetic radiation and outputs first and second beams. A first detector having a first wavelength filter and a second detector having a second wavelength filter receives the two beams from the splitters. One detector may be employed to produce a reference signal. The remaining detector or detectors produce an output signal which is a representation of a characteristic, such as absorbance of the sample. The output signals are operated on by a reference signal, and converted into a measurement absorbance.

Abstract: Color measuring systems and methods are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Abstract: A stimulus values direct reading colorimetric instrument comprising a plurality of photoelectric sensors having different spectral responsivities equal or approximately equal to color matching functions X(.lambda.), Y(.lambda.), and Z(.lambda.); and measuring and display device to measure and display the tri-stimulus values X,Y and Z and the chromaticity of the light to be measured by computing the photoelectric sensor output signals caused by the light, wherein the instrument calculates the stimulus values corresponding to the tri-stimulus values and measures the chomaticity by providing at least one corrective photoelectric sensors so as to maximize their spectral responsivities in the vicinity of the transmission threshold wavelengths of each sensor and taking the sum of the output signals from the sensors and the corrective sensor after multiplying each coefficient assigned to the signals by each output signal, respectively.

Abstract: An electro-optical system is devised for scanning a color document into electrical signals for reproduction of the color document. The electro-optical system comprises a white light source for generating a beam of white light for illuminating the color document being scanned. A self-focus lens array consisting of at least a first row, a second row, and a third row of rod lenses is used to focus the reflected light from the color document onto a linear photosensor array. To separate the reflected light into RGB components, a first strip of red filter film is attached to one end of the first row of rod lenses; a second strip of green filter film is attached to one end of the second row of rod lenses; and a third strip of blue filter film is attached to one end of the third row of rod lenses. The light passing through the self-focus lens array causes the linear photosensor array to generate electrical signals representative of the amounts of the red, green, and blue components in the reflected light.

Abstract: A spectroscopic apparatus capable of simultaneously producing spectroscopic images corresponding to a plurality of wavelengths and a spectroscopic image recording apparatus capable of recording the produced spectroscopic images, wherein an image producing unit produces a plurality of same images from a single input image by dividing a pupil of an optical system, a first spectroscopic unit produces a plurality of first spectroscopic images corresponding to the plurality of same images by extracting a predetermined wavelength component corresponding to each of the plurality of same images, and a second spectroscopic unit produces a plurality of second spectroscopic images corresponding to respective ones of the first spectroscopic images by extracting a predetermined wavelength component corresponding to each of the first spectroscopic images corresponding to the plurality of same images.

Abstract: A wavelength measurement system is provided which allows the very accurate measurement of wavelengths in a relatively small predetermined range. A transmission ratio is formed consisting of the power of an optical signal which has passed through a thin-film interference filter divided by the power of a control signal. A table look up is performed in a stored transmission ratio wavelength table. The system is also used in a self stabilizing laser, and a spectrometer.

Abstract: A method of determining area coverage of a printing original having printing areas and non-printing areas thereon, the printing areas being of a different color than that of the non-printing areas, the printing original having a location-dependent inhomogeneity independent of the area coverage, including optically scanning the original for determining a local diffuse reflection of a measured measuring field, the measuring result of the optical scanning being influenced by the inhomogeneity; determining at least two diffuse-reflection values from each measuring field, the diffuse-reflection values differing spectrally from one another in accordance with the color difference; and evaluating the two diffuse-reflection values and separating a component of the measuring result which is influenced by the area coverage, and a component of the measuring result which is influenced by the inhomogeneity; and the device thereof.

Abstract: A color classification apparatus for classifying the color component of a target object includes an imaging optical system, an image pickup device, optical bandpass filters, a transmission wavelength selection unit, a storage unit, a read unit, and a correction unit. The image pickup device is arranged on the imaging plane of the imaging optical system. The optical bandpass filters are optically arranged upstream the image pickup device, and have a plurality of different selectable optical transmission wavelength bands. The transmission wavelength selection unit selects one transmission wavelength band from the plurality of optical transmission wavelength bands.

Abstract: A differential spectrometry system detects very narrow-band spectral features, while providing much higher optical transmittance and signal-to-noise ratios than prior optical-filter-based spectrometer systems. A plurality of light detectors (10a, 10b) detect light that falls within respective wide wavebands. The wide wavebands have overlapping and non-overlapping portions, one of which is the desired narrow waveband. The detector outputs are operated upon to produce an output signal (22) which includes substantially only the desired narrow waveband. In the preferred embodiment, the light detectors (10a, 10b) are implemented with a pair of optical detectors (30a, 30b) and respective optical interference filters (24a, 24b). The filters have substantially identical cut-off wavelengths (.lambda..sub.2) and cut-on wavelengths that are shifted by .DELTA..lambda. with respect to each other (.lambda..sub.1 and (.lambda..sub.1 +.DELTA..lambda.), respectively).

Abstract: Methods for wavelength determination of a monochromatic beam are described. The methods involve a detector unit containing at least one variable filter and at least one pair of photo detectors. The detectors have photo sensitive regions with their areas varying with the position in one direction. The wavelength for maximum transmission of the variable filter varies in the same direction. By comparing the photo current values from the two detectors, wavelength of the incident beam is determined. Methods to construct wavelength discrimination junction photo detector pair and double barrier photo detector pair are also given.

Abstract: Measurement device, for the colorimetric measurement of a display screen. The device includes a first lens which forms the image of the Fourier transform of the elementary surface to be measured. An optical system is used to form a second lens which projects the image of the transform onto a set of detectors. The second lens (10) comprises an input lens (11) after the image plan (Fi) of the first lens (1), a colour filter (12) formed by filters (12l) which are associated with each colour, an output lens (13), downstream of the colour filter (12) for focusing the beams onto the detectors (7i, J) of the sensor (7), and a processing circuit (18).

Abstract: A first embodiment of the invention includes a light source (1) lighting two parallel optical branches (b1, b2) controlled respectively by two optical shutters (4, 6), one comprising a transparent cell (3) containing a substance to be studied, and the other being used to divert the light from the source. The light coming successively from one and from the other branch is applied selectively to three color filters (F1-F3) filtering three wavelengths selected according to the substance to be studied. The successive luminous intensities which have crossed each of the filters are measured through three detectors (D1 to D3) and the measurings are combined by means of a control (0). Analogous measuring sequences may be achieved with an embodiment comprising three light sources and a single detector. The device can be used for determination of the pH value of a substance.

Abstract: An instrument kit includes a photometric instrument and a standardizing ampoule. The standardizing ampoule includes a machine readable code that is recognized by the instrument when the ampoule is inserted to initiate a standardizing routine. An analysis kit includes an optical filter assembly and a sample ampoule to be used with the instrument. The filter assembly also includes a machine readable code that is detected by the instrument when inserted to identify the particular test to be conducted by the instrument. The instrument automatically applies the relationship between detected light and concentration of a substance for the particular test and displays the sample concentration in numeric digital form. The instrument operates automatically, and there are no buttons or other external input devices.

Abstract: The invention relates to a method of measuring the wavelength of an optical signal such as a light beam. The optical signal is directed toward a detector where its intensity is detected and stored. Several optical elements each having a different wavelength dependence are moved into the path of the optical beam one at a time and for each intensity is detected and stored. The wavelength of the optical signal is then approximately determined based upon the ratio of the detected intensity of the optical signal in the absence of any optical elements and the detected intensities of the optical signal in the presence of each optical element.

Abstract: In a Raman microscope, Raman scattered light from an illuminated area on a sample 10 is collected by an objective 12 and imaged by a lens 18 onto a detector in an image plane 20. A filter 16 selects only light of a desired Raman wavenumber shift. Since the tuning of this filter is sensitive to the angle of incidence, it is placed after the lens 18 instead of before it, and the distance from the objective 12 to the lens 18 is made substantially equal to the focal length of the lens 18. This ensures that chief rays 14A',14B' from different points on the sample 10 pass through the filter 16 at the same angle of incidence. The wavenumber selected by the filter is therefore the same for light from all points on the sample, which it would not be if the filter were placed before the lens 18.

Abstract: An incident optical signal is captured by an array of apertures and directed to pairs of fibers, each pair having a delay fiber with a unique length and a no-delay fiber. Each pair of fibers further has a unique transmission characteristic. Time interpolation is then performed using the transmission characteristic curve for each delay fiber and the duration from the time the optical signal arrives over the no-delay fibers and the time the signal arrives over the delay fibers to determine the wavelength. In a second embodiment, each pair of delay and no-delay fibers is replaced by a fiber splitter which directs light into a no-delay fiber and a delay fiber that have been split from the input of the splitter. In a third embodiment, two fiber splitters are used in place of the pairs of fibers. Each splitter has a number of branches for receiving light and an output end for guiding light onto the photodetectors.

Abstract: In the present equipment for spectroscopic measurement of a gas in a gas mixture, for example a gas in the atmosphere, a filter device is used to filter out one spectral line from other spectral lines belonging to other gases and the transmitted light is detected by a detector which gives a signal to devices for calculating and displaying the measurement data. The filter device consists of an interference filter (1), at least one fixed etalon (2) and a Fabry-Perot interferometer (1). In a preferred design, the filter can be fitted with two fixed etalons instead of one.

Abstract: A device for determining the color value of light includes a linear graded interference filter, which has only one expansion direction through which the light is incident on a number of photodetectors. The photodetectors are arranged adjacent to one another in the expansion direction of the graded interference filter and are used to supply measuring signals, on the basis of which the color value is calculated. Focusing optics arranged in front of the graded interference filter are used to focus the light onto the photodetectors. The light is fed via a plurality of optical guides, whose light exit ends are arranged closely adjacent to one another along one or more rows extending in the expansion direction of the graded interference filter. The focusing optics contain a cylindrical lens extending in the expansion direction. Advantageously, the photodetectors are PIN photodiodes and the optical waveguides are optical fibers.

Abstract: The optical properties measuring device of this invention performs preliminary emission of light from a light source prior to main light emission for sample measurement, and approximates the optical properties of the sample based on the output from a photosensor at the time of preliminary emission. Then, based on the approximated optical properties, the luminous energy for the main light emission for sample measurement is determined. Main light emission from the light source in accordance with the luminous energy determined this way is then performed, and the sample's optical properties are calculated based on the output at this time. In other words, this invention is characterized in that the sample's optical properties are approximated beforehand by means of this preliminary light emission, and the luminous energy at the time of the main light emission to perform sample measurement is changed in accordance with the result of this calculation.

Abstract: An in-situe chemical gas or fluid analyzer for vehicles, industrial, environmental and process control applications. As applied to a vehicle (1) having an internal combustion engine, the analyzer includes: (i) a source of electromagnetic radiation (14, 16); and (ii) a sampling cell (12) which collects emission gases of interest and which is capable of withstanding hostile environments while preserving a "clear" optical path between the sensor sampling cell and the source of radiation. The analyzer further includes: (iii) a solid state sensor (24, 26, 28, 30, 32 ) of monolithic construction which selectively detects electromagnetic radiation that is absorbed or emitted by one or more chemical species of interest, that compensates for temporal and spatial variations in illumination level provided by the source, and that provides an electrical signal output, in either analog or digital format, that is related to the measured concentrations.

Abstract: Light measurement apparatus includes an elongate member which has at one end thereof light emitter(s) and light detector(s). At least the end of the elongate member that has the light emitter(s) and light detector(s) is surrounded by a resiliently biased sheath. In use, when the elongate member is applied to a surface to take a reading, the sheath defines a light-tight enclosure. A related method for determining intensity and/or color of a colored spot on a surface of a test site uses the light measurement apparatus. The method includes bringing the end of the elongate member into contact with the surface, pressing the resiliently biased sheath towards the surface to define a light-tight enclosure, and measuring the intensity and/or color of the colored spot on the surface.

Abstract: A variable filter spectrophotometer, for use with sample and reference; has a main member, a filter unit, a drive, a detector, a light distribution system, and a clamping circuit. The main member defines first and second beam paths, which are intersected by the filter unit. The filter unit has filtering and opaque portions. The filter unit is continuously movable relative to the beam paths in a repeating cycle from a first filtering relation in which the filtering portion is interposed in the first beam path and the opaque portion completely blocks the second beam path, to a first dark relation in which both beam paths are blocked, to a second filtering relation in which the filtering portion is interposed in the second beam path and the first beam path is completely blocked, and to a second dark relation in which both beam paths are completely blocked. The filtering portion is variably transmissive along a direction of movement of the filter unit.

Abstract: A correlated color temperature measuring device for measuring the color temperature of light includes a sensor which individually senses plural light components of light incident thereon and for providing plural corresponding digital color component signals representative thereof, a memory which stores correction data for correcting the plural digital color temperature component signals, and a processor which receives the plural digital color component signals from the sensor. The processor accesses the correction data in the memory, corrects the plural color component signals from the sensor based on the correction data and derives a digital signal representative of the color temperature of the incident light. The derived digital signal may be displayed on a digital display or may be outputted on a digital I/O interface in response to a request for digital color temperature information.

Abstract: The intensity 2 of radiation coming from an object 1 to be measured and illuminated by collimated radiation is measured at several wavelengths by focusing the radiation, via a lens 4 and a planar mirror 6, on a detector group 3 having several detector elements (3a to 3d). The radiation coming from the object is directed by the lens and the mirror such that, by rotating the mirror, tilted at a small angle with respect to its axis 5, around this axis and by keeping the radiation on the surface of the mirror, the focus F of radiation is moved in a detector plane D along an uninterrupted circular path R crossing each detector element positioned substantially in the same plane and excited at a different wavelength.

Abstract: The present invention discloses a method for demodulating, processing and multiplexing the signals from an array of structurally integrated Bragg grating laser sensors in an optoelectronic element in order that this sensing information can be transmitted from the structure by means of a single channel and a user friendly interconnect or free-space propagation. The invention also discloses a method for determining the wavelength of narrowband optical signals such as arises from Bragg grating laser sensors and includes, for each sensor, processing the optical signal through a spectral filter with a spectral transmission function that can be accurately translated by a control parameter which has been calibrated with respective to wavelength. The filtered signal is compared to the reference signal at different values of the control parameter to determine a value of the control parameter where a predetermined relationship of the spectrally filtered signal and the reference signal is achieved.

Abstract: A two color radiation detector. A dispersive lens with a spectrally selective central obscuration focuses a first radiation band on a central location on focal plane array. The dispersive lens also focuses an annulus of out of focus radiation of a second radiation band concentric with the central location on the focal plane array. For point target detection the dispersive lens transmits plume band and guard band radiation to the staring focal plane array sensor. The staring focal plane array is located at the focal point of the plume band radiation. A spatial filter detects target signatures using information from the plume band and guard band radiation.

Abstract: A two-dimensional colorimeter focuses light through a beam splitter onto a rotary filter so that a first light receiving element can receive light from multiple points on a sample. A rotating filter can provide multiple measurements based upon different wavelengths of light. A portion of the light from the beam splitter also contacts a spectral sensor which separates the light from a particular point into primary wavelength elements which are converted into electrical signals. Based upon these primary wavelength elements, the first signals from the light receiving element are corrected. As a result, the measurement of chromaticity of multiple points on a sample can be performed accurately using a device of simple construction.

Abstract: A method and apparatus for determining the color of an object which is transparent, diffusing, and absorbent, by illuminating an area of the object by means of a diffuse light flux that is substantially uniform and isotropic, by picking up the light backscattered by a small fraction of the illuminated area of the object by means of an optical system that comprises achromatic doublets and both infrared and ultraviolet filters, together with a diaphragm, and spectrally analyzing said light by means of interference filters and photodetectors. The invention is particularly suitable for determining the color of teeth in the mouth.

Abstract: An absorption meter determines concentration of chlorophyll a and pheophytin in liquids. Particularly, an immersible absorption meter has a light source, a reflective flow tube, a signal detector, and means for determining the difference between the absorption coefficients at a first wavelength and a second wavelength. The light source may further include a plurality of filters and a selector that selects the filters. The concentration of substances in liquids is determined by measuring the absorption of light at a first wavelength and at a second wavelength, determining the difference between the absorption coefficients for the first and second wavelengths, and converting this data into concentrations.

Abstract: A spectroradiometer images a scene as a repeating sequence of spectral images, each of which spectral images depicts the scene at a preselected wavelength. In a preferred embodiment, the image is of size 256 by 192 pixels, and the sequence repetition rate is about 20-30 cycles per second. Full spectral analysis on the resulting sequences is performed substantially in real time. The spectroradiometer includes a light collector with a lens, a circularly variable spectral filter, and an optical gate which gates the output of the filter to a detector array which outputs the sequence of electronic spectral images. These images are corrected for systematic errors and calibrated, and correlated with a preselected spectral response function. The image may be further post-processed and displayed in video format or used otherwise.

Abstract: A postacquired spectrophotometer, for use with a sample and reference. The spectrophotometer has a filter unit, defining an axis of movement, and pluralities of designated sites and dark sites disposed in uniform relation to the axis. The designated and dark sites are disposed in alternation. Alternating designated sites have apertures and filters covering the apertures. Further, a main member, coaxial with the filter unit, has sample and reference beam paths, which are intersected by the sites. The main member has disposed, in operative relation to the actuators, an actuator sensor, which generates an integration actuator signal upon alignment with each integration actuator and a clamping actuator signal upon alignment with each clamping actuator. Moreover, a drive continuously moves the filter unit relative to the axis and beam paths.