Abstract: A new system for millimeter wave electronic imaging is described. This system utilizes a spatial light modulator in the focal plane of the collection optics. Each pixel of the modulator is driven by a specific high duty cycle modulation function provided by a modulation function generation circuit. Thus the throughput radiation at each pixel is uniquely labeled(encoded). A post modulation detector sums the signal from all the pixels. Subsequent to detection, the appropriate transform of the sum signal yields specific pixel throughput radiation intensity levels. Several configurations are described including one transmittance configuration and two reflectance configurations. Three specific millimeter wave transmittance embodiments and one reflectance embodiment are also described.

Abstract: The invention relates to a procedure for determining an identification of a sample of material, or its properties. Electromagnetic radiation from a radiation source (1) is reflected or transmitted through the sample. The radiation from the sample is collected and analyzed over several channels (7, 7', 7"), which modulate the radiation with a spectral transmission function which is unique for each channel. The modulated radiation is transmitted to one or several detectors (9, 9', 9") which produce output signals which are further electronically processed. The spectral range of each of the individual channels is common to all of the channels. Within the common range the channels are provided with different spectral transmission functions (7, 7',7") which are optimally chosen for a given application.

Abstract: A multi-slit type spectrometer includes a light diffracter which diffracts an incident light according to wavelengths; an optical shutter array member including a plurality of optical shutter elements arranged in correspondence with wavelength bands diffracted by the light diffracter, operable to transmit an incident ray according to an applied voltage, and made of PLZT. A zone of a given number of adjacent optical shutter elements is applied with a voltage corresponding to the wavelength bands of the rays incident upon the zone of adjacent optical shutter elements at a specified timing so that the rays respectively pass through or are reflected at the optical shutter elements. A signal processor receives the ray which has passed through or has been reflected at each optical shutter element and outputs an electrical signal according to the intensity of the received ray.

Abstract: An imaging spectrometer that includes a mask (214) that has an array of n rows (302) and n columns (304) of transmissive elements (306) for transmitting the light from a plurality of locations of an image and of opaque elements (308) for blocking light from a plurality of locations of the image. The transmissive and opaque elements are arranged in a Hadamard pattern having rows (and columns) that are different cyclic iterations of an m-sequence. A grating (110) disperses the transmitted light from the transmissive elements (306) in a linear spatial relationship in a predetermined relationship to the wavelength of the transmitted light. A detector array (406) has a plurality of detector elements (408) arranged in a row to receive the dispersed transmitted light from the grating (110). Each detector element (408) provides an intensity signal indicative of the intensity of the light impinging thereon.

Abstract: A multi-sample spectrometer which finds particular application in such applications as on-line process control and monitoring, employs a Hadamard encoding scheme and comprises a source of radiation, a primary encoder to encode radiation from the source, a sample receiver to position the samples in the radiation path, a secondary encoder to modulate the intensity of radiation directed to individual samples, and a detector for receiving radiation from the samples.

Abstract: A multi-slit type spectrometer includes a light diffracter which diffracts an incident light according to wavelengths; an optical shutter array member including a plurality of optical shutter elements arranged in correspondence with wavelength bands diffracted by the light diffracter, operable to transmit an incident ray according to an applied voltage, and made of PLZT. A zone of a given number of adjacent optical shutter elements is applied with a voltage corresponding to the wavelength bands of the rays incident upon the zone of adjacent optical shutter elements at a specified timing so that the rays respectively pass through or are reflected at the optical shutter elements. A signal processor receives the ray which has passed through or has been reflected at each optical shutter element and outputs an electrical signal according to the intensity of the received ray.

Abstract: A system for measuring angular relationships of wheels of a vehicle includes a radiation source mounted with respect to a first wheel for providing a radiation signal, an image detector having an active array of pixels mounted with respect to a second wheel for receiving an image from the radiation source and for producing an output in response to the radiation signal, and a radiation detector disposed in the path of the radiation from the radiation source for detecting the presence of the radiation signal. A controller is responsive to the presence of the radiation signal to activate the image detector to receive the image from the radiation source and determine an alignment angle of a wheel of the vehicle from the output of the image detector.

Abstract: Method and apparatus for analyzing energy emanating from a source by converting energy from the source into spectral components distributed according to frequency along a flat field, combining the spectral components into a beam, detecting the beam which combines the spectral components and demodulating the spectral components.

Abstract: Analysis of energy emanating from a source having a focal plane by converting the energy from the source into modulated spectral components simultaneously distributed according to frequency along a flat field, using, for example, a modulator, and then detecting and demodulating the spectral components, for example by a fast Fourier transform or synchronous demodulator with a ruled grating interposable between the source and the detector and a linear variable bandpass filter interposable between the source and the detector.

Abstract: In a spectrophotometer, a light source is provided in the form of a multiplicity of light emitting diodes which transmit light through an entrance slit to irradiate an oscillating grating. The light is dispersed by the grating toward an exit slit which transmits a narrow bandwidth of light to irradiate a sample. As the grating oscillates, the wavelength transmitted through the exit slit is scanned through a selected spectrum. The diodes in the array each emit light in a different wavelength band so that the diodes as a group emit light throughout the selected spectrum. As the grating oscillates, the diodes are energized and extinguished in sequence so that no more than two diodes will be energized at any given instant of time and the energized diode will be emitting light at the wavelength dispersed by the grating to the exit slit.

Abstract: A multi-slit type spectrometer includes a diffractor by which an incident light is diffracted according to wavelengths; an optical shutter array member including a plurality of optical shutter elements arranged in correspondence with wavelength bands diffracted by the diffractor, operable to transmit an incident ray according to an applied voltage, and made of PLZT. Each optical shutter element is applied with a voltage corresponding to the band of the ray incident upon the optical shutter element at a specified timing so that the ray passes through the optical shutter element. The spectrometer further includes a photosensor to convert the ray passed through the optical shutter element to an electrical signal, and a calculator to calculate the intensity of the incident ray for each band in accordance with the electrical signal output from the photosensor and the specified applying timing.

Abstract: A new type of fully-multiplexed imaging device is described for use at wavelengths where efficient focal plane array detectors are unavailable. It shares some properties in common with the familiar technique of cycle-redundancy (i.e. Hadamard transform) imaging, but many of its features and capabilities are unique. Some of these characteristics are, first, the new approach employs image encoding masks that are both transmitting and reflecting, thereby increasing optical efficiency, and second, the technique requires only 2.sqroot.N encoding masks to image a field of N pixels, a dramatically smaller number than that needed (.about.2N) by traditional methods. Dual complementary inputs are used for first-order passive rejection of radiation background interference. The resulting image spatial resolutions along two coordinate directions are completely independent of each other. The measured image is formed by a convergent tiling of the image plane, quite unlike conventional raster scanning.

Abstract: A new method for accurately and sequentially growing monolayers and creating new superlattice structures employing a MBE thermal source control technique employing a quasi-double beam atomic absorption background correction measurements with the beam blocked and with the beam unblocked and by calculating the concentration based on the: ##EQU1## and applying corrections for non-linear absorption curves because of comparable spectral bandwidth of the molecular beam.

Abstract: A random access monochromator is disclosed. This device has no mechanical parts and eliminates the need to scan sequentially the wavelengths of light contained in a light spectrum to select a desired wavelength or wavelengths from the spectrum. The device has high speed switching means, permits one to select multiple wavelengths and bandwidths at the same time, and has the ability to correct for non-linearity in prisms caused by their nonlinear or second order dispersion of light.

Abstract: A spectrophotometer includes an array of light emitting diodes configured for activation in successive Hadamard encodement patterns, a diffraction grating, an optical slit, a detector and electronic controls including a computer. In operation, the diffraction grating disperses and collimates radiation from the array and directs selected spectral components through the slit onto the detector whereupon the computer performs a Hadamard analysis on the detector signals.

Abstract: A color discrimination data input apparatus includes a light source for generating illumination light for illuminating a target object, a spectroscope for producing a spectrum having a plurality of spectral components, a color classification filter set to have a light-transmitting characteristic to pass only a light component having a wavelength range suitable for classification from the spectral components generated by the spectroscope in order to classify the spectral components reflected by the target object into predetermined classes, a photoelectric converting circuit for converting a reflected spectral component, upon radiation of the spectral component passing through the color classification filter on the target object, into an electrical signal, classifying circuit for classifying the reflected spectral components in accordance with the electrical signal output from the photoelectric converting circuit, the color estimating circuit of estimating a color of the target object from the reflected spectra

Abstract: The present invention is an apparatus for forming a spectrally weighted value from received multispectral radiation. The spectral weighting is done optically prior to detection of the received radiation by dispersing the received multispectral radiation into a plurality of wavelength bin areas. This dispersed radiation is then passed through a weighting filter which includes first and second filter elements for each of the wavelength bin areas. The filtered radiation is then converged to corresponding detectors with the spectrally weighted value formed by the difference between the signals of the first and second detectors. A pair of filters, two detectors and a subtracter are employed to produce a generalized weight factor having positive or negative weights. This system can form one or more spectrally weighted values from the radiation from a single pixel, or one spectrally weighted value form the radiation from a plurality of pixels.

Abstract: A Hadamard mask is placed in the entrance plane of a standard flat field grating spectrograph. A planar array is used as the detector. The Hadamard mask contains 2n-1 elements, where n is the number of elements in the detector array. This configuration produces a spectrograph with a wide aperture and hence high throughput, and allows rapid spectral measurements with no moving parts. It also allows simultaneous measurement of a randomly occurring pulse source.

Abstract: An imaging system for providing spectrographically resolved images. The system incorporates a one-dimensional spatial encoding mask which enables an image to be projected onto a two-dimensional image detector after spectral dispersion of the image. The dimension of the image which is lost due to spectral dispersion on the two-dimensional detector is recovered through employing a reverse transform based on presenting a multiplicity of different spatial encoding patterns to the image. The system is especially adapted for detecting Raman scattering of monochromatic light transmitted through or reflected from physical samples. Preferably, spatial encoding is achieved through the use of Hadamard mask which selectively transmits or blocks portions of the image from the sample being evaluated.

Abstract: An improved Raman spectrometer device is provided which provides useful spectral information in situations where Raman spectroscopy has heretofore been unworkable. The spectrometer of the invention makes use of a stationary electrooptical masking device in lieu of conventional slit scanning optics, with the mask being computer controlled to provide a multiplexing function, typically employing Hadamard mathematics. The stationary encoding mask permits use of a relatively inexpensive photodiode detector, as compared with photomultiplier tubes conventionally used in Raman instrumentation. Advantageously, unwanted Rayleigh scattered radiation can be completely eliminated, either by blanking those zones of the mask receiving such radiation, or physically locating the device in such orientation that the Rayleigh scattered radiation does not pass through operative portions of the mask.

Abstract: An improved masking device for optical-type radiations is provided and employed in improved optical apparatus, such as spectrometers, requiring alterable radiation masking. The masking device involves no movable parts, is adapted to operate in a fixed position and has radiation transmission and/or reflection characteristics which are selectively alterable merely by controlling electrical excitation applied to the device. The masking device typically has a plurality of separated and predisposedly offset, coplanar zones of solidified, electro-optically active material carried upon a typically transparent substrate and bounded by areas of an opaque material. The active material may be any of the crystalline or polycrystalline materials which have the property of changing their optical characteristic between being relatively transmissive and being relatively reflective and/or opaque for radiations of the wavelengths of interest, in response to the passage of electrical current through the material.

Abstract: Within a surveillance system there is included optical processor means for receiving a multispectral light image at an input and providing a spectrally modified image at an output, which comprises: an input means for receiving a light image; light dispersing means coupled to said input means for dispersing said received image into a constituent plurality or spectral components and distributing said plurality of spectral components over a predetermined area; means located in said area responsive to said spectral components located in said space for modifying at least one of said spectral components and for reflecting said spectral components, including modified spectral components, to a common plane in essentially overlapping registered relationship to reconstitute a multispectral image of different spectral content so as to eliminate clutter from within the image. Other disclosed systems provide for communications and color matching.

Abstract: Photo plotter aperture members each have a beam forming trasnsparent ring and a central transparent cross in communication with the ring. The rings of the different members are of different diameters but of the same thickness as the lines of the respective crosses to provide uniform exposure during half diameter strokes of the aperture members.

Abstract: An accessory for use with spectrophotometers for conducting IR emission spectra analyses of samples comprising a heated highly-reflecting surface for receiving the sample, an apertured reflecting mask located over the sample, and a curved reflector for collecting emissions from the sample via the aperture over a large solid angle to increase the signal-to-noise ratio.

Abstract: An improved masking device for optical-type radiations (e.g., infrared visible or ultraviolet) is provided and employed in improved optical apparatus, such as spectrometers, requiring alterable radiation masking. The masking device involves no movable parts, is adapted to operate in a fixed position and has radiation transmission and/or reflection characteristics which are selectively alterable merely by controlling electrical excitation applied to the device. The masking device typically has a plurality of separated and predisposedly offset, coplanar zones of solidified, electrooptically active material carried upon a typically transparent substrate and bounded by areas of an opaque material.

Abstract: Spectral analysis of a beam of radiation is carried out by splitting the beam of radiation into its respective spectral components and by applying a characteristic modulation to each of the spectral components before allowing them to fall on a common detector. The super-imposed signals generated by the detector and representative of the spectral components are then electronically segregated by reference to the characteristic modulations that have been applied to the individual spectral components. This is conveniently done by generating a series of modulated reference signals which have been modulated in exactly the same way as the spectral components of interest. The technique is not restricted to optical spectra but can also be used, for example, for X-ray spectra and mass spectra.

Abstract: A novel apparatus for the measurement of color of a sample which comprises an illumination means to illuminate the sample, an electro-optical sensing head to receive the light from the illuminated sample and to output electronic signals and an electronic processing unit to process the signals. The light source may in the preferred embodiment be the sun or the sample itself and a reference optical path is used for reference which is the same optical path as the optical path from the light from the sample. The tristimulus values X, Y, Z and the chromaticity coordinates x, y of the sample with respect to the CIE standards for luminance and chromaticity values are produced for accurate color measurement.

Abstract: A novel apparatus for the measurement of color of a sample which comprises an illumination means to illuminate the sample, an electro-optical sensing head to receive the light from the illuminated sample and to output electronic signals and an electronic processing unit adapted to process the signals. The system uses, in the preferred embodiment, a moving spatial filter to modulate a spectrum and a masking means to selectively mask the light from the modulated spectrum. A reference optical path and reference light signals are produced for subsequent processing with the light from the sample, corrected for any errors produced and processed in an analogue electronic unit to produce the tristimulus values X, Y, Z and the chromaticity coordinates x, y of the sample with respect to CIE standards for luminance and chromaticity values.