Abstract:
Apparatus and methods for wavelength-dependent detection are provided. A detector includes a hybrid filter having unpatterned and patterned filter layers and at least one light-detecting sensor that detects light in first and second wavelength bands from the patterned filter layer of the hybrid filter. The unpatterned filter layer passes light in two nonoverlapping wavelength bands relative to light in wavelength bands between or among the nonoverlapping wavelength bands. The patterned filter layer includes first and second regions configured respectively to pass light in the first and second wavelength bands of the nonoverlapping wavelength bands passed by the unpatterned filter layer.
Abstract:
Disclosed examples of optical systems having a plurality of light sources with each source having a different spectral outputs may be calibrated by measuring a spectral characteristic of the combined light with two measurements, e.g., one from a colorimeter and one from a sensor included in the system. Accordingly, one can determine a transform function in response to the two measures that models a feedback response of the optical system for each of a plurality of the inputs that would cause the optical system to generate radiant energy within a predetermined range of a spectrum. In order to calibrate the optical system, the transform function is programmed in the optical system to enable the optical system to transform an input to the optical system to a plurality of unique control signals each for controlling a respective light source of the plurality of light sources.
Abstract:
An illumination device for use with a product inspection machine inspecting products according to at least one characteristic. The invention also pertains to an illumination device for use in sorting machines that optically sort or separate nonstandard fungible objects from standard objects as they pass a viewing station by viewing such objects illuminated by at least one wavelength. The invention includes a plurality of arrays of semiconductor light sources impinging on passing product and at least one array of semiconductor light sources of wavelength and intensity equal to the plurality of arrays impinging on a background surface for detection and comparison.
Abstract:
A device for determining the surface topology and associated color of a structure, such as a teeth segment, includes a scanner for providing depth data for points along a two-dimensional array substantially orthogonal to the depth direction, and an image acquisition means for providing color data for each of the points of the array, while the spatial disposition of the device with respect to the structure is maintained substantially unchanged. A processor combines the color data and depth data for each point in the array, thereby providing a three-dimensional color virtual model of the surface of the structure. A corresponding method for determining the surface topology and associated color of a structure is also provided.
Abstract:
A color measurement instrument includes a housing and illuminators, a two-dimensional photodetector array, and an optics system within the housing. A UV filter wheel closes the housing to prevent contaminants from entering the housing. The filter wheel supports UV filters and non-UV glass that can be selectively aligned with the illuminators. The photodetectors can be read in parallel, and each photodetector includes a unique spectral filter. The optics system delivers light from the sample target area equally to each of the photodetectors.
Abstract:
To determine spectra, integrated multiple illuminant measurements from a non-fully illuminant populated color sensor may be converted into a fully populated spectral curve using a reference database. The reference database is partitioned into a plurality of clusters, and an appropriate centroid is determined for each cluster by, for example, vector quantization. Training samples that form the reference database may be assigned to the clusters by comparing the Euclidean distance between the centroids and the sample under consideration, and assigning each sample to the cluster having the centroid with the shortest Euclidean distance. When all training samples have been assigned, the resulting structure is stored as the reference database. When reconstructing the spectra for new measurements from the sensor, the Euclidean distances between actual color samples under measurement and each cluster centroid are measured. The spectra are then reconstructed using only the training samples from the cluster corresponding to the shortest Euclidean distance, resulting in improved speed and accuracy.
Abstract:
Devices, systems, and methods for measuring the color of a sample are disclosed. The exemplary device may have one or more light emitting diodes for directing a beam of ultraviolet light onto the sample and may also have one or more light emitting diodes for directing a beam of visible light onto the sample. The exemplary device may have a component for controlling the timing and power of operation of each light emitting diode. The exemplary device may also have at least one light detector for receiving the beam of light reflected from or transmitted through the sample and measuring at least one wavelength band of the received light. The exemplary device may further have a measurement analyzer for determining the color of the sample based on the measured light. The color may be determined for a specified illuminator incorporating effects of fluorescence.
Abstract:
A photoelectric sensor includes a light-emitting element and a light-receiving element and detects a mark on an object. Prior to the detection of the mark, a reference received light quantity level is sampled for the surface of an object not including the mark, for every color of light. A mark received light quantity level is then sampled for every color of light. The difference is obtained between the reference received light quantity level and the corresponding mark received light quantity level for each color of light. A ratio of the obtained difference to the reference received light quantity level is obtained. For the colors of light where the difference equals or exceeds a predetermined value, the color of light having the largest ratio is selected for emission from the light-emitting element in the detection of the mark.
Abstract:
An object to be imaged or detected is illuminated by a single broadband light source or multiple light sources emitting light at different wavelengths. The light is detected by a detector, which includes a light-detecting sensor covered by a hybrid filter. The hybrid filter includes a multi-band narrowband filter mounted over a patterned filter layer. The light strikes the narrowband filter, which passes light at or near the multiple wavelengths of interest while blocking light at all other wavelengths. The patterned filter layer alternately passes the light at one particular wavelength while blocking light at the other wavelengths of interest. This allows the sensor to determine either simultaneously or alternately the intensity of the light at the wavelengths of interest. Filters may also be mounted over the light sources to narrow the spectra of the light sources.
Abstract:
A system to provide radiant energy of selectable spectral characteristic (e.g. a selectable color combination) uses an integrating cavity to combine energy of different wavelengths from different sources. The cavity has a diffusely reflective interior surface and an aperture for allowing emission of combined radiant energy. Sources of radiant energy of different wavelengths, typically different-color LEDs, supply radiant energy into the interior of the integrating cavity. In the examples, the points of entry of the energy into the cavity typically are located so that they are not directly visible through the aperture. The cavity effectively integrates the energy of different wavelengths, so that the combined radiant energy emitted through the aperture includes the radiant energy of the various wavelengths. The apparatus also includes a control circuit coupled to the sources for establishing output intensity of radiant energy of each of the sources. Control of the intensity of emission of the sources sets the amount of each wavelength of energy in the combined output and thus determines a spectral characteristic of the radiant energy output through the aperture.