Abstract: Infusion fluid is flowed through a fluid delivery line of an infusion system. Optical signals having different wavelengths are transmitted through the fluid delivery line. The transmitted optical signals having the different wavelengths are received. At least one processor determines whether air or infusion fluid is disposed in the fluid delivery line based on the received optical signals having the different wavelengths.

Abstract: A photon number resolving detector system includes a photon source positioned at an input end, first and second photon detectors positioned at a detection end, and a plurality of optical couplers positioned between the input and detection ends. The plurality of optical couplers include an initial optical coupler optically coupled to the photon source, a final optical coupler optically coupled to the first and second photon detectors, and intermediate optical couplers positioned between the initial optical coupler and the final optical coupler. A first input link is optically coupled to the photon source and the initial optical coupler and a plurality of dual path spans are optically coupled to adjacent optical couplers. The plurality of dual path spans each include an undelayed path having an undelayed fiber link and a delayed path having a quantum memory positioned between and optically coupled to input and output sub-links.

Abstract: Systems and methods for manipulating art assets on a user interface that utilizes augmented reality (AR) to create a rewards program through STEM-based learning are described herein. A method includes transmitting an image captured by a first user of one or more images of a tangible object having a reference marker. The method further includes processing the image and in response to detecting the reference marker in the one or more images, transmitting an image of an AR character on a graphic user interface (GUI) along with a first visual programming object (first GUI element) associated with underlying code that, when manipulated on the screen with respect to an execution object, a second GUI element (second visual programming object), causes a change of state of the AR character from a first state to a second state.

Abstract: A test element analysis system for analytical examination of a sample. The system comprises a measurement device, which comprises a test element receptacle for receiving at least one test element at least partially, wherein the receptacle comprises at least one first and at least one second part, wherein the first part comprises at least one support surface for placement of the test element, wherein the second part comprises at least one optical detector for detecting at least one detection reaction of at least one test chemical contained in the test element, wherein the second part is movable relative to the first part, wherein the receptacle is configured to position the second part such that a test element may be inserted into the receptacle and to subsequently position the second part in a closed position such that at least one abutment surface of the second part rests on the test element.

Abstract: Disclosed is a process for determining a plurality of color quality indicators for controlling the color of a coating. Colorimetric coordinates of a color reference and the coating are ascertained for a plurality of coated surface elements using a spectrophotometer at a number of measurement geometries and a number of light sources. For each measurement geometry and each light source, color differences are calculated from the colorimetric coordinates of the color reference and the coating of the plurality of coated surface elements. The respective colorimetric coordinates are normalized with one weighting factor. Each of the plurality of color quality indicators is determined by means of a mapping, of functional values onto a scale value of a predetermined scale. The functional values are determined in each case for the number of measurement geometries and the number of light sources by means of a mathematical relationship.

Abstract: Apparatus and methods for analyzing single molecules and performing nucleic acid sequencing. An apparatus can include an assay chip that includes multiple pixels with sample wells configured to receive a sample, which, when excited, emits emission energy; at least one element for directing the emission energy in a particular direction; and a light path along which the emission energy travels from the sample well toward a sensor. The apparatus also includes an instrument that interfaces with the assay chip. The instrument includes an excitation light source for exciting the sample in each sample well; a plurality of sensors corresponding the sample wells. Each sensor may detect emission energy from a sample in a respective sample well. The instrument includes at least one optical element that directs the emission energy from each sample well towards a respective sensor of the plurality of sensors.

Abstract: A system having an auxiliary color selection body and a method for determining the colors of a dental object, i.e. the colors of tooth, residual limb or gingiva, is provided, wherein the auxiliary color selection body (10) has a substantially U-shaped or L-shaped or ring-shaped structure, on which at least one, preferably 4, reference features (18), for recognition of the auxiliary color selection body (10) is/are attached, and wherein, with respect to the reference features (18), a plurality of tooth, stump or gingiva color fields (30) are arranged on the color selection auxiliary body (10). It is provided for an image of a tooth (16) to be taken with the auxiliary color selection body (10) being adjacent thereto on at least two sides and the tooth color is determined based on this image (FIG. 1).

Abstract: Apparatus and methods for analyzing single molecule and performing nucleic acid sequencing. An apparatus can include an assay chip that includes multiple pixels with sample wells configured to receive a sample, which, when excited, emits emission energy; at least one element for directing the emission energy in a particular direction; and a light path along which the emission energy travels from the sample well toward a sensor. The apparatus also includes an instrument that interfaces with the assay chip. The instrument includes an excitation light source for exciting the sample in each sample well; a plurality of sensors corresponding the sample wells. Each sensor may detect emission energy from a sample in a respective sample well. The instrument includes at least one optical element that directs the emission energy from each sample well towards a respective sensor of the plurality of sensors.

Abstract: A color measuring apparatus includes a measurement assembly which includes at least one illumination assembly for applying substantially parallel illumination light to a measurement spot of a measurement object and a pick-up assembly for capturing the measurement light radiated back from the measurement spot in an observation direction and for converting the same into corresponding electrical signals. The illumination assembly includes at least two illumination subassemblies which illuminate the measurement spot from different illumination sub-directions near a first preset nominal illumination direction, each with preferably parallel illumination light. By the illumination from different illumination sub-directions slightly deviating from the nominal illumination direction, angular errors of the illumination assembly can be compensated for in a simple manner.

Abstract: A color measurement apparatus includes at least one illuminator, an imager, and circuitry. The circuitry is configured to normalize each pixel included in an imaging region of one of the spectral reflectance images of the measurement target irradiated with light at a specific illumination angle of the plurality of illumination angles, with one of the spectral reflectance images of the reference object irradiated with light at the specific illumination angle, for each of the plurality of illumination angles so as to generate normalized spectral reflectance images of the measurement target. The circuitry further calculates a numerical value of at least one color for each pixel of the normalized spectral reflectance images of the measurement target, for respective ones of the plurality of illumination angles, to measure color of the surface of the measurement target.

Abstract: In order to reduce a variation in the light amount of light detected in every reference measurement cycle in an absorption spectrometer 1, it is adapted to tilt at least one surface selected from among incident surfaces and emitting surfaces of all translucent members constituting a reference cell with respect to the light axis of light traveling along a light path.

Abstract: A material inspection apparatus includes a light source, a light receiver, a light converter, and a processing unit. The light source is configured to emit light to a surface of an object to be inspected. The light receiver is configured to receive light reflected from the surface of the object. The light converter is configured to convert the light received by the light receiver into an electric current. The processing unit is configured to determine, according to the electric current, a material of the surface of the object.

Abstract: A periphery band is around an excluded region. For automatically counting physical objects within the periphery band and the excluded region, an imaging sensor captures: a first image of the periphery band and the excluded region; and a second image of the periphery band and the excluded region. In response to the first image, a first number is counted of physical objects within the periphery band and the excluded region. Relevant motion is automatically detected within the periphery band, while ignoring motion within the excluded region. In response to the second image, a second number is counted of physical objects within the periphery band and the excluded region. In response to determining that a discrepancy exists between the detected relevant motion and the second number, the discrepancy is handled.

Abstract: An apparatus and method for measuring the attenuation and dispersion introduced by a sample into an optical signal are disclosed. The apparatus includes a chirped light source, a beam splitter and an optical detector. The beam splitter splits the optical signal generated by the light source into a reference optical signal and a sample optical signal. The sample and reference optical signals are mixed on the detector after the sample optical signal has traversed an experimental sample thus generating a signal having an AC component related to an attenuation and a dispersion introduced by the experimental sample. The optical paths traversed by the reference and sample optical signals between the beam splitter and the detector are chosen such that the reference optical signal and the sample optical signal overlap in time but do not arrive at the optical detector at the same time.

Abstract: A people counting system includes: a top-view, a first and a second side-view image-capturing device, capturing a top-view, a first and a second side-view image respectively; an image stitching module, stitching the top-view, the first and the second side-view image into an ultra wide-angle image; a ROI selecting module, selecting at least one recognition zone and a counting zone; a face recognition module, monitoring the recognition zone to determine a face location corresponding to a face through analyzing the recognition zone; a head recognition module, monitoring the counting zone to determine a head location corresponding to a head through analyzing the counting zone; an object tracking module, the head recognition module, generating a face track and a head track; and a people counting module, counting a first number of face tracks and a second number of head tracks passing through the counting zone and generating a counting result.

Abstract: A direct-view display includes an array of MEMS light modulators and a control matrix formed on a transparent substrate, where each light modulator can be driven into at least two states, and a controller for controlling the states of each light modulator in the array. The control matrix transmits data and actuation voltages to the array. The controller includes an input, a processor, a memory, and an output. The input receives image data encoding an image frame for display. The processor derives a plurality of sub-frame data sets from the image data, where each sub-frame data set indicates desired states of light modulators in multiple rows and multiple columns of the array. The memory stores the plurality of sub-frame data sets. The output outputs the plurality of sub-frame data sets according to an output sequence to drive light modulators into the states indicated in the sub-frame data sets.

Abstract: The scattered light from the measurement target substance passes through a light receiving window, and is received by a detector for +? scattered light and a detector for ?? scattered light which are arranged symmetrically to each other across an optical axis at an equal angle or an equal interval in a vertical direction. A light source is fixed by a light-source holder (that is a base member on which the light source is arranged), and the detectors are arranged on and fixed to a detector holder (that is a base member on which the detectors are arranged). In this manner, drift of the light quantity data caused by the thermal deformation of the optical system can be corrected by comparing values of the light quantity data of the detectors.

Abstract: An optical apparatus used for a 3D image pickup apparatus for taking two subject images having a disparity by using two lens apparatuses, each of which is directly connectable to an image pickup apparatus, and one image pickup apparatus, the optical apparatus including: a first attaching unit for detachably attaching a first lens apparatus; a second attaching unit for detachably attaching a second lens apparatus; a camera attaching unit for detachably attaching the image pickup apparatus, the image pickup apparatus including an image pickup portion; and a switch unit for alternately switching light rays from the first and second lens apparatuses to guide the light ray to the image pickup apparatus in a state that the first and second lens apparatuses and the image pickup apparatus are connected to the optical apparatus. Intermediate images are formed in the optical apparatus by the first and second lens apparatuses.

Abstract: The present invention relates to a light quality evaluating device, comprising a light receiving unit, first processing unit, a memory unit, a second processing unit, a display unit, and a power management unit, and being used for evaluating the light quality light based on physiological perception of human. In evaluating operation, it transfers a power spectrum of the light emitted from a light source to a luminance spectrum of light through a luminosity function. Next, the method compares the luminance spectrum of light with a corresponding luminance spectrum of blackbody radiation thereof. Therefore, an index of spectral resemblance with respect to the black body radiation (SRBR) would be calculated and then obtained, such that the SRBR can be used for evaluating the quality of the light emitted from the light source. Moreover, comparing to conventional CRI, SRBR is a better light quality evaluating method because of having fairness and consistency.

Abstract: The present invention relates to a light quality evaluating device, comprising a light receiving unit, first processing unit, a memory unit, a second processing unit, a display unit, and a power management unit, and being used for evaluating the light quality light based on physiological perception of human. In evaluating operation, it transfers a power spectrum of the light emitted from a light source to a luminance spectrum of light through a luminosity function. Next, the method compares the luminance spectrum of light with a corresponding luminance spectrum of blackbody radiation thereof. Therefore, an index of spectral resemblance with respect to the black body radiation (SRBR) would be calculated and then obtained, such that the SRBR can be used for evaluating the quality of the light emitted from the light source. Moreover, comparing to conventional CRI, SRBR is a better light quality evaluating method because of having fairness and consistency.

Abstract: Described herein is a method, system and computer program for analyzing a colorimetric assay that includes obtaining an image of the assay, optionally correcting for ambient lighting conditions in the image, converting the intensity data for at least one of the red channel, the green channel, or the blue channel to a first data point, recalling a predetermined standardized curve, comparing the first data point with the standardized curve, and identifying the value for the assay parameter from the standardized curve.

Abstract: A method of providing an indication as to the amount of milk remaining in a breast during lactation based on a determined fat content of milk that has been expressed from said breast is disclosed. The method of determining said fat content comprises measuring an optical characteristic of milk following expression and by comparing said measured optical characteristic with data representing a corresponding optical characteristic of a sample of milk having a known fat content to determine the fat content of said expressed milk which is indicative of the amount of milk remaining in the breast.

Abstract: A gas absorption spectroscopy system and method are provided. A sealed chamber is provided with a reference gas having a known moisture concentration. An illumination source is disposed in the sealed chamber and is configured to generate an illumination beam. A measurement cell is coupled to the sealed chamber and is configured for exposure to a gas sample such that illumination travelling through the measurement cell passes through the gas sample. A process window is disposed between the sealed chamber and the measurement cell. The process window is configured to receive the illumination beam from the illumination source and reflect a first portion of illumination while allowing a second portion of illumination to pass into the measurement cell. A reference detector is disposed to receive the first portion of illumination and provide a reference detector signal.

Abstract: A method for adjusting, calibrating and/or checking a function of a photometric sensor, which is embodied for measuring at least one measured variable in a medium, wherein the sensor works with at least one measuring wavelength and at least one reference wavelength, comprising the steps as follows: mounting a calibration insert in a receptacle provided therefor at the sensor, adjusting, calibrating and/or performing the function check, and removing the calibration insert, characterized in that the transmittance of light of the measuring wavelength and the transmittance of light of the reference wavelength through the calibration insert are different. The invention relates further to a calibration insert.

Abstract: This disclosure provides systems, methods and apparatus for calibration of analog display elements such as analog interferometric modulators (IMODs). In one aspect, display devices include both a light-turning layer and integrated color sensor in order to provide feedback on the operation of the display. In particular, the integrated color sensors can be used to determine a relative shift in a color signal output by an analog display element.

Abstract: The present invention improves an S/N ratio and light intensity resolution provided by an A/D converter, and an analyzer includes: a measurement cell irradiated with light during sample measurement; a dimming element irradiated with the light during reference measurement; an amplifier configured to amplify an analog light intensity signal outputted from a light detector; an A/D converter configured to convert the analog light intensity signal into a digital light intensity signal; and an arithmetic device configured to calculate absorbance using a digital sample light intensity signal outputted from the A/D converter during the sample measurement and a digital reference light intensity signal outputted from the A/D converter during the reference measurement, wherein an amplification factor of the amplifier is set such that the analog reference light intensity signal and the analog sample light intensity signal become less than or equal to a full scale of the A/D converter.

Abstract: The present invention is directed to a method and a system for producing one or more matching formulas to match color and coarseness appearance of a target coating on a substrate. The method provides providing a set of coating chips comprising at least two coating chips having different lightness values, and at least two coating chips having matching lightness values and different coarseness values. This invention provides a simple method and the system for matching color and coarseness appearance of the surface coating.

Abstract: This invention provides a novel methods and devices for measurement of particle concentration or changes in particle concentration over a wide linear range. The invention comprises one or more radiation sources and one or more detectors contained in a housing which is interfaced to a medium containing particulate matter. The one or more radiation sources are directed into the medium, scattered or transmitted by the particulate matter, and then some portion of the radiation is detected by the one or more detectors. Methods for confining the measurement to a specific volume within the medium are described. Algorithms are provided for combining the signals generated by multiple source-detector pairs in a manner that results in a wide linear range of response to changes in particle concentration. In one embodiment the sensor provides non-invasive measurements of biomass in a bioreactor. In another embodiment an immersible probe design is described, which may be suited for one-time use.

Abstract: Spectral information may be employed in process control and/or quality control of goods and articles. Spectral information may be employed in process control and/or quality control of media, for example financial instruments, identity documents, legal documents, medical documents, financial transaction cards, and/or other media, fluids for example lubricants, fuels, coolants, or other materials that flow, and in machinery, for example vehicles, motors, generators, compressors, presses, drills and/or supply systems. Spectral information may be employed in identifying biological tissue and/or facilitating diagnosis based on biological tissue.

Abstract: A method for determining a paint formulation includes: obtaining target color information for a target color, identifying a plurality of toners and corresponding concentrations of the toners in a paint formula that can be used to produce a paint having a color that is similar to the target color, and modifying the paint formula by removing one of the identified toners having a lowest concentration to produce a modified paint formula that can be used to produce a paint having a color that is similar to the target color, and determining if the modified paint formula meets user specified acceptance criteria. An apparatus that can be used to perform the method is also described.

Abstract: A detector detects the color of a medium after a gas to be identified and a reagent have chemically reacted with each other on the medium. A controller identifies color information, which is most similar to the color detected by the detector, from color information stored in a spectral database, and reads gas identifying information related to the identified color information, as gas identifying information representing the gas to be identified, from the spectral database.

Abstract: Large digital displays for entertainment, architectural and advertising displays have interconnected display panels with pluralities of light emitting elements. To solve calibration problems, each of the display panels stores measured luminance and chromaticity data for each of the light emitting elements of the panel. The luminance data is independent of the chromaticity data. A central controller can then perform calibration procedures so that the light emitting elements are matched across the entire display.

Abstract: A method for representing the structural information in a biological or physical sample is disclosed. In this method, a time-frequency representation of the spatial distribution within a sample is transformed into a color representation of the data. Furthermore, due to the directional sensitivity of the method for gathering the data, information about the structural anisotropy of the sample can also be encoded from the data. The application of this method to one or more regions within the sample enables a map to be generated which clearly illustrates quantitative measures of the structures present.

Abstract: Differences between an offline spectrophotometer and an inline spectrophotometer can result in differences between a hardcopy target color and a printed reproduction of that color. The inline spectrophotometer is inside of a printer and configured to measure printer output. As such, the inline spectrophotometer cannot conveniently measure the hardcopy target color. A printing error or an instrument offset can be determined and passed to a color correction module that updates the device dependent color specification associated with the given spot color. This color specification may be stored, for example, in the printer controller, and used when a document subsequently calls for that spot color, thereby providing accurate color reproduction from that particular printer incorporating that particular inline spectrophotometer.

Abstract: An apparatus and method for preparing a stain to match a target color of a selected substrate (e.g., wood species). The apparatus and method may include a computer system and hardware or software to display to a user of such system an image array depicting a target image of a stained building material and a plurality of images of colored stains as applied to the same or other building materials.

Abstract: An imaging system for imaging of a turbid medium comprises a radiation source to illuminate an object to be imaged. A detection system detects radiation from the object and includes a separation module which separates and distinguishes radiation components having respective wavelength ranges. An analysis module forms a comparison of respective radiation components. An image dataset is reconstructed on the basis of the comparison of respective radiation components. The comparison may involve the ratio of the levels of the high-wavelength radiation component to the low-wavelength radiation component, the relative difference of the levels of high-wavelength radiation component to the detected radiation, and the relative difference of the levels of the high-wavelength radiation component to the low-wavelength radiation component.

Abstract: A system removes a light sensor artifact from a light sensor in a printer that is used to obtain reflectance measurements from test patterns printed on an image substrate.

Abstract: Various embodiments include interferometric optical modulators comprising a substrate layer having a thickness between about 0.1 mm to about 0.45 mm thick and a method for manufacturing the same. The interferometric modulator can be integrated together with a diffuser in a display device. The thin substrate permits use of a thicker diffuser. The thinner substrate may increase resolution and reduce overall thickness of the interferometric modulator. The thicker diffuser may provide increased diffusion and durability.

Abstract: Method for approximating the spectrum of a plurality of color samples, the method including the procedures of measuring the color of a reference color sample in a color space, determining a reference sample estimated spectrum from the measured color, measuring the actual spectrum of the reference color sample, determining a spectral delta from the difference between the reference sample estimated spectrum and the actual spectrum, measuring the color of each of the color samples, for each of the color samples, determining a sample estimated spectrum from the measured color, and for each of the color samples, determining a sample approximated spectrum by adding the spectral delta to the respective sample estimated spectrum.

Abstract: A laser irradiation process includes: scanning a substrate with laser having a predetermined lasing frequency at different irradiation intensities to form a plurality of first irradiation areas corresponding to the irradiation intensities; illuminating the first irradiation areas to reflected light receive from the first irradiation areas; determining microcrystallization intensity based on the received reflected light; and determining irradiation intensity based on the thus determined microcrystallization intensity. The laser irradiation process uses the irradiation intensity for irradiating a polycrystalline film in a product semiconductor device.

Abstract: A colorimeter of a profile generator calorimetrically measures a color chart after elapse of a sufficient period of time from printing of the color chart, thereby producing post-dry-down colorimetric values. The colorimeter also calorimetrically measures certain patches selected from the color chart immediately after printing thereof, thereby producing pre-dry-down calorimetric values. Colorimetric value differences between the post-dry-down colorimetric values and the pre-dry-down colorimetric values are calculated. Using the calorimetric value differences and the post-dry-down calorimetric values, device-dependent data are converted into colorimetric values, which represent pre-dry-down device-independent data. The colors of a print prior to dry-down are predicted based on such converted colorimetric values.

Abstract: A method for representing the structural information in a biological or physical sample is disclosed. In this method, a time-frequency representation of the spatial distribution within a sample is transformed into a color representation of the data. Furthermore, due to the directional sensitivity of the method for gathering the data, information about the structural anisotropy of the sample can also be encoded from the data. The application of this method to one or more regions within the sample enables a map to be generated which clearly illustrates quantitative measures of the structures present.

Abstract: An image processing system includes a photographing apparatus and a processing apparatus. The photographing apparatus includes LEDs for emitting light with characteristics of spectroscopic distributions varied in a visible light area, an image pick-up device unit which picks-up a subject image that is illuminated by the LEDs and is formed by an image pick-up optical system and which outputs an image signal, and a control unit. The control unit sequentially lights-on the LEDs upon an instruction for photographing a subject spectroscopic image being input from an operating switch, picks-up the image, and thus controls the operation for capturing subject spectroscopic images. The processing apparatus includes a calculating device which performs a desired image calculation based on the image signal.

Abstract: A control station for a printing press, includes at least one true color monitor for displaying at least one soft proof serving as a color reference for printed copies printed during the printing process, and at least one standard light source for at least partial illuminating the control station to allow visual comparison, independent of room lighting, of a printed copy with the soft proof serving as the color reference. The luminosity produced by the at least one standard light source is variable, so that the luminosity produced by the at least one standard light source can be adjusted to match a brightness achievable on the true color monitor to match a contrast achievable on the true color monitor during the display of the soft proof.

Abstract: A method for estimating color measurements of color samples includes printing a color sample based on input data, measuring a color of the printed color sample with an in-line spectral sensor at a first temperature, and estimating a color of the printed color sample which would be output by a reference spectral sensor at a second temperature. The estimation is based on a thermochromatic model which represents relationships between measured colors of printed color samples on the in-line spectral sensor at the first temperature and the reference spectral sensor at the second temperature. The reference spectral sensor is a different type of sensor from the in-line spectral sensor, so the color response of the two spectral sensors is different, even when the measurement conditions are identical. Consequently, a set of printed spot color samples generate different measured colors at the second temperature on the in-line spectral sensor from the reference spectral sensor.

Abstract: Methods of optimizing the diameters of nanowire photodiode light sensors. The method includes comparing the response of nanowire photodiode pixels having predetermined diameters with standard spectral response curves and determining the difference between the spectral response of the photodiode pixels and the standard spectral response curves. Also included are nanowire photodiode light sensors with optimized nanowire diameters and methods of scene reconstruction.

Abstract: A color analysis system includes a plurality of light sources configured to illuminate a test patch. A sensor is configured to receive light from the plurality of light sources reflected from the test patch. A controller is configured to determine the color of the test patch in response to light received by the sensor reflected from the first light source, and adjust the color determination in response to light received by the sensor reflected from the first and second light sources.

Abstract: This invention provides a color matching test piece capable of freely changing a combination of a base color and an upper color to be overpainted one on another with less work. The color matching test piece 10 is formed of a clear-colorless film base 10a. A plurality of the color matching test pieces 10 painted with individual colors with respect to each color to be overpainted are prepared, and the test pieces 10 are stuck to a car body or the like with a defatting agent to reproduce the state of the overpainted color in order for color comparison relative to the original color of the car body. The color matching test piece 10 has peeling tabs 11 and jig holes 12 and is superposed on the other test pieces according to need.

Abstract: Based on area and color analyses, a cost-effective bi-directional people counter dedicated to the pedestrian flow passing through a gate or a door is proposed. Firstly, the passing people are roughly counted with the area of people projected on an image captured by a zenithal video camera. The moving direction of the pedestrian can be recognized by tracking each people-pattern with an analysis of its HSI histogram. To improve the accuracy of counting, the color vector extracted from the quantized histograms of intensity or hue is introduced to refine the early counting. Besides, the inherent problems of both people touching together and merge/split phenomenon can be overcome.

Abstract: A method of improving an initial color filter comprises a numerical generation of sinusoidal spectra. Two steps of selecting said spectra are then executed. The first selection is carried out according to a criterion of colorimetric similitude with respect to the initial filter. The second selection is carried out according to the capacity of dummy filters corresponding to each spectrum to restore hues in a natural manner. To do this, observations of samples of hues through each dummy filter are simulated numerically, using a color appearance model to take account of a visual perception of a human observer. In this way, an improved filter is determined, which has a color close to that of the initial filter and which affords a natural rendition of hues.