57 results about "Spectral fitting" patented technology

A method for predicting physical property data of an oil product by using a near infrared spectrum. The method comprises steps of: classifying oil products by properties; collecting a group of sample from each variety; determining a near infrared spectrum of each sample; determining physical property data of each sample by a routine method according to oil product varieties; combining determined sample near infrared spectrums side by side and establishing a database according to determined characteristic data; obtaining fitting spectrum by fitting database spectrums; calculating a fitting degree according to the fitting spectrum and a spectrum to be measured; comparing with a threshold; for a sample to be measured with complete spectrum fitting, database spectrum characteristics participated in fitting predicting characteristic data of the sample.

A system and a method for correcting, simultaneously at multiple-listener positions, distortions introduced by the acoustical characteristics includes warping room responses, intelligently weighing the warped room acoustical responses to form a weighted response, a low order spectral fitting to the weighted response, forming a warped filter from the low order spectral fit, and unwarping the warped filter to form the room acoustical correction filter.

The invention discloses an online measurement device and measurement method for the NO concentration in a high-NO2 and low-NO atmosphere. The online measurement device comprises an ozone generation unit, a connection pipe cleaning unit and a sampling pipe, wherein a connection reaction bin, an NO2 measuring instrument, a second mass flow meter and a first air pump are sequentially connected behind the sampling pipe; and the connection pipe cleaning unit comprises an electromagnetic three-way valve, an activated carbon tube, a current-limiting hole and a second air pump. By adopting a cavity-enhanced absorption spectroscopy, a sampling mode (actual atmosphere of ozone is added) or a zero point mode (actual atmosphere) is set through the electromagnetic three-way valve; absorption spectrum intensity signals of two modes are measured through an NO2 measuring instrument as a sampling spectrum and a reference spectrum respectively, and then NO in the atmosphere is converted into a concentration value of the NO2 through spectral fitting, that is to say, measurement of the NO concentration in the atmosphere environment is achieved, so that the online measurement device and measurement method have the characteristics of being free of NO2 concentration interference, a low detection limit, high sensitivity, high temporal-spatial resolution, high stability and low cost.

A method of characterising a sample from spectrometric data using calculation of spectral distance values is disclosed, for use in the field of mass spectrometry. Molecular formula assignment of peaks in mass spectral data is difficult and time-consuming, and the invention provides a computer implemented method of finding a most likely elemental composition of a measured spectral peak of interest. The method analyses isotopic peaks in a portion of the spectrum, using both their mass positions and intensities, to determine a spectral distance between those peaks and isotopic peaks of a candidate composition, finding peaks that match (140). A pattern spectral distance is determined (150) to provide a measure of the correspondence between a set of those peaks in the measured spectrum and peaks of each of a number of candidate compositions. The spectral fit is used to determine a most likely candidate composition.

The invention relates to a method for predicting the properties of an oil product through the near-infrared spectrum of the oil product. The method comprises: classifying oil products according to types, collecting a group of samples from each class of the oil products, determining the near-infrared spectrums of each sample, and determining the property data of each sample by using a standard method according to the classification of the oil products; carrying out second-order differentiation on the near-infrared spectrums of the samples, and establishing a database from absorbance and the determined property data; fitting the differential spectrum of the sample to be determined by using the differential spectrum of the sample spectrum of the database, and calculating the fitting degree ofthe fitted differential spectrum and the differential spectrum of the spectrum to be determined; and predicting the properties of the oil product to be determined by comparing the fitting degree to athreshold value through the property data of the database spectrum participating the fitting, wherein the oil product to be determined is subjected to complete spectrum fitting. With the method of the present invention, the properties of the oil product to be determined can be rapidly and accurately predicted.

The invention provides a portable thin film thickness measuring device and a film thickness measuring method thereof. Only two times of sample measurement is needed, so that the workload of users is not increased; the measurement performance is improved by means of a spectrum fitting method; three infrared distance measuring sensors on the measuring end face of the thickness measuring device are used for guaranteeing the vertical incidence relationship between standard samples and measuring beams, so that the operation convenience for a corrected sample measuring link is maintained. The portable thin film thickness measuring device has no reflector, so that a measuring light path is simpler, the overall structure is compact and a portable layout can be implemented conveniently. When the size of the conventional interference film thickness measuring instruments is reduced and portable measurement is allowed, the instruments can be applied to far more industrial environments; the instruments not only can serve as the portable film thickness instruments but also can be installed on a coating production line for online monitoring and measuring of thin films.

The invention provides a filter parameter optimization method based on visible light communication, comprising: firstly utilizing a spectrometer to detect the spectrum data of each monochromatic light, and employing a gauss or Lorentzen function for fitting to obtain a spectral fitting function; in dependence on a real system, determining the spectral function of a bias light and the total noise power of a receiving terminal; using the signal to interference ratio of each color light at the receiving terminal as an objective function, and meanwhile determining constraint conditions of filter parameters; first using a signal to interference ratio function to solve the partial derivative of each variable, and setting a partial derivative result to be zero, then fixing a variable, and optimizing another variable under the constraint conditions, and successively performing rounds of iteration to obtain the optimal solution of the filter parameters; and respectively solving objective functions of color lights to obtain the optimal value of parameters of each colored filter. The method is suitable for a plurality of filters, has a fast convergence rate in operation, and can better reduce interference among light colors.

A method for analyzing a temperature of exhaust gas includes calculating an approximate temperature at least one time by fitting a measured spectrum to a portion of theoretical spectra defined in association with a first temperature range using a temperature determined in the an immediately previous preceding temperature analysis as a reference, and then determining a calculated temperature by fitting the measured spectrum to all the theoretical spectra over a second temperature range that is narrower than the first temperature range, using the approximate temperature as a reference.

The invention discloses an optical fiber sensing dynamic signal demodulation method based on spectral fitting and a difference algorithm. The method comprises the following steps: performing scanning to obtain spectral ripples; fitting the spectral ripples to obtain a static spectrum; performing difference processing on the spectral ripples and the static spectrum to obtain difference signals; fitting extreme points of the spectral ripples to obtain upper and lower edge envelope curves; performing difference processing on the upper and lower edge envelope curves to obtain a spectral change function, performing normalization processing on the difference signals and the spectral change function to obtain envelope-removed difference signals, converting wavelength into time according to scanning speed and initial wavelength to obtain envelope-removed time-domain dynamic signals. According to the method, the dynamic signals are obtained by performing difference processing on the spectral ripples and a fitting curve of the spectral ripples, environmental interference such as temperature, humidity and the like can be eliminated, and the recovered dynamic signals hardly have dc component; meanwhile, broadband light is taken as input of an optical fiber sensor, and the complexity of an optical fiber sensing device is reduced.

A method for spectral interpretation in absorption spectroscopy uses a nonlinear spectral fitting algorithm for interpretation of spectral features in complex absorption spectra. The algorithm combines two spectral modeling techniques for generating spectral models to be used in the curve fitting process: a line-shape model and a basis-set model. The selected models for all gas components are additively combined using a least squares minimization, allowing for quantification of multiple species simultaneously.

The invention discloses a method for simultaneously determining multi-element contents in aluminium bronze. The method comprises the following determination steps of preparing a sample solution, preparing a working curve solution, determining an analyzing spectrum line of elements to be determined, determining the content of elements in the sample by an ICP (Inductively Coupled Plasma) method and correcting the spectrum disturbance by a multi-element spectral fitting method. According to the method disclosed by the invention, the enrichment or separated treatment for trace elements is avoided; after the sample is dissolve and treated at one time, the trace, the dose and the content of major elements can be simultaneously determined; the spectrum disturbance of a matrix to the elements to be determined is effectively corrected by a matrix matching and multi-element spectral fitting method; the analysis period is effectively shortened; the method has the advantages of quickness, simplicity, convenience, accuracy and reliability, and is suitable for quality control over the multi-element content in aluminium bronze products.

The invention discloses a method of calculating initial parameter values of an energy spectral response function based on the method of moments estimation. The method solves the problems of blindness in selecting the initial values for a fitting function and incorrect fittings or even potential fitting function divergence and the like in traditional methods. The problem of the selection difficulty of multiple parameter values of the response function of a detector is addressed in the method, based on the method of moments, an equation group is built for the various parameters in the response function, and the solved results for the equations are the initial values of various parameters. The method solves the problems of randomness and chance in traditional methods and improves on the fitting precision and accuracy of the response function; compared with the traditional methods, the method is more accurate and effective for determining the response function of the detector, broadening the spectrum and calculating the peak area, and avoids the fitting failure of the response function caused by the mistake selection of the initial values, in the meantime, the speed and accuracy of analyzing Gamma or Alpha energy spectrum are improved, and the method has great significance for the automatic peak shape function fitting and the resolution of energy spectrum.

The invention provides a leaf pigment remote sensing inversion method based on a FOLIUM model. The method comprises the steps that 1, on the basis of the FOLIUM model, green leaf LOPEX93/colorful leaf LOPEX_ZJU data concentrated hemisphere reflection and transmission spectral data, various parameters of the FOLIUM model, a minimum distance spectral fitting method and a least square method optimization method are utilized, and a method for achieving inversion of contents of various pigments corresponding to green/colorful leaves is achieved; 2, the inversion function of the FOLIUM model on all the pigments is elaborated by constructing a scatter diagram by means of measured values and inversion values of all the pigments, and the function of the FOLIUM model is compared with that of a PROSPECT-5 model; 3, comparative evaluation utilizing a accuracy evaluation function root-mean-square error, a deviation, a corrected standard deviation and variation coefficient inversion accuracy is achieved. According to the leaf pigment remote sensing inversion method based on the FOLIUM model, a green/colorful leaf hemisphere reflection and transmission spectra can be utilized for inversion of contents of photosynthetic pigments including chlorophyll a, chlorophyll b and carotenoid or non-photosynthetic pigments including anthocyanin, and compared with the PROSPECT-5 model, the inversion accuracy of total chlorophyll and carotenoid can be improved; physio-ecological characteristics of plant bodies can be monitored more accurately.

The invention discloses a reflective terahertz time-domain spectral thickness measurement method based on an evolutionary optimization algorithm. A self-built all-optical excitation and receiving non-contact reflection type terahertz time-domain spectrum detection system is adopted, filtering noise reduction and Fourier transform are carried out on a reference signal and a sample signal, a MATLABcross-correlation function is utilized to obtain an intrinsic phase shift, and a coating sample refractive index spectrum and an extinction coefficient spectrum in a terahertz frequency band range areobtained. The constructed terahertz wave and medium interaction theoretical model becomes more accurate, full-spectrum fitting is carried out on a theoretical reflection terahertz time-domain waveform and an experimental sample signal by utilizing an evolutionary optimization algorithm, and the number of iterations or convergence precision is determined; according to the method, the constructed terahertz wave and medium interaction theoretical model is more accurate in a mode close to reality, measurement errors caused by factors such as inherent phase shift errors and metal substrate complexrefractive indexes changing along with frequency spectra are avoided, echo pulse detection precision is improved, coating detection depth resolution is enhanced, and thickness detection is achieved.

A GC sample carbon ladder is generated with the help of one or more of the following techniques: correction of solvent effects; fit analysis of the spectrum obtained for a target member of the carbon ladder and a reference spectrum; fit analysis of a sample carbon ladder in comparison with reference spectral features; constraints for proper order of elution; and/or inclusion of all members in a selected carbon ladder set.

The invention discloses a method for quickly testing quality of a cobalt silicide based on reflectance-spectral fitting, and the method comprises steps of: 1, irradiating on line a zone, in which the cobalt silicide is formed, with detection light beams by utilizing a reflectance-spectral measurement tool after the cobalt silicide is formed; 2, receiving the detection light beams reflected by the zone, in which the cobalt silicide is formed, by utilizing the reflectance-spectral measurement tool; 3, making a reflectance spectrum according to the reflected the detection light beams by utilizing the reflectance-spectral measurement tool; 4, plotting a corresponding intrinsic curve according to the reflectance spectrum by utilizing the reflectance-spectral measurement tool; 5, judging whether the proportion of each compound in which the cobalt silicide is formed in accord with the requirement of technology or not according to the intrinsic curve of the reflectance spectrum, and if YES, subsequent processes for a wafer are carried out; if NO, an abnormal production process is stopped. According to the invention, the waste of large amount of cost and time is avoided and the loss is reduced.

The invention discloses an ultrahigh spectral resolution enhancing method based on deconvolution, and particularly relates to the technical field of spectral analysis. According to the method, a stimulated Brillouin gain spectrum mathematical model generated by a single-mode polarization maintaining optical fiber in a spectral analysis system based on a stimulated Brillouin effect is built firstly; then at each spectral sampling point of the spectral analysis system, based on the stimulated Brillouin gain spectrum mathematical model, the deconvolution is carried out on a measured ultrahigh spectrum; and finally, spectral defects possibly existing in the ultrahigh spectrum obtained by the deconvolution are eliminated by adopting a Pade approximation spectral fitting method, so that the enhancement of the ultrahigh spectral resolution is achieved. By adopting the spectral resolution enhancing method, the spectral resolution capability of the spectral analysis system based on the stimulated Brillouin effect is greatly improved, the spectral resolution limitation of the stimulated Brillouin gain spectrum width to the spectral analysis system is broken through, and the spectral resolution is increased to be less than 1 MHz from a limited range of tens of MHz.

The invention relates to an underwater sound source position and power spectrum joint estimation method based on Sparse Spectral Fitting, and provides an underwater sound source position and Power Spectral Density (PSD) joint estimation method based on Sparse Spectral Fitting (SpSF) aiming at a vertical linear array consisting of isotropic acoustic hydrophone. According to the method, the sparsityof the position of a sound source in a test water area is utilized, the test water area is meshed, a sparse signal recovery model is established, the relation between a sampling covariance matrix andthe PSD of radiation noise is deduced, and finally the position of the sound source and the PSD of the radiation noise are estimated simultaneously by utilizing a SpSF method.

The invention belongs to the technical field of spectrum detection, and particularly relates to a spectrum demodulation system and a spectrum demodulation method based on a screen light source of mobile equipment. The spectrum demodulation system utilizes a screen of the mobile equipment terminal as a light source for spectral imaging detection, emits light of different wavelengths by adjusting the screen, serves as a light source of a spectral imaging system, realizes illumination on a target, acquires a spectral image system by using spectral imaging equipment, and obtains spectral information of the target at different wavelengths by adopting a spectral fitting algorithm. Compared with the prior art, the common portable mobile equipment screen can serve as the light source, a complex light source environment composed of the conventional optical structure is replaced by means of fitting the portable mobile equipment screen and software, thereby providing portability, being small in size and light in weight, and being capable of being used in different scenarios.

The invention provides a fusion method for generating a high-spatial-resolution multispectral image, which is used for fusing an image with high spatial resolution and less spectral bands and an imagewith low spatial resolution and more spectral bands to generate an image with high spatial resolution and multispectral bands, and comprises the following steps of: generating an image with high spatial resolution and multispectral bands, and comprises the steps of: extracting a spectrum base from the image with low spatial resolution; comparing the existing wave band of the high-spatial-resolution image with the reconstructed wave band, and resolving to obtain a coefficient corresponding to the spectrum base; and reconstructing all spectrums of the high-spatial-resolution pixels through linear combination of the spectrum bases and the corresponding coefficients of the spectrum bases, so that an image with high spatial resolution and multispectral bands is generated. According to the fusion method for generating the high-spatial-resolution multispectral image, the advantages of the two images can be combined on the basis of spectral fitting, the spectral similarity between geographicdata is fully utilized, and an effective method is provided for producing the high-spatial-resolution multiband image.

The invention discloses a detection method of oil type and composition of spilled oil of sea surface crashed plane based on alternating penalty trilinear decomposition. Original fluorescence spectrumdata of N samples of aviation kerosene and lubricating oil under different volume ratio configurations is acquired through a fluorescence spectrophotometer. Delaunay interpolation correction is executed for the obtained original fluorescence spectrum data, and corrected three-dimensional fluorescence spectrum data is obtained. The three-dimensional fluorescence spectrum data is processed through acore consistency diagnostic function, and the number of compositions needed when parsing the three-dimensional fluorescence spectrum data through the alternating penalty trilinear decomposition (APTLD) algorithm is obtained. The three-dimensional fluorescence spectrum data is processed through the APTLD algorithm, load matrixes A, B and C of pure oil and mixed oil of the aviation kerosene and lubricating oil are obtained. The load matrixes B and C of the pure oil of the aviation kerosene and lubricating oil and the load matrixes B and C of the mixed oil of the aviation kerosene and lubricating oil are subjected to data fitting, thus, a spectrum fitted curve under a corresponding relation of fluorescence relative intensity and excitation and emission wavelength of the aviation kerosene andlubricating oil is obtained, and degree of correlation of each spectrum curve is judged through root-mean-square error (RMSE) and a correlation function corrcoef.