157 results about "Background spectrum" patented technology

The invention discloses a apparatus and method for adjustable multiple reflection optical absorption, which adopts the principle of multiple reflection to design a optical absorbing pool; light beam multiple reflects by main reflector and two auxiliary reflectors so as to effectively accrete the length of detecting optical path in a small spacing. The multiple reflection optical absorbing pool has compact structure and can do alternative measurement to sample spectrum and background spectrum.

The invention belongs to the technical field of remote sensing image processing, and specifically relates to a low-rank expression and learning dictionary-based hyperspectral image abnormity detection algorithm. According to the algorithm, a method for introducing low-rank expression in the abnormity detection problems is used for decomposing the two-dimensional hyperspectral image data into the sum of a low-rank matrix expressing background and a sparse matrix expressing abnormity, and then enabling a basic abnormity detection algorithm to act on the sparse matrix to obtain the abnormity detection result; and furthermore, the concept of a learning dictionary is imported in the low-rank expression algorithm, and the learning dictionary is obtained through an algorithm of random selection and gradient descent and is capable of expressing the background spectrums in hyperspectral images. Through the importing of the learning dictionary, the abnormity information can be better separated from the hyperspectral image data, so that better detection result can be obtained; and meanwhile, the robustness of the algorithm for the initial parameters can be improved, so that the computing cost is reduced and important value is provided for the actual abnormity detection application.

The invention relates to a raman spectra pretreatment method for removing the effects of background noises. The raman spectra pretreatment method comprises the following steps: 1) obtaining an information raman spectrum and a background spectrum; 2) respectively carrying out first-order differentiation on the information raman spectrum and the background spectrum to obtain a differential difference spectrum; 3) carrying out segment treatment on the differential difference spectrum; 4) carrying out effective information reservation on the differential difference spectrum processed in step 3); 5) carrying out respective sectional integration on the effective part of the differential difference spectrum processed in step 4); and 6) correcting a mutational site of the integral spectrum obtained in step 5), so as to obtain the preprocessed raman information spectrum. The method is used for the pretreatment of the raman spectrum; the effective raman information can be effectively extracted from the complicated background noises; and the method is simple and easy to implement.

A fourth embodiment of the present invention is a method of generating a temperature compensated absorbance spectrum. The method includes the steps of: a. providing a sample spectrum and an estimated temperature of a backdrop object; b. from a set of known temperature spectra related to a known background temperature, selecting at least two known temperature spectra representing a background temperature above and below the estimated temperature; c. comparing the sample spectrum to the known temperature spectra in order to determine a sample background spectrum; and d. calculating an absorbance spectrum from the sample spectrum and the background spectrum.

A spectrometer for detecting and quantifying elements in a sample. An exciter ionizes atoms in the sample, and the atoms thereby produce characteristic x-rays. A detector receives the x-rays and produces signals based on the x-rays. A filter system selectively blocks the x-rays from attaining the detector. The selective blocking of the x-rays is accomplished based on an energy of the x-rays. An analyzer receives the signals from the detector and detects and quantifies the elements in the sample based at least in part on the signals. In this manner, detector receives the light element x-rays, and the medium and heavy element x-rays are filtered out to avoid overwhelming the detector. This invention combines the large solid angle, high efficiency, and ability to measure the continuous background spectrum of the energy dispersive x-ray detector with the selectivity of the wavelength dispersive x-ray detector. It thus enables faster and more accurate measurement of light elements in thin films. This invention enhances the light element performance of a system by enabling higher throughput, lower e-beam and x-ray dose to the sample, and improved accuracy from the capability to measure the background radiation.

Featured is a method for reducing frequency of taking background spectra in FTIR or FTIR-ATR spectroscopy. Such a method includes determining if there is a pre-existing reference spectrum available and if such a reference spectrum is available, acquiring a present reference scan before acquiring a sample scan. The method also includes comparing the present reference scan with the pre-existing reference spectrum to determine if there is one or more non-conformities therebetween and if there is/are one or more nonconformities, determining if the one or more non-conformities are resolvable or not. If the one or more non-conformities are resolvable; resolve each non-conformity in a determined manner and thereafter acquiring a scan of the sample, and if the non-conformities are not resolvable, then acquiring a new reference sample and thereafter acquiring a scan of the sample.

The invention discloses a method and a device for online detecting quality index of yellow rice wine in bottle. The online detection device comprises an illumination system, an air conditioning system, a conveying belt, a receiving lens fixing device, a receiving lens, an optical fiber, a spectrometer, a computer, a trigger circuit and a photoelectric switch. The method comprises the following steps of: collecting the near IR spectrum of an empty bottle of a yellow rice wine sample in the bottle as the background spectrum; reducing the background spectrum from the spectrum of an original yellow rice wine sample in bottle as the sample spectrum; constructing the correction model of the key quality index of yellow wine according to the spectra and a physical and chemical analysis result by adopting partial least-squares regression method; and online detecting the quality of the yellow rice wine according to corresponding model. Based on near IR spectral analysis technology, the invention can achieve online detection of the key quality indexes of the yellow rice wine sample, including total sugar, solids, alcohol degree, total acid, amino acid nitrogen as well as pH value, thus achieving online and rapid quality analysis of yellow rice wine product, reduced detection time and cost and ensured product quality.

The invention provides a multichannel analyzer for use in a multichannel spectrometer, which comprises a standard spectrum calibrator for obtaining energy calibration parameters of said multichannel spectrometer; an environment background spectrum calibrator for obtaining parameters of a current and a previous environment background spectrum; a peak shift detector for analyzing the parameters of the current and previous environment background spectrum to determine whether a peak shift occurs between them and to determine a correction coefficient of the peak shift; and a parameter corrector for correcting the energy calibration parameters of said multichannel spectrometer using said peak shift correction coefficient. The invention also provides a method for correcting a peak shift of a multichannel spectrometer adapted in the multichannel analyzer. The method for correcting and the multichannel analyzer can correct and monitor the peak shift of the multichannel spectrometer in real time.

A method for passive background correction during spatially or angularly resolved detection of emission that is based on the simultaneous acquisition of both the passive background spectrum and the spectrum of the target of interest.

The present invention discloses a high spectrum sub-pixel object detecting method. The method includes that: a reverse model of the objective spectrum and the pixel spectrum two-dimensional matrix of the image needing to be detected is created, the regression coefficient vector of the reverse model is acquired; the Mahalanobis distance of each pixel is acquired according to the regression coefficient vector; the pixel corresponding to the regression coefficient of the Mahalanobis distance being greater than the threshold is determined as the sub-pixel objective point. The present invention also provides a high spectrum sub-pixel object detecting device, the sub-pixel object detecting method and the device thereof using the present invention need the prior information of the background terminal spectrum; are not sensitive to the complexity of the background spectrum; and have higher object detecting accuracy and faster operation speed.

The invention relates to a method for identifying an illegal drone based on remote control and a picture transmission signal, comprising: firstly learning a binary background spectrum template from the spectrum diagram to identify a WIFI and a picture transmission signal, constructing a template matrix, masking the frequency point thereon, and constructing a binarized frequency hopping detection matrix from the spectrogram so as to obtain the effective number of frames and the number of frequency hoppings, determining whether there is a drone remote control signal at a certain moment by comparing, if there is a drone remote control signal, extracting the model characteristic parameters thereof and matching through the unmanned aircraft model characteristic parameter database to identify the model of the illegal drone. The method provided by the invention abstracts the spectrogram into a plurality of binarization matrices, which greatly reduces the calculation amount, and is capable ofeffectively eliminating the interference of the WIFI or the spurious signal on the remote control signal detection of the drone, thereby accurately identifying the illegal drone and the model thereof,and gaining good real-time capability, anti-interference performance and accuracy.

Methods and systems are provided for estimating background spectral content in a hyperspectral imaging (HSI) scene. A HSI processor computes a scene covariance matrix for each of a plurality of sparsely sampled pixel sets, identifies and removes the spectral content of contaminating pixels from the covariance matrices, and checks the consistency among the plurality of decontaminated covariance matrices, iteratively re-sampling and re-computing said matrices until an acceptable consistency is achieved, and then computes a final decontaminated covariance matrix representative of the background spectral content of the scene. Alternate approaches to pixel sampling, and/or using fewer spectral dimensions than are available for the pixels are presented.

The invention provides a method for rapidly determining caffeine in a drink. The method comprises the steps as follows: acquiring multi-wavelength chromatographic data of drink samples and a caffeine standard solution; deducting data with the peak retention time identical with the caffeine standard solution from the chromatographic data of the drink samples; combining a plurality of drink samples and deducting chromatographic data of to-be-determined components, obtaining a background spectrum database containing no caffeine component, and calculating the amount of main components; reducing the dimension of the background database through singular value decomposition in combination with the amount of the main components to obtain a background database with a smaller data size; and calculating the content of the to-be-determined components in the drink samples by using space included angle criteria so as to realize quantification of the caffeine in the drink samples. The method is high in analysis efficiency, low in operation intensity, low in analysis cost, capable of reducing machine hours and reagent loss, good in robustness, simple and quite suitable for rapid assay determination of mass similar samples.

The invention relates to a method for rapid and sensitive test of phthalic acid ester compounds. An ion mobility spectrometry technology using a radioactive source as an ionization source is used as a basic test technology, and in the positive ion mode, a doping agent is added into a circulation gas path to establish the method for test of the phthalic acid ester compounds. Background spectrum peaks of an ion mobility spectrum in the positive ion mode can be purified by addition of the doping agent, and selectivity and sensitivity of the test of the phthalic acid ester compounds can be improved.

The invention discloses a low-background spectrum unscrambling method based on a sodium iodide detector. The method comprises the following steps: (1) a gamma detector after energy calibration actually measures a radionuclide spectrum and a natural background spectrum, and noise reduction is carried out; (2) a deconvolution algorithm is adopted to process a gamma energy spectrum after noise reduction; (3) a peak searching algorithm carries out searching on all potential peak positions of the gamma energy spectrum after noise reduction, and a peak position list is acquired; and (4) the peak position list information and a nuclide library are combined to be together inputted to a fuzzy logic system, the system gives the peak position recognition confidence for any nuclide characteristic peakin the nuclide library, constraints are set to further adjust the peak position recognition confidence, and thus, a nuclide list and the nuclide recognition confidence are acquired. The low-background spectrum unscrambling method based on the sodium iodide detector has the advantages of accurate peak position reduction, remarkable improvement of energy resolution, decomposition of an overlapped peak, low error recognition rate, accurate background nuclide analysis and accurate low activity nuclide analysis, and can be used for nuclide recognition and activity calculation for radiation monitoring equipment such as a gated radiation monitor and a nuclide recognition instrument.

The invention discloses a method for directly measuring potassium sorbate in soybean sauce. The method comprises the following steps: processing to-be-measured samples; establishing a background spectrum database; establishing a potassium sorbate standard spectrum database; and performing spectral measurement of to-be-measured soybean sauce samples and measurement of the potassium sorbate content in the to-be-measured soybean sauce samples. The method is high in analysis efficiency, simple to operate, low in analysis cost, capable of reducing loss of a reagent, good in robustness, simple, and particularly suitable for rapid analytic measurement of the potassium sorbate content in large-scale soybean sauce samples.

The invention discloses an X-ray fluorescence spectroscopy on-line detecting method for heavy metals in industrial ambient air. The industrial ambient air is subjected to continuous sampling by utilization of a sampling pump. Particles in the air are subjected to diameter cutting through a diameter cutter head. The heavy metals in the air are enriched by utilization of a tape air filtering membrane. An advanced energy dispersive X-ray fluorescence (EDXRF) analysis system is adopted to collect a filtering membrane background spectrum and an enriched-sample spectrum. Influences of tape base elements on detection are eliminated by utilizing a background deduction method. Inversion of concentrations of the heavy metals in the air is achieved by adopting an algorithm for least-squares fitting. Multi-element on-line automatic measurement of heavy metal pollution in the industrial ambient air is achieved.

The invention relates to a method for extracting an absorption characteristic peak in gas field monitoring. The method comprises the following steps: a smooth filtering step, a characteristic peak seeking step, a window linear fitting step and a characteristic peak background calculation and deduction step, wherein in the smooth filtering step, obtaining an original spectral array, then creating a smooth spectral array by adopting a moving average method and transferring to the absorption characteristic peak seeking step; in the characteristic peak seeking step, creating a first-order differential spectral array and a second-order differential spectral array and transferring left and right endpoints xL and xR of the absorption characteristic peak to the window linear fitting step; in the window linear fitting step, adopting a least square method to fit scattered data points in windows at the left and the right ends of the characteristic peak to obtain slopes and intercepts of fitting straight lines on the left side and the right side and transferring to the characteristic peak background calculation and deduction step; in the characteristic peak background calculation and deduction step, calculating a spectral background array within the range of the absorption characteristic peak through recursive interpolation for many times, and deducting a vector of a spectral intensity value stored in the smooth spectral array from a vector of a spectral intensity value stored in the spectral background array obtained by calculation to obtain a spectral array after background deduction and transferring to the smooth filtering step.

The invention discloses a near-shore aquaculture area remote sensing image extraction method based on multi-feature and spectrum fusion, and the method comprises the steps: firstly preprocessing an inputted original remote sensing image, extracting a feature spectrum through a feature index method, and forming a ground feature feature set; secondly, using an improved constraint energy minimizationalgorithm for enhancing a target ground object in a culture area and weakening background spectral information; then using an Otsu method for calculating a threshold value, and preliminarily extracting the target ground object in combination with a single-waveband threshold value; and finally, carrying out customized elimination on the preliminarily extracted result by applying a gray-level co-occurrence texture matrix or an object-oriented method according to the ground object characteristics, and outputting a final result of culture area extraction. Compared with a traditional target detection method, the method has the advantages that even in a breeding area with the obvious foreign matter same spectrum phenomenon, background ground object interference can still be effectively overcome, a high-precision raft breeding area extraction result can be obtained, and the high-precision extraction requirement of the raft breeding area can be well met.

A data processing device for processing a reference background spectrum and a measurement spectrum of a radioactive material represented by a multichannel spectrum to acquire energy region information of detected gamma rays is provided, said data processing device comprising: energy region dividing means for degenerating said multichannel spectrum into a degenerated spectrum of limited channels, each degenerated spectrum representing an energy region; degenerated spectrum calculating means for calculating a background degenerated spectrum and measurement degenerated spectrum based on said background spectrum and said measurement spectrum corresponding to said degenerated spectrum of limited channels respectively; energy ratio calculating means for calculating a energy ratio based on the calculated background degenerated spectrum and measurement degenerated spectrum; peak-detection means, for searching a peak value in the calculated energy ratios; energy region determining means for determining a corresponding energy region of said gamma rays based on the searched peak value in the energy ratios. A corresponding radiation detection method and a radiation detection system employing the data processing device are also provided.

The invention discloses an arc heater water leakage fault diagnosis system based on atomic emission spectroscopy. The air is heated by an arc heater and expanded and accelerated by an effuser to formhigh temperature air flow. The flow field spectrum formed by the arc heater is focused by a spectrometric compression film. The focused flow field spectrum is transmitted to a spectral measurement module through an optical fiber. The spectral intensity of the oxygen atomic characteristic spectrum and the spectral intensity of the background spectrum are measured by using the spectral measurement module and then the relative intensity is calculated. The relative intensity is compared with the intensity threshold by a data processing terminal, and the water leakage fault of the arc heater is judged according to the comparison result. When the judgment result indicates water leakage, power supply to the arc heater is disconnected. Rapid diagnosis of the low enthalpy arc heater water leakage fault can be realized so that safe operation of the heater can be guaranteed; and the operation state of the heater can also be monitored in real time so as to provide reference to analysis of the long-term operation stability.

A method to determine a distribution profile of an element in a film. The method comprises exciting an electron energy of an element deposited in a first film, obtaining a first spectrum associating with the electron energy, and removing a background spectrum from the first spectrum. Removing the background value generates a processed spectrum. The method further includes matching the processed spectrum to a simulated spectrum with a known simulated distribution profile for the element in a film comparable to the first film. A distribution profile is obtained for the element in the first film based on the matching of the processed spectrum to a simulated spectrum selected from the set of simulated spectra.

The invention discloses an spectrometer air chamber switching apparatus used in an on-line spectrometric analysis of gas, which comprises a measuring air chamber, a sample air chamber, a linear bearing, a vertical movement mechanism and a spacing sensor; the measuring air chamber and the sample air chamber are fixedly arranged on the base of the air chamber, the base of the air chamber is fixedlyconnected with a connection installing plate by a fastening screw; the linear bearing comprises a guide rod and a bearing base, the guide rod is fixedly arranged on the floor, the bearing base is fixedly arranged on the connection installing plate. The measuring gas chamber is placed in an optical path when a normal measurement is performed, the switching apparatus places the corresponding standard sample gas chamber in the optical path under the control of a computer when the background needs to be scanned again. The switching apparatus places the measuring air chamber into the optical path again after the background spectrum is completed scanned, the spectrometer is recovered to a normal spectrum scanning and a spectrometric analysis. The method omits the time of cleaning the air chamber when the background is scanned, which substantially reduces the missed measurement data during the spectrum on-line analytical process, and avoids the system analysis error introduced by residual gas due to the unclean gas chamber.

The invention provides a pollution-gas differential optical absorption spectroscopy measurement system with optical fiber structure. The measurement system is characterized in that a xenon lamp light source is disposed in a lamp holder; light beams emitted by the xenon lamp light source are coupled to the transmitting optical fibers connected with the lamp holder; the first bundle of the optical fibers of the transmitting optical fibres are connected with a first optical switch; the second bundle of the optical fibers of the transmitting optical fibers are connected with a transmitting/receiving telescope; the second light beam penetrates through the optical switch and then is used as a background spectrum and enters in receiving optical fibers; the first light beam is transmitted after being reflected by a plane mirror of the transmitting/receiving telescope, reflected via a corner reflector, then received by the transmitting/receiving telescope and coupled to the receiving optical fibers; the receiving optical fibers penetrate through a second optical switch and a sample box and then are connected with a spectrograph; the first light beam and the second light beam are coupled by the receiving optical fibers to form the third light beam; the third light beam is received by the spectrograph; the spectrum of the third light beam is monitored by the spectrograph; and content information of the pollution gas is obtained by a data processing system according to monitored results. The measurement system is liable to disassemble and assembly, and is compact in structure and high in spectrum utilization rate.