82 results about "Cross Calibration" patented technology

The invention relates to a cross radiation calibration method based on the optimization algorithm of a hyper-spectral sensor; the cross radiation calibration method comprises the following steps of: (1) selecting an image to be calibrated; (2) selecting a reference image; (3) cutting out a region covered jointly by the two images, and selecting a uniform ground object to be used as a cross calibration interesting region; (4) working out the entrance pupil radiant brightness of the two sensors in each waveband and a gas absorbing characteristic curve, and removing gas absorption characteristics; (5) screening out the optimal wave band and the optimal interpolation scheme; (6) carrying out the cross radiation calibration on the optimal wave band of the hyper-spectral sensor; (7) interpolating the radiant brightness of the calibrated hyper-spectral waveband, reconstructing a hyper-spectral curve, loading the gas absorption characteristics to serve as the radiant brightness of the reference sensor; and (8) realizing the cross radiation calibration on the hyper-spectral sensor by using a multispectral sensor. The cross radiation calibration method can realize the in-orbit cross radiation calibration of a space-borne imaging spectrometer and has business popularization prospect.

A multiple modality imaging system (10) includes a MR scanner (12) which defines an MR imaging region (18), a nuclear imaging scanner (26) which defines a nuclear imaging region (34), an CT scanner (36) which defines an CT imaging region (42). Each scanner (12, 26, 36) having a longitudinal axis along which a common patient support (46) moves linearly through the MR, nuclear, and CT imaging regions (18, 34, 42). A marker (130, 140, 150), for use with the system (10), includes a radio-isotope marker (132) which is imageable by the nuclear imaging scanner (26) and the CT scanner (36) surrounded by a flexible silicone MR marker (134) which is imageable by the MR scanner (12) and the CT scanner (36). A calibration phantom(162), for use with the image scanner (10), includes a plurality of the markers (130, 140, 150) supported by a common frame having a known and predictable geometry.

Methods and apparatus for an automated system for cross calibration based on data stored by a plant computer and data storage unit or a plant monitoring system. The automated system includes a processor executing software for retrieving data, determining average temperatures, determining deviations, and determining new calibration curve coefficients for deviating instruments. In another embodiment, the processor executes software for loading the historical data, selecting data points, removing deviate data, analyzing the data, reporting the data, and for recalibrating instruments that were determined to be deviating.

The invention provides a cross radiation calibration method and system for a large observation angle sensor. The method comprises steps that a to-be-calibrated image and a reference image are registered, random sampling of each set of corresponding wave bands of the to-be-calibrated image and the reference image is respectively carried out to acquire corresponding calibration points; for each wave band, cross calibration for each pair of calibration points is carried out respectively, a BRDF adjusting coefficient is established as a ratio of a surface bidirectional reflection distribution function of the to-be-calibrated image and a surface bidirectional reflection distribution function of the reference image, and processing is carried out in an iteration mode; for each wave band, points with average mean values greater than a preset threshold are deleted from the cross calibration result, averaging is carried out, and a final radiation calibration coefficient is acquired. The method is advantaged in that BRDF values of the to-be-calibrated image and the reference image can be respectively calculated without a complex model, calculation is simple and stable, strong operationality is realized, and an error caused by introducing auxiliary data for BRDF calculation and influence of abnormal calibration points on the result can be further avoided.

The invention discloses a method for measuring the six-freedom-degree displacement and attitude of a model. A cross calibration rack is used for simulating a model and a wind tunnel coordinate system is established by using an absolute measuring arm; on the basis of measurement of coordinate values of a first circular hole, a second circular hole, a third circular hole and a fourth circular hole in the cross calibration rack under the wind tunnel coordinate system, a vector L1 of an axis of a first rod piece and a vector L2 of an axis of a second rod piece are calculated and an included angel between the vector L1 and a horizontal plane, an included angle between vector L1 and a vertical surface, and an included angle between the vector L2 and the horizontal plane are calculated; a pitching angle, a yaw angle and a rolling angle of the cross calibration rack are calculated and thus a pitching angle, a yaw angle, and a rolling angle of the model are calculated; and a mass center coordinate of the model under the wind tunnel coordinate system is calculated by using a coordinate value of a calibration hole in the wind tunnel coordinate system. Therefore, the integrated measuring problem of the displacement and attitude of the wind tunnel testing model can be solved; and measurement on the six-freedom-degree displacement and attitude of the model is realized. The measuring precision is high and the calculation speed is fast.

The invention provides a remote sensor radiometric calibration method based on hyperspectral data and a calibration system. The method comprises the steps of collecting hyperspectral remote sensing data in real time through a hyperspectral remote sensor serving as a reference remote sensor, collecting the imager channel reflectivity in real time through a channel imager serving as a remote sensorto be calibrated, and converting the hyperspectral remote sensing data into imager channel simulated reflectivity; establishing a projection area by taking the interaction of running orbits of the reference remote sensor and the remote sensor to be calibrated as a center and taking the sub-satellite point resolution as an interval; and projecting the imager channel simulated reflectivity and the imager channel reflectivity to the projection area, extracting effective cross-calibration data pairs for pixels of the hyperspectral remote sensing data, and calculating the radiometric calibration coefficient of the remote sensor to be calibrated according to the effective cross-calibration data pairs so as to correct the imager channel reflectivity collected by the remote sensor to be calibratedin real time.

The invention relates to an MODIS image-based apparent reflectance model construction method and system and a calibration method. According to the construction method, corresponding image apparent reflectance and related angle information through selecting an effective calibration field image; a nuclear driving model is utilized to obtain an apparent reflectance correction coefficient, so as to establish an apparent reflectance model; and the apparent reflectance model is used for obtaining apparent reflectance, so as to cross calibration between different sensor satellite image pairs. The construction method is suitable for in-orbit calibration of multi-spectrum satellites, particularly the cross calibration between large-angle images; and the method has the advantages of being high in calibration precision and being used for re-calibration of history data. Satellite-earth synchronous experiments do not need to be carried out, and the assumption that lambert performance must exist atthe field is cancelled, so that the cross calibration of small-angle images can be realized, and the cross calibration of large-angle images can be realized, thereby greatly improving the calibrationfrequency and precision.

The invention discloses a relay zero-cross detection method and device and a relay zero-cross calibration method and device. The relay zero-cross detection method comprises the following steps: when a relay is turned on, monitoring the voltage phase of a controlled end of the relay; obtaining the time interval of adjacent two times of zero-cross of the voltage phase; and sending the time interval to the zero-cross calibration side of the relay. The relay is detected by setting the independent zero-cross detection device, and is free of requirement for product circuit; and meanwhile, the relay does not need to be screened again, so that the research and development time of the product can be effectively reduced, and the production cost of the product is reduced.

The invention discloses a data collection system based on a plurality of data routes and the cross-calibration and a data collection method adopted the system. The data collection system of the invention comprises a measuring channel, at least two measuring routes connected with the measuring channel and a measured data control unit connected with each measuring route. The measuring channel can be used for receiving input signals. Each measuring route comprises an analog-to-digital converter and an amplifier, the magnification factor of which is different from that of other routes. Each measuring route has a different measuring range. The measured data control unit comprises an input buffer, an output buffer, a cross-calibration computing module consisting of a digital logic circuit and a digital signal processor. The invention has the advantages that the invention can automatically adjust the best measurement range, and the measuring results are more accurate.

When estimating an arterial input function or a patient under study, cross- calibration factors are generated by comparing nuclear scan data of a radioactive material (e.g., F18) and measuring a sample of the radioactive material in a gamma counter. The derived cross-calibration factors are applied to venous samples collected from the patient during a nuclear scan after infusion with a radioactive tracer, to convert gamma values counted by the gamma counter into concentration values. The concentration values are used to optimize an initial estimated input function, thereby generating an arterialized input function.

The invention relates to a geometric cross-calibration method and system for spaceborne SAR images. The method comprises the steps of step 1), establishing an atmospheric delay correction model of images to be calibrated; step 2) establishing a geometric calibration model of the images to be calibrated; step 3), selecting pairs of points with the same name from the images to be calibrated and reference images; step 4, according to imaging time of the images to be calibrated, using global atmospheric data provided by NCEP and ionospheric electron content distribution data provided by the European Orbit Determination Center (CODE), through the atmospheric delay correction model established in the step 1), calculating atmospheric delay correction values of the image to be calibrated; step 5),substituting the several pairs of points with the same name obtained in step 3) and the atmospheric delay correction values obtained in step 4) into the geometric calibration model established in step 2) to complete geometric calibration parameter solution. The method can achieve the normalization and short-period geometric calibration of a SAR satellite, do not need to arrange targets in advanceon the ground, and greatly save manpower and financial cost.

The invention discloses a multi-spectral load site-free cross calibration method based on hyperspectral loads. According to the method, site measured data are replaced by hyperspectral data with the high radiation calibration accuracy, on-track calibration replacement of multi-spectral loads is achieved, the on-track radiation calibration frequency can be effectively increased, a large amount of manpower and a large number of material resources needed by site calibration are saved, and the problem that on-track radiation calibration is limited by the site measured data at present is solved. By means of the multi-spectral load site-free cross calibration method, the hyperspectral loads are introduced into cross calibration, the spectrum matching algorithm is improved, and the method is also suitable for on-track cross calibration of the multi-spectral loads in other wave bands.

The invention discloses a water color satellite atmospheric layer top radiation product quality evaluation and cross calibration method. The method comprises the following steps: establishing a multi-source satellite quasi-synchronization effective pixel selection constraint condition; finding that radiation signal abnormity caused by the natural process has high interstellar correlation; designing a multi-source satellite radiation product error analytical equation; combining a dynamic cross radiation calibration mechanism; and determining the influence of the radiation product quality on the water color product. According to the scheme, constraint conditions of quasi-synchronous observation are specified for the first time, an analytic equation of multi-source satellite radiation product errors is determined, dynamic evaluation and cross calibration of the water radiation product quality are achieved, the defect that a traditional method is seriously influenced by abnormal signals caused by the natural process is overcome, and the water radiation product quality and the automatic service level are improved; and moreover, the method is easy to implement, can be used for dynamically monitoring and improving the quality of water radiation products, and has wider practical application value and economic value.

A method of electronic portal imaging (EPID) for radiation dosimetric measurement and quality assurance (QA) in radiation therapy is provided that includes imaging a calibration photon beam and a treatment beam using an EPID imager disposed between a plastic water build-up phantom and a plastic water back-scatter phantom that is thicker than the plastic water build-up phantom, correcting the EPID images using an off-axis correction map that takes into account a horn-shape of a photon fluence profile, deconvolving the corrected EPID images using a Monte Carlo simulated EPID response kernel, the deconvolved corrected EPID images provide a primary photon fluence map, reconstructing a relative dose map using the primary photon fluence map convolving with a Monte Carlo simulated pencil-beam dose distribution kernel, and generating an absolute dose map using cross calibration to a 10x10 cm2 square field that is compared with a planned dose distribution for QA analysis.

Automated plant instrumentation system for cross calibration based on data stored by a plant computer and data storage unit or a plant monitoring system. The automated system includes a processor executing software for retrieving data, determining average temperatures, determining deviations, and determining new calibration curve coefficients for deviating instruments. In another embodiment, the processor executes software for loading the historical data, selecting data points, removing deviate data, analyzing the data, reporting the data, and for recalibrating instruments that were determined to be deviating.

The invention provides a satellite remote sensing image physical color uniformity method. The method comprises the steps that 1) a cross calibration method is used, and a Dunhuang radiation correction field is used as a transmission platform and a MODIS image is used as a reference standard to acquire the absolute radiation calibration factor of a certain camera of a GF-1 satellite WFV sensor; 2) a statistical analysis method is used to establish the correlation model of the adjacent camera image DN value; 3) a simulation method is used to establish the correlation model of the adjacent camera image apparent radiance; 4) a self-radiation calibration calibration model is established to realize absolute radiation calibration of another camera; and 5) each camera calibration coefficient is used to convert the image DN value to the apparent radiance to realize image physical color uniformity. Compared with the traditional color uniformity method, physical color uniformity between cameras is realized without destroying the original image radiation information.

The invention discloses an on-satellite high-precision cross-calibration system. The system comprises a one-dimensional pointing device, a calibration device, a control module, an optical system, a spectrograph, a detector, and a video module; the diffused light obtained by enabling the sun to irradiate a diffuse panel in the calibration device can be used for performing absolute radiometric calibration on itself; a scene image which is the same as other remote sensors can be acquired through the one-dimensional pointing device for the ground scene, and a cross-calibration method can be used for performing the cross-calibration on other remote sensors of the same platform. The photoelectric conversion is realized through the optical system, the spectrograph and the detector; an electric signal is output in a digital signal way after passing through the video module. The system disclosed by the invention can realize the acquisition of the diffused light of the diffuse panel and the acquisition of ground scene light in one set of system, and realize the higher precision absolute calibration on itself and the high-precision cross-calibration precision on other remote sensors.

The invention belongs to the technical field of remote sensing, and discloses a sea ice density acquisition method based on a space-time system point value, which comprises the following steps: acquiring original strip data and preprocessing to obtain day-scale brightness temperature data; performing cross calibration on the daily scale brightness temperature data to obtain calibrated daily scalebrightness temperature data; calculating and obtaining initial sea ice density by utilizing an ASI algorithm; giving a primary sea ice density condition, a spatial position condition and a time condition, selecting sample points for calculating a daily sea ice system point value and a seawater system point value, and taking an average value of the sample points as a daily new system point value; calculating and obtaining secondary sea ice density by utilizing an ASI algorithm on the basis of the new daily coefficient value; and removing false ice by using a weather filter and a maximum sea icerange mask to obtain daily-scale sea ice density. According to the invention, the problem of low precision of sea ice density obtained in the prior art is solved. The precision of the sea ice densityobtained by the method is higher than that of sea ice density obtained based on a fixed system point value.

The invention discloses a switch-on type and continuous inflow type dual-purpose density current test device and method. The device comprises a water storage tank, a vacuum pump, a sediment suspensioninstrument, a flowmeter, a flow guide pipe, a drain pipe, a valve switch, a water tank, pulleys, a guide rod and a guide rail. The device also comprises scale lines and a cross calibration line. Thetest method of the switch-on type and continuous inflow type dual-purpose density current test device comprises the following steps: the test preparation process, the test process, the instrument arrangement process and the data processing and analysis process. The device has the advantages of novel design, simple structure, good integrity, wide applicability to working conditions and high test accuracy; the device can simulate the switch-on type and continuous inflow type density current flow process under the influence of different density current concentration, bed roughness and topographicabrupt change and the continuous inflow type density current movement process under different degrees of gate opening; and the test process is easy to operate, the test efficiency is high and the test design is flexible.

The invention discloses an agricultural and forestry crop identification method based on medium-high resolution time sequence remote sensing data. The method comprises the steps of 1) carrying out thecross calibration on remote sensing images observed by multiple medium-high resolution remote sensors in the same region at different times; 2) for remote sensing images with different spatial resolutions, forming a remote sensing time sequence data set with consistent spatial resolutions and short time intervals on the basis of cross calibration; 3) segmenting the agriculture and forestry land parcels in the remote sensing image by using an image segmentation method to obtain the boundary of each land parcel; 4) analyzing the remote sensing time sequence data set by taking the land parcels as units, and counting the average value and variance of the spectral band reflectivity, the normalized vegetation index and the leaf area index of the land parcels in each period; sorting the statistical characteristics according to time to form a plurality of characteristic curves of the plot; and 5) matching the plurality of characteristic curves of the agriculture and forestry land parcels withthe phenological characteristic library to obtain the crop types of the land parcels.

The invention discloses a simulation method for remote sensing data under arbitrary spectral response characteristic, and belongs to the technical field of earth observation. In the method, the input hyperspectral data is subjected to iteration decorrelation, and hyperspectral data with improved spectral resolution is acquired; and the hyperspectral data with the improved spectral resolution is sampled according to the spectral response characteristic to be simulated, and hyperspectral or multispectral data under the spectral response characteristic to be simulated is acquired. The simulation method can be used for simulating the hyperspectral or multispectral data with arbitrary central wavelength position, arbitrary spectral resolution or arbitrary shape spectral response function by the existing hyperspectral data, and has higher accuracy of simulating data than the conventional spectral interpolation method and wave-band synthesis method so as to contribute to improving radiometric cross-calibration accuracy and data comparison and verification accuracy of a hyperspectral remote sensor.

Improved cross-calibration between magnetic resonance imaging (MRI) coordinates and optical tracking coordinates is provided. Initial calibration is performed with a calibration tool that includes wireless active markers that can be tracked using the MRI scanner, and an optical marker that can be tracked using the optical tracking system. Data from one or more poses of this tool are used to provide an initial cross-calibration. In use, this initial calibration is corrected to account for differences between actual camera position and the reference location. Here the reference location is the camera location at which the initial calibration was performed.

A method of electronic portal imaging (EPID) for radiation dosimetric measurement and quality assurance (QA) in radiation therapy is provided that includes imaging a calibration photon beam and a treatment beam using an EPID imager disposed between a plastic water build-up phantom and a plastic water back-scatter phantom that is thicker than the plastic water build-up phantom, correcting the EPID images using an off-axis correction map that takes into account a horn-shape of a photon fluence profile, deconvolving the corrected EPID images using a Monte Carlo simulated EPID response kernel, the deconvolved corrected EPID images provide a primary photon fluence map, reconstructing a relative dose map using the primary photon fluence map convolving with a Monte Carlo simulated pencil-beam dose distribution kernel, and generating an absolute dose map using cross calibration to a 10×10 cm2 square field that is compared with a planned dose distribution for QA analysis.

The invention relates to an optical remote sensing satellite radiation cross calibration method based on a stable radiation source, and the method comprises the following steps: a, carrying out the calibration of an optical remote sensing satellite through a satellite-borne black body, and obtaining a calibration coefficient; b, calculating a radiation value of the stable radiation source according to the calibration coefficient; c, repeating the step (a) and the step (b) to obtain a series of calibration coefficients and radiation values; and d, selectively performing radiation correction according to the decay condition of the radiation measurement performance of the optical remote sensing satellite. The method can achieve the stable correction of the in-orbit absolute radiation reference of the optical remote sensing satellite, and provides support for the quantitative processing and application of remote sensing data.

An online monitoring system for industrial processes, such as nuclear power processes, including a data acquisition unit configured to sample output signals simultaneously from a plurality of process sensors, and a computing unit configured to record sampled output signals from the data acquisition unit and to cross-correlate the output signals from two or more of the process sensors to diagnose operation of the industrial process, identify loose parts and / or degradation of industrial plant equipment, enable virtual sensing, calculate sensor response time using the noise analysis technique, and to verify sensor calibration using the cross calibration method and / or empirical and / or physical modeling.

The invention discloses an electric cooker and a zero-crossing calibration circuit and a zero-crossing calibration method thereof. The electric cooker comprises a resonance circuit, a power switch tube and a drive module. The resonance circuit is connected with a collector electrode of the power switch tube, and has a first node. The zero-crossing calibration circuit comprises a zero-crossing detection unit, a resonance voltage detection unit and a control unit, wherein the zero-crossing detection unit is used for detecting a zero-crossing point of an input AC power supply to output a zero-crossing signal; the resonance voltage detection unit is connected with the first node to detect resonance voltage of the first node; the zero-crossing detection end of the control unit is connected withthe zero-crossing detection unit; the AD sampling end of the control unit is connected with the resonance voltage detection unit; and the control unit judges that zero-cross detection is wrong, and carries out processing on the zero-crossing signal in the process where the zero-crossing detection end detects that the zero-passing signal changes from a falling edge to a rising edge, and when the AD sampling end samples the resonance voltage of the first node and the resonance voltage of the first node is larger than a preset voltage.

The invention provides a multi-dimensional cross calibration method in the test and measurement. The method comprises the following steps of determining a measured physical quantity and a real directly-measured parameter; determining all factors influencing the measured physical quantity; determining an intersection of all the factors and a measuring point of each factor containing the measured physical quantity; first measuring a direct parameter value at the intersection, and then measuring a direct parameter value of each measuring point of each factor and a value at the intersection of other factors in measurement; determining the relation between the measured physical quantity and the direct parameter as well as between the direct parameters; normalizing error values of all the factors on the intersection; calculating a value of the measured physical quantity, and completing the calibration and measurement. The method is not subjected to the limit of the dimensions, the relation between the direct parameter and each factor can be conveniently approximated through a polyline method, and the method is easily realized on the engineering; by adopting the normalization concept, only the points on the intersection are measured, so that the measurement data are greatly reduced; by adopting the polyline method, the measurement precision is high.

The invention discloses a reference load and target load cross calibration track design method. According to the method, an observation equation of a reference load and a target load for a specific ground calibration field is established according to task requirements of the reference load and the target load for cross calibration of the specific ground calibration field, and a fast non-dominatedsorting genetic algorithm NSGA-II is adopted for optimizing the reference load track, enabling the cross interval time of the reference load and the target load to meet the task requirement, and enabling the cross interval time to be the shortest and the cross frequency to be the maximum, so that the method is high in applicability, and the calibration efficiency of the reference load can be effectively improved.

The invention provides a cross calibration method and device for the significant wave height of a wave buoy, electronic equipment and a storage medium. The method comprises the steps of acquiring historical remote sensing wave significant wave height data and historical wave significant wave height data observed by buoys of different specifications; performing space-time matching, numerical discrete averaging and matching regression on the historical remote sensing wave significant wave height data and historical wave significant wave height data observed by buoys of different specifications,and establishing a buoy significant wave height cross calibration equation; acquiring wave observation data of a to-be-calibrated wave buoy, the wave observation data being significant wave height data of waves; and correcting the wave significant wave height data through the buoy significant wave height cross calibration equation to obtain corrected buoy wave significant wave height data. By implementing the embodiment of the invention, cross calibration can be performed on significant wave height observation of buoys of different specifications, the consistency of significant wave heights ofwaves in observation data of a wave buoy is improved, and the application reliability and application value of wave observation by a wave buoy are effectively improved.