The gray level values of target pixels of infrared images processed by the SUSAN noise filtering algorithm and the background filtering algorithm are calculated,assuming that the target distance is given in image acqu...The gray level values of target pixels of infrared images processed by the SUSAN noise filtering algorithm and the background filtering algorithm are calculated,assuming that the target distance is given in image acquisition.The equivalent blackbody temperature is obtained by the temperature calibration model that represents the quantitative relation,at a certain integration time,between the gray level value and the equivalent blackbody temperature.The temperature calibration model has been acquired by the curve fitting with the experimental data of blackbody temperature calibration using Origin 6.0.Then the target radiance can be determined by the radiant flux equivalence model built on condition that the target radiant flux received by the infrared detector is equivalent to that of the blackbody placed in front of the infrared detector at a close distance.This measuring method is based on the temperature calibration parameters and real image information,so it can avoid subjectivity of the traditional theory modeling methods.展开更多
[Objective] This study was conducted to evaluate the feasibility of deter- mining crude protein in ramie using near-infrared （NIR） spectrometer. [Method] Par- tial least square regression （PLSR） was performed to e...[Objective] This study was conducted to evaluate the feasibility of deter- mining crude protein in ramie using near-infrared （NIR） spectrometer. [Method] Par- tial least square regression （PLSR） was performed to establish a calibration model based on 50 samples for predicting the crude protein content in ramie, and the model was validated with data in the validation set consisting of 10 samples. [Result] The correlation coefficient of the model was 0.98. There was a good correla- tion between the predicted values by the near-infrared prediction model and the measured values by chemical analysis, and the relative error was 3.54% on aver- age between the predicted and the measured values. [Conclusion] The results showed that it is feasible to determine crude protein content in ramie using NIR spectroscopy-based prediction model.展开更多
A Fourier transform （FT） spectrum of praseodymium （Pr） extending from UV to IR was investigated. Hyperfine （hf） structures of unclassified lines with sufficiently high signal to noise ratio （SNR） were analyzed...A Fourier transform （FT） spectrum of praseodymium （Pr） extending from UV to IR was investigated. Hyperfine （hf） structures of unclassified lines with sufficiently high signal to noise ratio （SNR） were analyzed and some new levels were found. We present these new levels in this work. Some of the new levels have energies almost equal to the energies of already known or other new levels, distinguished either by different values of angular momentum J or by their parity.展开更多
A new algorithm of nonuniformity correction for infrared focal plane array(IRFPA) is reported,which is a combined algorithm based on both the two-point correction and artificial neural networks correction. The combine...A new algorithm of nonuniformity correction for infrared focal plane array(IRFPA) is reported,which is a combined algorithm based on both the two-point correction and artificial neural networks correction. The combined algorithm is calibrated by two-point correction,and the calibrated correction coefficients are automatically modified by BP algorithm. So it is not only calibrated,but also real-time processed. In adaptive nonuniformity correction algorithm,the phenomena ghost artifact and target fade-out are avoided by edge extraction. In order to get intensified image,the modified median filters are adopted. The simulated data indicates the proposed scheme is an effective algorithm.展开更多
In addition to the conventional methods of the calibration model construction, such as PCR （principal components regression） and PLS （partial least-squares）, a MPM （mathematical programming method） is developed ...In addition to the conventional methods of the calibration model construction, such as PCR （principal components regression） and PLS （partial least-squares）, a MPM （mathematical programming method） is developed and proposed for practical use in NIR analyses of agricultural and food products. The proposed method involves the mathematical programming techniques to seek the regression coefficients for the calibration model calculation. It is based on the optimization theory used for finding the extremum of the objective function in the given domain of a vector space and employs the method of the complementarity problems solving. The MPM algorithm is described in detail. The MPM was tested on an InfraLUM FT-10 NIR analyzer of Lumex company with samples of dry milk （for fat）, corn （for protein） and rye flour （for moisture）. The obtained results show that the MPM can be used for constructing multivariate calibrations with the qualitative characteristics superior over those of the classical PCR and PLS methods of analysis.展开更多
A method is proposed to compensate the output drift for cooled infrared imaging systems at various ambient temperatures. By calibrating the cryogenic infrared detector which absorbs the radiant flux of blackbody direc...A method is proposed to compensate the output drift for cooled infrared imaging systems at various ambient temperatures. By calibrating the cryogenic infrared detector which absorbs the radiant flux of blackbody directly, the internal factors can be obtained. Then, by combining the calibration result of infrared imaging system at an arbitrary ambient temperature, the output drift can be calculated and compensated at various integration time and ambient temperatures. Experimental results indicate that the proposed method can eliminate the effect of ambient temperature fluctuation on the system output efficiently.展开更多
A calibration board composed of 8×8 near-infrared surface-mounted diodes(NIR-SMDs)(940 nm)is designed.Meanwhile,a common binocular measurement system with the average error less than 0.1320 mm is used to obtain t...A calibration board composed of 8×8 near-infrared surface-mounted diodes(NIR-SMDs)(940 nm)is designed.Meanwhile,a common binocular measurement system with the average error less than 0.1320 mm is used to obtain the geometric information of this board.A calibration method with the designed pattern is performed to obtain the parameters of the near-infrared camera(NIRC).In the experiment,the average relative errors of focal length and principal point are 0.244%and 0.735%,respectively.The mean of image residuals is less than 0.01 pixel.The error of three-dimensional(3D)measurement is less than 0.3 mm.All those results indicate that the designed calibration board is suitable and accurate for calibrating NIRC.展开更多
Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the lim...Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency.展开更多
Consensus methods have presented promising tools for improving the reliability of quantitative models in near-infrared(NIR) spectroscopic analysis.A strategy for improving the performance of consensus methods in multi...Consensus methods have presented promising tools for improving the reliability of quantitative models in near-infrared(NIR) spectroscopic analysis.A strategy for improving the performance of consensus methods in multivariate calibration of NIR spectra is proposed.In the approach,a subset of non-collinear variables is generated using successive projections algorithm(SPA) for each variable in the reduced spectra by uninformative variables elimination(UVE).Then sub-models are built using the variable subsets and the calibration subsets determined by Monte Carlo(MC) re-sampling,and the sub-model that produces minimal error in cross validation is selected as a member model.With repetition of the MC re-sampling,a series of member models are built and a consensus model is achieved by averaging all the member models.Since member models are built with the best variable subset and the randomly selected calibration subset,both the quality and the diversity of the member models are insured for the consensus model.Two NIR spectral datasets of tobacco lamina are used to investigate the proposed method.The superiority of the method in both accuracy and reliability is demonstrated.展开更多
基金Supported by Innovation Project of Chinese Academy of Sciences(Grant No.C04708Z)
文摘The gray level values of target pixels of infrared images processed by the SUSAN noise filtering algorithm and the background filtering algorithm are calculated,assuming that the target distance is given in image acquisition.The equivalent blackbody temperature is obtained by the temperature calibration model that represents the quantitative relation,at a certain integration time,between the gray level value and the equivalent blackbody temperature.The temperature calibration model has been acquired by the curve fitting with the experimental data of blackbody temperature calibration using Origin 6.0.Then the target radiance can be determined by the radiant flux equivalence model built on condition that the target radiant flux received by the infrared detector is equivalent to that of the blackbody placed in front of the infrared detector at a close distance.This measuring method is based on the temperature calibration parameters and real image information,so it can avoid subjectivity of the traditional theory modeling methods.
文摘[Objective] This study was conducted to evaluate the feasibility of deter- mining crude protein in ramie using near-infrared （NIR） spectrometer. [Method] Par- tial least square regression （PLSR） was performed to establish a calibration model based on 50 samples for predicting the crude protein content in ramie, and the model was validated with data in the validation set consisting of 10 samples. [Result] The correlation coefficient of the model was 0.98. There was a good correla- tion between the predicted values by the near-infrared prediction model and the measured values by chemical analysis, and the relative error was 3.54% on aver- age between the predicted and the measured values. [Conclusion] The results showed that it is feasible to determine crude protein content in ramie using NIR spectroscopy-based prediction model.
文摘A Fourier transform （FT） spectrum of praseodymium （Pr） extending from UV to IR was investigated. Hyperfine （hf） structures of unclassified lines with sufficiently high signal to noise ratio （SNR） were analyzed and some new levels were found. We present these new levels in this work. Some of the new levels have energies almost equal to the energies of already known or other new levels, distinguished either by different values of angular momentum J or by their parity.
文摘A new algorithm of nonuniformity correction for infrared focal plane array(IRFPA) is reported,which is a combined algorithm based on both the two-point correction and artificial neural networks correction. The combined algorithm is calibrated by two-point correction,and the calibrated correction coefficients are automatically modified by BP algorithm. So it is not only calibrated,but also real-time processed. In adaptive nonuniformity correction algorithm,the phenomena ghost artifact and target fade-out are avoided by edge extraction. In order to get intensified image,the modified median filters are adopted. The simulated data indicates the proposed scheme is an effective algorithm.
文摘In addition to the conventional methods of the calibration model construction, such as PCR （principal components regression） and PLS （partial least-squares）, a MPM （mathematical programming method） is developed and proposed for practical use in NIR analyses of agricultural and food products. The proposed method involves the mathematical programming techniques to seek the regression coefficients for the calibration model calculation. It is based on the optimization theory used for finding the extremum of the objective function in the given domain of a vector space and employs the method of the complementarity problems solving. The MPM algorithm is described in detail. The MPM was tested on an InfraLUM FT-10 NIR analyzer of Lumex company with samples of dry milk （for fat）, corn （for protein） and rye flour （for moisture）. The obtained results show that the MPM can be used for constructing multivariate calibrations with the qualitative characteristics superior over those of the classical PCR and PLS methods of analysis.
文摘A method is proposed to compensate the output drift for cooled infrared imaging systems at various ambient temperatures. By calibrating the cryogenic infrared detector which absorbs the radiant flux of blackbody directly, the internal factors can be obtained. Then, by combining the calibration result of infrared imaging system at an arbitrary ambient temperature, the output drift can be calculated and compensated at various integration time and ambient temperatures. Experimental results indicate that the proposed method can eliminate the effect of ambient temperature fluctuation on the system output efficiently.
基金supported by the National Natural Science Foundation of China(No.81101130)the Fundamental Research Funds for Central Universities under the South China University of Technology(No.2012ZZ0095)the Science and Technology Program of Guangdong Province(No.2012B031800026)
文摘A calibration board composed of 8×8 near-infrared surface-mounted diodes(NIR-SMDs)(940 nm)is designed.Meanwhile,a common binocular measurement system with the average error less than 0.1320 mm is used to obtain the geometric information of this board.A calibration method with the designed pattern is performed to obtain the parameters of the near-infrared camera(NIRC).In the experiment,the average relative errors of focal length and principal point are 0.244%and 0.735%,respectively.The mean of image residuals is less than 0.01 pixel.The error of three-dimensional(3D)measurement is less than 0.3 mm.All those results indicate that the designed calibration board is suitable and accurate for calibrating NIRC.
基金supported by the National Natural Science Foundation of China (Grant No. 40971227)the International Corporation Program of Science and Technology Ministry of China (Grant No. 2010DFA21880)
文摘Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency.
基金supported by the National Natural Science Foundation of China (20835002)
文摘Consensus methods have presented promising tools for improving the reliability of quantitative models in near-infrared(NIR) spectroscopic analysis.A strategy for improving the performance of consensus methods in multivariate calibration of NIR spectra is proposed.In the approach,a subset of non-collinear variables is generated using successive projections algorithm(SPA) for each variable in the reduced spectra by uninformative variables elimination(UVE).Then sub-models are built using the variable subsets and the calibration subsets determined by Monte Carlo(MC) re-sampling,and the sub-model that produces minimal error in cross validation is selected as a member model.With repetition of the MC re-sampling,a series of member models are built and a consensus model is achieved by averaging all the member models.Since member models are built with the best variable subset and the randomly selected calibration subset,both the quality and the diversity of the member models are insured for the consensus model.Two NIR spectral datasets of tobacco lamina are used to investigate the proposed method.The superiority of the method in both accuracy and reliability is demonstrated.
