Exactly capturing three dimensional (3D) motion i nf ormation of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision s yst...Exactly capturing three dimensional (3D) motion i nf ormation of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision s ystem and a method for determining 3D motion parameters of an object from binocu lar sequence images are introduced. The main steps include camera calibration, t he matching of motion and stereo images, 3D feature point correspondences and re solving the motion parameters. Finally, the experimental results of acquiring th e motion parameters of the objects with uniform velocity and acceleration in the straight line based on the real binocular sequence images by the mentioned meth od are presented.展开更多
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
The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue channels.This paper presents three major cali-bratio...The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue channels.This paper presents three major cali-bration experiments of the all-sky imager,geometric an-gular calibration,optical calibration,and radiometric calibration,and then infers an algorithm to retrieve rela-tive radiance from the all-sky images.Field experiments show that the related coefficient between retrieved radi-ance and measured radiance is about 0.91.It is feasible to use the algorithm to retrieve radiance from images.The paper sets up a relationship between radiance and the im-age,which is useful for using the all-sky image in nu-merical-simulations that predict more meteorological pa-rameters.展开更多
Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should...Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should possess uniform background and contain marker shadow only, but in fact marker images always possess nonuniform background and are contaminated by noise and unwanted anatomic information, making the extraction very difficult. A target-orientated marker shadow extraction method was proposed. With this method a proper threshold for marker image binarization can be determined.展开更多
To extract quantitative biophysical parameters such as leaf biomass and leaf chlorophyll concentration from the remotely sensed imagery, the effect of atmospheric attenuation must be removed. The refined empirical li...To extract quantitative biophysical parameters such as leaf biomass and leaf chlorophyll concentration from the remotely sensed imagery, the effect of atmospheric attenuation must be removed. The refined empirical line （REL） method was used to calibrate the IKONOS multispectral imagery. The IKONOS digital numbers （DN） were converted to the at-satellite reflectance, then the linear relation between at-satellite reflectance and surface spectral reflectance （ρA） was derived from six bright targets of known reflectance in the image, and modelled estimates of the image reflectance at ρA=0. Validation targets were used to test the feasibility of REL method. The mean relative errors between ρA retrieved from IKONOS image using REL method and ground-measured ρA were 11%, 13%, 3% and 5% in the IKONOS blue, green, red and near-infrared （NIR） respectively. When dark targets are unavailable or measurement of dark target is inconvenient, the REL method was most crucial for retrieving surface spectral reflectance. The REL offers a simple approach for quantitative retrieval of biophysical parameters from IKONOS imagery.展开更多
In this paper, we proposed a novel resolution criterion（improved calibrated normalized resolution product, r＊＇） to evaluate separation quality of fingerprints. By comparing with the calibrated normalized resolutio...In this paper, we proposed a novel resolution criterion（improved calibrated normalized resolution product, r＊＇） to evaluate separation quality of fingerprints. By comparing with the calibrated normalized resolution product（r＊） and the hierarchical chromatographic response function（HCRF）, the validity of this criterion was demonstrated by experimental chromatograms. The soy isoflavone extract was selected as the analytical object. The initial and end percentages of methanol and elution time affecting gradient elution were tested by orthogonal design. The final optimized conditions were as follows. It was detected by UV absorbance at 254 nm, column temperature was maintained at 36 oC, solvent A was 0.1%（v/v） acetic acid, solvent B was methanol, gradient elution was from 34% to 65% B in a linear gradient in 25 min, and the flow-rate was set at 1.0 m L/min. In addition, the main ingredients of the soy isoflavone extract were confirmed by LC-ESI/MS.展开更多
This study is aimed at using the Empirical Line Method （ELM） to eliminate atmospheric effects with respect to visible and near infrared bands of advanced spaceborne thermal emission and reflection radiometer （ASTER...This study is aimed at using the Empirical Line Method （ELM） to eliminate atmospheric effects with respect to visible and near infrared bands of advanced spaceborne thermal emission and reflection radiometer （ASTER） and enhanced thematic mapper plus （ETM＋） data. Two targets （Amran limestone as light target and quartz-biotite-sericite-graphite schists as dark target）, which were widely exposed and easy to identify in the imagery were selected. The accuracy of the atmospheric correction method was evaluated from three targets （vegetation cover, Amran limestone and Akbra shale） of the surface reflectance. Analytical spectral devices （ASD） FieldSpec3 was used to measure the spectra of target samples. ETM＋ data were less influenced by the atmospheric effect when compared to ASTER data. Normalized differences vegetation indices （NDVI） displayed good results with reflectance data when compared with digital number （DN） data because it is highly sensitive to ground truth reflectance （GTR）. Most of the differences observed before and after calibration of satellite images （ASTER and ETM＋） were absorbed in the SWlR region.展开更多
Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required.In this paper,we investigate the unwrapping,epipolar geometry and stereo rectification issues fo...Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required.In this paper,we investigate the unwrapping,epipolar geometry and stereo rectification issues for omnidirectional vision when the particular mirror model and the camera parameters are unknown in priori.First,the omnidirectional camera is calibrated under the Taylor model,and the parameters related to this model are obtained.In order to make the classical computer vision algorithms of conventional perspective cameras applicable,the ring omnidirectional image is unwrapped into two kinds of panoramas:cylinder and cuboid.Then the epipolar geometry of arbitrary camera configuration is analyzed and the essential matrix is deduced with its properties being indicated for ring images.After that,a simple stereo rectification method based on the essential matrix and the conformal mapping is proposed.Simulations and real data experimental results illustrate that our methods are effective for the omnidirectional camera under the constraint of a single view point.展开更多
文摘Exactly capturing three dimensional (3D) motion i nf ormation of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision s ystem and a method for determining 3D motion parameters of an object from binocu lar sequence images are introduced. The main steps include camera calibration, t he matching of motion and stereo images, 3D feature point correspondences and re solving the motion parameters. Finally, the experimental results of acquiring th e motion parameters of the objects with uniform velocity and acceleration in the straight line based on the real binocular sequence images by the mentioned meth od are presented.
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.
基金supported by the national natural science foundation of China (Grant Nos.40505006 and 40775026)
文摘The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue channels.This paper presents three major cali-bration experiments of the all-sky imager,geometric an-gular calibration,optical calibration,and radiometric calibration,and then infers an algorithm to retrieve rela-tive radiance from the all-sky images.Field experiments show that the related coefficient between retrieved radi-ance and measured radiance is about 0.91.It is feasible to use the algorithm to retrieve radiance from images.The paper sets up a relationship between radiance and the im-age,which is useful for using the all-sky image in nu-merical-simulations that predict more meteorological pa-rameters.
基金Project of Science and Technology Committee of Shanghai Municipality (No.2528(3))
文摘Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should possess uniform background and contain marker shadow only, but in fact marker images always possess nonuniform background and are contaminated by noise and unwanted anatomic information, making the extraction very difficult. A target-orientated marker shadow extraction method was proposed. With this method a proper threshold for marker image binarization can be determined.
基金Project supported by the Hi-Tech Research and Development Pro-gram (863) of China (Nos. 2002AA130010-2-7 and 2003AA131020- 04-06) and the National Natural Science Foundation of China (No. 40171065)
文摘To extract quantitative biophysical parameters such as leaf biomass and leaf chlorophyll concentration from the remotely sensed imagery, the effect of atmospheric attenuation must be removed. The refined empirical line （REL） method was used to calibrate the IKONOS multispectral imagery. The IKONOS digital numbers （DN） were converted to the at-satellite reflectance, then the linear relation between at-satellite reflectance and surface spectral reflectance （ρA） was derived from six bright targets of known reflectance in the image, and modelled estimates of the image reflectance at ρA=0. Validation targets were used to test the feasibility of REL method. The mean relative errors between ρA retrieved from IKONOS image using REL method and ground-measured ρA were 11%, 13%, 3% and 5% in the IKONOS blue, green, red and near-infrared （NIR） respectively. When dark targets are unavailable or measurement of dark target is inconvenient, the REL method was most crucial for retrieving surface spectral reflectance. The REL offers a simple approach for quantitative retrieval of biophysical parameters from IKONOS imagery.
基金National Higher-Education Institution General Research and Development Funding(Grant No.JKP2011010)
文摘In this paper, we proposed a novel resolution criterion（improved calibrated normalized resolution product, r＊＇） to evaluate separation quality of fingerprints. By comparing with the calibrated normalized resolution product（r＊） and the hierarchical chromatographic response function（HCRF）, the validity of this criterion was demonstrated by experimental chromatograms. The soy isoflavone extract was selected as the analytical object. The initial and end percentages of methanol and elution time affecting gradient elution were tested by orthogonal design. The final optimized conditions were as follows. It was detected by UV absorbance at 254 nm, column temperature was maintained at 36 oC, solvent A was 0.1%（v/v） acetic acid, solvent B was methanol, gradient elution was from 34% to 65% B in a linear gradient in 25 min, and the flow-rate was set at 1.0 m L/min. In addition, the main ingredients of the soy isoflavone extract were confirmed by LC-ESI/MS.
文摘This study is aimed at using the Empirical Line Method （ELM） to eliminate atmospheric effects with respect to visible and near infrared bands of advanced spaceborne thermal emission and reflection radiometer （ASTER） and enhanced thematic mapper plus （ETM＋） data. Two targets （Amran limestone as light target and quartz-biotite-sericite-graphite schists as dark target）, which were widely exposed and easy to identify in the imagery were selected. The accuracy of the atmospheric correction method was evaluated from three targets （vegetation cover, Amran limestone and Akbra shale） of the surface reflectance. Analytical spectral devices （ASD） FieldSpec3 was used to measure the spectra of target samples. ETM＋ data were less influenced by the atmospheric effect when compared to ASTER data. Normalized differences vegetation indices （NDVI） displayed good results with reflectance data when compared with digital number （DN） data because it is highly sensitive to ground truth reflectance （GTR）. Most of the differences observed before and after calibration of satellite images （ASTER and ETM＋） were absorbed in the SWlR region.
基金supported by the National Natural Science Foundation of China (Nos.60502006,60534070 and 90820306)the Science and Technology Plan of Zhejiang Province,China (No.2007C21007)
文摘Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required.In this paper,we investigate the unwrapping,epipolar geometry and stereo rectification issues for omnidirectional vision when the particular mirror model and the camera parameters are unknown in priori.First,the omnidirectional camera is calibrated under the Taylor model,and the parameters related to this model are obtained.In order to make the classical computer vision algorithms of conventional perspective cameras applicable,the ring omnidirectional image is unwrapped into two kinds of panoramas:cylinder and cuboid.Then the epipolar geometry of arbitrary camera configuration is analyzed and the essential matrix is deduced with its properties being indicated for ring images.After that,a simple stereo rectification method based on the essential matrix and the conformal mapping is proposed.Simulations and real data experimental results illustrate that our methods are effective for the omnidirectional camera under the constraint of a single view point.
