Image fusion is performed between one band of multi-spectral image and two bands of hyperspectral image to produce fused image with the same spatial resolution as source multi-spectral image and the same spectral reso...Image fusion is performed between one band of multi-spectral image and two bands of hyperspectral image to produce fused image with the same spatial resolution as source multi-spectral image and the same spectral resolution as source hyperspeetral image. According to the characteristics and 3-Dimensional （3-D） feature analysis of multi-spectral and hyperspectral image data volume, the new fusion approach using 3-D wavelet based method is proposed. This approach is composed of four major procedures： Spatial and spectral resampling, 3-D wavelet transform, wavelet coefficient integration and 3-D inverse wavelet transform. Especially, a novel method, Ratio Image Based Spectral Resampling （RIBSR）method, is proposed to accomplish data resampling in spectral domain by utilizing the property of ratio image. And a new fusion rule, Average and Substitution （A＆S） rule, is employed as the fusion rule to accomplish wavelet coefficient integration. Experimental results illustrate that the fusion approach using 3-D wavelet transform can utilize both spatial and spectral characteristics of source images more adequately and produce fused image with higher quality and fewer artifacts than fusion approach using 2-D wavelet transform. It is also revealed that RIBSR method is capable of interpolating the missing data more effectively and correctly, and A＆S rule can integrate coefficients of source images in 3-D wavelet domain to preserve both spatial and spectral features of source images more properly.展开更多
Successful restoration of blurred images depends primarily on the knowledge about the degradationparameter.Defocus blur model in the frequency domain is characterized by concentric rings and the blurradius of the poin...Successful restoration of blurred images depends primarily on the knowledge about the degradationparameter.Defocus blur model in the frequency domain is characterized by concentric rings and the blurradius of the point spread function(PSF)can be identified conveniently in the frequency field for peopleby manual means rather than for computer.This paper introduces a practical method for computer to esti-mate the defocus blur parameter in cepstrum area.Fourier transform plays an intermediate role in the pathto cepstrum domain.We suggest a weighted adjustment operation in the frequency domain and then con-vert it to the cepstrum field to increase the accuracy of recognition.展开更多
N-FINDR is a very popular algorithm of endmember (EM) extraction for its automated property and high efficiency. Unfortunately, innumerable volume calculation, initial random selection of EMs and blind searching for E...N-FINDR is a very popular algorithm of endmember (EM) extraction for its automated property and high efficiency. Unfortunately, innumerable volume calculation, initial random selection of EMs and blind searching for EMs lead to low speed of the algorithm and limit the applications of the algorithm. So in this paper two measures are proposed to speed up the algorithm. One of the measures is substituting distance calculation for volume calculation. Thus the avoidance of volume calculation greatly decreases the computational cost. The other measure is resorting dataset in terms of pixel purity likelihood based on pixel purity index (PPI) concept. Then, initial EMs can be selected well-founded and a fast searching for EMs is achieved. Numerical experiments show that the two measures speed up the original algorithm hundreds of times as the number of EMs is more than ten.展开更多
The parallel spectral-domain optical coherence tomography（PSDOCT） is described for highspeed optical coherence tomography（OCT） without lateral scanning. In this setup, the self-elimination of auto-correlation（AC...The parallel spectral-domain optical coherence tomography（PSDOCT） is described for highspeed optical coherence tomography（OCT） without lateral scanning. In this setup, the self-elimination of auto-correlation（AC） interference algorithm was used for eradicating the AC interference and ghost images. However, when performed in free space OCT, this algorithm still generated a weak DC component. The algorithm was improved by adding the background intensity part to compensate for the mutual interference between object and reference arms. The results demonstrate that the DC component can be eradicated. Compared with conventional QCT and complex Fourier-domain optical coherence to- mography, the advantages of PSDOCT with the improved algorithm in free space are that it has no moving parts to generate consecutive phase shift, the structure of the object can be reconstructed immediately and automatically, and the speed is approximately 16 times faster than those of the other two in the same case.展开更多
An adaptive image denosing technique was proposed to achieve the tradeoff between details retain and noises removal. In order to achieve this objective, the contourlet transform was introduced and a new threshold meth...An adaptive image denosing technique was proposed to achieve the tradeoff between details retain and noises removal. In order to achieve this objective, the contourlet transform was introduced and a new threshold method, namely CWinShrink, is presented. It shrinks the contourlet coefficients with adaptive shrinkage factors. The shrinkage factors were calculated with reference to the sum of squares of the contourlet coefficients within the neighborhood window. This approach achieves enhanced results for images those are corrupted with additive Gaussian noise. In numerical comparisons with various methods, for a set of noisy images （the PSNR range fi＇om 10.86dB to 26.91dB） , the presented method outperforms VisuShrink and Wiener filter in terms of the PSNR. Experiments also show that this method not only keeps the details of image but also yields denoised images with better visual quality.展开更多
This paper presents a novel face recognition algorithm. To provide additional variations to training data set, even-odd decomposition is adopted, and only the even components (half-even face images) are used for furth...This paper presents a novel face recognition algorithm. To provide additional variations to training data set, even-odd decomposition is adopted, and only the even components (half-even face images) are used for further processing. To tackle with shift-variant problem,Fourier transform is applied to half-even face images. To reduce the dimension of an image,PCA (Principle Component Analysis) features are extracted from the amplitude spectrum of half-even face images. Finally, nearest neighbor classifier is employed for the task of classification. Experimental results on ORL database show that the proposed method outperforms in terms of accuracy the conventional eigenface method which applies PCA on original images and the eigenface method which uses both the original images and their mirror images as training set.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
The demands for high quality products are increasing in the market, so several tests are performed. These analyses are destructive, time consuming and sometimes expensive. The spectral imaging technique is an alternat...The demands for high quality products are increasing in the market, so several tests are performed. These analyses are destructive, time consuming and sometimes expensive. The spectral imaging technique is an alternative that can reduce costs and time and increase the efficiency and cost-effectiveness of these analyses. In this context, the aim of this study was to verify the spectral behavior of the tomato in function of the maturation and its potential use for non-destructive evaluation of food quality. Eighty tomatoes of the Italian group were selected in four stages of maturation （green, pink, light red and red）. Images were collected in wavelengths 480 nm to 710 nm （every 10 nm）. After the images were collected, the fruits were submitted to the physical-chemical analyses. The following parameters were analyzed： color, color index （CI）, pH, soluble solids （SS）, total titratable acidity （TTA） and ratio （SS/TTA）. After characterization the mean spectrum was obtained by the extraction of the spectral characteristics. It was observed that the spectral behavior was the same for all stages of maturation. It was possible to differentiate the green tomatoes in the wavelengths from 520 nm to 560 nm and from 610 nm to 660 nm. These intervals represent the area of reflection of chlorophyll and lycopene, respectively. Near the wavelength 560 nm, the highest absorbance was recorded by ripe tomatoes due to the concentration of lycopene. It is concluded that the best wavelengths for analysis are those in which green has the highest reflectance and it is possible to apply this technique for non-destructive analysis of the maturation of tomatoes.展开更多
This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on ...This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on the skewness-kurtosis test. In the end, a multivariate Gaussian distribution mathematical expression of background clutter image is given.展开更多
Given an essentially normal operator T with connected spectrum and ind (λ-T)>0 for λ in ρ F(T)∩σ(T) , and a positive number ∈ ,the authors show that theree xists a compact K with ‖K‖&...Given an essentially normal operator T with connected spectrum and ind (λ-T)>0 for λ in ρ F(T)∩σ(T) , and a positive number ∈ ,the authors show that theree xists a compact K with ‖K‖<∈ such that T+K is strongly irreducible.展开更多
文摘Image fusion is performed between one band of multi-spectral image and two bands of hyperspectral image to produce fused image with the same spatial resolution as source multi-spectral image and the same spectral resolution as source hyperspeetral image. According to the characteristics and 3-Dimensional （3-D） feature analysis of multi-spectral and hyperspectral image data volume, the new fusion approach using 3-D wavelet based method is proposed. This approach is composed of four major procedures： Spatial and spectral resampling, 3-D wavelet transform, wavelet coefficient integration and 3-D inverse wavelet transform. Especially, a novel method, Ratio Image Based Spectral Resampling （RIBSR）method, is proposed to accomplish data resampling in spectral domain by utilizing the property of ratio image. And a new fusion rule, Average and Substitution （A＆S） rule, is employed as the fusion rule to accomplish wavelet coefficient integration. Experimental results illustrate that the fusion approach using 3-D wavelet transform can utilize both spatial and spectral characteristics of source images more adequately and produce fused image with higher quality and fewer artifacts than fusion approach using 2-D wavelet transform. It is also revealed that RIBSR method is capable of interpolating the missing data more effectively and correctly, and A＆S rule can integrate coefficients of source images in 3-D wavelet domain to preserve both spatial and spectral features of source images more properly.
基金the National Natural Science Foundation of China(No.30570485)
文摘Successful restoration of blurred images depends primarily on the knowledge about the degradationparameter.Defocus blur model in the frequency domain is characterized by concentric rings and the blurradius of the point spread function(PSF)can be identified conveniently in the frequency field for peopleby manual means rather than for computer.This paper introduces a practical method for computer to esti-mate the defocus blur parameter in cepstrum area.Fourier transform plays an intermediate role in the pathto cepstrum domain.We suggest a weighted adjustment operation in the frequency domain and then con-vert it to the cepstrum field to increase the accuracy of recognition.
基金Sponsored by the National Natural Science Foundation of China (Grant No 60402025 and 60302019)
文摘N-FINDR is a very popular algorithm of endmember (EM) extraction for its automated property and high efficiency. Unfortunately, innumerable volume calculation, initial random selection of EMs and blind searching for EMs lead to low speed of the algorithm and limit the applications of the algorithm. So in this paper two measures are proposed to speed up the algorithm. One of the measures is substituting distance calculation for volume calculation. Thus the avoidance of volume calculation greatly decreases the computational cost. The other measure is resorting dataset in terms of pixel purity likelihood based on pixel purity index (PPI) concept. Then, initial EMs can be selected well-founded and a fast searching for EMs is achieved. Numerical experiments show that the two measures speed up the original algorithm hundreds of times as the number of EMs is more than ten.
文摘The parallel spectral-domain optical coherence tomography（PSDOCT） is described for highspeed optical coherence tomography（OCT） without lateral scanning. In this setup, the self-elimination of auto-correlation（AC） interference algorithm was used for eradicating the AC interference and ghost images. However, when performed in free space OCT, this algorithm still generated a weak DC component. The algorithm was improved by adding the background intensity part to compensate for the mutual interference between object and reference arms. The results demonstrate that the DC component can be eradicated. Compared with conventional QCT and complex Fourier-domain optical coherence to- mography, the advantages of PSDOCT with the improved algorithm in free space are that it has no moving parts to generate consecutive phase shift, the structure of the object can be reconstructed immediately and automatically, and the speed is approximately 16 times faster than those of the other two in the same case.
基金Sponsored by Key Lab of Optoelectronic Technology &System,Department of Education, China(Grant No.200373 -1 -2).
文摘An adaptive image denosing technique was proposed to achieve the tradeoff between details retain and noises removal. In order to achieve this objective, the contourlet transform was introduced and a new threshold method, namely CWinShrink, is presented. It shrinks the contourlet coefficients with adaptive shrinkage factors. The shrinkage factors were calculated with reference to the sum of squares of the contourlet coefficients within the neighborhood window. This approach achieves enhanced results for images those are corrupted with additive Gaussian noise. In numerical comparisons with various methods, for a set of noisy images （the PSNR range fi＇om 10.86dB to 26.91dB） , the presented method outperforms VisuShrink and Wiener filter in terms of the PSNR. Experiments also show that this method not only keeps the details of image but also yields denoised images with better visual quality.
文摘This paper presents a novel face recognition algorithm. To provide additional variations to training data set, even-odd decomposition is adopted, and only the even components (half-even face images) are used for further processing. To tackle with shift-variant problem,Fourier transform is applied to half-even face images. To reduce the dimension of an image,PCA (Principle Component Analysis) features are extracted from the amplitude spectrum of half-even face images. Finally, nearest neighbor classifier is employed for the task of classification. Experimental results on ORL database show that the proposed method outperforms in terms of accuracy the conventional eigenface method which applies PCA on original images and the eigenface method which uses both the original images and their mirror images as training set.
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.
文摘The demands for high quality products are increasing in the market, so several tests are performed. These analyses are destructive, time consuming and sometimes expensive. The spectral imaging technique is an alternative that can reduce costs and time and increase the efficiency and cost-effectiveness of these analyses. In this context, the aim of this study was to verify the spectral behavior of the tomato in function of the maturation and its potential use for non-destructive evaluation of food quality. Eighty tomatoes of the Italian group were selected in four stages of maturation （green, pink, light red and red）. Images were collected in wavelengths 480 nm to 710 nm （every 10 nm）. After the images were collected, the fruits were submitted to the physical-chemical analyses. The following parameters were analyzed： color, color index （CI）, pH, soluble solids （SS）, total titratable acidity （TTA） and ratio （SS/TTA）. After characterization the mean spectrum was obtained by the extraction of the spectral characteristics. It was observed that the spectral behavior was the same for all stages of maturation. It was possible to differentiate the green tomatoes in the wavelengths from 520 nm to 560 nm and from 610 nm to 660 nm. These intervals represent the area of reflection of chlorophyll and lycopene, respectively. Near the wavelength 560 nm, the highest absorbance was recorded by ripe tomatoes due to the concentration of lycopene. It is concluded that the best wavelengths for analysis are those in which green has the highest reflectance and it is possible to apply this technique for non-destructive analysis of the maturation of tomatoes.
文摘This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on the skewness-kurtosis test. In the end, a multivariate Gaussian distribution mathematical expression of background clutter image is given.
文摘Given an essentially normal operator T with connected spectrum and ind (λ-T)>0 for λ in ρ F(T)∩σ(T) , and a positive number ∈ ,the authors show that theree xists a compact K with ‖K‖<∈ such that T+K is strongly irreducible.
