The image shape feature can be described by the image Zernike moments. In this paper, we points out the problem that the high dimension image Zernike moments shape feature vector can describe more detail of the origin...The image shape feature can be described by the image Zernike moments. In this paper, we points out the problem that the high dimension image Zernike moments shape feature vector can describe more detail of the original image but has too many elements making trouble for the next image analysis phases. Then the low dimension image Zernike moments shape feature vector should be improved and optimized to describe more detail of the original image. So the optimization algorithm based on evolutionary computation is designed and implemented in this paper to solve this problem. The experimental results demonstrate the feasibility of the optimization algorithm.展开更多
Removal of cloud cover on the satellite remote sensing image can effectively improve the availability of remote sensing images. For thin cloud cover, support vector value contourlet transform is used to achieve multi-...Removal of cloud cover on the satellite remote sensing image can effectively improve the availability of remote sensing images. For thin cloud cover, support vector value contourlet transform is used to achieve multi-scale decomposition of the area of thin cloud cover on remote sensing images. Through enhancing coefficients of high frequency and suppressing coefficients of low frequency, the thin cloud is removed. For thick cloud cover, if the areas of thick cloud cover on multi-source or multi-temporal remote sensing images do not overlap, the multi-output support vector regression learning method is used to remove this kind of thick clouds. If the thick cloud cover areas overlap, by using the multi-output learning of the surrounding areas to predict the surface features of the overlapped thick cloud cover areas, this kind of thick cloud is removed. Experimental results show that the proposed cloud removal method can effectively solve the problems of the cloud overlapping and radiation difference among multi-source images. The cloud removal image is clear and smooth.展开更多
We studied the wall motion characteristics of the ascending aorta by velocity vector imaging (VVI) in primary hypertension patients. The ascending aortas both in 30 patients with primary hypertension and 30 normal c...We studied the wall motion characteristics of the ascending aorta by velocity vector imaging (VVI) in primary hypertension patients. The ascending aortas both in 30 patients with primary hypertension and 30 normal controls were examined by Acuson sequoia 512 equiped with VVI. The maximum velocity (Vs, Ve) of every point on the anterior wall of ascending aorta both in systole and diastole was measured. The aortic diameter was wider in the hypertension patients than that in the healthy subjects (P〈0.05). The movement amplitude of the anterior wall of the ascending aorta in long axis view in the hypertension patients was lower than that in the healthy subjects (P〈0.05). The motion and time to peak in systole of each point of the ascending aorta in the healthy subjects had no significant difference (P〉0.05). The velocity curves of the anterior wall of ascending aorta both in the hypertension and healthy subjects were regular, and the curve in systole was named S wave and that in diastole named E wave. The velocity of S wave and E wave was slower in the hypertension patients than that in the healthy subjects (P〈0.05). The time to peak of S wave on the anterior wall of ascending aorta in systole was shorter in the hypertension patients than in the healthy subjects (P〈0.05). VVI could be used to accurately and directly observe the movement character of the ascending aorta walls, which would help us understand the elasticity of great arteries in patients with hypertension.展开更多
Information hiding schemes based on vector quantization (VQ) usually require lengthy VQ encoding and decoding processes. In this paper, we propose an efficient information hiding method based on closest paired tree ...Information hiding schemes based on vector quantization (VQ) usually require lengthy VQ encoding and decoding processes. In this paper, we propose an efficient information hiding method based on closest paired tree structure vector quantization (CPTSVQ). The simulation result shows that the execution time of the proposed scheme is much shorter than that attained by previous approaches.展开更多
A method to detect airports in large space-borne synthetic aperture radar(SAR) imagery is studied.First,the large SAR imagery is segmented according to amplitude characteristics using maximum a posteriori(MAP) est...A method to detect airports in large space-borne synthetic aperture radar(SAR) imagery is studied.First,the large SAR imagery is segmented according to amplitude characteristics using maximum a posteriori(MAP) estimator based on the heavytailed Rayleigh model.The attention is then paid on the object of interest(OOI) extracted from the large images.The minimumarea enclosing rectangle(MER) of OOI is created via a rotating calipers algorithm.The projection histogram(PH) of MER for OOI is then computed and the scale and rotation invariant feature for OOI are extracted from the statistical characteristics of PH.A support vector machine(SVM) classifier is trained using those feature parameters and the airport is detected by the SVM classifier and Hough transform.The application in space-borne SAR images demonstrates the effectiveness of the proposed method.展开更多
A comprehensive assessment of the spatial-aware supervised learning algorithms for hyper-spectral image(HSI)classification was presented.For this purpose,standard support vector machines(SVMs),multinomial logistic reg...A comprehensive assessment of the spatial-aware supervised learning algorithms for hyper-spectral image(HSI)classification was presented.For this purpose,standard support vector machines(SVMs),multinomial logistic regression(MLR)and sparse representation(SR) based supervised learning algorithm were compared both theoretically and experimentally.Performance of the discussed techniques was evaluated in terms of overall accuracy,average accuracy,kappa statistic coefficients,and sparsity of the solutions.Execution time,the computational burden,and the capability of the methods were investigated by using probabilistic analysis.For validating the accuracy a classical benchmark AVIRIS Indian pines data set was used.Experiments show that integrating spectral-spatial context can further improve the accuracy,reduce the misclassification error although the cost of computational time will be increased.展开更多
A method for fast and low bit-rate compression of digital holograms based on a new vector quantization (VQ) method known as the skip-dimension VQ (SDVQ) is proposed. Briefly, a complex hologram is converted into a...A method for fast and low bit-rate compression of digital holograms based on a new vector quantization (VQ) method known as the skip-dimension VQ (SDVQ) is proposed. Briefly, a complex hologram is converted into a real off-axis hologram, and partitioned into a set of image vectors. The image vectors are passed into a graphic processing unit (GPU), and compressed through SDVQ into a set of code indices considerably smaller in data size than the source hologram. Experimental evaluation reveals that our scheme is capable of compressing a digital hologram to a compression ratio of over 500 times, in approximately 20-22 ms.展开更多
INTRODUCTIONlschemic stroke accounts for 70% of all the cerebrovascular diseases. Severe stenosis and occlusions ofextracranial and intracranial artery are all important risk factors causing ischemic stroke. Based on ...INTRODUCTIONlschemic stroke accounts for 70% of all the cerebrovascular diseases. Severe stenosis and occlusions ofextracranial and intracranial artery are all important risk factors causing ischemic stroke. Based on the widespread observation worldwide, intracranial atherosclerosis is the most common vascular lesions in Asians, Hispanics, and Africans. Therefore, accurate and noninvasive methods fbr early diagnosis of stroke in individuals without significant stenosis of the extracranial carotid artery is of considerable clinical interest.展开更多
Background Pulmonary hypertension (PH) is a set of pathophysiological syndromes characterized by increased pulmonary artery pressure and pulmonary vascular resistance,resulting in increased right ventricular afterlo...Background Pulmonary hypertension (PH) is a set of pathophysiological syndromes characterized by increased pulmonary artery pressure and pulmonary vascular resistance,resulting in increased right ventricular afterload.The left and right ventricles interact through hemodynamics.What impact will PH have on synchronization and function of the left ventricle (LV)? The aim of this study was to evaluate the synchronization of the left ventricular wall motion and left ventricular function in patients with varying degrees of PH using velocity vector imaging (Wl) technology.Methods Sixty patients with chronic PH served as the experimental group,and 20 healthy volunteers served as the control group.According to the different degrees of pulmonary artery systolic pressure,the experimental group was divided into three groups:mild,moderate,and severe PH groups.The time to peak systolic longitudinal velocity (Tvl),the peak systolic longitudinal velocity (Vsl),the peak diastolic longitudinal velocity (Vel),the peak systolic longitudinal strain (SI),and strain rate (SRI) in 18 segments were measured in each group.Results TvI in the control group and each group with PH was reduced from basal to apical segment,and in control group Tvl in various segments of the same wall and in different walls showed no significant difference (P >0.05).With increase in pulmonary artery pressure,Tvl values measured showed an increasing trend in groups with PH.In groups with PH,Vsl and Vel of each wall were reduced sequentially from basal to apical segments,showing gradient change; Vsl and Vel values measured showed a decreasing trend with increase in pulmonary artery pressure,in which the differences of Vel values measured in the control group and the mild PH group were statistically significant (P <0.01),and the differences between other groups were statistically significant (P <0.01).In groups with PH,SI and SRI in basal segment and the middle segment of each wall were decreased; the difference between groups was statistically significant (P <0.01).Conclusions Asynchronization of the LV and decreased left ventricular function were present in patients with chronic PH;WI technology can accurately evaluate left ventricular function in patients with PH,and indicators such as Tvl,Vsl,and Vel are valuable.展开更多
Background The velocity vector imaging is an ultrasound speckle imaging that was recently developed, which is based on the two-dimensional gray scale image, with more accurate tracking process and more conve-nient and...Background The velocity vector imaging is an ultrasound speckle imaging that was recently developed, which is based on the two-dimensional gray scale image, with more accurate tracking process and more conve-nient and time-saving operation method can quantitatively displays the varied curve of myocardial velocity and direction sampling taking from multiple parts in one cardiac cycle by tracking the space motion of echo spots of the cardiovascular tissue, and then analyze their movements, avoiding the angular dependence and the limita-tions of analysis section that could effect on Doppler technology. The technology provides a new auxiliary method for the diagnosis and treatment of cardiovascular disease and is valuable on clinical diagnosis and scientific re-search and a wide horizon of development.展开更多
Background Umbilical cord around neck, a common obstetric complication, affects fetal hemodynamics. Does it influence fetal cardiac functions? The purpose of this study was to investigate the left and right ventricu...Background Umbilical cord around neck, a common obstetric complication, affects fetal hemodynamics. Does it influence fetal cardiac functions? The purpose of this study was to investigate the left and right ventricular systolic and diastolic functions of fetuses with umbilical cord around neck in the third trimester by applying velocity vector imaging (VVI). Methods Thirty-five cases of fetuses with umbilical cord around neck whose gestational ages from 35 to 40 weeks were selected, including 20 cases of umbilical artery ratio of the highest systolic velocity (S) to the lowest diastolic velocity (D) (S/D) 〈3.0 and 15 cases of umbilical artery S/D ≥3.0, while 20 cases of normal fetuses of 35–40 gestational weeks were selected as the control group. The changes in longitudinal velocity, strain, and strain rate of fetal left and right ventricle in systole and diastole in two groups, and the changes in fetal cardiac function under the situation of umbilical cord around neck were analyzed.Results Longitudinal strain and strain rate overall of fetal left and right ventricle in systole and diastole were less in fetuses with umbilical artery S/D 33.0 and umbilical cord around neck than those in fetuses with umbilical artery S/D 〈3.0 and those in control group (P 〈0.05); there was no significant difference (P 〉0.05) in longitudinal strain and strain rate overall of fetal left and right ventricle in systole and diastole between fetuses with umbilical artery S/D 〈3.0 and those in control group.Conclusions Left and right ventricular systolic and diastolic dysfunction was detected in fetuses with umbilical cord around neck and umbilical artery S/D 33.0. VVI could sensitively respond to cardiac function changes in fetuses with umbilical cord around neck, which provides another valuable method in the evaluation of fetal cardiac function.展开更多
基金the National Natural Science Foundation of China (60303029)
文摘The image shape feature can be described by the image Zernike moments. In this paper, we points out the problem that the high dimension image Zernike moments shape feature vector can describe more detail of the original image but has too many elements making trouble for the next image analysis phases. Then the low dimension image Zernike moments shape feature vector should be improved and optimized to describe more detail of the original image. So the optimization algorithm based on evolutionary computation is designed and implemented in this paper to solve this problem. The experimental results demonstrate the feasibility of the optimization algorithm.
基金supported by the National Natural Science Foundation of China(61172127)the Natural Science Foundation of Anhui Province(1408085MF121)
文摘Removal of cloud cover on the satellite remote sensing image can effectively improve the availability of remote sensing images. For thin cloud cover, support vector value contourlet transform is used to achieve multi-scale decomposition of the area of thin cloud cover on remote sensing images. Through enhancing coefficients of high frequency and suppressing coefficients of low frequency, the thin cloud is removed. For thick cloud cover, if the areas of thick cloud cover on multi-source or multi-temporal remote sensing images do not overlap, the multi-output support vector regression learning method is used to remove this kind of thick clouds. If the thick cloud cover areas overlap, by using the multi-output learning of the surrounding areas to predict the surface features of the overlapped thick cloud cover areas, this kind of thick cloud is removed. Experimental results show that the proposed cloud removal method can effectively solve the problems of the cloud overlapping and radiation difference among multi-source images. The cloud removal image is clear and smooth.
文摘We studied the wall motion characteristics of the ascending aorta by velocity vector imaging (VVI) in primary hypertension patients. The ascending aortas both in 30 patients with primary hypertension and 30 normal controls were examined by Acuson sequoia 512 equiped with VVI. The maximum velocity (Vs, Ve) of every point on the anterior wall of ascending aorta both in systole and diastole was measured. The aortic diameter was wider in the hypertension patients than that in the healthy subjects (P〈0.05). The movement amplitude of the anterior wall of the ascending aorta in long axis view in the hypertension patients was lower than that in the healthy subjects (P〈0.05). The motion and time to peak in systole of each point of the ascending aorta in the healthy subjects had no significant difference (P〉0.05). The velocity curves of the anterior wall of ascending aorta both in the hypertension and healthy subjects were regular, and the curve in systole was named S wave and that in diastole named E wave. The velocity of S wave and E wave was slower in the hypertension patients than that in the healthy subjects (P〈0.05). The time to peak of S wave on the anterior wall of ascending aorta in systole was shorter in the hypertension patients than in the healthy subjects (P〈0.05). VVI could be used to accurately and directly observe the movement character of the ascending aorta walls, which would help us understand the elasticity of great arteries in patients with hypertension.
基金supported by the National Natural Science Foundation of China under Grant No.60133012 and No.661272374
文摘Information hiding schemes based on vector quantization (VQ) usually require lengthy VQ encoding and decoding processes. In this paper, we propose an efficient information hiding method based on closest paired tree structure vector quantization (CPTSVQ). The simulation result shows that the execution time of the proposed scheme is much shorter than that attained by previous approaches.
文摘A method to detect airports in large space-borne synthetic aperture radar(SAR) imagery is studied.First,the large SAR imagery is segmented according to amplitude characteristics using maximum a posteriori(MAP) estimator based on the heavytailed Rayleigh model.The attention is then paid on the object of interest(OOI) extracted from the large images.The minimumarea enclosing rectangle(MER) of OOI is created via a rotating calipers algorithm.The projection histogram(PH) of MER for OOI is then computed and the scale and rotation invariant feature for OOI are extracted from the statistical characteristics of PH.A support vector machine(SVM) classifier is trained using those feature parameters and the airport is detected by the SVM classifier and Hough transform.The application in space-borne SAR images demonstrates the effectiveness of the proposed method.
基金National Key Research and Development Program of China(No.2016YFF0103604)National Natural Science Foundations of China(Nos.61171165,11431015,61571230)+1 种基金National Scientific Equipment Developing Project of China(No.2012YQ050250)Natural Science Foundation of Jiangsu Province,China(No.BK20161500)
文摘A comprehensive assessment of the spatial-aware supervised learning algorithms for hyper-spectral image(HSI)classification was presented.For this purpose,standard support vector machines(SVMs),multinomial logistic regression(MLR)and sparse representation(SR) based supervised learning algorithm were compared both theoretically and experimentally.Performance of the discussed techniques was evaluated in terms of overall accuracy,average accuracy,kappa statistic coefficients,and sparsity of the solutions.Execution time,the computational burden,and the capability of the methods were investigated by using probabilistic analysis.For validating the accuracy a classical benchmark AVIRIS Indian pines data set was used.Experiments show that integrating spectral-spatial context can further improve the accuracy,reduce the misclassification error although the cost of computational time will be increased.
文摘A method for fast and low bit-rate compression of digital holograms based on a new vector quantization (VQ) method known as the skip-dimension VQ (SDVQ) is proposed. Briefly, a complex hologram is converted into a real off-axis hologram, and partitioned into a set of image vectors. The image vectors are passed into a graphic processing unit (GPU), and compressed through SDVQ into a set of code indices considerably smaller in data size than the source hologram. Experimental evaluation reveals that our scheme is capable of compressing a digital hologram to a compression ratio of over 500 times, in approximately 20-22 ms.
文摘INTRODUCTIONlschemic stroke accounts for 70% of all the cerebrovascular diseases. Severe stenosis and occlusions ofextracranial and intracranial artery are all important risk factors causing ischemic stroke. Based on the widespread observation worldwide, intracranial atherosclerosis is the most common vascular lesions in Asians, Hispanics, and Africans. Therefore, accurate and noninvasive methods fbr early diagnosis of stroke in individuals without significant stenosis of the extracranial carotid artery is of considerable clinical interest.
基金This work is supported by a grant from the Natural Science Foundation of Hebei Province (No. 2010000550).
文摘Background Pulmonary hypertension (PH) is a set of pathophysiological syndromes characterized by increased pulmonary artery pressure and pulmonary vascular resistance,resulting in increased right ventricular afterload.The left and right ventricles interact through hemodynamics.What impact will PH have on synchronization and function of the left ventricle (LV)? The aim of this study was to evaluate the synchronization of the left ventricular wall motion and left ventricular function in patients with varying degrees of PH using velocity vector imaging (Wl) technology.Methods Sixty patients with chronic PH served as the experimental group,and 20 healthy volunteers served as the control group.According to the different degrees of pulmonary artery systolic pressure,the experimental group was divided into three groups:mild,moderate,and severe PH groups.The time to peak systolic longitudinal velocity (Tvl),the peak systolic longitudinal velocity (Vsl),the peak diastolic longitudinal velocity (Vel),the peak systolic longitudinal strain (SI),and strain rate (SRI) in 18 segments were measured in each group.Results TvI in the control group and each group with PH was reduced from basal to apical segment,and in control group Tvl in various segments of the same wall and in different walls showed no significant difference (P >0.05).With increase in pulmonary artery pressure,Tvl values measured showed an increasing trend in groups with PH.In groups with PH,Vsl and Vel of each wall were reduced sequentially from basal to apical segments,showing gradient change; Vsl and Vel values measured showed a decreasing trend with increase in pulmonary artery pressure,in which the differences of Vel values measured in the control group and the mild PH group were statistically significant (P <0.01),and the differences between other groups were statistically significant (P <0.01).In groups with PH,SI and SRI in basal segment and the middle segment of each wall were decreased; the difference between groups was statistically significant (P <0.01).Conclusions Asynchronization of the LV and decreased left ventricular function were present in patients with chronic PH;WI technology can accurately evaluate left ventricular function in patients with PH,and indicators such as Tvl,Vsl,and Vel are valuable.
文摘Background The velocity vector imaging is an ultrasound speckle imaging that was recently developed, which is based on the two-dimensional gray scale image, with more accurate tracking process and more conve-nient and time-saving operation method can quantitatively displays the varied curve of myocardial velocity and direction sampling taking from multiple parts in one cardiac cycle by tracking the space motion of echo spots of the cardiovascular tissue, and then analyze their movements, avoiding the angular dependence and the limita-tions of analysis section that could effect on Doppler technology. The technology provides a new auxiliary method for the diagnosis and treatment of cardiovascular disease and is valuable on clinical diagnosis and scientific re-search and a wide horizon of development.
文摘Background Umbilical cord around neck, a common obstetric complication, affects fetal hemodynamics. Does it influence fetal cardiac functions? The purpose of this study was to investigate the left and right ventricular systolic and diastolic functions of fetuses with umbilical cord around neck in the third trimester by applying velocity vector imaging (VVI). Methods Thirty-five cases of fetuses with umbilical cord around neck whose gestational ages from 35 to 40 weeks were selected, including 20 cases of umbilical artery ratio of the highest systolic velocity (S) to the lowest diastolic velocity (D) (S/D) 〈3.0 and 15 cases of umbilical artery S/D ≥3.0, while 20 cases of normal fetuses of 35–40 gestational weeks were selected as the control group. The changes in longitudinal velocity, strain, and strain rate of fetal left and right ventricle in systole and diastole in two groups, and the changes in fetal cardiac function under the situation of umbilical cord around neck were analyzed.Results Longitudinal strain and strain rate overall of fetal left and right ventricle in systole and diastole were less in fetuses with umbilical artery S/D 33.0 and umbilical cord around neck than those in fetuses with umbilical artery S/D 〈3.0 and those in control group (P 〈0.05); there was no significant difference (P 〉0.05) in longitudinal strain and strain rate overall of fetal left and right ventricle in systole and diastole between fetuses with umbilical artery S/D 〈3.0 and those in control group.Conclusions Left and right ventricular systolic and diastolic dysfunction was detected in fetuses with umbilical cord around neck and umbilical artery S/D 33.0. VVI could sensitively respond to cardiac function changes in fetuses with umbilical cord around neck, which provides another valuable method in the evaluation of fetal cardiac function.