当印第安娜波利斯500即将投产时,克莱斯勒公司遇到了问题。它的'蝰蛇速度'牌汽车的新引擎已由计算机设计完成,而用传统方法制造排气管所需时间太长。但是三维造型技术可以解决这个难题。利用计算机对排气管的成象来引导激光束...当印第安娜波利斯500即将投产时,克莱斯勒公司遇到了问题。它的'蝰蛇速度'牌汽车的新引擎已由计算机设计完成,而用传统方法制造排气管所需时间太长。但是三维造型技术可以解决这个难题。利用计算机对排气管的成象来引导激光束对液态光敏塑料加工,工程师们可以在几小时内制出关键部件的实物复制品,使生产汽车的时间缩短了6个星期。三维造型技术又称桌上制造工艺(Desrt op Manu-facturing)。展开更多
On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of p...On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of phase diagrams) method. The liquid phase is modeled as the associate model with the constituent species Ni, Yb and YbNi3, owing to the sharp change of the enthalpy of mixing of liquid phase at the composition of around 25% Yb (mole fraction). The terminal solid solutions FCC_A1 (Ni/Yb) and BCC_A2 (Yb) are described by the substitutional solution model with the Redlich?Kister polynomial. The intermetallic compounds, Yb2Ni17, YbNi5, YbNi3, YbNi2, α-YbNi and β-YbNi, are treated as strict stoichiometric compounds, since there are no noticeable homogeneity ranges reported for these compounds. A set of self-consistent thermodynamic parameters for the Ni?Yb binary system are obtained. According to the presently assessed results, the thermochemical properties and the phase boundary data can be well reproduced.展开更多
With the development of image processing technology and computer, computer vision technology has been widely used in the production of agriculture,and has made many important achievements. This paper reviews its-resea...With the development of image processing technology and computer, computer vision technology has been widely used in the production of agriculture,and has made many important achievements. This paper reviews its-research progress on diagnosis of agricultural products, water diagnosis, weed identification,product quality testing and grading, agricultural picking and sorting and other as- pects, and finally put forward its existing problems and prospects for the future.展开更多
In this paper, white light digital image analysis in frequency domination area for measuring 3D displacement is put forward. The measuring system has the characteristics of whole-field, non-contact and omni-bearing me...In this paper, white light digital image analysis in frequency domination area for measuring 3D displacement is put forward. The measuring system has the characteristics of whole-field, non-contact and omni-bearing measurement. It is simple and the coherent light is not demanded. Gray images before and after deformation are recorded using two CCDs at two different shooting angles, then digitalized and analyzed by frequency domination correlation arithmetic. The 2D displacement obtained is used to formulate 3D displacement via mathematical transformation. The experimental plate is 40,mm in length, 30,mm in width and 10 mm in height. The definite displacement is given using a 3D precise adjusting frame. The 3D displacement is calculated and compared with the definite displacement. The error is 4%-11% and the availability of this method was certified. Using this method, the compression deformation of a thin-wall cylinder with 140 mm in height, 64 mm in inner diameter and 64.6,mm in external diameter, was also measured. This method is proper to measure dynamic deformation.展开更多
A semiautomatic segmentation method based on active contour is proposed for computed tomography (CT) image series. First, to get initial contour, one image slice was segmented exactly by C-V method based on Mumford-Sh...A semiautomatic segmentation method based on active contour is proposed for computed tomography (CT) image series. First, to get initial contour, one image slice was segmented exactly by C-V method based on Mumford-Shah model. Next, the computer will segment the nearby slice automatically using the snake model one by one. During segmenting of image slices, former slice boundary, as next slice initial contour, may cross over next slice real boundary and never return to right position. To avoid contour skipping over, the distance variance between two slices is evaluated by an threshold, which decides whether to initiate again. Moreover, a new improved marching cubes (MC) algorithm based on 2D images series segmentation boundary is given for 3D image reconstruction. Compared with the standard method, the proposed algorithm reduces detecting time and needs less storing memory. The effectiveness and capabilities of the algorithm were illustrated by experimental results.展开更多
A novel semi-fragile audio watermarking algorithm in DWT domain is proposed in this paper.This method transforms the original audio into 3-layer wavelet domain and divides approximation wavelet coefficients into many ...A novel semi-fragile audio watermarking algorithm in DWT domain is proposed in this paper.This method transforms the original audio into 3-layer wavelet domain and divides approximation wavelet coefficients into many groups.Through computing mean quantization of per group,this algorithm embeds the watermark signal into the average value of the wavelet coefficients.Experimental results show that our semi-fragile audio watermarking algorithm is not only inaudible and robust against various common images processing,but also fragile to malicious modification.Especially,it can detect the tampered regions effectively.展开更多
The classical edge detectors work fine with the high quality pictures, but often are not good enough for noisy images because they cannot distinguish edges of different significance. The paper presented a novel approa...The classical edge detectors work fine with the high quality pictures, but often are not good enough for noisy images because they cannot distinguish edges of different significance. The paper presented a novel approach to multiscale edge detection for noisy images using wavelet transforms based on Lipschitz regularity coefficients and a cascade algorithm. The relationship between wavelet transform and Lipschitz regularity was established. The proposed wavelet based edge detection algorithm combined the coefficients of wavelet transforms along with a cascade algorithm which significantly improves the result. The comparison between the proposed method and the classical edge detectors was carried out. The algorithm was applied to various images and its performance was discussed. The results of edge detection of contaminated images using the proposed algorithm show that it works better than the classical edge detectors.展开更多
AIM： TO investigate colonic endocrine cells in lympho- cytic colitis （LC） patients. METHODS： Fifty-seven patients with LC were in- cluded. These patients were 41 females and 16 males, with an average age of 49 yea...AIM： TO investigate colonic endocrine cells in lympho- cytic colitis （LC） patients. METHODS： Fifty-seven patients with LC were in- cluded. These patients were 41 females and 16 males, with an average age of 49 years （range 19-84 years）. Twenty-seven subjects that underwent colonoscopy with biopsies were used as controls. These subjects underwent colonoscopy because of gastrointestinal bleeding or health worries, where the source of bleed- ing was identified as haemorrhoids or angiodysplasia. They were 19 females and 8 males with an average age of 49 years （range 18-67 years）. Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. Biopsies were fixed in 4% buffered paraformaldehyde, embedded in paraffin and cut into 5 μm-thick sections. The sections immunostained by the avidin-biotin-complex method for se- rotonin, peptide YY （PYY）, pancreatic polypeptide （PP） enteroglucagon and somatostatin cells. The cell densi- ties were quantified by computerised image analysis using Olympus software. RESULTS： The colon of both the patient and the control subjects were macroscopically normal. Histo- pathological examination of colon biopsies from con- trols revealed normal histology. All patients fulfilled the diagnosis criteria required for of LC： an increase in intraepithelial lymphocytes （〉 20 lymphocytes/100 epithelial cells） and surface epithelial damage with increased lamina propria plasma cells and absent or minimal crypt architectural distribution. In the colon of both patients and control subjects, serotonin-, PYY-, PP-, enteroglucagon- and somatostatin-immunoreac- tive cells were primarily located in the upper part of the crypts of Lieberk0hn. These cells were basket- or flask-shaped. There was no statistically significant dif- ference between the right and left colon in controls with regards to the densities of serotonin- and PYY- immunoreactive cells （P = 0.9 and 0.1, respectively）. Serotonin cell density in the right colon in controls was 28.9 ± 1.8 and in LC patients 41.6±2.6 （P = 0.008）. In the left colon, the corresponding figures were 28.5± 1.9 and 42.4± 2.9, respectively （P = 0.009）. PYY cell density in the right colon of the controls was 10.1 ± 1 and of LC patients 41 ± 4 （P = 0.00006）. In the left colon, PYY cell density in controls was 6.6± 1.2 and in LC patients 53.3 ± 4.6 （P = 0.00007）. CONCLUSION： The change in serotonin cells could be caused by an interaction between immune cells and serotonin cells, and that of PYY density might be sec- ondary.展开更多
A combined computational and experimental investigation to examine temperature and soot volume fraction in coflow ethylene-air diffusion flames was presented.A numerical simulation was conducted by using a relatively ...A combined computational and experimental investigation to examine temperature and soot volume fraction in coflow ethylene-air diffusion flames was presented.A numerical simulation was conducted by using a relatively detailed gas-phase chemistry and complex thermal and transport properties coupled with a semi-empirical two-equation soot model.Thermal radiation was calculated using the discrete ordinates method.An image processing technique and a decoupled reconstruction method were used to simultaneously measure the distributions of temperature and soot volume fraction.The results show that the maximum error for temperature does not exceed 10% between the prediction and the measurement.And the maximum error is 6.9% for soot volume fraction between prediction and measurement.Additional simulations were performed to explore the effects of global equivalence ratio on diffusion flames and the soot formation.The results display that the soot formation increases with decreasing the coflow air velocity.And the soot formation in each case appears in the annular region,where the temperature ranges from about 1 000 K to 2 000 K and the profile becomes taller and wider when the coflow air is decreased.展开更多
A novel Bacterial Foraging Algorithm (BFA) based neural network is presented for image compression. To improve the quality of the decompressed images, the concepts of reproduction, elimination and dispersal in BFA are...A novel Bacterial Foraging Algorithm (BFA) based neural network is presented for image compression. To improve the quality of the decompressed images, the concepts of reproduction, elimination and dispersal in BFA are firstly introduced into neural network in the proposed algorithm. Extensive experiments are conducted on standard testing images and the results show that the pro- posed method can improve the quality of the reconstructed images significantly.展开更多
An improved image registration method is proposed based on mutual infor- mation with hybrid optimizer. Firstly, mutual information measure is combined with morphological gradient information. The essence of the gradie...An improved image registration method is proposed based on mutual infor- mation with hybrid optimizer. Firstly, mutual information measure is combined with morphological gradient information. The essence of the gradient information is that locations a large gradient magnitude should be aligned, but also the orientation of the gradients at those locations should be similar. Secondly, a hybrid optimizer combined PSO with Powell algorithm is proposed to restrain local maxima of mutual information function and improve the registration accuracy to sub-pixel level. Lastly, muhlresolution data structure based on Mallat decomposition can not only improve the behavior of registration function, but also improve the speed of the algorithm. Experimental results demonstrate that the new method can yield good registration result, superior to traditional optimizer with respect to smoothness and attraction basin as well as convergence speed.展开更多
文摘当印第安娜波利斯500即将投产时,克莱斯勒公司遇到了问题。它的'蝰蛇速度'牌汽车的新引擎已由计算机设计完成,而用传统方法制造排气管所需时间太长。但是三维造型技术可以解决这个难题。利用计算机对排气管的成象来引导激光束对液态光敏塑料加工,工程师们可以在几小时内制出关键部件的实物复制品,使生产汽车的时间缩短了6个星期。三维造型技术又称桌上制造工艺(Desrt op Manu-facturing)。
基金Project(51271027)supported by the National Natural Science Foundation of ChinaProject(T201308)supported by Shenzhen Key Laboratory of Special Functional Materials of Shenzhen University,China
文摘On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of phase diagrams) method. The liquid phase is modeled as the associate model with the constituent species Ni, Yb and YbNi3, owing to the sharp change of the enthalpy of mixing of liquid phase at the composition of around 25% Yb (mole fraction). The terminal solid solutions FCC_A1 (Ni/Yb) and BCC_A2 (Yb) are described by the substitutional solution model with the Redlich?Kister polynomial. The intermetallic compounds, Yb2Ni17, YbNi5, YbNi3, YbNi2, α-YbNi and β-YbNi, are treated as strict stoichiometric compounds, since there are no noticeable homogeneity ranges reported for these compounds. A set of self-consistent thermodynamic parameters for the Ni?Yb binary system are obtained. According to the presently assessed results, the thermochemical properties and the phase boundary data can be well reproduced.
文摘With the development of image processing technology and computer, computer vision technology has been widely used in the production of agriculture,and has made many important achievements. This paper reviews its-research progress on diagnosis of agricultural products, water diagnosis, weed identification,product quality testing and grading, agricultural picking and sorting and other as- pects, and finally put forward its existing problems and prospects for the future.
基金National Natural Science Foundation of China (No.10472080).
文摘In this paper, white light digital image analysis in frequency domination area for measuring 3D displacement is put forward. The measuring system has the characteristics of whole-field, non-contact and omni-bearing measurement. It is simple and the coherent light is not demanded. Gray images before and after deformation are recorded using two CCDs at two different shooting angles, then digitalized and analyzed by frequency domination correlation arithmetic. The 2D displacement obtained is used to formulate 3D displacement via mathematical transformation. The experimental plate is 40,mm in length, 30,mm in width and 10 mm in height. The definite displacement is given using a 3D precise adjusting frame. The 3D displacement is calculated and compared with the definite displacement. The error is 4%-11% and the availability of this method was certified. Using this method, the compression deformation of a thin-wall cylinder with 140 mm in height, 64 mm in inner diameter and 64.6,mm in external diameter, was also measured. This method is proper to measure dynamic deformation.
文摘A semiautomatic segmentation method based on active contour is proposed for computed tomography (CT) image series. First, to get initial contour, one image slice was segmented exactly by C-V method based on Mumford-Shah model. Next, the computer will segment the nearby slice automatically using the snake model one by one. During segmenting of image slices, former slice boundary, as next slice initial contour, may cross over next slice real boundary and never return to right position. To avoid contour skipping over, the distance variance between two slices is evaluated by an threshold, which decides whether to initiate again. Moreover, a new improved marching cubes (MC) algorithm based on 2D images series segmentation boundary is given for 3D image reconstruction. Compared with the standard method, the proposed algorithm reduces detecting time and needs less storing memory. The effectiveness and capabilities of the algorithm were illustrated by experimental results.
基金We wish to thank the National Basic Research Program of China （973 Program） for Grant 2007CB311203, the National Natural Science Foundation of China for Grant 60821001, the Specialized Research Fund for the Doctoral Program of Higher Education for Grant 20070013007 under which the present work was possible.
文摘A novel semi-fragile audio watermarking algorithm in DWT domain is proposed in this paper.This method transforms the original audio into 3-layer wavelet domain and divides approximation wavelet coefficients into many groups.Through computing mean quantization of per group,this algorithm embeds the watermark signal into the average value of the wavelet coefficients.Experimental results show that our semi-fragile audio watermarking algorithm is not only inaudible and robust against various common images processing,but also fragile to malicious modification.Especially,it can detect the tampered regions effectively.
文摘The classical edge detectors work fine with the high quality pictures, but often are not good enough for noisy images because they cannot distinguish edges of different significance. The paper presented a novel approach to multiscale edge detection for noisy images using wavelet transforms based on Lipschitz regularity coefficients and a cascade algorithm. The relationship between wavelet transform and Lipschitz regularity was established. The proposed wavelet based edge detection algorithm combined the coefficients of wavelet transforms along with a cascade algorithm which significantly improves the result. The comparison between the proposed method and the classical edge detectors was carried out. The algorithm was applied to various images and its performance was discussed. The results of edge detection of contaminated images using the proposed algorithm show that it works better than the classical edge detectors.
文摘AIM： TO investigate colonic endocrine cells in lympho- cytic colitis （LC） patients. METHODS： Fifty-seven patients with LC were in- cluded. These patients were 41 females and 16 males, with an average age of 49 years （range 19-84 years）. Twenty-seven subjects that underwent colonoscopy with biopsies were used as controls. These subjects underwent colonoscopy because of gastrointestinal bleeding or health worries, where the source of bleed- ing was identified as haemorrhoids or angiodysplasia. They were 19 females and 8 males with an average age of 49 years （range 18-67 years）. Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. Biopsies were fixed in 4% buffered paraformaldehyde, embedded in paraffin and cut into 5 μm-thick sections. The sections immunostained by the avidin-biotin-complex method for se- rotonin, peptide YY （PYY）, pancreatic polypeptide （PP） enteroglucagon and somatostatin cells. The cell densi- ties were quantified by computerised image analysis using Olympus software. RESULTS： The colon of both the patient and the control subjects were macroscopically normal. Histo- pathological examination of colon biopsies from con- trols revealed normal histology. All patients fulfilled the diagnosis criteria required for of LC： an increase in intraepithelial lymphocytes （〉 20 lymphocytes/100 epithelial cells） and surface epithelial damage with increased lamina propria plasma cells and absent or minimal crypt architectural distribution. In the colon of both patients and control subjects, serotonin-, PYY-, PP-, enteroglucagon- and somatostatin-immunoreac- tive cells were primarily located in the upper part of the crypts of Lieberk0hn. These cells were basket- or flask-shaped. There was no statistically significant dif- ference between the right and left colon in controls with regards to the densities of serotonin- and PYY- immunoreactive cells （P = 0.9 and 0.1, respectively）. Serotonin cell density in the right colon in controls was 28.9 ± 1.8 and in LC patients 41.6±2.6 （P = 0.008）. In the left colon, the corresponding figures were 28.5± 1.9 and 42.4± 2.9, respectively （P = 0.009）. PYY cell density in the right colon of the controls was 10.1 ± 1 and of LC patients 41 ± 4 （P = 0.00006）. In the left colon, PYY cell density in controls was 6.6± 1.2 and in LC patients 53.3 ± 4.6 （P = 0.00007）. CONCLUSION： The change in serotonin cells could be caused by an interaction between immune cells and serotonin cells, and that of PYY density might be sec- ondary.
基金Projects(50806024,50806023 and 50806026) supported by the National Natural Science Foundation of China
文摘A combined computational and experimental investigation to examine temperature and soot volume fraction in coflow ethylene-air diffusion flames was presented.A numerical simulation was conducted by using a relatively detailed gas-phase chemistry and complex thermal and transport properties coupled with a semi-empirical two-equation soot model.Thermal radiation was calculated using the discrete ordinates method.An image processing technique and a decoupled reconstruction method were used to simultaneously measure the distributions of temperature and soot volume fraction.The results show that the maximum error for temperature does not exceed 10% between the prediction and the measurement.And the maximum error is 6.9% for soot volume fraction between prediction and measurement.Additional simulations were performed to explore the effects of global equivalence ratio on diffusion flames and the soot formation.The results display that the soot formation increases with decreasing the coflow air velocity.And the soot formation in each case appears in the annular region,where the temperature ranges from about 1 000 K to 2 000 K and the profile becomes taller and wider when the coflow air is decreased.
基金Supported by the National Natural Science Foundation of China (No.60572100)by the Royal Society (U.K.) International Joint Projects 2006/R3-Cost Share with NSFC (No.60711130233)
文摘A novel Bacterial Foraging Algorithm (BFA) based neural network is presented for image compression. To improve the quality of the decompressed images, the concepts of reproduction, elimination and dispersal in BFA are firstly introduced into neural network in the proposed algorithm. Extensive experiments are conducted on standard testing images and the results show that the pro- posed method can improve the quality of the reconstructed images significantly.
文摘An improved image registration method is proposed based on mutual infor- mation with hybrid optimizer. Firstly, mutual information measure is combined with morphological gradient information. The essence of the gradient information is that locations a large gradient magnitude should be aligned, but also the orientation of the gradients at those locations should be similar. Secondly, a hybrid optimizer combined PSO with Powell algorithm is proposed to restrain local maxima of mutual information function and improve the registration accuracy to sub-pixel level. Lastly, muhlresolution data structure based on Mallat decomposition can not only improve the behavior of registration function, but also improve the speed of the algorithm. Experimental results demonstrate that the new method can yield good registration result, superior to traditional optimizer with respect to smoothness and attraction basin as well as convergence speed.
