A Pyramidal Morphology Algorithm is developed for speckle reduction of SARimages in this paper. For reducing the loss of information in the pyramidal algorithm for morphologyprocessing, in this modified algorithm, the...A Pyramidal Morphology Algorithm is developed for speckle reduction of SARimages in this paper. For reducing the loss of information in the pyramidal algorithm for morphologyprocessing, in this modified algorithm, the sub-images are processed parallel in the downsamplingoperation and the sub-images are reconstructed in the upsampling operation. It can be applied toimage filtering parallel. After analysis the computer simulations show that these two kinds offilters are both effective in speckle reduction of SAR images. The modified parallel algorithm doesbetter than the original algorithm and Lee filter on some characteristics.展开更多
On the eve of the occurrence of geological hazards,part of the rock and soil body begins to burst,rub,and fracture,generating infrasound signals propagating outward.3D advanced positioning of the landslide has remaine...On the eve of the occurrence of geological hazards,part of the rock and soil body begins to burst,rub,and fracture,generating infrasound signals propagating outward.3D advanced positioning of the landslide has remained unsolved,which is important for disaster prevention.Through the Fourier transform and Hankel transform of the wave equation in cylindrical coordinates,this work established a three-dimensional axisymmetric sound field model based on normal waves,and designed a 4-element helix triangular pyramid array with vertical and horizontal sampling capabilities.Based on this,the three-dimensional matching localization algorithm of infrasound for geological hazards is proposed.Applying the algorithm to the infrasound signal localization of rock and soil layers,it was found that the helix triangular pyramid array can achieve accurate estimation of depth and distance with a smaller number of array elements than the traditional array,and may overcome the azimuth symmetry ambiguity.This study shows the application prospects of this method for predicting geohazards position several hours in advance.展开更多
As a part of quantum image processing,quantum image filtering is a crucial technology in the development of quantum computing.Low-pass filtering can effectively achieve anti-aliasing effects on images.Currently,most q...As a part of quantum image processing,quantum image filtering is a crucial technology in the development of quantum computing.Low-pass filtering can effectively achieve anti-aliasing effects on images.Currently,most quantum image filterings are based on classical domains and grayscale images,and there are relatively fewer studies on anti-aliasing in the quantum domain.This paper proposes a scheme for anti-aliasing filtering based on quantum grayscale and color image scaling in the spatial domain.It achieves the effect of anti-aliasing filtering on quantum images during the scaling process.First,we use the novel enhanced quantum representation(NEQR)and the improved quantum representation of color images(INCQI)to represent classical images.Since aliasing phenomena are more pronounced when images are scaled down,this paper focuses only on the anti-aliasing effects in the case of reduction.Subsequently,we perform anti-aliasing filtering on the quantum representation of the original image and then use bilinear interpolation to scale down the image,achieving the anti-aliasing effect.The constructed pyramid model is then used to select an appropriate image for upscaling to the original image size.Finally,the complexity of the circuit is analyzed.Compared to the images experiencing aliasing effects solely due to scaling,applying anti-aliasing filtering to the images results in smoother and clearer outputs.Additionally,the anti-aliasing filtering allows for manual intervention to select the desired level of image smoothness.展开更多
Lucas-Kanade(LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of th...Lucas-Kanade(LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of this algorithm are continuously emerging,a systematic performance evaluation is still lacking. This forms the primary aim of the present work. Three warping schemes in the family of LK algorithm: forward/inverse/symmetric warping, are evaluated in a prototype flow of a hierarchy of multiple two-dimensional vortices. Second-order Newton descent is also considered here. The accuracy & efficiency of all these LK variants are investigated under a large domain of various influential parameters. It is found that the constant displacement constraint, which is a necessary building block for GPU acceleration, is the most critical issue in affecting LK algorithm's accuracy, which can be somehow ameliorated by using second-order Newton descent. Moreover, symmetric warping outbids the other two warping schemes in accuracy level, robustness to noise, convergence speed and tolerance to displacement gradient, and might be the first choice when applying LK algorithm to PIV measurement.展开更多
基金the National Natural Science Foundation of Jiangsu Province.China.( No.BK2 0 0 10 47)
文摘A Pyramidal Morphology Algorithm is developed for speckle reduction of SARimages in this paper. For reducing the loss of information in the pyramidal algorithm for morphologyprocessing, in this modified algorithm, the sub-images are processed parallel in the downsamplingoperation and the sub-images are reconstructed in the upsampling operation. It can be applied toimage filtering parallel. After analysis the computer simulations show that these two kinds offilters are both effective in speckle reduction of SAR images. The modified parallel algorithm doesbetter than the original algorithm and Lee filter on some characteristics.
基金Project(41877219)supported by the National Natural Science Foundation of ChinaProject(cstc2019jcyj-msxmX0585)supported by Natural Science Foundation of Chongqing,ChinaProject(KJ-2018016)supported by Science and Technology Project of Planning and Natural Resources Bureau of Chongqing Government,China。
文摘On the eve of the occurrence of geological hazards,part of the rock and soil body begins to burst,rub,and fracture,generating infrasound signals propagating outward.3D advanced positioning of the landslide has remained unsolved,which is important for disaster prevention.Through the Fourier transform and Hankel transform of the wave equation in cylindrical coordinates,this work established a three-dimensional axisymmetric sound field model based on normal waves,and designed a 4-element helix triangular pyramid array with vertical and horizontal sampling capabilities.Based on this,the three-dimensional matching localization algorithm of infrasound for geological hazards is proposed.Applying the algorithm to the infrasound signal localization of rock and soil layers,it was found that the helix triangular pyramid array can achieve accurate estimation of depth and distance with a smaller number of array elements than the traditional array,and may overcome the azimuth symmetry ambiguity.This study shows the application prospects of this method for predicting geohazards position several hours in advance.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62172268 and 62302289)the Shanghai Science and Technology Project(Grant Nos.21JC1402800 and 23YF1416200)。
文摘As a part of quantum image processing,quantum image filtering is a crucial technology in the development of quantum computing.Low-pass filtering can effectively achieve anti-aliasing effects on images.Currently,most quantum image filterings are based on classical domains and grayscale images,and there are relatively fewer studies on anti-aliasing in the quantum domain.This paper proposes a scheme for anti-aliasing filtering based on quantum grayscale and color image scaling in the spatial domain.It achieves the effect of anti-aliasing filtering on quantum images during the scaling process.First,we use the novel enhanced quantum representation(NEQR)and the improved quantum representation of color images(INCQI)to represent classical images.Since aliasing phenomena are more pronounced when images are scaled down,this paper focuses only on the anti-aliasing effects in the case of reduction.Subsequently,we perform anti-aliasing filtering on the quantum representation of the original image and then use bilinear interpolation to scale down the image,achieving the anti-aliasing effect.The constructed pyramid model is then used to select an appropriate image for upscaling to the original image size.Finally,the complexity of the circuit is analyzed.Compared to the images experiencing aliasing effects solely due to scaling,applying anti-aliasing filtering to the images results in smoother and clearer outputs.Additionally,the anti-aliasing filtering allows for manual intervention to select the desired level of image smoothness.
基金supported by the National Natural Science Foundation of China(Grant Nos.11372001 and 11490552)
文摘Lucas-Kanade(LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of this algorithm are continuously emerging,a systematic performance evaluation is still lacking. This forms the primary aim of the present work. Three warping schemes in the family of LK algorithm: forward/inverse/symmetric warping, are evaluated in a prototype flow of a hierarchy of multiple two-dimensional vortices. Second-order Newton descent is also considered here. The accuracy & efficiency of all these LK variants are investigated under a large domain of various influential parameters. It is found that the constant displacement constraint, which is a necessary building block for GPU acceleration, is the most critical issue in affecting LK algorithm's accuracy, which can be somehow ameliorated by using second-order Newton descent. Moreover, symmetric warping outbids the other two warping schemes in accuracy level, robustness to noise, convergence speed and tolerance to displacement gradient, and might be the first choice when applying LK algorithm to PIV measurement.
