A new method for reconstructing a 3-dimensional object from serial cross-sectionsis presented in this paper.The method is based on the principle of sampling and considersevery point in cross-sections as a sampling poi...A new method for reconstructing a 3-dimensional object from serial cross-sectionsis presented in this paper.The method is based on the principle of sampling and considersevery point in cross-sections as a sampling point and performs the interpolating of nonlinearfunction with these sampling points.Compared with other methods,this method has manyadvantages such as higher precision and fewer requested known sampling points.The result ofreconstruction with this method is an“entity”which involves the exterior shape and interiorconstruction information of the object simultaneously.展开更多
This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility...This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility of decreasing the exposure dose in digital breast tomosynthesis (DBT). These two existing algorithms were implemented using a DBT system and experimentally evaluated using contrast-detail (CD) phantom measurements, such as contrast-to-noise ratio (CNR), root mean square error (RMSE), intensity profile, and artifact spread function (ASF), and the results obtained with FBP and SIRT were compared. The potential dose reduction, contrast improvement, quantum noise reduction, and artifact reduction in DBT were evaluated using different exposures and the two reconstruction techniques. The effectiveness of each technique for enhancing the visibility of a CD phantom was quantified with respect to CNR and RMSE, and artifact reduction was quantified with respect to the intensity profile and ASF. SIRT produced reconstructed images with CNR values indicative of high-contrast detection. Image error was smaller in the in-focus plane SIRT images, and artifacts were decreased in these images according to the determined intensity profiles and ASF. These results suggest that when using SIRT, the exposure dose could possibly be decreased to half.展开更多
How to protect cultural retics is of great significance to the transmission and dissemination of history and culture.Digital 3-dimensional(3D)modeling of cultural relics is an effective way to preserve them.The effici...How to protect cultural retics is of great significance to the transmission and dissemination of history and culture.Digital 3-dimensional(3D)modeling of cultural relics is an effective way to preserve them.The efficiency and complexity of cultural relic model reconstruction algorithms are significant challenges due to redundant data.To tackle the above issue,a 3D reconstruction algorithm,named COLMAP+LSH,was proposed for movable cultural relics based on salient region optimization.COLMAP+LSH algorithm introduces saliency region detection and locality-sensetive Hashing(LSH)to achieve efficient,accurate,and robust digital 3D modeling of cultural relics.Specifically,400 cultural model data were collected through offline and online collection.COLMAP+LSH algorithm detects the salient region interactively and reduces the number of images in the salient region by feature diffusion.Additionally,COLMAP+LSH algorithm utilizes LSH to calculate the image selection scores and employs the image selection scores to reduce the redundant image.The experiments on the self-constructed cultural relics dataset show that COLMAP+LSH algorithm can efficiently achieve image feature diffusion and ensure the quality of artifact reconstruction while selecting most of the redundant image data.展开更多
We establish an improved GP iterative algorithm for the extrapolation of band-limited function to fully 3-dimensional image reconstruction by the convolution-backprojection algorithm. Numerical experiments demonstrate...We establish an improved GP iterative algorithm for the extrapolation of band-limited function to fully 3-dimensional image reconstruction by the convolution-backprojection algorithm. Numerical experiments demonstrate that the image resolving power of IGP algorithm is better than that of the original GP algorithm for noisy data.展开更多
Electrical impedance tomography(EIT)image reconstruction is a non-linear problem.In general,finite element model is the critical basis of EIT image reconstruction.A 3D human thorax modeling method for EIT image recons...Electrical impedance tomography(EIT)image reconstruction is a non-linear problem.In general,finite element model is the critical basis of EIT image reconstruction.A 3D human thorax modeling method for EIT image reconstruction is proposed herein to improve the accuracy and reduce the complexity of existing finite element modeling methods.The contours of human thorax and lungs are extracted from the layers of magnetic resonance imaging(MRI)images by an optimized Otsu’s method for the construction of the 3D human thorax model including the lung models.Furthermore,the GMSH tool is used for finite element subdivision to generate the 3D finite element model of human thorax.The proposed modeling method is fast and accurate,and it is universal for different types of MRI images.The effectiveness of the proposed method is validated by extensive numerical simulation in MATLAB.The results show that the individually oriented 3D finite element model can improve the reconstruction quality of the EIT images more effectively than the cylindrical model,the 2.5D model and other human chest models.展开更多
Acoustic rhinometry could numerically describe up- per airway condition of air draft by drawing a graph plotting the distance from the nostril vs. the cross-sectional area. Some decreases on the graph correspond to th...Acoustic rhinometry could numerically describe up- per airway condition of air draft by drawing a graph plotting the distance from the nostril vs. the cross-sectional area. Some decreases on the graph correspond to the typical anatomic structures of human nasal cavity. The 3-dimensional, computing fluid dynamic model of the same person was developed based on computed tomography scans. The veracity of the CFD model was valued by contrasting the relevant areas of stenosis site between the model and the AR graph. The aim in this study is to make clear how to use an AR to help improve and enrich the CFD model with the information of graph acquired from the measurement. The combination of AR and CT can be used to establish a living human nasal cavity model with higher significant information content.展开更多
文摘A new method for reconstructing a 3-dimensional object from serial cross-sectionsis presented in this paper.The method is based on the principle of sampling and considersevery point in cross-sections as a sampling point and performs the interpolating of nonlinearfunction with these sampling points.Compared with other methods,this method has manyadvantages such as higher precision and fewer requested known sampling points.The result ofreconstruction with this method is an“entity”which involves the exterior shape and interiorconstruction information of the object simultaneously.
文摘This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility of decreasing the exposure dose in digital breast tomosynthesis (DBT). These two existing algorithms were implemented using a DBT system and experimentally evaluated using contrast-detail (CD) phantom measurements, such as contrast-to-noise ratio (CNR), root mean square error (RMSE), intensity profile, and artifact spread function (ASF), and the results obtained with FBP and SIRT were compared. The potential dose reduction, contrast improvement, quantum noise reduction, and artifact reduction in DBT were evaluated using different exposures and the two reconstruction techniques. The effectiveness of each technique for enhancing the visibility of a CD phantom was quantified with respect to CNR and RMSE, and artifact reduction was quantified with respect to the intensity profile and ASF. SIRT produced reconstructed images with CNR values indicative of high-contrast detection. Image error was smaller in the in-focus plane SIRT images, and artifacts were decreased in these images according to the determined intensity profiles and ASF. These results suggest that when using SIRT, the exposure dose could possibly be decreased to half.
基金supported by the National Key Research and Development Project(2021YFF0901700)。
文摘How to protect cultural retics is of great significance to the transmission and dissemination of history and culture.Digital 3-dimensional(3D)modeling of cultural relics is an effective way to preserve them.The efficiency and complexity of cultural relic model reconstruction algorithms are significant challenges due to redundant data.To tackle the above issue,a 3D reconstruction algorithm,named COLMAP+LSH,was proposed for movable cultural relics based on salient region optimization.COLMAP+LSH algorithm introduces saliency region detection and locality-sensetive Hashing(LSH)to achieve efficient,accurate,and robust digital 3D modeling of cultural relics.Specifically,400 cultural model data were collected through offline and online collection.COLMAP+LSH algorithm detects the salient region interactively and reduces the number of images in the salient region by feature diffusion.Additionally,COLMAP+LSH algorithm utilizes LSH to calculate the image selection scores and employs the image selection scores to reduce the redundant image.The experiments on the self-constructed cultural relics dataset show that COLMAP+LSH algorithm can efficiently achieve image feature diffusion and ensure the quality of artifact reconstruction while selecting most of the redundant image data.
基金G.R. Qu is partially supported by the National Natural Science Foundation of China (No. 60372015, 60772041) the Science Foundation of Beijing Jiaotong University (2002SM54)+2 种基金M. Jiang is partially supported by the National Key Basic Research Special Foundation of China (2003CB716101) National Science Foundation of China (60325101, 60272018, 60628102) Ministry of Education (306017), Engineering Research Institute of Peking University, and Microsoft Research Asia.
文摘We establish an improved GP iterative algorithm for the extrapolation of band-limited function to fully 3-dimensional image reconstruction by the convolution-backprojection algorithm. Numerical experiments demonstrate that the image resolving power of IGP algorithm is better than that of the original GP algorithm for noisy data.
基金the National Natural Science Foundation of China(No.61371017)。
文摘Electrical impedance tomography(EIT)image reconstruction is a non-linear problem.In general,finite element model is the critical basis of EIT image reconstruction.A 3D human thorax modeling method for EIT image reconstruction is proposed herein to improve the accuracy and reduce the complexity of existing finite element modeling methods.The contours of human thorax and lungs are extracted from the layers of magnetic resonance imaging(MRI)images by an optimized Otsu’s method for the construction of the 3D human thorax model including the lung models.Furthermore,the GMSH tool is used for finite element subdivision to generate the 3D finite element model of human thorax.The proposed modeling method is fast and accurate,and it is universal for different types of MRI images.The effectiveness of the proposed method is validated by extensive numerical simulation in MATLAB.The results show that the individually oriented 3D finite element model can improve the reconstruction quality of the EIT images more effectively than the cylindrical model,the 2.5D model and other human chest models.
文摘Acoustic rhinometry could numerically describe up- per airway condition of air draft by drawing a graph plotting the distance from the nostril vs. the cross-sectional area. Some decreases on the graph correspond to the typical anatomic structures of human nasal cavity. The 3-dimensional, computing fluid dynamic model of the same person was developed based on computed tomography scans. The veracity of the CFD model was valued by contrasting the relevant areas of stenosis site between the model and the AR graph. The aim in this study is to make clear how to use an AR to help improve and enrich the CFD model with the information of graph acquired from the measurement. The combination of AR and CT can be used to establish a living human nasal cavity model with higher significant information content.
