基于计算机三维建模的“工程制图”课程测绘实践研究 3

分析了计算机三维建模运用于制图测绘环节的必要性,以锻炼学生的实践能力、设计思维及团队精神为目的,提出了运用项目教学法引领测绘训练的全过程,并将计算机三维建模作为测绘训练的主线;实践表明,该教学方法的改革不仅使得课程设计质量较好,学生对机械设计专业的认识也有了较大的提高.     

Region of Interest Imaging for a General Trajectory with the Rebinned BPF Algorithm

The back-projection-filtration(BPF) algorithm has been applied to image reconstruction for cone-beam configurations with general source trajectories.The BPF algorithm can reconstruct 3-D region-of-interest(ROI) images from data containing truncations.However,like many other existing algorithms for cone-beam configurations,the BPF algorithm involves a back-projection with a spatially varying weighting factor,which can result in the non-uniform noise levels in reconstructed images and increased computation ti...     

Consistency Conditions for Cone-Beam CT Data Acquired with a Straight-Line Source Trajectory

A consistency condition is developed for computed tomography(CT) projection data acquired from a straight-line X-ray source trajectory.The condition states that integrals of normalized projection data along detector lines parallel to the X-ray path must be equal.The projection data is required to be untruncated only along the detector lines parallel to the X-ray path,a less restrictive requirement compared to Fourier conditions that necessitate completely untruncated data.The condition is implemented numeri...     

Dual-Energy Technique at Low Tube Voltages for Small Animal Imaging

We investigate the feasibility of dual-energy method for image contrast enhancement in small animal studies using a low kV X-ray radiographic system.A robust method for X-ray spectrum estimation from transmission measurements,based on expectation-maximization(EM) method,is applied to an X-ray specimen radiographic system for dual energy imaging of a mouse.From transmission measurements of two known attenuators at two different X-ray tube voltages,the X-ray energy spectra are reconstructed using the EM-based...     

Investigation of Sparse Data Mouse Imaging Using Micro-CT with a Carbon-Nanotube-Based X-ray Source

There has been a renewed interest in algorithm development for image reconstruction from highly incomplete data in computed tomography(CT).Such algorithms may lead to reduced imaging dose and time,and to the design of innovative configurations tailored to specific imaging tasks.In recent years,a carbon-nanotube(CNT)-based field-emission x-ray source has been developed,which offers easy electronic control of radiation and thus can be an ideal candidate for gated imaging.We have recently proposed algorithms f...     

数字图书馆在电子教学中的应用研究

讨论了数字化环境下图书馆应该为学习者提供的服务内容,研究了数字图书馆建设中的实用性,分析了电子教学与科研所带来的机遇与挑战,并指出了在协同环境中人为因素的重要性.