اسلاید پاورپوینت: اشعه (ray) ، نحوه (method) و ساختمان (structure)…

 

عناوین اصلی استخراج شده از این فایل پاورپوینت

عناوین اصلی استخراج شده از این فایل پاورپوینت

● Data Acquisition, Representation and Reconstruction
● Acquisition Methods
● X-Rays
● X-Rays – Physics
● X-Rays – Visibility
● X-Rays – Images
● CT or CAT – Principles
● CT or CAT – Methods
● CT – Reconstruction: FBP
● CT – Reconstruction: ART
● CT – FBP vs. ART
● CT – 2D vs. 3D
● CT or CAT – Advantages
● CT or CAT – Disadvantages
● MRI
● MRI – polarized
● MRI – Signal to Noise Ratio
● PET/SPECT
● Ultrasound
● Ultrasound (2)
● Ultrasound (3)
● Computational Methods (CM)
● CM – Approach
● CM – Methods
● CM – Solutions (Structured)
● CM – Solutions (Unstructured)
● CM – Grid Types (2)
● CM – Grid Examples
● CM – Structured vs. Unstructured
● Synthetic Methods
● Grid Types
● Data Representation
● Data Representation (2)
● Data Characteristics
● Data Objects
● Data Objects: structures
● Cell Types for Unstructured Grid
● Data Attributes
● Where are we now …
● Interpolation (1)
● Color Mapping
● Interpolation (2)
● Interpolation (3)
● Interpolation (4)
● Interpolation (5)
● Interpolation (6)
● Interpolation (7)
● Interpolation (8)
● Interpolation (9)
● Interpolation (10)
● Interpolation (11)
● Contours
● Interpolation
● The Need for Interpolation
● General Process
● How? – Convolution
● Reconstruction
● General Process – Frequency Domain
● Pre-Filtering
● Ideal Reconstruction with Sinc function
● Reconstructing Derivatives
● Possible Errors
● How Good? = Error
● Sources of Aliasing
● Reconstruction Kernels
● Higher Dimensions
● Interpolation (an example)
● Put Things in Perspective

نوع زبان : انگلیسی حجم : ۱٫۲۹ مگا بایت
نوع فایل : اسلاید پاورپوینت تعداد اسلایدها: ۷۱ صفحه
زمان استخراج مطلب : ۲۰۱۸/۱۱/۰۲ ۰۳:۳۹:۱۷ پسوند فایل : ppt

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این مطلب در تاریخ ۲۰۱۸/۱۱/۰۲ ۰۳:۳۹:۱۷ به صورت خودکار استخراج شده است. در صورت اعلام عدم رضایت تهیه کننده ی آن، طبق قوانین سایت از روی وب گاه حذف خواهد شد. همچنین این مطلب برگرفته از وب سایت زیر است و مسئولیت انتشار آن با منبع اصلی است.

http://web.eecs.utk.edu/~huangj/CS594S02/acquisition.ppt

بخشی از محتوای متن استخراج شده از این فایل ppt

بخشی از محتوای متن استخراج شده از این فایل ppt

data acquisition representation and reconstruction jian huang cs ۵۹۴ spring ۲ ۲ this set of slides references slides developed by profs. machiraju ohio state torsten moeller simon fraser and han wei shen ohio state . acquisition methods x rays computer tomography ct or cat mri or nmr pet spect ultrasound computational what about microscopic scanners what about electron microscopes what about voxelization discretization what about synthetic methods provide links to the numerous online tutorials x rays photons produced by an electron beam similar to visible light but higher energy x rays physics associated with inner shell electrons as the electrons decelerate in the target through interaction they emit electromagnetic radiation in the form of x rays. patient between an x ray source and a film radiograph cheap and relatively easy to use potentially damaging to biological tissue x rays visibility bones contain heavy atoms with many electrons which act as an absorber of x rays commonly used to image gross bone structure and lungs excellent for detecting foreign metal objects main disadvantage lack of anatomical structure all other tissue has very similar absorption coefficient for x rays x rays images add images ct or cat principles computerized axial tomography introduced in ۱۹۷۲ by hounsfield and cormack natural progression from x rays based on the principle that a three dimensional object can be reconstructed from its two dimensional projections based on the radon transform a map from an n dimensional space to an n ۱ dimensional space ct or cat methods measures the attenuation of x rays from many different angles a computer reconstructs the organ under study in a series of cross sections or planes combine x ray pictures from various angles to reconstruct ۳d structures ct reconstruction fbp filtered back projection common method uses radon transform and fourier slice theorem f x y f y x s gf s gf r u f u v spatial domain frequency domain ct reconstruction art algebraic reconstruction technique iterative technique attributed to gordon reconstructed model actual data slices projection back projection initial guess ct fbp vs. art computationally cheap clinically usually ۵ projections per slice problematic for noisy projections still slow better quality for fewer projections better quality for non uniform project. guided reconstruct. initial guess fbp art ct ۲d vs. ۳d linear advancement slice by slice typical method tumor might fall between ‘cracks’ takes long time helical movement ۵ ۸ times faster a whole set of trade offs ct or cat advantages significantly more data is collected superior to single x ray scans far easier to separate soft tissues other than bone from one another e.g. liver kidney data exist in digital form can be analyzed quantitatively adds enormously to the diagnostic information used in many large hospitals and medical centers throughout the world ct or cat disadvantages significantly more data is collected soft tissue x ray absorption still relatively similar still a health risk mri is used for a detailed imaging of anatomy mri nuclear magnetic resonance nmr or magnetic resonance imaging mri most detailed anatomical information high energy radiation is not used i.e. save based on the principle of nuclear resonance medicine uses resonance properties of protons mri polarized all atoms core with an odd number of protons have a ‘spin’ which leads to a magnetic behavior hydrogen h very common in human body very well magnetizing stimulate to form a macroscopically measurable magnetic field mri signal to noise ratio proton density pictures measures h mri is good for tissues but not for bone signal recorded in frequency domain noise the more protons per volume unit the more accurate the measurements better snr through decreased resolution pet spect positron emission tomography single photon emission computerized tomography recent technique involves the emission of particles of antimatter by compounds injected into the body being scanned follow the movements of the injected compound and its metabolism reconstruction techniques similar to ct filter back projection iterative schemes ultrasound the use of high frequency sound ultrasonic waves to produce images of structures within the human body above the range of sound audible to humans typically above ۱mhz piezoelectric crystal creates sound waves aimed at a specific area of the body change in tissue density reflects waves echoes are recorded ultrasound ۲ delay of reflected signal and amplitude determines the position of the tissue still images or a moving picture of the inside of the body there are no known examples of tissue damage from conventional ultrasound imaging commonly used to examine fetuses in utero in order to ascertain size position or abnormalities also for heart liver kidneys gallbladder breast eye and major blood vessels ultrasound ۳ by far least expensive very safe very noisy ۱d ۲d ۳d scanners irregular sampling reconstruction problems computational methods cm computational field simulations computational fluid dynamics flow simulations computational chemistry electron electron interactions molecular surfaces computational mechanics fracture computational manufacturing die casting cm approach continuous physical model partial ordinary differential equation ode pde e.g. navier stokes equation for fluid flow e.g. hosted equations e.g. schrödinger equation for waves quantum continuous solution doesn’t exist for most part numerical approximation solution ۱. discretize solution space grid generation explicit ۲. replace continuous operators with discrete ones ۳. solve for physical quantities cm methods grid generation non elliptical methods algebraic conformal hyperbolic parabolic biharmonic elliptical methods based on elliptical pde’s numerical methods newton runge kutta finite element finite differences time varying cm solutions structured pde usually constrained given at boundary map from computational to physical space polar maps elliptical non elliptical structured grids computational parametric physical f x t cm solutions unstructured usually scattered data set delaunay triangulation element size optimization start with initial tetrahedral grid interactively insert grid points insertion guided by curvature and distance to surface advancing front method start with boundary advance boundary towards inside until filled cm grid types ۲ multiblock structured grids multiple structured grids connected not necessarily structured hybrid grids structured unstructured chimera grids multiple structured grids partially overlapping hierarchical grids generated by quad tree and octree like subdivision schemes aka embedded or semi structured grids include figures from the nielson book cm grid examples cm structured vs. unstructured consider discretization points as samples points cells or voxels structured addressing cell i j k provides location of neighbors boundaries of volume easy to determine unstructured no addressing mechanism adjacency list required cannot determine the boundaries easily cells never of same size cells are hexahedrons tetrahedrons curved patches synthetic methods ۳d discretization techniques  voxelization scan conversion of geometric objects planes triangles cylinders sphere cone nurbs bezier patches synthetic methods solid textures hyper texture ۳d textures fur marble hair turbulent flow ۳d regular grid has texture values grid types uniform rectilinear regular curvilinear structured grids regular irregular hybrid curved unstructured grids data representation regular contour stacks raster rle raster point list rle data representation ۲ polygon mesh curvilinear …

کلمات کلیدی پرکاربرد در این اسلاید پاورپوینت: اشعه (ray), نحوه (method), ساختمان (structure), برآمدگی (projection), بافته (tissue),

این فایل پاورپوینت شامل ۷۱  اسلاید و به زبان انگلیسی و حجم آن ۱٫۲۹ مگا بایت است. نوع قالب فایل ppt بوده که با این لینک قابل دانلود است. این مطلب برگرفته از سایت زیر است و مسئولیت انتشار آن با منبع اصلی می باشد که در تاریخ ۲۰۱۸/۱۱/۰۲ ۰۳:۳۹:۱۷ استخراج شده است.

http://web.eecs.utk.edu/~huangj/CS594S02/acquisition.ppt

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