E62 BME 140 Lecture Notes - Lecture 9: Tomographic Reconstruction, Gaussian Noise, Photon
6 Nov 2015
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Document Summary
Image: representation of the distribution of some property of an object or scene. Images displayed or printed represent tis distribution with a brightness or color. Pet (positron emission tomography) image: can detect glucose metabolic rate (functional) Ct (computer tomography) image: can detect attenuation coefficient (anatomical) Pet/ct combined: can detect both attenuation and glucose metabolism. (functional and anatomical) A continuous image is a function: g(x,y,z,t) A discrete image is a matrix: g. A finite set of numbers (real or complex valued) Both describe some property of an object: Physical measures of image quality: resolution (amount of blur) Object property -> imaging system -> image data. The amount blurred depends upon h. an image is a blurred version of an object. Image contrast: relates to differences in image values between various points within the image, such as between an object of interest and the surround background. Is small features are present on a large uniform background:
