Digital signal and image processing

Imaging - Efford chapter 2, 3








HSI model: Hue, Saturation, Intensity. H and S specify colour. 



Sampling: the reduction of a continuous signal to a discrete signal
Quantization: the process of mapping a large set of input values to a smaller set – such as rounding values to some unit of precision




Basic image manipulation - Efford chapter 5






Frequency domain - Efford chapter 8




Geometric operations - Efford chapter 9

Segmentation - Efford chapter 10

Morphological Image Processing - Efford chapter 11

Biosignal Analysis - Van Bemmel and Musen chapter 8













Medical Imaging - Van Bemmel and Musen chapter 9


there are 3 key scientific principles that underly 3 key medical image acquisition methods:
- if you shoot beams of very high-frequency energy through an object, the amount of energy that comes out the other side (as opposed as being absorbed) depends on material properties inside the object (Computer Tomography)

- if you shoot beams of somewhat lower-frequency energy into biological tissue, the amount of time it takes for the tissue to release that energy depends on the type of material (Magnetic Resonance Imaging)

- if you inject biological tissue with a radioactive substance, you can tell where the substance goes by detecting the radioactive decay (Positron Emission Tomography and Single-Photon Emission Computed Tomography)



Ultrasound

produced by piezoelectric crystals that transform electrical energy into acoustic energy and vice-versa;
these crystals can vibrate with frequencies about 2 - 10 MHz

Distinction between one- or two-dimensional ways of visualisation.

Ultrasound has no harmful side effect, the echo scan is an important technique for examining pregnant women and young children.


Radiology


digital subtraction angiography (DSA)

type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a 'pre-contrast image' or the mask from later images, once the contrast medium has been introduced into a structure

CT



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