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Digital Image Processing. Tania Stathaki Location: Room 812 Extension: 46229 Email: t.stathaki@ic.ac.uk. LOGISTICS OF THE COURSE. Duration 20 lectures Assessment 100% exam There isn't any coursework or homework. IMAGE PROCESSING. Textbook
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Digital Image Processing Tania Stathaki Location: Room 812 Extension: 46229 Email: t.stathaki@ic.ac.uk
LOGISTICS OF THE COURSE • Duration • 20 lectures • Assessment • 100% exam • There isn't any coursework or homework
IMAGE PROCESSING • Textbook – R. C. Gonzalez, R. E. Woods, Digital Image Processing, Addison Wesley, 1993, ISBN 0-201-50803-6
Digital storage (disk) Imaging systems Sample and quantize Digital computer On-line buffer output Display object observe digitize store process Refresh/store Record FROM ANALOG TO DIGITAL
Sampling 256x256 64x64
0 255 255 0 0 0 0 255 0 0 0 0 255 0 0 0 0 255 0 0 0 255 255 255 0 Quantisation – 8 bits
Quantisation cont. 256x256 256 levels 256x256 32 levels
Quantisation cont. 256x256 256 levels 256x256 2 levels
Image Processing • manipulation of multidimensional signals image (photo) video CT, MRI
Image Processing • Why? – Coding/compression – Enhancement, restoration, reconstruction – Analysis, detection, recognition, understanding – Visualization
Part I: Image Transforms Original Image Fourier Transform Amplitude Phase
Part II: Image Enhancement Original Image High Pass Filtering
Part III: Image Restoration Distorted Image Restored Image
Distortion due to Camera Misfocus Original image Distorted image
Distortion due to Camera Misfocus Camera lens
Distortion due to motion Camera lens
Distortion due to Random Noise Original image Distorted image
Part IV: Image Compression • Signal-Processing Based: Encoder Compressed Representation H Decoder
Images are not directly amenable to computer analysis • Computers work with numerical (rather than pictorial) data. • An image must be converted to numerical form before processing by computer can commence. • Picture elements or pixels • Rectangular sampling grid • Brightness of the image
APPLICATIONS • Medical images • Satellite images • Astronomy • Radar images
Medical Images: UltrasoundFive-month Foetus (lungs, liver and bowel)