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Introduction 2007 Theo Schouten 1 Human Eye •6-7 106 Cones, 120 106 Rods •Reaction time: 0.1 sec (enough for transferring 100 nerve stimuli) •Parallel processing by 1010 nerve cells (neurons) •Adjustment to light intensity (factor 1010) •Stereo: 2 eyes and their continuous movement, focusing •Continuous assimilation of Theo moving images 2007 Schouten 2 Visual effects 2007 Theo Schouten 3 Steps in image processing • • • • • • Production (CCD camera, CT, MRI ) Storage, transmission and compression Transformation eg to a Fourier or Wavelet space Restoration, e.g. lens distortions or movement Enhancement: making suitable for an application Segmentation: finding (parts of) relevent objects – finding edges: local deviations in an image – finding surface areas: local similarities • Describing and measuring of regions and objects • Image understanding (Pattern recognition, classical, neural networks, AI) 2007 Theo Schouten 4 Special methods • 2 and 3 D Computed Tomography (CT) images to make it possible to view the interior of an object. • binary images, e.g. mathematical morphology • color and in general multispectral images • texture (fine structures on a surface) • 3-D reconstruction out of stereo images • video processing (movement, 3-D) • 3D image processing 2007 Theo Schouten 5 Computing challenges • the large amount of data • high complexity of algorithms • high speed requirements – parallel machines, algorithms – special purpose chips, CPU’s • real-time requirements – image recorders, robots, production machines 2007 Theo Schouten 6 Optimizing code /* slow.c */ #define SIZE 4096 float imin[SIZE][SIZE], imout[SIZE][SIZE]; int main(int argc, char **argv) { int i, j, k, l; /* initialize image */ for(i=0; i < SIZE; i++) for(j=0; j < SIZE; j++) imin[j][i] = (i+j) % 256; /* average each pixel with its neighbours */ for(i=0; i < SIZE; i++) { for(j=0; j < SIZE; j++) { if( i == 0 || j == 0 ) imout[j][i] = imin[j][i]; else if( i == SIZE-1 || j == SIZE-1 ) imout[j][i] = imin[j][i]; else { imout[j][i] = 0; for(k=-1; k < 2 ; k++) for(l=-1; l < 2; l++) imout[j][i] += imin[j+l][i+k]; imout[j][i] /= 9 ; }}}} 2007 Theo Schouten 7 Relation other science fields • • • • • • • • • • • Signal Analysis; 1D signal. Geometry; position, orientation and size of objects from 3-D measurements Linear Algebra Estimation Theory; eg compression of images or in determining the movement of objects. Statistical Pattern recognition; classification Syntactical Pattern recognition; structure of an image Artificial Intelligence; representation and manipulation of knowledge information that is extracted from images. Real Time Systems; interaction with other machines. System and Computer Architecture; parallel (1 CPU per pixel); special processors Computer Graphics; for projecting the images and showing the results of the manipulations User Interfaces; for good interaction with the software systems used for image manipulations. 2007 Theo Schouten 8 Uses of image processing • Medical Imaging • Machine en Robot vision (industrial production and inspection ) • Remote Sensing (satellite and aerial photos) • graphical and game industry, image editing in combination with computer graphics • consumer photo and video editing 2007 Theo Schouten 9 Integrated Examination • • • • • 4 assignments 1st individual, rest in groups working towards a goal all assignments must have been handed in final grade is average if all grades are 5 or more – otherwise the lowest grade 2007 Theo Schouten 10 FEED Fast Exact Euclidean Distance transformation Joint research with Egon van den Broek en Harco Kuppens 2007 Theo Schouten 11 Video Surveillance 2007 Theo Schouten 12 Depth from floor contact 2007 Theo Schouten 13