lec8 - Announcements HW 1 is due today HW2 will be...

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1 CSE152, Spr. 2010 Intro Computer Vision Filtering Introduction to Computer Vision CSE 152 Lecture 8 CSE152, Spr. 2010 Intro Computer Vision Announcements • HW 1 is due today • HW2 will be available later today or tomorrow • See links on web page for reading on binary image processing (e-reserves) • Midterm May 5 CSE152, Spr 2010 Intro Computer Vision Binary System Summary 1. Acquire images and binarize (tresholding, color labels, etc.). 2. Possibly clean up image using morphological operators. 3. Determine regions (blobs) using connected component exploration 4. Compute position, area, and orientation of each blob using moments 5. Compute features that are rotation, scale, and translation invariant using Moments (e.g., Eigenvalues of normalized moments). CSE152, Spr 2010 Intro Computer Vision Four & Eight Connectedness Eight Connected Four Connected CSE152, Spr 2010 Intro Computer Vision Recursive Labeling Connected Component Exploration 2 1 CSE152, Spr 2010 Intro Computer Vision Properties extracted from binary image A tree showing containment of regions Properties of a region 1. Genus – number of holes 2. Centroid 3. Area 4. Perimeter 5. Moments (e.g., measure of elongation) 6. Number of “extrema” (indentations, bulges) 7. Skeleton
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CSE152, Spr 2010 Intro Computer Vision Moments (related to moments of intertia) B(x,y) • Fast way to implement computation over n by m image or window • One object The order of the M jk moment is j +k. CSE152, Spr 2010 Intro Computer Vision Central Moments μ jk = i m Λ Ν Μ Ξ Π Ο n = 1 j m = 1 i j n Λ Ν Μ Ξ Π Ο ( x ) ( i m ) ( y ) ( j n ) M mn CSE152, Spr 2010 Intro Computer Vision Normalized Moments CSE152, Spr 2010 Intro Computer Vision Region orientation from Second Moment Matrix 1. Compute second centralized moment matrix 2. Compute Eigenvectors of Moment Matrix to obtain orientation 3. Eigenvalues are independent of orientation, translation! • Symmetric, positive definite matrix • Positive Eigenvalues • Orthogonal Eigenvectors m 20 m 11 m 11 m 02 Ρ Σ ΢ Τ Φ Υ CSE152, Spr 2010 Intro Computer Vision Moments • Regular Moments M jk • Central Moments μ jk : Translation invariant • Normalized Moments m jk : Translation and scale Invariant • Eigenvalues of Second Moment Matrix: translation, scale, and rotation invariant. • Hu Moments: Higher than second order,
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lec8 - Announcements HW 1 is due today HW2 will be...

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