Computer Vision, winter CS Department, Technion
Topics The Gaussian Pyramid The Laplacian Pyramid Applications: Pattern Matching Coding (Compression) Enhancement Blending
Gaussian Pyramid
Approximation filter is not Gaussian A 5 tap binomial kernel: 2D extension:
Pattern Matching
Laplacian Pyramid
Approximation of the Laplacian of each scale Constructed by Difference of Gaussian (DoG) layers
Laplacian Pyramid
Image Coding
Enhancement
Pyramid Blending
Step I - Create Blend Masks
Step II Weighted sum over each Laplacian pyramid scale (of the images) independently Gaussian pyramid of masks, or simple resizing of masks to correct dimensions Blend 1 Blend 1 Mask Blend 2Blend 2 Mask
Step III Standard Laplacian pyramid reconstruction of blended scales
Implementation Issues Image registration Feathering Over/under flows outside [0,1] MATLAB function: impyramid() Only Gaussian pyramid ‘reduce’ or ‘expand’ modes MATLAB function: imresize() Useful for masks resizing