1. Computer Vision, winter 2012-13 CS Department, Technion

2. Topics The Gaussian Pyramid The Laplacian Pyramid Applications: Pattern Matching Coding (Compression) Enhancement Blending

3. Gaussian Pyramid

4. Approximation filter is not Gaussian A 5 tap binomial kernel: 2D extension:

5. Pattern Matching

6. Laplacian Pyramid

7. Approximation of the Laplacian of each scale Constructed by Difference of Gaussian (DoG) layers

8. Laplacian Pyramid

9. Image Coding

11. Enhancement

13. Pyramid Blending

14. Step I - Create Blend Masks

15. 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

16. Step III Standard Laplacian pyramid reconstruction of blended scales

17. 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