Computer Vision, winter 2012-13 CS Department, Technion.
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Transcript of Computer Vision, winter 2012-13 CS Department, Technion.
![Page 1: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/1.jpg)
Image Pyramids
Computer Vision, winter 2012-13CS Department, Technion
![Page 2: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/2.jpg)
TopicsThe Gaussian PyramidThe Laplacian PyramidApplications:
Pattern MatchingCoding (Compression)EnhancementBlending
![Page 3: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/3.jpg)
Gaussian Pyramid
![Page 4: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/4.jpg)
Gaussian PyramidApproximation filter is not Gaussian
A 5 tap binomial kernel:
2D extension:
1[1,4,6,4,1]
16
1 4 6 4 1
4 16 24 16 41
6 24 36 24 6256
4 16 24 16 4
1 4 6 4 1
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Pattern Matching
![Page 6: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/6.jpg)
Laplacian Pyramid
![Page 7: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/7.jpg)
Laplacian PyramidApproximation of the Laplacian of each scaleConstructed by Difference of Gaussian (DoG)
layers
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Laplacian Pyramid
![Page 9: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/9.jpg)
Image Coding
![Page 10: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/10.jpg)
![Page 11: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/11.jpg)
Enhancement
![Page 12: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/12.jpg)
Enhancement
![Page 13: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/13.jpg)
Pyramid Blending
![Page 14: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/14.jpg)
Step I - Create Blend Masks
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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 1Blend 1 MaskBlend 2Blend 2 Mask
![Page 16: Computer Vision, winter 2012-13 CS Department, Technion.](https://reader035.fdocuments.us/reader035/viewer/2022062423/56649e0b5503460f94af270b/html5/thumbnails/16.jpg)
Step IIIStandard Laplacian pyramid
reconstruction of blended scales
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Implementation IssuesImage registrationFeatheringOver/under flows outside [0,1]MATLAB function: impyramid()
Only Gaussian pyramid‘reduce’ or ‘expand’ modes
MATLAB function: imresize()Useful for masks resizing