image pyramids pre-filter images to collect information at different scalespre-filter images to...
Post on 21-Dec-2015
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Image PyramidsImage Pyramids
• Pre-filter images to collect information Pre-filter images to collect information at different scalesat different scales
• More efficient computation, allowsMore efficient computation, allowslarger motionslarger motions
Pyramid CreationPyramid Creation
• ““Gaussian” PyramidGaussian” Pyramid
• ““Laplacian” PyramidLaplacian” Pyramid– Created from GaussianCreated from Gaussian
pyramid by subtractionpyramid by subtractionLLii = G = Gii – expand(G – expand(Gi+1i+1))
SzeliskiSzeliski
Octaves in the Spatial DomainOctaves in the Spatial Domain
Bandpass ImagesBandpass Images
Lowpass Images
SzeliskiSzeliski
BlendingBlending
• Blend over too small a region: seamsBlend over too small a region: seams
• Blend over too large a region: ghostingBlend over too large a region: ghosting
Multiresolution BlendingMultiresolution Blending
• Different blending regions for different Different blending regions for different levels in a pyramid [Burt & Adelson]levels in a pyramid [Burt & Adelson]– Blend low frequencies over large regions Blend low frequencies over large regions
(minimize seams due to brightness (minimize seams due to brightness variations)variations)
– Blend high frequencies over small regions Blend high frequencies over small regions (minimize ghosting)(minimize ghosting)
Minimum-Cost CutsMinimum-Cost Cuts
• Instead of blending high frequencies Instead of blending high frequencies along a straight line, blend along line of along a straight line, blend along line of minimum differences in image minimum differences in image intensitiesintensities
Minimum-Cost CutsMinimum-Cost Cuts
Moving object, simple blending Moving object, simple blending blur blur
[Davis 98][Davis 98]