Wrap Up 15-463: Computational Photography Alexei Efros, CMU, Fall 2005 © Robert Brown.
Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU,...
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Transcript of Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU,...
![Page 1: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/1.jpg)
Comparing Images
Adopted from Frederic Heger
15-463: Computational PhotographyAlexei Efros, CMU, Fall 2008
![Page 2: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/2.jpg)
Distance Metrics
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= Euclidian distance of 5 units
= Grayvalue distance of 50 values
= ?
x
y
x
y
![Page 3: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/3.jpg)
Beyond SSD…
?
![Page 4: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/4.jpg)
Space Shuttle Cargo Bay
Image Representations: Histograms
global histogram•Represent distribution of features
• Color, texture, depth, …
Images from Dave Kauchak
![Page 5: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/5.jpg)
Image Representations: Histograms
Joint histogram• Requires lots of data• Loss of resolution to
avoid empty bins
Images from Dave Kauchak
Marginal histogram• Requires independent features• More data/bin than
joint histogram
![Page 6: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/6.jpg)
Space Shuttle Cargo Bay
Image Representations: Histograms
Adaptive binning• Better data/bin distribution, fewer empty bins• Can adapt available resolution to relative feature importance
Images from Dave Kauchak
![Page 7: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/7.jpg)
EASE Truss Assembly
Space Shuttle Cargo Bay
Image Representations: Histograms
Clusters / Signatures• “super-adaptive” binning• Does not require discretization along any fixed axis
Images from Dave Kauchak
![Page 8: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/8.jpg)
Issue: How to Compare Histograms?
Bin-by-bin comparisonSensitive to bin size. Could use wider bins …… but at a loss of resolution
Cross-bin comparisonHow much cross-bin influence is necessary/sufficient?
![Page 9: Comparing Images Adopted from Frederic Heger 15-463: Computational Photography Alexei Efros, CMU, Fall 2008.](https://reader035.fdocuments.us/reader035/viewer/2022062715/56649d7f5503460f94a62734/html5/thumbnails/9.jpg)
Red Car Retrievals (Color histograms)
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Histogram matching distance