SURF: Speeded Up Robust Features: Difference between revisions

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* [https://link.springer.com/chapter/10.1007/11744023_32 Springer Link to Paper (ECCV 2006) Paywall]
* [https://link.springer.com/chapter/10.1007/11744023_32 Springer Link to Paper (ECCV 2006) Paywall]
* [http://people.ee.ethz.ch/~surf/eccv06.pdf Paper]
* [http://people.ee.ethz.ch/~surf/eccv06.pdf Paper]
* [[:File:Surf_speeded_up_robust_features_eccv06.pdf | Mirror]]
* [[Media:Surf_speeded_up_robust_features_eccv06.pdf | Mirror]]


;Authors:
;Authors:
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* Sample Haar-wavelet responses in x and y-direction at points around each feature
* Sample Haar-wavelet responses in x and y-direction at points around each feature
** Using integral images, only 6 operations are need to compute in x or y direction (Fig. 2 middle)
** Using integral images, only 6 operations are need to compute in x or y direction (Fig. 2 middle)
**: We have 6 distinct corners so we need 5 fma operations in total for each direction.
**: We have 6 distinct corners so we need 6 fma operations in total for each direction. (Actually 5 if one value is just multiplied by 1)
* Using a 360-degree (pivoting) sliding window with radius <math>\frac{\pi}{3}</math>,  calculate the sum of all horizontal and vertical responses yielding vector. Note the window moves in increments of <math>\frac{\pi}{3}</math>
* Using a 360-degree (pivoting) sliding window with radius <math>\frac{\pi}{3}</math>,  calculate the sum of all horizontal and vertical responses yielding vector. Note the window moves in increments of <math>\frac{\pi}{3}</math>
* Pick the direction with the largest vector.
* Pick the direction with the largest vector.