Patent Document ID: 20110194772
Application ID: 12873595
Patent Status: 0

Claim One:
1. A method for keypoints scale-space extraction and description in an image, the method comprising the following steps: a) Filtering the image with triangle kernel filters at different scales b) Computing an approximation of a determinant of Hessian at each scale, where this approximation at each scale k, is calculated as |∂ k xx (i, j)·∂ k yy (i, j)−∂ k xy (i, j) 2 | where 
 
 
 where L(k, i, j) is the filtered image response obtained in step a) at scale k at point (i, j) and here d 1 and d 2 are design parameters c) Searching for extremum values both within a single scale and along the scale space of the approximation of the determinant of Hessian obtained in step b) and calculating the keypoints from these extrema values d) For each keypoint, localised at an extremum value, detecting the dominant orientations from gradient information calculated using the filtered image response obtained in step a) e) Calculating for each dominant orientation a keypoint descriptor