Patent ID: 8675934
Filing Date: 2014-03-18
Classification: G06K,G06T

Abstract:
1. A method for segmenting an image comprising pixels, the method comprising: applying a second derivative operator to the pixels to derive first and second eigenvalues and an orientation angle for each of the pixels; generating a seeding grid comprising an array of a subset of the pixels; growing a set of contours using the subset of pixels as potential contour starting points; pruning the set of contours to generate a pruned set of contours; determining a contour strength vector for each of the contour pixels based on a maximum positive one of the eigenvalues and the orientation angle of the respective contour pixel; generating a partial ellipse representing an estimated location of an object in the image by combining the contour strength vectors with a set of directional operators; dividing the partial ellipse into a plurality of support sectors, each sector including a respective control point on the partial ellipse; for each of the pruned contours centered in a respective sector, setting a contour strength to be a maximum of dot products of the respective contour strength vectors with a normal to the partial ellipse at the respective sector's control point, and setting a contour position to be a location of the maximum product; adjusting a position of each sector control point based on the contour positions weighted by the contour strengths of the pruned contours centered in the respective sector; fitting the partial ellipse to the adjusted positions of the control points to generate a partial fitted ellipse; and generating a segmentation mask of the object based on the partial fitted ellipse.