Patent ID: 8897600

Claim:
A method for determining vanishing point candidates of a text portion in an image document that is distorted by perspective, comprising the steps of: image binarization, wherein said image is binarized; performing connected component analysis, wherein pixel blobs are detected in said at least one text portion of said binarized image and wherein for each of said pixel blobs a position determining pixel is selected on a pixel blob baseline of the pixel blob, said position determining pixel defining the position of the pixel blob in the binarized image; estimating a number of text lines in a Cartesian coordinate system, each text line representing an approximation of a horizontal or vertical text direction of said text portion, on the basis of the position determining pixels; transforming each of said text lines to a data point in a homogenous coordinate system; assigning a confidence level to each of the data points; grouping a number of data points having a confidence level above a predetermined threshold into a priority sample array; clustering the data points in the priority sample array into a number of sample groups, wherein each sample group comprises at least two data points; assigning a group confidence value to each sample group on the basis of at least the confidence level assigned to each data point in the sample group; applying a RANSAC algorithm to determine among said data points a set of inliers with respect to a first fitted line, wherein said RANSAC algorithm is initiated with the sample group having the highest group confidence value in the priority sample array; estimating at least one vanishing point candidate from the text lines corresponding to said set of inliers.