Method and system for correcting projective distortions with elimination steps on multiple levels

摘要

Method, system, device and computer program product for projective correction of an image containing at least one text portion that is distorted by perspective. The method includes the steps of image binarization, connected component analysis, horizontal vanishing point determination, vertical vanishing point determination and projective correction. The horizontal vanishing point is determined by estimating text baselines by means of position determining pixels of pixel blobs, identifying horizontal vanishing point candidates from the baselines, and determining a horizontal vanishing point from the candidates. The vertical vanishing point is determined on the basis of vertical features of the text portion. The method includes a first elimination step on the level of position determining pixels, a second elimination step on the level of text baselines and a third elimination step on the level of horizontal vanishing point candidates.

主权项

1. A method for projective correction of an image containing at least one text portion that is distorted by perspective, the method comprising the steps of:
image binarization, wherein said image is binarized; 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; horizontal vanishing point determination, comprising the steps of: estimating text baselines by means of said position determining pixels of said pixel blobs, identifying horizontal vanishing point candidates from said estimated text baselines, and determining a horizontal vanishing point of said at least one text portion by means of said horizontal vanishing point candidates; vertical vanishing point determination, wherein a vertical vanishing point is determined for said at least one text portion on the basis of vertical features thereof; and projective correction, wherein said perspective in said image is corrected on the basis of said horizontal and vertical vanishing points; wherein said horizontal vanishing point determination comprises a first elimination step on the level of said position determining pixels, a second elimination step on the level of text baselines and a third elimination step on the level of horizontal vanishing point candidates.