Skew detection

摘要

Presented is a skew detection apparatus. In one form, the apparatus estimates skew based on the locations of a set of foreground content pixels or a set of edge pixels that are nearest to the side of an image of a document. In another form, the apparatus includes a skew estimation unit adapted to estimate skew based on the orientation of foreground or background content in the interior of a document. In another form, the apparatus estimates skew using segments of an image of a document. Also presented is a document image processing apparatus including the skew detection apparatus.

主权项

1. A skew detection apparatus, the apparatus comprising:
an input to receive an image of a document; and a processor to,
for each of a plurality of sides of the image:
determine locations of a set of foreground pixels or a set of edge pixels of the document that are nearest to the side of the image;generate from said set of pixels an estimate of a probability distribution of values of an angle of a line joining two pixels of a subset of pairs of pixels chosen from among all possible pairs of pixels from the set, wherein a distance between the pixels in each pair of the chosen subset of pairs of pixels is predefined; anddetermine the angle corresponding to a maximum value of a plurality of values in the estimated probability distribution,produce a first estimated skew angle by combining said angles determined for each of the plurality of sides of the image, andestimate a first confidence value for the first estimated skew angle.