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US 9,317,766 B2Granted
Method and device for extracting distorted straight line from image
AssigneeFujitsu Limited
InventorsYun Zheng, Shufu Xie, Pan Pan, Yuan He, Jun Sun
Life of this patent
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Abstract
A method and a device for extracting a distorted straight line from an image. The method includes performing a line segment detection process on the image; for each line segment detected, finding adjacent line segments having a low non-collinear degree with a current line segment, so as to combine them together to obtain one or more line segment combinations; and extracting the distorted straight line according to the line segment combination.
Claims10
A method for extracting a distorted straight line from an image, comprising:
- performing a line segment detection process on the image;
- for each line segment detected, finding adjacent line segments having a low non-collinear degree with a current line segment, so as to combine them together to obtain one or more line segment combinations;
- and
- extracting the distorted straight line according to the line segment combination,
- wherein finding adjacent line segments having a low non-collinear degree with a current line segment further comprises:
- defining an adjoining rectangular area along a slope direction of the current line segment;
- and
- searching another line segment whose non-collinear degree with a current line segment is lower than a predetermined threshold as the adjacent line segment within the adjoining rectangular area in accordance with a principle:
- the middle first, then both sides;
- and
- from near to far,
- wherein the non-collinear degree is measured by calculating a connection angle with the following formula, the less the connection angle, the lower the non-collinear degree:
- connection angle=max(abs(a2−a1),abs(a2−a3));
- wherein
- a1 is an angle between the current line segment and a predetermined reference line;
- a2 is an angle between a connection line of the current line segment with the another line segment and the predetermined reference line;
- and
- a3 is an angle between the another line segment and the predetermined reference line.
15 more elements
A device for extracting a distorted straight line from an image, comprising:
- a detecting module configured to perform a line segment detection process on the image;
- a combining module configured to, for each line segment detected, find adjacent line segments having a low non-collinear degree with a current line segment, so as to combine them together to obtain one or more line segment combinations;
- and
- an extracting module configured to extract the distorted straight line according to the line segment combination,
- wherein finding adjacent line segments having a low non-collinear degree with a current line segment further comprises:
- defining an adjoining rectangular area along a slope direction of the current line segment;
- and
- searching another line segment whose non-collinear degree with a current line segment is lower than a predetermined threshold as the adjacent line segment within the adjoining rectangular area in accordance with a principle:
- the middle first, then both sides;
- and
- from near to far,
- wherein the non-collinear degree is measured by calculating a connection angle with the following formula, the less the connection angle, the lower the non-collinear degree:
- connection angle=max(abs(a2−a1),abs(a2−a3));
- wherein
- a1 is an angle between the current line segment and a predetermined reference line;
- a2 is an angle between a connection line of the current line segment with the another line segment and the predetermined reference line;
- and
- a3 is an angle between the another line segment and the predetermined reference line.
15 more elements
Dependencies are inferred from the claim text.