Image analysis – Image transformation or preprocessing – Measuring image properties
Patent
1996-04-04
1999-05-04
Shalwala, Bipin
Image analysis
Image transformation or preprocessing
Measuring image properties
382290, 382291, 382292, 382294, 382296, 358452, 358537, G06K 932, G06K 936, H04N 146, H04N 1387
Patent
active
059012536
ABSTRACT:
An arrangement is described for determining the skew angle of a document image without requiring text or other skew detection information in the document or without human intervention. The arrangement accomplishes this by determining an edge of the document image within a scan image and uses that edge to determine the skew angle of the document image. The edge can be determined by locating the first or last document image pixel of each scan line of pixels in the scan image that belongs to the document image. This is accomplished by comparing each pixel of each scan line of pixels with a predetermined scan line of background pixels. The skew angle of the document image is then determined by computing the slope of the detected edge in the scan image. An arrangement of determining the boundary of the document image is also described. The arrangement does this by locating (1) a first document image pixel and a last document image pixel for the first scan line of the document image in the scan image, (2) a first document image pixel and a last document image pixel for the last scan line of the document image in the scan image, (3) a leftmost document image pixel of the document image in the scan image, and (4) a rightmost document image pixel of the document image in the scan image.
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Hewlett--Packard Company
Li Thomas X.
Mariam Daniel G.
Shalwala Bipin
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