Skew angle checker for scanned documents.
Namespace:
AForge.ImagingAssembly: AForge.Imaging (in AForge.Imaging.dll) Version: 2.1.4.0 (2.1.4.0)
Syntax
| C# |
|---|
public class DocumentSkewChecker |
Remarks
The class implements document's skew checking algorithm, which is based on Hough line transformation. The algorithm is based on searching for text base lines - black line of text bottoms' followed by white line below.
Note:The routine supposes that a white-background document is provided
with black letters. The algorithm is not supposed for any type of objects, but for
document images with text.The range of angles to detect is controlled by MaxSkewToDetect property.
The filter accepts 8 bpp grayscale images for processing.
Sample usage:
CopyC#// create instance of skew checker DocumentSkewChecker skewChecker = new DocumentSkewChecker( ); // get documents skew angle double angle = skewChecker.GetSkewAngle( documentImage ); // create rotation filter RotateBilinear rotationFilter = new RotateBilinear( -angle ); rotationFilter.FillColor = Color.White; // rotate image applying the filter Bitmap rotatedImage = rotationFilter.Apply( documentImage );
Initial image:
Deskewed image:
