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Straighten image

version 1.4 (5.34 KB) by

The function finds the document orientation.



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The function is useful for automatic image straightening.

Three different approaches how to find the image orientation were implemented: Fourier transform, Hough transform and region properties.

The principle of using Fourier transformation for orientation detection is well described at:

Hough transformation finds lines in the picture. The description of Hough transformation is at:

In a similar problem, horizon detection, only the longest line determines the image orientation:

However, in text orientation detection it is beneficial to consider all lines' direction to improve signal-to-noise ratio. This late approach is implemented.

Finally region properties binarizes the image and then uses REGIONPROPS from Image Processing Toolbox to calculate blob's orientation.

Comments and Ratings (3)




Improved text description. Added blob detection.


Added Fast Fourier Transform.

MATLAB Release
MATLAB 6.5 (R13)

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