Deskewing a scanned image

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Skew is an artifact that might appear during document scanning process and it consists of getting the document’s text/images be rotated at a slight angle. It can have various causes but the most common are paper getting misplaced during a scan. Therefore, deskew is the process of detecting and fixing this issue on scanned files (ie, bitmap) so deskewed images will have the text/images correctly and horizontally aligned.

Deskewing an image can help a lot, if you want to improve the readability of scanned images. For example, think of a camera that automatically takes photos of goods with a barcode. If the skew angle is too high, the barcode can not be detected. After deskewing, the barcode can be read.

Below is an example of skewed scanned text and deskewed output.

Skewed image

Deskewed image

Skewed image Deskewed image