An Integrated Skew Detection And Correction Using Fast Fourier Transform And DCT

Skew detection and correction is very important task before pre-processing of an image and it is a major problem in scanned documents, if it not detected correctly it will lead wrong result in future during image analysis. During the scanning of the document, skew is being often introduced in the document image. To measure the processed time and speed taken by skew detection algorithm, the Fast Fourier Transform (FFT) technique is applied as it is fast approach for finding the angle of skewed document. This technique is used by firstly applying DCT compression and thresholding on image to reduce timing computation and after that Fourier spectrum is obtained. Further this spectrum is divided into four quadrants and detected skewed angle of each quadrant is measured. And finally Input image is rotated by using bilinear interpolation method.