Patent ID: 8358871

Claim:
A skewed image data detecting and correcting method for use in an image processing apparatus, the skewed image data detecting and correcting method comprising steps of: receiving an image data, and performing a binary digitizing operation on the image data to obtain a binary image data, wherein each pixel of the binary image data is expressed by a single bit; rotating the binary image data by multiple different rotating angles, thereby obtaining multiple rotated binary image data; totalizing pixel numbers of all horizontal rows of the rotated binary image data, thereby obtaining corresponding multiple horizontal pixel number distribution curves; performing a high-pass filtering procedure to filter off low-frequency noise contained in the horizontal pixel number distribution curves, thereby obtaining corresponding multiple high-frequency signal curves; calculating square sums of respective high-frequency signal curves, thereby obtaining corresponding multiple index values; and performing a rotating correction operation on the image data according to the rotating angle corresponding to a maximum of the index values, thereby obtaining a corrected image data.