Method for determining the amount of skew of image, method for

Abstract

Method for determining and correcting the amount of an skew of image which may be read by an image reader, preferably one with with an automatic paper feeding device. Information dependent on the angle of skew of image is obtained in a plurality of the directions with respect to image data and the amount of skew is determined based on the information obtained. Measurement of the information is performed in two or more stages (or steps). At the first stage, the measurement is performed within a narrow range of angles including a reference direction. If no skew angle is detected in the narrow range, then the measurement is performed again at the second stage in a wider range of angles. If a skew angle is detected in the first stage, the second stage is omitted. With the skew angle determined, the image data is rotated in accordance with the skew angle detected to cancel the skew. No correction of the image data is performed if skew angle detection does not result in either the first or the second stage. Preferably, correction of the image data is omitted if the detected skew angle falls within a very small range of angles.