Image Inclination Measurement Based on Edge Directions and an Analysis of Relation between Visual Inclination

This paper proposes a method to measure the inclined angle of an objective image based on the most frequent edge direction. This paper also describes a relation between the measured inclined angles by the proposal method and the visual inclined angles. An edge direction is changed according to the inclination of an objective image. The most frequent edge direction is supposed to show the global inclination of the image. The proposed method measures the inclined angle of the image by detecting the edge direction with the peak in the histogram that represents the distribution of all edge directions in the image. The experimental results show that the measured inclined angles by the proposed method were similar to the visual inclined angles evaluated by the subjects.