Movement Invariants-based Algorithm for Medical Image Tilt Correction

In this paper,the edge detection for a medical image is performed based on Sobel operator,and the bounding box is obtained,by which the effective medical sub-image is extracted.Then,the centroid and the normalized central moments of the medical sub-image are calculated,and the rotation angle is obtained by minimizing the second-order central moment based on its rotation invariance.Finally,the whole medical image is rotated around the centroid by- to correct the tilted image.Furthermore,inspired by the uniformity degree of the image,the rotation angle is revised,which achieves a better correction effect and performance.The experimental results show that the proposed algorithms are fairly reliable and accurate for the determination of tilt angles,and are practical and effective tilt correction techniques.