基于Matlab的双线性插值算法在图像旋转中的应用

插值运算作为一种标准的运算方法在图像处理领域,尤其是在图像的放大、旋转和卷积处理过程中有着广泛的应用.本文提出了一种新的双线性插值算法,通过对超出图像边界的区域进行取模操作,实现图像阵的循环.采用Matlab编程实现该算法,并应用到图像旋转中.实验证明,用该算法旋转图像时,在特定角度（90.、180.和270.）可以完整显示原始图像;任意角度旋转时,可以看到超出图像范围的像素部分自动进入了斜线对侧,较好地显示出图像旋转的边界变化和旋转位置的循环.

Application of Bilinear Interpolation Algorithm in Image Rotation Based on Matlab

As a standard operation method, interpolation has been used widely in image processing, especially in magnification, rotation and convolution of images. In this paper, an improved method for bilinear interpolation was put forward, mode operation was taken in the region beyond the image border, which led to the circulation of image matrixes. The im- proved algorithm was carried out with Matlab software and applied in image rotations. The results show that the algorithm can fully display the original image at particular angles （90°, 180° and 270°）, the parts beyond the range of original image were automatically filled by the contralateral pixels of the diagonals if image was rotated at any angle. The changes of the boundaries and the cycles of the particular pixels can be found in rotated images. The improved algorithm is better applied in image rotations.