在具有旋转不变性图像矩的传统算法中,必须将图像的坐标从直角坐标系转换到极坐标系,这种转换不仅会极大地增大计算量,并且会产生明显的舍入误差,从而导致以图像矩为特征的图像识别误差率上升,利用图像矩重建的图像质量下降。为了消除在像素坐标的转换过程中带来的不利影响,以圆谐傅里叶矩的计算为例,介绍了一种直接在直角坐标系下计算图像矩的方法。实验证明,这种方法不仅彻底消除了像素的坐标转换带来的误差,而且大幅降低了计算量。

The traditional method of computing rotation invariant moments of image,which needs to convert the image into the polar coordinate system,not only increases the computational load greatly,but also creates large rounding error,and results in error rate increase during image recognition and reconstructed image quality deterioration with image moments. To avoid the disadvantages caused during the process of pixel conversion,this paper took the computation of radical harmonic Fourier moments as example,and proposed a new method of computing moments in rectangular coordinate system immediately. The results of the experiments show that the new method can not only eliminate error caused by coordinate conversion,but also significantly reduce computational load.