中文说明： Hu的七个不变矩在图像处理，尤其是特征提取方面是很重要的一个概念。本代码实现了图像的7个不变矩的计算和输出。
English Description：
Hu's seven moment invariants are very important concepts in image processing, especially in feature extraction. This code realizes the calculation and output of 7 invariant moments of the image.