将lena图像沿逆时针方向旋转30度，显示旋转后的图像； 找一副彩色图像，计算其Y、U、V分量并计算值；-lena homework 4

用Arnold变换实现lena灰度图像的加密，然后用反变换对加密后的图像进行解密。-Lena grayscale images achieve encryption using Arnold transform, and then use the inverse transform of the image decrypting encrypted.