中文说明：利用离散余弦变换，增强图像色彩，这是对增对彩色图像的，对图像较暗的区域也有很好的改善，增强了对比度，可惜代码不是对所有图像都适合，对图像尺寸有一定要求
English Description：
Using the discrete cosine transform, enhance image colors, this is for additional color images, on the darker areas of the image are also very good improvements, enhanced contrast, unfortunately, the code is not fit for all images, has certain requirements for image size