Lab和RGB互相转换代码，网上找了很多效果都不好，有的甚至转换过去再转换回来颜色都不一样了，有的存在除0的风险。改代码经过本人修改后验证的，用于图像处理效果都是对的。-Lab and RGB mutual conversion code, find a lot of the effect is not good, and some even converted in the past and back again are not th