1. 理解彩色图像的颜色分层原理和方法

　　2. 利用颜色分层方法对彩色图像进行分层处理

　　3. 实现对身份证标准图像的背景分离和皮肤区域提取-1 understand the color image color layering principles and methods

(2) the use of color layered approach for hierarchical processing of color images

3 to achieve the standard of identity and separation of the background image to extract the skin region