说明：  特征提取是计算机视觉和图像处理中的一个概念。它指的是使用计算机提取图像信息，决定每个图像的点是否属于一个图像特征。特征提取的结果是把图像上的点分为不同的子集，这些子集往往属于孤立的点、连续的曲线或者连续的区域。
(Feature extraction is a concept in computer vision and image processing. It refers to using a computer to extract the image information, the decision of each image point whether an image feature. Feature extraction point of the image is divided into different subsets, the subset of often are isolated points, a continuous curve or continuous area.)