开发环境:win10 anaconda python3.6 opencv3
1、四种特征提取算法简介(需要深入的同学可以参考其他博主的博客)
SIFT特征主要提取图像的局部特征,对平移、旋转、尺度缩放、亮度变化、遮挡和噪声等具有很好的不变性,对视觉变化、仿射变换也保持一定程度的稳定性。SURF可以说是从SIFT发展而来的,速度上优于SIFT,快了一个数量级(10倍),并且稳定性要高于SIFT。而FAST算法提取了大量的特征点,但在计算时间上,比SIFT要快两个数量级 比SURF快一个数量级。ORB算法基于FAST算法,但是提取的特征点质量比FAST高,特征点数目比FAST较少。
实验数据在这篇博客:点击打开链接
计算速度: ORB>>SURF>>SIFT(各差一个量级)
旋转鲁棒性: SURF>ORB~SIFT(表示差不多)
模糊鲁棒性: SURF>ORB~SIFT
尺度变换鲁棒性: SURF>SIFT>ORB(ORB并不具备尺度变换性)
2、代码+效果对比
# -*- coding: utf-8 -*- """ Spyder Editor This is a temporary script file. """ import cv2 img = cv2.imread(r'C:\Users\Pictures\Camera Roll/test.jpg') gray= cv2.cvtColor(img,cv2.COLOR_BGR2GRAY) # one SIFT #sift = cv2.xfeatures2d.SIFT_create() #kp1 = sift.detect(gray,None) #img1=cv2.drawKeypoints(gray,kp1,img) #cv2.imshow("sift_Image", img1) #cv2.imwrite(r'C:\Users\Pictures\Camera Roll/sift_test.jpg',img1) #Compare four alogorithms #Another SIFT sift = cv2.xfeatures2d.SIFT_create() (kps, descs) = sift.detectAndCompute(gray, None) img1=cv2.drawKeypoints(gray, kps, img, flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS) cv2.imshow('SIFT_Algorithm', img1) # SURF surf = cv2.xfeatures2d.SURF_create() (kps2, descs2) = surf.detectAndCompute(gray, None) img2=cv2.drawKeypoints(gray, kps2, img, flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS) cv2.imshow('SURF_Algorithm', img2) # FAST fast = cv2.FastFeatureDetector_create() kps3 = fast.detect(gray, None) img3=cv2.drawKeypoints(gray, kps3, img, flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS) cv2.imshow('FAST_Algorithm', img3) # ORB orb = cv2.ORB_create() kps4 = orb.detect(gray, None) (kps4, des4) = orb.compute(gray, kps4) img4=cv2.drawKeypoints(gray, kps4, img, flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS) cv2.imshow('ORB_Algorithm', img4)
最终的图像对比为: