python – 使用OpenCV和SIFT / SURF校正扫描图像以匹配原始图像
发布时间:2020-12-20 11:55:50 所属栏目:Python 来源:网络整理
导读:我有一个数字形式的原始页面和同一页面的几个扫描版本.我的目标是对扫描的页面进行校正,使其尽可能与原始页面匹配.我知道我可以使用 here所述的概率霍夫变换来固定旋转但扫描的纸张尺寸也不同,因为有些人将页面缩放到不同的纸张格式.我认为OpenCV中的findHom
我有一个数字形式的原始页面和同一页面的几个扫描版本.我的目标是对扫描的页面进行校正,使其尽可能与原始页面匹配.我知道我可以使用
here所述的概率霍夫变换来固定旋转但扫描的纸张尺寸也不同,因为有些人将页面缩放到不同的纸张格式.我认为OpenCV中的findHomography()函数与SIFT / SURF的关键点组合正是我解决这个问题所需要的.但是,我只是无法让我的deskew()函数工作.
我的大多数代码源于以下两个来源: import numpy as np import cv2 from matplotlib import pyplot as plt # FIXME: doesn't work def deskew(): im_out = cv2.warpPerspective(img1,M,(img2.shape[1],img2.shape[0])) plt.imshow(im_out,'gray') plt.show() # resizing images to improve speed factor = 0.4 img1 = cv2.resize(cv2.imread("image.png",0),None,fx=factor,fy=factor,interpolation=cv2.INTER_CUBIC) img2 = cv2.resize(cv2.imread("imageSkewed.png",interpolation=cv2.INTER_CUBIC) surf = cv2.xfeatures2d.SURF_create() kp1,des1 = surf.detectAndCompute(img1,None) kp2,des2 = surf.detectAndCompute(img2,None) FLANN_INDEX_KDTREE = 0 index_params = dict(algorithm=FLANN_INDEX_KDTREE,trees=5) search_params = dict(checks=50) flann = cv2.FlannBasedMatcher(index_params,search_params) matches = flann.knnMatch(des1,des2,k=2) # store all the good matches as per Lowe's ratio test. good = [] for m,n in matches: if m.distance < 0.7 * n.distance: good.append(m) MIN_MATCH_COUNT = 10 if len(good) > MIN_MATCH_COUNT: src_pts = np.float32([kp1[m.queryIdx].pt for m in good ]).reshape(-1,1,2) dst_pts = np.float32([kp2[m.trainIdx].pt for m in good ]).reshape(-1,2) M,mask = cv2.findHomography(src_pts,dst_pts,cv2.RANSAC,5.0) matchesMask = mask.ravel().tolist() h,w = img1.shape pts = np.float32([[0,0],[0,h - 1],[w - 1,0]]).reshape(-1,2) dst = cv2.perspectiveTransform(pts,M) deskew() img2 = cv2.polylines(img2,[np.int32(dst)],True,255,3,cv2.LINE_AA) else: print("Not enough matches are found - %d/%d" % (len(good),MIN_MATCH_COUNT)) matchesMask = None # show matching keypoints draw_params = dict(matchColor=(0,# draw matches in green color singlePointColor=None,matchesMask=matchesMask,# draw only inliers flags=2) img3 = cv2.drawMatches(img1,kp1,img2,kp2,good,**draw_params) plt.imshow(img3,'gray') plt.show() 解决方法
结果我非常接近解决我自己的问题.
这是我的代码的工作版本: import numpy as np import cv2 from matplotlib import pyplot as plt import math def deskew(): im_out = cv2.warpPerspective(skewed_image,np.linalg.inv(M),(orig_image.shape[1],orig_image.shape[0])) plt.imshow(im_out,'gray') plt.show() orig_image = cv2.imread(r'image.png',0) skewed_image = cv2.imread(r'imageSkewed.png',0) surf = cv2.xfeatures2d.SURF_create(400) kp1,des1 = surf.detectAndCompute(orig_image,des2 = surf.detectAndCompute(skewed_image,5.0) # see https://ch.mathworks.com/help/images/examples/find-image-rotation-and-scale-using-automated-feature-matching.html for details ss = M[0,1] sc = M[0,0] scaleRecovered = math.sqrt(ss * ss + sc * sc) thetaRecovered = math.atan2(ss,sc) * 180 / math.pi print("Calculated scale difference: %.2fnCalculated rotation difference: %.2f" % (scaleRecovered,thetaRecovered)) deskew() else: print("Not enough matches are found - %d/%d" % (len(good),MIN_MATCH_COUNT)) matchesMask = None (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |