OpenCV-Python系列之对极几何

import numpy as np
import cv2 as cv
img1=cv.imread("data1/1.png",0) # queryimage  left image
img2=cv.imread("data1/2.png",0) # trainimage right image
sift=cv.SIFT_create()
# sift1=cv.xfeatures2d.SIFT_create()

kp1,des1=sift.detectAndCompute(img1,None)
kp2,des2=sift.detectAndCompute(img2,None)

# FLANN parameters
FLANN_INDEX_KDTREE=1
index_params=dict(algorithm=FLANN_INDEX_KDTREE,trees=5)
search_params=dict(checks=50)
flann=cv.FlannBasedMatcher(index_params,search_params)
matches=flann.knnMatch(des1,des2,k=2)
good=[]
pts1=[]
pts2=[]
# ratio test as per Lowe's paper
for i,(m,n) in enumerate(matches):
    if m.distance<0.8*n.distance:
        good.append(m)
        pts2.append(kp2[m.trainIdx].pt)
        pts1.append(kp1[m.queryIdx].pt)

pts1=np.int32(pts1)
pts2=np.int32(pts2)
F,mask=cv.findFundamentalMat(pts1,pts2,cv.FM_LMEDS)
print("F矩阵")
print(F)
# we select only inlier points
pts1=pts1[mask.ravel()==1]
pts2=pts2[mask.ravel()==1]

def drawlines(img1, img2, lines, pts1, pts2):
    ''' img1 - image on which we draw the epilines for the points in img2
        lines - corresponding epilines '''
    r, c = img1.shape
    img1 = cv.cvtColor(img1, cv.COLOR_GRAY2BGR)
    img2 = cv.cvtColor(img2, cv.COLOR_GRAY2BGR)
    for r, pt1, pt2 in zip(lines, pts1, pts2):
        color = tuple(np.random.randint(0, 255, 3).tolist())
        x0, y0 = map(int, [0, -r[2]/r[1]])
        x1, y1 = map(int, [c, -(r[2]+r[0]*c)/r[1]])
        img1 = cv.line(img1, (x0, y0), (x1, y1), color, 1)
        img1 = cv.circle(img1, tuple(pt1), 5, color, -1)
        img2 = cv.circle(img2, tuple(pt2), 5, color, -1)
    return img1, img2

lines1=cv.computeCorrespondEpilines(pts2.reshape(-1,1,2),2,F)
lines1=lines1.reshape(-1,3)
img5,img6=drawlines(img1,img2,lines1,pts1,pts2)
# Find epilines corresponding to points in left image(first image) and  drawing its lines on right image
lines2=cv.computeCorrespondEpilines(pts1.reshape(-1,1,2),1,F)
lines2=lines2.reshape((-1,3))
img3,img4=drawlines(img2,img1,lines2,pts2,pts1)
# plt.subplot(1,2,1), plt.imshow(img5)
# plt.subplot(1,2,2), plt.imshow(img3)
cv.imshow("img5",img5)
cv.imshow("img3",img3)
cv.waitKey(0)