Open Source Computer Vision Library https://opencv.org/
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import numpy as np
import cv2, cv
from common import anorm
help_message = '''SURF image match
USAGE: findobj.py [ <image1> <image2> ]
'''
def match(desc1, desc2, r_threshold = 0.75):
res = []
for i in xrange(len(desc1)):
dist = anorm( desc2 - desc1[i] )
n1, n2 = dist.argsort()[:2]
r = dist[n1] / dist[n2]
if r < r_threshold:
res.append((i, n1))
return np.array(res)
def draw_match(img1, img2, p1, p2, status = None, H = None):
h1, w1 = img1.shape[:2]
h2, w2 = img2.shape[:2]
vis = np.zeros((max(h1, h2), w1+w2), np.uint8)
vis[:h1, :w1] = img1
vis[:h2, w1:w1+w2] = img2
vis = cv2.cvtColor(vis, cv.CV_GRAY2BGR)
if H is not None:
corners = np.float32([[0, 0], [w1, 0], [w1, h1], [0, h1]])
corners = np.int32( cv2.perspectiveTransform(corners.reshape(1, -1, 2), H).reshape(-1, 2) + (w1, 0) )
cv2.polylines(vis, [corners], True, (255, 255, 255))
if status is None:
status = np.ones(len(p1), np.bool_)
green = (0, 255, 0)
red = (0, 0, 255)
for (x1, y1), (x2, y2), inlier in zip(np.int32(p1), np.int32(p2), status):
col = [red, green][inlier]
if not inlier:
cv2.line(vis, (x1, y1), (x2+w1, y2), col)
cv2.circle(vis, (x1, y1), 2, col, -1)
cv2.circle(vis, (x2+w1, y2), 2, col, -1)
return vis
if __name__ == '__main__':
import sys
try: fn1, fn2 = sys.argv[1:3]
except:
fn1 = '../c/box.png'
fn2 = '../c/box_in_scene.png'
print help_message
img1 = cv2.imread(fn1, 0)
img2 = cv2.imread(fn2, 0)
surf = cv2.SURF(1000)
kp1, desc1 = surf.detect(img1, None, False)
kp2, desc2 = surf.detect(img2, None, False)
desc1.shape = (-1, surf.descriptorSize())
desc2.shape = (-1, surf.descriptorSize())
print 'img1 - %d features, img2 - %d features' % (len(kp1), len(kp2))
m = match(desc1, desc2)
matched_p1 = np.array([kp1[i].pt for i, j in m])
matched_p2 = np.array([kp2[j].pt for i, j in m])
H, status = cv2.findHomography(matched_p1, matched_p2, cv2.RANSAC, 10.0)
print '%d / %d inliers/matched' % (np.sum(status), len(status))
vis = draw_match(img1, img2, matched_p1, matched_p2, status, H)
cv2.imshow('find_obj SURF', vis)
cv2.waitKey()