test.py

# coding=UTF-8
import cv2
import numpy as np
from matplotlib import pyplot as plt

img1 = cv2.imread('hp-label.PNG', 0)  # trainImage
img2 = cv2.imread('input.PNG', 0)  # queryImage

orb = cv2.ORB_create(edgeThreshold=4, patchSize=16)  # ORB
# http://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_feature2d/py_fast/py_fast.html
# Вместо детекторов можно пытаться использовать совпадения по шаблону http://robocraft.ru/blog/computervision/3046.html

# найдем точки
kp1 = orb.detect(img1, None)
kp2 = orb.detect(img2, None)

# получим сжатое представление о найденных точках
kp1, des1 = orb.compute(img1, kp1)
kp2, des2 = orb.compute(img2, kp2)

# зарисуем ключевые точки и сохраним
img3 = cv2.drawKeypoints(img1, kp1, None, color=(255, 0, 0))
img4 = cv2.drawKeypoints(img2, kp2, None, color=(255, 0, 0))
cv2.imwrite('tmp_hp-label.png', img3)
cv2.imwrite('tmp_input.png', img4)

bf = cv2.BFMatcher(cv2.NORM_HAMMING, crossCheck=True)

# Match descriptors.
matches = bf.match(des1,des2)

# Sort them in the order of their distance.
matches = sorted(matches, key = lambda x:x.distance)

#зарисуем совпадения
img5 = cv2.drawMatches(img1,kp1,img2,kp2,matches, None, flags=2)

cv2.imwrite('tmp_input_vs_label.png', img5)

#будем искать объекты на картинке
good = matches
for m in matches:
    if m.distance < 0.7:
        good.append(m)

#Кривая выдклялка - но она нам и не понадобится - у нас будет http://www.learnopencv.com/blob-detection-using-opencv-python-c/
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(-1,1,2)

    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,h-1],[w-1,0] ]).reshape(-1,1,2)
    dst = cv2.perspectiveTransform(pts,M)

    img2 = cv2.polylines(img2,[np.int32(dst)],True,255,3, cv2.LINE_AA)

draw_params = dict(matchColor = (0,255,0), # draw matches in green color
                   singlePointColor = None,
                   matchesMask = matchesMask, # draw only inliers
                   flags = 2)

img6 = cv2.drawMatches(img1,kp1,img2,kp2,good,None,**draw_params)
cv2.imwrite('tmp_selection_result.png', img6)

plt.imshow(img6, 'gray')
plt.show()