问cv2 SIFT +蛮力匹配没有提供好的结果

EN

MIN_MATCH_COUNT = 10
sift = cv2.xfeatures2d.SIFT_create(sigma=1.6, contrastThreshold=0.04,edgeThreshold = 15)

kp1, des1 = sift.detectAndCompute(rgb, None)
kp2, des2 = sift.detectAndCompute(thermal, None)

bf = cv2.BFMatcher()
matches = bf.knnMatch(des1, des2, k=2)
good = []
for m, n in matches:
    if m.distance < 0.8 * n.distance:
        good.append(m)

good = sorted(good, key=lambda x: x.distance)
img3 = cv2.drawMatches(rgb, kp1, thermal, kp2, good, None, flags=2)

    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, maxIters=1000)
    matchesMask = mask.ravel().tolist()

    h, w, c = rgb.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)

    thermal = cv2.polylines(thermal, [np.int32(dst)], True, 255, 3, cv2.LINE_AA) # draw lines around as a box
    draw_params = dict(matchColor=(0, 255, 0),  # draw matches in green color
                   singlePointColor=None,
                   matchesMask=matchesMask,  # draw only inliers
                   flags=2)

    img3 = cv2.drawMatches(rgb, kp1, thermal, kp2, good, None, **draw_params)