特征匹配+單應性

Question

我已經在python中關注了opencv的教程。 我正在使用OpenCV 3.2和Python 3.6.1。 代碼是這樣寫的：

import cv2
import numpy as np
import matplotlib.pyplot as plt

MIN_MATCH_COUNT = 10

img1 = cv2.imread('test.jpg',0)
img2 = cv2.imread('hanapin_mo.jpg',0)

sift = cv2.xfeatures2d.SIFT_create()

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

FLANN_INDEX_KDTREE = 1
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)

good = []
for m,n in matches:
    if m.distance <0.7*n.distance:
        good.append(m)

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,d = 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)

else:
    print("Not enough matches are found - {}/{}".format(len(good), MIN_MATCH_COUNT) )
    matchesMask = None

draw_params = dict(matchColor = (0,250,0),
                   singlePointColor = None,
                   matchesMask = matchesMask,
                   flags = 2)

img3 = cv2.drawMatchesKnn(img1, kp1, img2, kp2, good, None, **draw_params)

plt.imshow(img3, 'gray'),plt.show()

當我運行模塊時，發生錯誤：

追溯（最近一次通話最近）：文件“ C：/ Users / Albert Eli Reyes / Desktop / SIFT / SIFT.py”，第35行，在h，w，d = img1.shape ValueError：沒有足夠的值可用於解包（預期3，得到2）

    h,w,d = 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)

說“沒有足夠的值要解包”是什么意思？ 我應該怎么做才能使其運行？

Answer 1

形狀函數僅輸出兩個值的元組。 您試圖獲取三個值，而該函數僅返回兩個值

h,w = img1.shape

上面的工作

Answer 2

好吧，這意味着img1.shape僅返回兩個值。 因此，如果刪除d變量初始化，則代碼應該可以正常工作，因為我仍然看不到在代碼中使用它。

h, w = img1.shape