为什么使用cv2.getRotationMatrix2D和cv2.warpAffine旋转图像会返回零矩阵

Question

我是cv2库的初学者。我在python 3.7中使用cv2库来旋转图像。这是我的代码

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

img = cv2.imread("messi.jpg")
(h, w) = img.shape[:2]
(cX, cY) = (w // 2, h // 2)

# grab the rotation matrix (applying the negative of the
# angle to rotate clockwise), then grab the sine and cosine
# (i.e., the rotation components of the matrix)
M = cv2.getRotationMatrix2D((cX, cY), 10, 1.0)
cos = np.abs(M[0, 0])
sin = np.abs(M[0, 1])

# compute the new bounding dimensions of the image
nW = int((h * sin) + (w * cos))
nH = int((h * cos) + (w * sin))

# adjust the rotation matrix to take into account translation
M[0, 2] += (nW / 2) - cX
M[1, 2] += (nH / 2) - cY

# perform the actual rotation and return the image
image = cv2.warpAffine(img, M, (nW, nH))

此代码返回零矩阵。谁能帮我调试一下并告诉我为什么会发生吗？

Answer 1

该代码似乎还可以，并且对我有用，但是您不显示图像...

旋转矩阵的输出是：

[[ 0.98480775  0.17364818 -0.25563765]
 [-0.17364818  0.98480775 99.97181918]]

在opencv中，您必须处理waitKey尝试最后执行这些操作，它会暂停cv2直到按下逃脱键。

cv2.imshow("image", image)

while True:
    keyboard = cv2.waitKey(2320)
    if keyboard == 27:
        break
cv2.destroyAllWindows()