在python中使用opencv时断言失败

我在python的opencv中进行相机校准，并且按照本页上的教程进行操作。我的代码是完全从页面复制的，而对参数的调整很小。

码：

import numpy as np
import cv2
import glob

# termination criteria
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)

# prepare object points, like (0,0,0), (1,0,0), (2,0,0) ....,(6,5,0)
objp = np.zeros((6*7,3), np.float32)
objp[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)

# Arrays to store object points and image points from all the images.
objpoints = [] # 3d point in real world space
imgpoints = [] # 2d points in image plane.

images = glob.glob('../easyimgs/*.jpg')
print('...loading')
for fname in images:
    print(f'processing img:{fname}')
    img = cv2.imread(fname)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    print('grayed')
    # Find the chess board corners
    ret, corners = cv2.findChessboardCorners(gray, (8, 11),None)

    # If found, add object points, image points (after refining them)
    if ret == True:
        print('chessboard detected')
        objpoints.append(objp)

        corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)
        imgpoints.append(corners2)

        # Draw and display the corners
        img = cv2.drawChessboardCorners(img, (8,11), corners2,ret)
        cv2.namedWindow('img',0)
        cv2.resizeWindow('img', 500, 500)
        cv2.imshow('img',img)
        cv2.waitKey(500)
        cv2.destroyAllWindows()


img2 = cv2.imread("../easyimgs/5.jpg")
print(f"type objpoints:{objpoints[0].shape}")
print(f"type imgpoints:{imgpoints[0].shape}")

ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)
h,  w = img2.shape[:2]
newcameramtx, roi=cv2.getOptimalNewCameraMatrix(mtx,dist,(w,h),1,(w,h))
dst = cv2.undistort(img2, mtx, dist, None, newcameramtx)

# crop the image
x,y,w,h = roi
dst = dst[y:y+h, x:x+w]
cv2.namedWindow('result', 0)
cv2.resizeWindow('result', 400, 400)
cv2.imshow('result',dst)

cv2.destroyAllWindows()

但是当我运行它时，错误显示为：

Traceback (most recent call last):
  File "*/undistortion.py", line 51, in <module>
    ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)
cv2.error: OpenCV(3.4.2) C:\projects\opencv-python\opencv\modules\calib3d\src\calibration.cpp:3143: error: (-215:Assertion failed) ni == ni1 in function 'cv::collectCalibrationData'

这是我的形象。

我在互联网上搜索到许多人也面临这个问题。但是博客上的大多数解决方案都说这是由第一个参数和第二个参数的类型引起的，该参数calibrateCamera()是objpointsand imgpoints。但是这些都是在c ++上针对opencv的解决方案。

谁能告诉我如何在python中解决它？