如何在python中找到open-cv摄像机校准常数，OpenCV错误：cv :: calibrateCamera中的断言失败（nimages> 0）

Question

我想用以下代码找到相机校准常数。 但是，我有一些我不知道的错误消息。 请帮我。

import cv2
import numpy as np
import glob[enter image description here][1]

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

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

# 3d point in real world space
object_points = []
# 2d points in image plane
image_points = []
h, w = 0, 0

images = glob.glob('chess board/*.jpg')

for file_name in images:
    image = cv2.imread(file_name)
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    h, w = gray.shape[:2]

    # find chess board corners
    ret, corners = cv2.findChessboardCorners(gray, (7, 7), None)

    # add object points, image points
    if ret:
        object_points.append(object_point)
        cv2.cornerSubPix(gray, corners, (11, 11), (-1, -1), criteria)
        image_points.append(corners)

        # draw and display the corners
        cv2.drawChessboardCorners(image, (7, 7), corners, ret)
        cv2.imshow('image', image)
        cv2.waitKey(500)

# calibration
retval, cameraMatrix, distCoeffs, rvecs, tvecs = cv2.calibrateCamera(object_points, image_points, (w, h), None, None)

print "camera matrix:\n", cameraMatrix

# pi camera intrinsic parameters
ay = cameraMatrix[1, 1]
u0 = cameraMatrix[0, 2]
v0 = cameraMatrix[1, 2]
print "Ay:", ay
print "u0:", u0
print "v0:", v0

cv2.destroyAllWindows()ode here

这是我收到的错误消息：

C：\\ Python27 \\ python.exe“ C：/ Users / MOMO / PycharmProjects / test / training image / picam_calibration.py” OpenCV错误：cv :: calibrateCamera，文件......中的断言失败（nimages> 0） .. \\ opencv \\ modules \\ calib3d \\ src \\ calibration.cpp，第3415行回溯（最近一次调用）：文件“ C：/ Users / MOMO / PycharmProjects / test / training image / picam_calibration.py”，第40行，在retval，cameraMatrix，distCoeffs，rvecs，tvecs = cv2.calibrateCamera（object_points，image_points，（w，h），None，None）cv2.error：........ \\ opencv \\ modules \\ calib3d \\ src \\ calibration .cpp：3415：错误：（-215）函数cv :: calibrateCamera中的nimages> 0

Answer 1

您应该检查传递给函数findChessboardCorner的拐角大小是否正确，在代码中为（7，7）。

这符合您的棋盘格图案吗？