python - 使用 Python 和 OpenCV 错误校准网络摄像头

Question

对这一切都很陌生，我正在尝试按照 this 对网络摄像头进行校准指导和使用下面的代码。我收到以下错误..

OpenCV Error: Assertion failed (ni > 0 && ni == ni1) in collectCalibrationData, file /build/buildd/opencv-2.4.8+dfsg1/modules/calib3d/src/calibration.cpp, line 3193

cv2.error: /build/buildd/opencv-2.4.8+dfsg1/modules/calib3d/src/calibration.cpp:3193: error: (-215) ni > 0 && ni == ni1 in function collectCalibrationData

谁能解释这个错误是什么以及如何修复它？

(底部的完整错误)

import numpy as np
import cv2
import glob


criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)
# Arrays to store object points and image points from all the images.
objpoints = [] # 3d point in real world 
imgpoints = [] # 2d points in image plane.
images = glob.glob('*.png')


objp = np.zeros((6*7,3), np.float32)
objp[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)
objp = objp * 22


for fname in images:

    img = cv2.imread(fname)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    ret = False
    # Find the chess board corners
    ret, corners = cv2.findChessboardCorners(gray, (6,9))
    # If found, add object points, image points (after refining them)
    if ret == True:
        objpoints.append(objp)
        cv2.cornerSubPix(gray, corners, (11,11), (-1,-1), criteria)

        imgpoints.append(corners)
        # Draw and display the corners 
        cv2.drawChessboardCorners(img, (6,9), corners, ret)
        cv2.imshow('img',img)
        cv2.waitKey(0)

cv2.waitKey(0)
for i in range (1,5):
    cv2.waitKey(1)
    cv2.destroyAllWindows()
    cv2.waitKey(1)


ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)

OpenCV Error: Assertion failed (ni > 0 && ni == ni1) in collectCalibrationData, file /build/buildd/opencv-2.4.8+dfsg1/modules/calib3d/src/calibration.cpp, line 3193 Traceback (most recent call last): File "", line 1, in File "/usr/lib/python2.7/dist-packages/spyderlib/widgets/externalshell/sitecustomize.py", line 540, in runfile execfile(filename, namespace) File "/home/students/Test/test.py", line 49, in ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None) cv2.error: /build/buildd/opencv-2.4.8+dfsg1/modules/calib3d/src/calibration.cpp:3193: error: (-215) ni > 0 && ni == ni1 in function collectCalibrationData

Answer 1

我遇到了同样的问题，你的主要错误(我知道是因为我自己犯的)是你改变了棋盘大小(示例中默认为 7x6，你的是 6x9)，但是你忽略了改变大小在例程顶部的初始化代码中

objp = np.zeros((6*7,3), np.float32)
objp[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)

要使其适用于多种棋盘尺寸，您可以像这样调整代码:

# checkerboard Dimensions
cbrow = 5
cbcol = 7

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

.
.
.
ret, corners = cv2.findChessboardCorners(gray, (cbcol, cbrow), None)