电话摄像机校准-opencv

Question

我正在尝试使用OpenCV中提供的教程和棋盘上的图片来校准手机摄像头，但是代码未显示最终结果，因此我一直着这个错误：

NameError                                 Traceback (most recent call last)
<ipython-input-16-9dc3cfc36f25> in <module>
     33 
     34 cv2.destroyAllWindows()
---> 35 ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)

NameError: name 'gray' is not defined

这是我运行的代码

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*9,3), np.float64)
objp[:,:2] = np.mgrid[0:9,0:6].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('*/Users/ASUS/Desktop/Homework/Homework_1/im.jpg')

for fname in images:
    img = cv2.imread(fname)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)

    # Find the chess board corners
    ret, corners = cv2.findChessboardCorners(gray, (9,6),None)
    print(ret)

    # If found, add object points, image points (after refining them)
    if ret == True:
        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, (9,6), corners2,ret)
        cv2.imshow('img',img)
        cv2.waitKey(500)

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

Answer 1

您将图像加载到for循环中，并且仅在此处定义gray。然后，您可以在最后一行的循环外部引用它，以获取图像尺寸，但gray不在范围内。

创建一个用于保存for循环之前图像尺寸的变量并将其填充到循环内部应该可以解决问题。

dims = None

for fname in images:
    img = cv2.imread(fname)
    dims = img.shape[::-1]

(...)

ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, dims, None, None)