CODEWITHSUNDEEP
pythonopencvnameerror
Isaac
Isaac

Reputation: 13

Python + OpenCV name not defined

I'm using a source code example from Open CV for Python documentation as follows:

import numpy as np
import cv2
import glob

# termination criteria in this, 30 max number of iterations, 0.001 minimum accuracy
# CV_TERMCRIT_ITER or CV_TERMCRIT_EPS, tells the algorithm that we want to terminate either after some number of iterations or when the convergence metric reaches some small value (respectively).
# The next two arguments set the values at which one, the other, or both of these criteria should terminate the algorithm.
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.float32)
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('*.jpg')

# fname= 'C:\\Users\\Bender\\Desktop\\fotospayloads\\'

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)

    # 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()

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

Unfortunately when I run the source code I get the following error: "NameError: name 'gray' is not defined" (line 50).

Any help would be very much appreciated.

Thanks

Isaac

Upvotes: 0

Views: 5289

Answers (1)

Marko Šarkanj
Marko Šarkanj

Reputation: 165

There are no images in folder where your script is located and that is why glob.glob('.jpg') does not return any files and grey object is not created.

Upvotes: 1

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