Python OpenCV相机校准cv :: imshow错误

Question

I am trying to calibrate an SJ4000 camera using OpenCV 2.4.11 in Python 2.7 in Anaconda.

However, I am unable to run the script available here: http://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_calib3d/py_calibration/py_calibration.html#setup

I am even testing it with the sample images available in samples/cpp/ , images left01.jpg to left14.jpg . It is able to detect the chessboard in the images, but once it hits this line:

cv2.imshow('img',img)

It throws an error:

error: ..\..\..\modules\highgui\src\window.cpp:261: error: (-215) size.width>0 && size.height>0 in function cv::imshow

EDIT 1: After further debugging, I have found that img = cv2.drawChessboardCorners(img, (7,6), corners2,ret) results in a None object.

How do I solve this?

Thanks for any help!

Answer 1

Hooray! All solved after some further debugging. I suspect this is a version issue.

I changed

corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)
imgpoints.append(corners2)
# Draw and display the corners
img1 = cv2.drawChessboardCorners(img, (7,6), corners2,ret)

To

cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)
# Draw and display the corners
cv2.drawChessboardCorners(img, (7,6), corners,ret)

And everything works perfectly!