I have a set of points on a paper and i want to calibrate my camera using those points. I ve put colors on each point and have done a color thresholding and am currently having all the image points I ve also took object points respectively when i try to calibrate with calibrate camera function its giving me an error. \ OpenCV Error: Assertion failed (ni >= 0) in collectCalibrationData, file /home/mac/OpenCV-2.4.1/modules/calib3d/src/calibration.cpp, line 3172 terminate called after throwing an instance of 'cv::Exception' what(): /home/mac/OpenCV-2.4.1/modules/calib3d/src/calibration.cpp:3172: error: (-215) ni >= 0 in function collectCalibrationData
is there any way to get past this?