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Are distortion coefficients returned by cv::stereoCalibrate correct?

asked 2013-08-28 10:48:27 -0500

dumbDumb gravatar image

updated 2013-09-27 12:05:54 -0500

// This bug is fixed by Pritam Shete(http://code.opencv.org/projects/opencv/repository/revisions/a430abd02eaf38e0d42f075acbb47210c2b191c8)

Hi,

I tried to use cv::stereoCalibrate to calibrate the cameras. However the distortion coefficients returned by cv::stereoCalibrate seemed to be wrong. I didn't set up the flag "CALIB_THIN_PRISM_MODEL"(I passed CV_CALIB_RATIONAL_MODEL as the flag), but I still got the nonzero s1, s2, s3, and s4 in returned array.

Is this correct result?

In calibration.cpp - line#2038, I thought distCoeffs->cols == 12, and Dist[k] had only 8 component. Why there is no code setting the last 4 components in distortion coefficients to zero?

The distortion coefficients I got are

distCoeffs1:[k_1_A, k_2_A, p_1_A, p_2_A, k_3_A, k_4_A, k_5_A, k_6_A, k_1_B, k_2_B, p_1_B, p_2_B]

distCoeffs2:[k_1_B, k_2_B, p_1_B, p_2_B, k_3_B, k_4_B, k_5_B, k_6_B, ?, ?, ?, ?]

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As StevenPuttemans always says, dont use hashtags in the tags. Although they get proposed, they create doubles and make forum search harder.

Moster gravatar imageMoster ( 2013-08-28 12:01:39 -0500 )edit
2

Refer to OpenCv documentation on Camera calibration - http://docs.opencv.org/doc/tutorials/calib3d/camera_calibration/camera_calibration.html

Please see the equations before watching the code, they would give you logical explanation of the camera calibration process.

utkarshmankad gravatar imageutkarshmankad ( 2013-08-28 23:33:39 -0500 )edit

Thank you. I had read the documentation. I don't know why the last four components(s_1, s_2, s_3, s_4) returned by cv::stereoCalibrate are nonzero when I only pass CV_CALIB_RATIONAL_MODEL as "flag". Are those four components are effective when I pass CALIB_THIN_PRISM_MODEL to cv::stereoCalibrate. Or should I set those components in 12-element distortion coefficients to zero by myself before calling initUndistortRectifyMap?

dumbDumb gravatar imagedumbDumb ( 2013-08-29 02:24:24 -0500 )edit

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answered 2013-09-27 12:08:45 -0500

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Asked: 2013-08-28 10:48:27 -0500

Seen: 597 times

Last updated: Sep 27 '13