Problem with undistortion by OpenCV

[imrasp]

I have tried to undistort the image from Euroc dataset using intrinsic and distortion coefficient provided by the dataset itself which using Kalibr as a calibration tool. The result is completely distorted as follow:

original image: undistorted image:

The method for unsidtort is (provided by opencv)

cv::undistort(image, imageUndistorted, intrinsic, distCoeffs);

I have try to undistort the image capture on my action camera and calibrated by opencv camera calibration. the result as follow:

original image: undistorted image:

I tried recalibrate Euroc using calibration dataset on kalibr and got the same result as it provided in the datasets.

What did I do wrong on undistort the image and what is the different between Kalibr and Opencv for calibrating monocular camera

[schneith]

Maybe the models between Kalibr/OpenCV are not matching. Kalibr implements distortion models that are not supported by OpenCV (e.g. the 'equidistant' model). Could you verify that the models are correct?

[imrasp]

@schneith Please suggest me a bit more on this, I am new to these calibration methods. Kalibr seems to support all distortion model (this link) including radial tangential which is the same as opencv distortion model. This is some context I copied from opencv website:

For the distortion OpenCV takes into account the radial and tangential factors.

This is the camera specification proposed by Euroc dataset

rate_hz: 20
resolution: [752, 480]
camera_model: pinhole
intrinsics: [458.654, 457.296, 367.215, 248.375] #fu, fv, cu, cv
distortion_model: radial-tangential
distortion_coefficients: [-0.28340811, 0.07395907, 0.00019359, 1.76187114e-05]

I think Euroc using the same distortion model as opencv but using these value I got the result above.

[HTLife]

Is there any way to convert kalibr distortion model to OpenCV supported format?

[NikolausDemmel]

pinhole-radtan is the same as the OpenCV model. pinhole-equi seems to be the same as OpenCV's "fisheye" camera model.

[HTLife]

@NikolausDemmel Thank you! I can now calibrate image with kalibr format yaml for by OpenCV.

The sample project is provided here for someone who might need it in the future. https://github.com/HTLife/tumvi_fisheye_calib