# Revision history [back]

### marker to gl-matrix via OpenCV.js

Let's assume we get rvecs and tvecs via cv.estimatePoseSingleMarkers()

Then going through each marker, we can get the 1x3 vectors like:

const rotation = [rvecs.doublePtr(0, i), rvecs.doublePtr(0, i), rvecs.doublePtr(0, i)];
const translation = [tvecs.doublePtr(0, i), tvecs.doublePtr(0, i), tvecs.doublePtr(0, i)];


How can this be converted so it's compatible with gl-matrix's fromRotationTranslation?

Specifically - it seems gl-matrix expects the rotation in a quaternion... I see some sample C++ code to do that conversion here, but it assumes a Rodrigues function in OpenCV to get from the 1x3 vector to a 3x3 rotation matrix - I think?

The Rodrigues function seems to be missing in OpenCV.js...

### marker to gl-matrix via OpenCV.js

Let's assume we get rvecs and tvecs via cv.estimatePoseSingleMarkers()

Then going through each marker, we can get the 1x3 vectors like:like this (found in online samples):

const rotation = [rvecs.doublePtr(0, i), rvecs.doublePtr(0, i), rvecs.doublePtr(0, i)];
const translation = [tvecs.doublePtr(0, i), tvecs.doublePtr(0, i), tvecs.doublePtr(0, i)];


How can this be converted so it's compatible with gl-matrix's fromRotationTranslation?

Specifically - it seems gl-matrix expects the rotation in a quaternion... I see some sample C++ code to do that conversion here, but it assumes a Rodrigues function in OpenCV to get from the 1x3 vector to a 3x3 rotation matrix - I think?

The Rodrigues function seems to be missing in OpenCV.js...OpenCV.js... and it's not clear to me what _exactly_ cv.estimatePoseSingleMarkers() is returning in each rvec (is it euler radians? something else?)

### marker to gl-matrix via OpenCV.js

Let's assume we get rvecs and tvecs via cv.estimatePoseSingleMarkers()

Then going through each marker, we can get the 1x3 vectors like this (found in online samples):

const rotation = [rvecs.doublePtr(0, i), rvecs.doublePtr(0, i), rvecs.doublePtr(0, i)];
const translation = [tvecs.doublePtr(0, i), tvecs.doublePtr(0, i), tvecs.doublePtr(0, i)];


How can this be converted so it's compatible with gl-matrix's fromRotationTranslation?

Specifically - it seems gl-matrix expects the rotation in a quaternion... I see some sample C++ code to do that conversion here, but it assumes a Rodrigues function in OpenCV to get from the 1x3 vector to a 3x3 rotation matrix - I think?

The Rodrigues function seems to be missing in OpenCV.js... and it's not clear to me what _exactly_ exactly cv.estimatePoseSingleMarkers() is returning in each rvec (is it euler radians? something else?)

### marker to gl-matrix via OpenCV.js

Let's assume we get rvecs and tvecs via cv.estimatePoseSingleMarkers()

Then going through each marker, we can get the 1x3 vectors like this (found in online samples):

const rotation = [rvecs.doublePtr(0, i), rvecs.doublePtr(0, i), rvecs.doublePtr(0, i)];
const translation = [tvecs.doublePtr(0, i), tvecs.doublePtr(0, i), tvecs.doublePtr(0, i)];


How can this be converted so it's compatible with gl-matrix's fromRotationTranslation?

Specifically - it seems gl-matrix expects the rotation in a quaternion... I see some sample C++ code to do that conversion here, but it assumes a Rodrigues function in OpenCV to get from the 1x3 vector to a 3x3 rotation matrix - I think?

The Rodrigues function seems to be missing in OpenCV.js... and it's not clear to me what exactly cv.estimatePoseSingleMarkers() is returning in each rvec (is it euler radians? something else?)