# Problem with building pose Mat from rotation and translation matrices

I have two images captured in the same space (scene), one with known pose. I need to calculate the pose of the second (query) image. I have obtained the relative camera pose using essential matrix. Now I am doing calculation of camera pose through the matrix multiplication (here is a formula).

I try to build the 4x4 pose Mat from rotation and translation matrices. My code is following

```
Pose bestPose = poses[best_view_index];
Mat cameraMotionMat = bestPose.buildPoseMat();
cout << "cameraMotionMat: " << cameraMotionMat.rows << ", " << cameraMotionMat.cols << endl;
float row_a[4] = {0.0, 0.0, 0.0, 1.0};
Mat row = Mat::zeros(1, 4, CV_64F);
cout << row.type() << endl;
cameraMotionMat.push_back(row);
// cameraMotionMat.at<float>(3, 3) = 1.0;
```

Earlier in code. Fora each view image:

```
Mat E = findEssentialMat(pts1, pts2, focal, pp, FM_RANSAC, F_DIST, F_CONF, mask);
// Read pose for view image
Mat R, t; //, mask;
recoverPose(E, pts1, pts2, R, t, focal, pp, mask);
Pose pose (R, t);
poses.push_back(pose);
```

Initially method bestPose.buildPoseMat() returns Mat of size (3, 4). I need to extend the Mat to size (4, 4) with row [0.0, 0.0, 0.0, 1.0] (zeros vector with 1 on the last position). Strangely I get following output when print out the resultant matrix

[0.9107258520121255, 0.4129580377861768, 0.006639390377046724, 0.9039011699443721; 0.4129661348384583, -0.9107463665340377, 0.0001652925667582038, -0.4277340727282191; 0.006115059555925467, 0.002591307168000504, -0.9999779453436902, 0.002497598952195387;

0, 0.0078125, 0, 0]

Last row does not look like it should be: [0, 0.0078125, 0, 0] rather than [0.0, 0.0, 0.0, 1.0]. Is this implementation correct? What could a problems with this matrix?

please show, what is in

`cameraMotionMat`

, originally, and maybe you need to explain, how you obtain that (the steps that produced that)thank you. Code for the method buildPoseMat:

cameraMotionMat before adding a row (returned from method buildPoseMat):

Updated the question as well.

@berak I solved the issue using this solution. I suppose now to calculate camera pose for the query image using the pose of the best matching view image and the related camera transformation Mat (

`cameraMotionMat`

) by means of Mat product following formula from here (p2). That could look like this:Is this solution correct?