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### Triangulation gives weird results for rotation

If I start at the origin and use triangulatePoints the result looks like expected; These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get results that look as expected to me:

When I rotate the first camera by 45 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 45 degrees before calling

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

hconcat(new_frame->local_R, new_frame->local_t, new_frame->local_pose);
new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K*P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots.

### Triangulation gives weird results for rotation

If I start at the origin and use triangulatePoints the result looks like expected; These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get results that look as expected to me:

When I rotate the first camera by 45 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 45 degrees before calling

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

hconcat(new_frame->local_R, new_frame->local_t, new_frame->local_pose);
new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K*P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected; expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results that look as expected to me:(x positive is right, y positive is down):

When I rotate the first camera by 45 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 45 degrees before calling

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * KP0 and K*P1 KP1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results (x positive is right, y positive is down):

When I rotate the first camera by 45 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 45 degrees before calling

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the KP0 and KP1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots.plots and so the rotation is behaving strangely. I can't figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results (x positive is right, y positive is down):

When I rotate the first camera by 45 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 45 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the KP0 and KP1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I can't figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results (x positive is right, y positive is down):

When I rotate the first camera by 45 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 45 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the KP0 and KP1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I can't figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the KK * P0 and KK * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I can't figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I can't haven't been able to figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

EDIT: here is a gif of whats going on as I rotate through 360 degrees.

t

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

EDIT: here is a gif of whats going on as I rotate through 360 degrees.

tWhat am I missing?

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

EDIT: here is a gif of whats what's going on as I rotate through 360 degrees. degrees around Y. The cameras are still parallel. What am I missing?

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

EDIT: here is a gif of what's going on as I rotate through 360 degrees around Y. The cameras are still parallel. What am I missing?missing, shouldn't the shape of the point cloud remain the same if both camera poses remain in relative positions even thought they have been rotated around the origin?

### Triangulation gives weird results for rotation

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

EDIT: here Here is a gif of what's going on as I rotate through 360 degrees around Y. The cameras are still parallel. What am I missing, shouldn't the shape of the point cloud remain the same if both camera poses remain in relative positions even thought they have been rotated around the origin?origin? Why are the points squashed into the X axis?

### Triangulation gives weird results for rotation

OpenCV version 3.4.2

I am taking a stereo pair and using recoverPose to get the [R|t] pose of the camera, If I start at the origin and use triangulatePoints the result looks somewhat like expected although I would have expected the z points to be positive;

These are the poses of the cameras [R|t]

p0: [1, 0, 0, 0;
0, 1, 0, 0;
0, 0, 1, 0]

P1: [0.9999726146107655, -0.0007533190856300971, -0.007362237354563941, 0.9999683127209806;
0.0007569149205790131, 0.9999995956157767, 0.0004856419317479311, -0.001340876868928852;
0.007361868534054914, -0.0004912012195572309, 0.9999727804360723, 0.007847012372698725]


I get these results where the red dot and the yellow line indicates the camera pose (x positive is right, y positive is down):

When I rotate the first camera by 58.31 degrees and then use recoverPose to get the relative pose of the second camera the results are wrong.

Pose matrices where P0 is rotated by 58.31 degrees around the y axis before calling my code below.

P0: [0.5253219888177297, 0, 0.8509035245341184, 0;
0, 1, 0, 0;
-0.8509035245341184, 0, 0.5253219888177297, 0]

P1: [0.5315721563840478, -0.0007533190856300971, 0.8470126770406503, 0.5319823932782873;
-1.561037994149129e-05, 0.9999995956157767, 0.0008991799591322519, -0.001340876868928852;
-0.8470130118915117, -0.0004912012195572309, 0.5315719296650566, -0.8467543535708145]


(x positive is right, y positive is down)

The pose of the second frame is calculated as follows:

new_frame->E = cv::findEssentialMat(last_frame->points, new_frame->points, K, cv::RANSAC, 0.999, 1.0, new_frame->mask);
int res = recoverPose(new_frame->E, last_frame->points, new_frame->points, K, new_frame->local_R, new_frame->local_t, new_frame->mask);
// https://stackoverflow.com/questions/37810218/is-the-recoverpose-function-in-opencv-is-left-handed
// Convert so transformation is P0 -> P1
new_frame->local_t = -new_frame->local_t;
new_frame->local_R = new_frame->local_R.t();

new_frame->pose_t = last_frame->pose_t + (last_frame->pose_R * new_frame->local_t);
new_frame->pose_R = new_frame->local_R * last_frame->pose_R;
hconcat(new_frame->pose_R, new_frame->pose_t, new_frame->pose);


I then call triangulatePoints using the K * P0 and K * P1 on the corresponding points.

I feel like this is some kind of coordinate system issue as the points I would expect to have positive z values have a -z value in the plots and so the rotation is behaving strangely. I haven't been able to figure out what I need to do to fix it.

EDIT: Here is a gif of what's going on as I rotate through 360 degrees around Y. The cameras are still parallel. What am I missing, shouldn't the shape of the point cloud remain the same if both camera poses remain in relative positions even thought they have been rotated around the origin? Why are the points squashed into the X axis?