cam Look at method

[EgalYue]

This R is the wrong one! https://github.com/EgalYue/Mobile_Marker_Based_Navigation/blob/6ffd21f7e1b3d67433a21e11998cc9fe925947c8/python/vision/camera.py#L268

Before that we get the right cam distribution because of following code: we got the right axis direction (because of R.T, but it should be R not R.T), but the cam.R is not the right one!!! https://github.com/EgalYue/Mobile_Marker_Based_Navigation/blob/6ffd21f7e1b3d67433a21e11998cc9fe925947c8/python/vision/camera_distribution.py#L53

For example: We set camera at [1,0,0] and using look at method, but if we using the old look at method we got R = [[ 0. 0. 1. 0.] [ 0. 1. 0. 0.] [-1. 0. 0. 0.] [ 0. 0. 0. 1.]]

This R is wrong!!!

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ we should use this R https://github.com/EgalYue/Mobile_Marker_Based_Navigation/blob/6ffd21f7e1b3d67433a21e11998cc9fe925947c8/python/vision/camera.py#L262

And the real R should be R = [[ 0. 0. -1. 0.] [ 0. 1. 0. 0.] [ 1. 0. 0. 0.] [ 0. 0. 0. 1.]]

[raultron]

I think the look at method assumes that the camera is placed above the points. For example, in my case, the 4 points were on the X-Y plane. Try to move now your camera above the points and see if it still works.

[raultron]

I ported that code from this one: https://www.3dgep.com/understanding-the-view-matrix/

[EgalYue]

ok, i will try it again

[raultron]

I know what is wrong there, we have to adapt it. They use the Y up convention and we are using the Z up convention. The whole method has to be rewritten to follow our convention and then it should be consistent independently if the camera is above or below the points.

[raultron]

If you want to be sure about the transformations take a look to the ROS tf python package. I think now that I get how everything works I will switch my code to use the basics from that package

[raultron]

This is another one that I will integrate later, is a good camera model in python: https://github.com/ros-perception/vision_opencv/blob/kinetic/image_geometry/src/image_geometry/cameramodels.py

[EgalYue]

ok, I will check look at method again, the problem is: R = [e1,e2,e3], e1 e2 e3 should be Column vector not Row vector.

[EgalYue]

I tested cam at [1,1,1]

This is the Wrong R: https://github.com/EgalYue/Mobile_Marker_Based_Navigation/blob/86818dfef778dcb3d1d927b5420c592088086ace/python/vision/camera.py#L268

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ This is the Right R: https://github.com/EgalYue/Mobile_Marker_Based_Navigation/blob/86818dfef778dcb3d1d927b5420c592088086ace/python/vision/camera.py#L262

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R = [xaxis, yaxis, zaxis]. xaxis, yaxis, zaxis should be Column vector not Row vector. And i will read the link, which you gived me.