Found bugs when trying to use stereo_image_proc about zed_cpu_ros HOT 8 CLOSED

Hi Prarinya,

For this part, I referenced the official zed_ros_warpper. Looks like it's wrong.

So the Rectification matrix should be

[Rx  0   0 ]
[0   1   0 ]
[0   0   Rz]

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But I noticed the value giving in my zed config is

RX_2K=0.00388714
RX_FHD=0.00388714
RX_HD=0.00388714
RX_VGA=0.00388714
RZ_2K=-0.00139603
RZ_FHD=-0.00139603
RZ_HD=-0.00139603
RZ_VGA=-0.00139603

I am not sure this RX and RZ is indicating which value in the 3x3 Rectification Matrix, Do you have any idea?

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I think RX and RZ should refer to the extrinsic rotation matrix. From the look, I guess they gave the rotation angles in radian \theta_x and \theta_z.

From wikipedia https://en.wikipedia.org/wiki/Rotation_matrix#In_three_dimensions , rotation matrix can be calculated by finding rotation in every axes. So you got R_x(\theta_x), R_z(\theta_z), R_y=I. The final rotation matrix R = R_z(\theta_z) x I x R_x(\theta_x)

So, I did calculated the above equations. The resultant rotation matrix R look similar to the rotation matrix I got from other stereo camera (very close to identity matrix).

I am not sure if I was wrong about this. Please check on this if able. At the moment, I set the R to identity matrix, and stereo_image_proc package work very well with this setting.

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Cool, The recent commits also set the R matrix as identity, but I again failed to do the image_proc for some reason, how did you do that?

Also, I think it's better to do a calibration yourself using ROS's stero_proc package. I got a launch file that can do this which you might want to check out.

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Here I found an interesting explanation,
stereolabs/zed-ros-wrapper#39
The rotation (in rotation vector form, convertible into matrix with Rodrigues formula) are the following:

Rx = RX (in rad),
Ry = CV,
Rz = RZ.

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Thanks for the info on rotation matrix.

For the calibration, I used the ZED calibration tool in the ZED SDK. It gave a better calibration for me. However, they seem to record it in float32 not float64. So the precision are very limited. How about your case ?

By the way, it works with your roslaunch like a charm. Thank you for you great work.

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the ZED calibration works better for me also.

Thank you for your compliment!

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Hi @prarinya-s
Can you help me check if the new commits are right in terms of the rectification?
I don't have the camera with me, so I can't really check if it works or not.
09ffa6e
Thanks.

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