Need help with projection and deprojection

July 10, 2019 12:08
Edited

I have a D435 looking the top of a table (0.80m between camera and table). I project point (0,0,0.80) to pixel and display it. I draw the point on the table, so the camera (0,0,0.80) is aligned with it.
Then I draw a second point on the table 10cm away on x and on y of the first one. And I try to project point (0.1, 0.1, 0.81) - the second point I drew on the table with 0.81 => distance between second point and camera - to pixel and display it again. My second point and my second pixel is not aligned at all.

You can see on the image the shift.

I use pyrealsense2 with a config 640, 480 for color and depth. I get the intrinsics with the video stream profile. And I just use get_distance() and rs.rs2_project_point_to_pixel() functions.

I don't know if I'm doing it good. At the final I just need good coordonate from the camera in order to give them to a robot with a transformation matrix.

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MartyG

July 10, 2019 12:35

Edited
Your project reminds me of RealSense users who have attempted to get a 'pose' with the camera that would be usable by a robot. The link below contains links to approaches taken by users trying to use the D435 with a robot arm for the purposes of picking items from a bin..

https://forums.intel.com/s/question/0D70P000006GEZUSA4
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Bastien Ferbu

July 10, 2019 14:37

Edited
Ok I think I found my error. I used the intrinsics of the depth profile, when I changed it to the color profile the points seems to match! Thank you @MartyG, the link helped me. I'll try with more points but I think it's a good start :p
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MartyG

July 10, 2019 15:25
Glad you found a solution. Good luck with the rest of your project!
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