Displaying the April Tag on a smartphone

[nirmalsnair]

Thanks again for providing the code! ⭐

I've successfully connected two depth cameras in Unity, and the calibration process is underway, detecting the April Tag. However, the calibration accuracy is low as the point clouds aren't aligning properly. I suspect this could be due to using my smartphone to display the April Tag instead of printing it on an A4 paper.

I have a couple of questions:

1. Is it feasible to perform calibration by displaying the April Tag on a smartphone, or is a printed version necessary?
2. If calibration using a smartphone is possible, what adjustments should be made in the code to accommodate the altered marker size?

[ababilinski]

Hi @nirmalsnair
Thank you! I haven't updated in a while so I'm glad it's still working properly and helping developers.

Regarding your questions:

1. It is possible to use a smartphone, but it might result in bad pose estimation since the image isn't clear.
2. You can change the expected marker size in RsCameraPoseEstimation.cs

[nirmalsnair]

Sorry for the delayed response. Yes, the code is working without any issues.

I printed the April Tag on an A4 paper, and now the alignment is very good. However, there's a slight translational difference along the x and z axes, though the orientation is perfect. I think tweaking the marker size should fix that. Thanks for the help!

[nirmalsnair]

Hello again!

I experimented with values for Tag Size under Assets > RealSenseAprilTags > Examples > CameraCalibration > Prefabs > Cameras > Camera Pose Estimation. However, the point clouds still exhibit a slight misalignment.

Tag Size = 0.110

Tag Size = 0.114

Tag Size = 0.115 (Default)

Tag Size = 0.116

Tag Size = 0.120

---

Do you have any insights into what might be causing this issue? I am using an A4-size April Tag. Appreciate your assistance!

[nirmalsnair]

Hi @ababilinski, any ideas to rectify this slight misalignment issue?