Transcript of text FAQ questions from the Intel multiple Realsense cameras webinar

MartyG · ‎01-09-2019

The transcript below is taken from the text Q&A section of Intel's September 2018 webinar session on using multiple RealSense cameras. A transcript of extracts from the voice-spoken parts of this webinar can be found at the link below:

https://forums.intel.com/s/question/0D50P0000490XJeSAM/extracts-from-the-webinar-handson-with-multiple-intel-realsense-d415-amp-d435-camera-systems

TRANSCRIPT OF TEXT FAQ

Is it possible to get microsecond sync of RGB and depth on the D435?

Yes for the D415, but NO for the D435. The D435's color camera is NOT HW synced.

How do we do combined reconstruction from all cameras?

You need to calibrate the cameras extrinsic pose, we used Vicalib, and then perform a ridged transform of the point clouds using the extrinsics into the same space.

How do I turn the cameras on / off individually from software?

We would suggest that you look at the pipeline in librealsense, it should have open and close functionality

What time protocol does D435 use?

We dont use a protocol per se. The HW sync is a voltage pulse. The time stamp you can query is for system time or HW time (recommended).

Is there any example code of the skeleton tracking neural network?

Not currently.

Can simulation be done on Gazebo with multiple cameras?

I believe so, if you are able to transform the cameras based on their extrinsics to reflect the real world.

All of the D series cameras were advertised with camera syncronization. When will the D435 have support for hardware sync?

The D435 can HW sync depth, but NOT color. This will not be supported in the future either, as it is a HW limitation. The D415 can sync color and depth.

What kind of compression is used on the depth data? LZW?

Huffman

We have multiple D415 cameras connected with hardware sync. Each has a dedicated USB host controller. A lot of times, individual streams depth or color stop updating and don't return until camera restart. Could this be HW sync related or a problem with the USB bus?

It could be ESD related to the HW sync cable, which is why we recommend the RC filter at the cable ends.

So, what's about sync cable? If I want to connect several cameras (more then 2) with sync, is it possible?

We use a single master camera, that is connected to all other slaves

Will you publish depth decompression source code in SDK?

Yes.