How to stream more camera streams to Jetson or Raspberry pi? If the time determinism is not important.

asked 2020-02-06 06:57:30 -0600

femust gravatar image


I have the following case which I am not sure how to solve:

I have two Asus xtion pro and Jetson Nano. Jetson Nano is able to stream only one asux xtion pro at a time.

So my solution currently is to use ros::topic::waitforTransport when I need to get data from one point cloud wait some time (let's say 0.5s) and get a point cloud from the other sensor (time robustness it's not important in this application).

So If I want a typical XYZ point cloud everything works nice. On the other hand when I want XYZRGB cloud then it's also fine in terms of XYZ but with color is a problem, because it's blurry-whity.

I did some tests, and it seems that the reason is auto-exposure, since when I open in rviz, there is a kind of flash at the beginning and then it's fine. Because of this flash, the point cloud is whity despite the real color. When I am using only one camera and I am saving data there is RGBXYZ normally (when I'm streaming all the time point clouds). So it seems that the problem is with the "waitforTransport" since it seems it asks asus to turn on. Then asus sends data back, but in the meantime asus wants to do auto-exposure - for this reason the point cloud is either not properly colored or blurry-white (more frequently). So the question is what should i do in this case?

In general application is that I have a rotating frame, two Asus and i want to catch point cloud with color and then icp-ed them together.

Thanks for suggestions.

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I'm not sure I can answer the question you proposed, but I'm curious why you think it can only stream one feed at a time, how do you have this connected / setup?

stevemacenski gravatar image stevemacenski  ( 2020-02-06 12:48:05 -0600 )edit

well because if i run openni2 camera node it says that the camera can be connected to only one usb-bus but as far as i know jetson nano doesn't provide two usb buses for camera but only kind-of-shared-bus, because of this i'm afraid that the data may be lost for some reasons during msg passing.

femust gravatar image femust  ( 2020-02-06 14:01:54 -0600 )edit