Apriltag node slows down

[ikhann]

Hi, First of all, thank you for such a project.

Let's get to the point. My system:

• Jetson Orin NX 16Gb and AverMedia D131 Carrier board.
• Jetpack 5.1.1 (L4T 35.3.1) with MAXN NV Power and running Jetson Clocks.
• DP 3.1 Release

AprilTags with a static camera pose:

SW Flow:

graph LR
NITROS
A(usb_cam) -->|/image_raw|B(isaac_ros_apriltag)
A(usb_cam) -->|/camera_info|B(isaac_ros_apriltag)
B(isaac_ros_apriltag) --> |/tf|C(USER SW)
B(isaac_ros_apriltag) --> |/tag_detections|C(USER SW)

Main parameters:

classDiagram
      class usb_cam{
          -double framerate=15
          -int image_width=2592
          -int image_height=1944
      }
      class isaac_ros_apriltag{
          -double size=0.074
          -int max_tags=64
      }

I recorded a few bag files and visualized measurements, one of them:

Here you can see how data publishing stably for 30 seconds at a frequency of about 10Hz, then you can observe a ~7-second pause, which is observed only in the topic of the Isaac Apriltag node. From time to time, freeze data can be more/less frequent and longer/shorter. On what it depends, I can not understand.

I also noticed that at this moment the consumed voltage drops. This is clearly related to the slowing down of the node, but it is difficult to say whether this is the cause of the hang or the consequence. You can see this behavior starting from the 5th second in the video below:

https://github.com/NVIDIA-ISAAC-ROS/isaac_ros_apriltag/assets/21182465/cdf6182d-0308-4eec-87d2-18d2ec76b9b6

So, in this regard, I have a question. Have you ever encountered a similar problem, and, in your opinion, what might be the problem that needs solving?

Thank you for your help!

[swapnesh-wani-nvidia]

Thank you for the detailed explanation. Did you see the same behavior with a different camera and/or different resolution? Also, I noticed in the attached video that the fan rpm is not showing any numbers. Could you please check if the fan is set to max rpm jetsom_clocks --fan

[ikhann]

Hi @swapnesh-wani-nvidia ! Thank you for the response.

Yes, I saw the same with a different resolution. Even when I lowered the camera’s resolution to 1080p, I observed the same hangs.

I have a max 100% FAN speed running with the command sudo jetson_clocks --fan:

In addition, to determine the cause of the power drops, I will check the performance of Apriltag detection by connecting a carrier board to another power supply source. I will keep you informed of my findings.

[ikhann]

Hi @swapnesh-wani-nvidia ! Thank you for the response.

Yes, I saw the same with a different resolution. Even when I lowered the camera’s resolution to 1080p, I observed the same hangs.

I have a max 100% FAN speed running with the command sudo jetson_clocks --fan:

In addition, to determine the cause of the power drops, I will check the performance of Apriltag detection by connecting a carrier board to another power supply source. I will keep you informed of my findings.

I tested the performance with the various power supply sources. The result is the same. Apparently, the power drops for some time were due to the lack of computations.