Publish to ROS image topic in different FPS

lincolnxlw

Hi,

In my application, I run the pipeline in 30 FPS for object detection, then the pipeline publish image to ROS topics for downstream tasks, which only need 5 FPS. The node publishing image to ROS is similar to this example.

The example use `dai::rosBridge::BridgePublisher` to publish image data in the same rate as the pipeline. Publishing ROS image message in such high rate costs a lot of network bandwidth and CPU especially for devices like Raspberry Pi. Is there a way to publish in a lower FPS than the original pipeline?

Thanks

Lincoln

jakaskerl

lincolnxlw
The is no way to do this from ROS (publisher) side, but you can add a filter on depthai side using a Script node.

# Define the script content
script.setScript("""
# Python script to pass only every sixth frame
counter = 0

while True:
    # Get incoming frame
    frame = node.io['in'].get()
    
    # Check if counter is a multiple of 6
    if counter % 6 == 0:
        node.io['out'].send(frame)
    
    # Increment counter
    counter += 1
""")

Thansk,
Jaka

lincolnxlw

jakaskerl

It works great. Thanks!

Lincoln