An Edge TPU stream processing element for rt-ai using the Coral USB Accelerator

A Coral USB Accelerator turned up yesterday so of course it had to be integrated with rt-ai to see what it could do. Creating a Python-based SPE from the object detection demo in the API download didn’t take too long. I used the MobileNet SSD v2 COCO model as a starting point to generate this example output:

The very basic rt-ai test design looks like this:

Using 1280 x 720 video frames from the webcam, I was getting around 2 frames per second from the CoralSSD SPE. This isn’t as good as the Intel NCS 2 SPE but that is a compiled C++ SPE whereas the Coral SPE is a Python 3 SPE. I haven’t found a C++ API spec for the Edge TPU as yet. Perhaps by investigating the SWIG-generated Python interface I could link the compiled libraries directly but that’s for another day…