@divyansh and I have gotten object detection to work with fastai v1. The dev notebook is at https://github.com/rohitgeo/singleshotdetector
This creates a Dynamic SSD based on the number of grid cells, zoom levels and aspect ratios for the anchor boxes.
We haven’t trained the network fully in the dev notebook… like unfreezing and fine-tuning, and using Focal Loss (which is supported) etc, but are getting good results already. Hope you find it useful!
See Dynamic SSD implementation for fastai v1 for more details.