Professor Howard, in the 2018 Advanced Course (Part 2) presented an example of SSD Single Shot Object Detection. It was a very interesting albeit complex notebook; unfortunately, it was written in Fastai V0.7.
I have ported the SSD notebook into Fastai V1 and it works very well. You can find it in my GitHub at https://colab.research.google.com/github/jav0927/course-v3/blob/master/SSD_Object_Detection.ipynb
This was the most challenging model in the course and also a wonderful learning tool. I hope it will be of value to the community. In developing the model, I was inspired by previous work by Henin.