OpenCV + Yolo DNN
https://docs.opencv.org/3.4.0/da/d9d/tutorial_dnn_yolo.html
How to easily Detect Objects with Deep Learning on Raspberry Pi
What’s new in YOLO v3
https://towardsdatascience.com/yolo-v3-object-detection-53fb7d3bfe6b
How to train YOLOv2 to detect custom objects
https://medium.com/@manivannan_data/how-to-train-yolov2-to-detect-custom-objects-9010df784f36
this test uses the number of 297 NFPA images for training.
How to train YOLOv3 to detect custom objects
https://medium.com/@manivannan_data/how-to-train-yolov3-to-detect-custom-objects-ccbcafeb13d2
coco dataset