YOLO (2015), YOLOv2 (2016), and YOLOv3 (2018)

You Only Look Once (YOLO) is the most popular single-shot object detection model, primarily due to its never-ending improvement story. Even though the first version, called simply YOLO, was created before SSD architecture, it kept improving over the years. We will examine the long road the YOLO family achieved, along with the novelties and improvements each new version has.

Let’s start with the base architecture created in 2016.

YOLO architecture

As it is a single-shot detector, we already assume that the architecture achieves object detection at one step, likely as SSD. But when we check the architecture, we can see that it works in an even simpler way than SSD.