Detecting multiple objects in images and tracking them in videos Chris Fotache Dec 10 In my previous story, I went over how to train an image classifier in PyTorch , with your own images, and then use it for image recognition. Now I’ll show you how to use a pre-trained classifier to detect multiple objects in an image, and later track them across a video. What’s the difference between image classification (recognition) and object detection? In classification, you identify what’s the main object in the image and the entire image is classified by a single class. In detection, multiple objects are identified in the image, classified, and a location is also determined (as a bounding box). Object Detection in Images There are several algorithms for object detection, with YOLO and SSD among the most popular. For this story, I’ll use YOLOv3 . I won’t get into the technical details of how YOLO (You Only Look Once) works — you can read that here — but...