subtopic

Detection vs classification and the success metric

Learn the difference: classification says WHAT is in the image (Project 1); detection says WHAT and WHERE (a box around each object); segmentation marks the exact pixels. For safety we need detection: find every head with or without a helmet. Decide the score: mAP@0.5 overall and recall on 'head' (no helmet), because missing an unsafe worker is worse than a false alarm.