Object detection¶
Classification says what is in an image; detection also says where — a bounding box plus a class plus a confidence, for every object at once.
How YOLO-style detectors work¶
- The image is processed once by a CNN ("You Only Look Once") — fast enough for a robot's live camera.
- The network proposes boxes everywhere, scores each (class + confidence), and near-duplicate boxes are merged.
- Output per frame: a list like
ball (0.97) at [x, y, w, h].
From detection to behavior¶
A detection is just data — behavior comes from the loop around it:
- Detect the target in the frame.
- Compare its box position to the frame center → steering error.
- Compare its box size to a target size → distance, so speed.
- Repeat every frame — the perception → control loop.
This is exactly what the object detection practice builds, and why "follow me" robots feel alive.
Training your own detector¶
Same supervised recipe, richer labels: instead of a class per image you draw boxes per image. All the data lessons from supervised learning apply doubly — box quality is label quality.