In the field of object detection, the anchor box is an auxiliary tool for defining the position and size of the object.Object detection algorithms usually use convolutional neural networks (CNNs) to identify objects in images, and anchor boxes are predefined rectangular boxes at different locations and sizes.

Anchor boxes help the model learn the location and size changes of objects, allowing it to adapt to objects of different shapes and sizes. By using multiple anchor boxes, the model can detect multiple objects and classify and locate them. This technique is commonly used in object detection algorithms such as Faster R-CNN and YOLO.