Single stage and two-stage target detection

       In the target detection algorithm , The process of the target frame from scratch and the frame change to a certain extent reflects that the detection is Two stages still Single stage Of .

Two-stage：

The first stage ： Focus on finding out where the target object appears , Get advice box , Ensure sufficient accuracy and recall

The second stage ： Focus on classifying suggestion boxes , Find a more precise location

Advantages and disadvantages ： Usually, the accuracy is high , But slower

Typical algorithm ：R-CNN、SPP-Net、Fast R-CNN and Faster R-CNN

One-stage：

The first stage ： Focus on finding out where the target object appears , Get advice box , Ensure sufficient accuracy and recall

The second stage ： Focus on classifying suggestion boxes , Find a more precise location

Advantages and disadvantages ： The speed is generally higher than Two-stage Algorithm faster , But there is a loss of accuracy

Typical algorithm ：SSD、YOLO