The principle and function of focus

yolov5 Medium Focus Module understanding _ Xiaocai's blog -CSDN Blog _focus structure

https://github.com/ultralytics/yolov5/issues/847

https://github.com/ultralytics/yolov5/issues/207

Design thinking ： In theory, from high-resolution images , Periodically extract pixels and reconstruct them into low resolution images , That is, stack the four adjacent positions of the image , focusing wh Dimension information to c Channel empty , Improve the receptive field of each point , And reduce the loss of original information . This component is not intended to increase the accuracy of the network , But to reduce the amount of calculation , Increase the speed .