How R-CNN works on object detection?

Region with Convolutional Neural Network (R-CNN) is proposed by Girshick et al. in 2013. It changed the object detection field fundamentally. By leveraging selective search, CNN and SVM, Girshick et al. achieved a very good result in VOC 2012. This story will introduce R-CNN while later series will cover Fast R-CNN, Faster R-CNN and Mask R-CNN that is introduced by Girshick and other team members as well. Besides, there are other objection detection approaches such as Single-Shot Object Detector (SSD) and You Only Look Once (YOLO). The objective of image classification is classifying the category of the whole image.