Abstract:Convolutional Neural Network (CNN) has become the state-of-the-art for object detection task. In this paper, we have explained different object detection models based on CNN. We have categorized those detection models according to two different approaches: two-stage approach and one-stage approach. Through this paper, we have shown advancements in object detection model from R-CNN to latest RefineDet. We have discussed the model description and training details of each model. We have also drawn a comparison among those models.