Clipping-Based Post Training 8-Bit Quantization of Convolution Neural Networks for Object Detection

Fueled by the development of deep neural networks, breakthroughs have been achieved in plenty of computer vision problems, such as image classification, segmentation, and object detection. These models usually have handers and millions of parameters, which makes them both computational and memory expensive. Motivated by this, this paper proposes a post-training quantization method based on the clipping operation for neural network compression. By quantizing parameters of a model to 8-bit using our proposed methods, its memory consumption is reduced, its computational speed is increased, and its performance is maintained. This method exploits the clipping operation during training so that it saves a large computational cost during quantization. After training, this method quantizes the parameters to 8-bit based on the clipping value. In addition, a fully connected layer compression is conducted using singular value decomposition (SVD), and a novel loss function term is leveraged to further diminish the performance drop caused by quantization. The proposed method is validated on two widely used models, Yolo V3 and Faster R-CNN, for object detection on the PASCAL VOC, COCO, and ImageNet datasets. Performances show it effectively reduces the storage consumption at 18.84% and accelerates the model at 381%, meanwhile avoiding the performance drop (drop < 0.02% in VOC).