基于加权Hash特征与卷积辅助网络的ACF行人检测研究

Research on ACF Pedestrian Detection Based on Improved Hash Code and Auxiliary CNN

传统的ACF+AdaBoost行人检测框架在达到较为理想的检测率时,误检率也会迅速增高,难以满足实际需求。针对该问题,本文提出了一种自适应加权的Hash码特征,用来增加行人特征的多样性。在此基础上,通过级联一个辅助网络降低系统的误检率,该辅助网络采用了浅层的CNN结构,在保证系统实时性的前提下对AdaBoost分类器的分类结果进行二次分类。在INRIA数据中进行检测实验的结果表明,改进的Hash码简单、易算,对行人的表征能力强,在不影响实时性的前提下,把系统的MR-FPPI(Miss rate against false positives per image)从17.05%降低到16.31%。系统级联辅助CNN后系统的MR-FPPI降低到16.93%,而加入Hash码通道,且级联辅助CNN后,系统的MR-FPPI降低到15.96%,检测性能得到较为明显的提高。

When the traditional ACF + AdaBoost pedestrian detection framework achieves a better detection rate, the false detection rate will also increase rapidly;and it is difficult to meet the actual demand. In order to solve this problem, we proposed an adaptive weighted Hash Code feature to increase the diversity of pedestrian features. Beside this, an auxiliary network is designed to reduce the false detection rate of the system. The proposed auxiliary network uses a shallow CNN structure to re-classify the results of AdaBoost detector on the premise of ensuring the real-time performance of the system. The results of experiments performed in INRIA dataset show that the improved Hash Code is simple, easy to calculate, and has a strong ability to characterize pedestrians. Without affecting real-time performance ,the system has MR-FPPI ( Miss Rate against False Positives per Image) from 17. 05% to 16. 31%. After cascading the CNN classifier, the MR-FPPI of the system is reduced to 16. 93%. When the Hash Code channel and cascading assisted CNN are both utilized, the MR-FPPI of the system is reduced to 15. 96%. The detection performance has significant improvement compared with the traditional ACF + Adaboost system.