PPCensor: Architecture for real-time pornography detection in video streaming

Convolutional neural network (CNN) models are typically composed of several gigabytes of data, requiring dedicated hardware and significant processing capabilities for proper handling. In addition, video-detection tasks are typically performed offline, and each video frame is analyzed individually, meaning that the video's categorization (class assignment) as normal or pornographic is only complete after all the video frames have been evaluated. This paper proposes the Private Parts Censor (PPCensor), a CNN-based architecture for transparent and near real-time detection and obfuscation of pornographic video frame regions. Our contribution is two-fold. First, the proposed architecture is the first that addresses the detection of pornographic content as an object detection problem. The objective is to apply user-friendly content filtering such that an inevitable false positive will obfuscate only regions (objects) within the video frames instead of blocking the entire video. Second, the PPCensor architecture is deployed on dedicated hardware, and real-time detection is deployed using a video oriented streaming proxy. If a pornographic video frame is identified in the video, the system can hide pornographic content (private parts) in real time without user interaction or additional processing on the user's device. Based on more than 50,000 objects labeled manually, the evaluation results show that the PPCensor is capable of detecting private parts in near real time for video streaming. Compared to cutting-edge CNN architectures for image classification, PPCensor achieved similar results, but operated in real time. In addition, when deployed on a desktop computer, PPCensor handled up to 35 simultaneous connections without the need for additional processing on the end-user device. (c) 2020 Elsevier B.V. All rights reserved.