An Effective and Robust Detector for Logo Detection

In recent years, intellectual property (IP), which represents literary, inventions, artistic works, etc, gradually attract more and more peoples attention. Particularly, with the rise of e-commerce, the IP not only represents the product design and brands, but also represents the images/videos displayed on e-commerce platforms. Unfortunately, some attackers adopt some adversarial methods to fool the well-trained logo detection model for infringement. To overcome this problem, a novel logo detector based on the mechanism of looking and thinking twice is proposed in this paper for robust logo detection. The proposed detector is different from other mainstream detectors, which can effectively detect small objects, long-tail objects, and is robust to adversarial images. In detail, we extend detectoRS algorithm to a cascade schema with an equalization loss function, multi-scale transformations, and adversarial data augmentation. A series of experimental results have shown that the proposed method can effectively improve the robustness of the detection model. Moreover, we have applied the proposed methods to competition ACM MM2021 Robust Logo Detection that is organized by Alibaba on the Tianchi platform and won top 2 in 36489 teams. Code is available at https://github.com/jiaxiaojunQAQ/Robust-Logo-Detection.

Improving Adversarial Transferability with Gradient Refining

Deep neural networks are vulnerable to adversarial examples, which are crafted by adding human-imperceptible perturbations to original images. Most existing adversarial attack methods achieve nearly 100% attack success rates under the white-box setting, but only achieve relatively low attack success rates under the black-box setting. To improve the transferability of adversarial examples for the black-box setting, several methods have been proposed, e.g., input diversity, translation-invariant attack, and momentum-based attack. In this paper, we propose a method named Gradient Refining, which can further improve the adversarial transferability by correcting useless gradients introduced by input diversity through multiple transformations. Our method is generally applicable to many gradient-based attack methods combined with input diversity. Extensive experiments are conducted on the ImageNet dataset and our method can achieve an average transfer success rate of 82.07% for three different models under single-model setting, which outperforms the other state-of-the-art methods by a large margin of 6.0% averagely. And we have applied the proposed method to the competition CVPR 2021 Unrestricted Adversarial Attacks on ImageNet organized by Alibaba and won the second place in attack success rates among 1558 teams.

Object Hider: Adversarial Patch Attack Against Object Detectors

Deep neural networks have been widely used in many computer vision tasks. However, it is proved that they are susceptible to small, imperceptible perturbations added to the input. Inputs with elaborately designed perturbations that can fool deep learning models are called adversarial examples, and they have drawn great concerns about the safety of deep neural networks. Object detection algorithms are designed to locate and classify objects in images or videos and they are the core of many computer vision tasks, which have great research value and wide applications. In this paper, we focus on adversarial attack on some state-of-the-art object detection models. As a practical alternative, we use adversarial patches for the attack. Two adversarial patch generation algorithms have been proposed: the heatmap-based algorithm and the consensus-based algorithm. The experiment results have shown that the proposed methods are highly effective, transferable and generic. Additionally, we have applied the proposed methods to competition Adversarial Challenge on Object Detection that is organized by Alibaba on the Tianchi platform and won top 7 in 1701 teams. Code is available at: https://github.com/FenHua/DetDak

Sparse Black-box Video Attack with Reinforcement Learning

Black-box adversarial attacks on video recognition models have been explored. Considering the temporal interactions between frames, a few methods try to select some key frames, and then perform attacks on them. Unfortunately, their selecting strategy is independent with the attacking step, resulting in the limited performance. Instead, we argue the frame selection phase is closely relevant with the attacking phase. The key frames should be adjusted according to the attacking results. For that, we formulate the black-box video attacks into Reinforcement Learning (RL) framework. Specifically, the environment in RL is set as the threat model, and the agent in RL plays the role of frame selecting. By continuously querying the threat models and receiving the attacking feedback, the agent gradually adjusts its frame selection strategy and adversarial perturbations become smaller and smaller. A series of experiments demonstrate that our method can significantly reduce the adversarial perturbations with efficient query times.