Large-scale text-to-image generation models with an exponential evolution can currently synthesize high-resolution, feature-rich, high-quality images based on text guidance. However, they are often overwhelmed by words of new concepts, styles, or object entities that always emerge. Although there are some recent attempts to use fine-tuning or prompt-tuning methods to teach the model a new concept as a new pseudo-word from a given reference image set, these methods are not only still difficult to synthesize diverse and high-quality images without distortion and artifacts, but also suffer from low controllability. To address these problems, we propose a DreamArtist method that employs a learning strategy of contrastive prompt-tuning, which introduces both positive and negative embeddings as pseudo-words and trains them jointly. The positive embedding aggressively learns characteristics in the reference image to drive the model diversified generation, while the negative embedding introspects in a self-supervised manner to rectify the mistakes and inadequacies from positive embedding in reverse. It learns not only what is correct but also what should be avoided. Extensive experiments on image quality and diversity analysis, controllability analysis, model learning analysis and task expansion have demonstrated that our model learns not only concept but also form, content and context. Pseudo-words of DreamArtist have similar properties as true words to generate high-quality images.
Object detection, as a fundamental computer vision task, has achieved a remarkable progress with the emergence of deep neural networks. Nevertheless, few works explore the adversarial robustness of object detectors to resist adversarial attacks for practical applications in various real-world scenarios. Detectors have been greatly challenged by unnoticeable perturbation, with sharp performance drop on clean images and extremely poor performance on adversarial images. In this work, we empirically explore the model training for adversarial robustness in object detection, which greatly attributes to the conflict between learning clean images and adversarial images. To mitigate this issue, we propose a Robust Detector (RobustDet) based on adversarially-aware convolution to disentangle gradients for model learning on clean and adversarial images. RobustDet also employs the Adversarial Image Discriminator (AID) and Consistent Features with Reconstruction (CFR) to ensure a reliable robustness. Extensive experiments on PASCAL VOC and MS-COCO demonstrate that our model effectively disentangles gradients and significantly enhances the detection robustness with maintaining the detection ability on clean images.