Shadow Removal and Relighting

Report on Current Developments in Shadow Removal and Relighting Research

General Direction of the Field

The recent advancements in shadow removal and relighting research are pushing the boundaries of what is possible in computer vision, particularly in enhancing scene understanding and photorealism. The field is moving towards more comprehensive and versatile solutions that address the complexities of both direct and indirect lighting conditions, as well as the intricacies of human portraits and facial performances.

  1. Integration of Semantic and Geometric Priors: A notable trend is the incorporation of semantic and geometric priors into shadow removal networks. This approach allows for more accurate and context-aware shadow removal, particularly in challenging indoor and outdoor scenes with complex lighting conditions. The use of attention mechanisms and concatenation techniques to integrate these priors is proving to be effective in improving the generalization and robustness of shadow removal methods.

  2. Generative Models for High-Fidelity Shadow Removal: There is a growing emphasis on using generative models, particularly diffusion models, for high-fidelity shadow removal in portraits. These models are capable of reconstructing human appearances from scratch, effectively handling the ill-posed nature of shadow removal in portraits. The integration of pre-trained models with compositional repurposing frameworks is enabling more natural and robust shadow removal, even in the presence of hard shadows and diverse lighting conditions.

  3. Test-Time Adaptation for Shadow Detection: The field is also witnessing advancements in test-time adaptation techniques for shadow detection. By leveraging light-intensity information during the testing phase, models can achieve more consistent and accurate shadow detection, even when faced with diverse real-world lighting conditions. This approach is particularly promising for enhancing the generalization capabilities of deep learning models in shadow detection.

  4. Diffusion-Based Facial Relighting: The use of diffusion models for facial relighting is emerging as a powerful tool for achieving high-fidelity and dynamic relighting of facial performances. These models allow for precise control over lighting conditions, enabling the creation of photorealistic images and sequences under complex lighting scenarios. The integration of advanced lighting representations and high dynamic range imaging further enhances the realism and versatility of these relighting techniques.

Noteworthy Papers

  • OmniSR: Introduces a novel rendering pipeline and dataset for comprehensive shadow removal under both direct and indirect lighting conditions, significantly advancing the field's ability to handle complex indoor and outdoor scenes.

  • Generative Portrait Shadow Removal: Proposes a generative diffusion model for high-fidelity portrait shadow removal, effectively addressing the limitations of existing methods by reconstructing human appearances from scratch.

  • Test-Time Intensity Consistency Adaptation for Shadow Detection: Presents a test-time adaptation framework that enhances shadow detection accuracy by leveraging light-intensity consistency, outperforming state-of-the-art methods in balanced error rate.

  • DifFRelight: Develops a diffusion-based framework for free-viewpoint facial performance relighting, achieving precise lighting control and high-fidelity relit facial images, advancing photorealism in facial relighting.

Sources

OmniSR: Shadow Removal under Direct and Indirect Lighting

Generative Portrait Shadow Removal

Test-Time Intensity Consistency Adaptation for Shadow Detection

DifFRelight: Diffusion-Based Facial Performance Relighting

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