Główne pojęcia
PIE effectively learns from unpaired positive/negative samples and smoothly realizes non-semantic regional enhancement by incorporating physics-inspired contrastive learning and an unsupervised regional segmentation module.
Streszczenie
The paper proposes a physics-inspired contrastive learning approach called PIE for real-world cross-scene low-light image enhancement (LLE). It addresses three key challenges:
- Eliminating the need for pixel-correspondence paired training data and instead training with unpaired images.
- Incorporating physics-inspired contrastive learning for LLE and designing the Bag of Curves (BoC) method to generate more reasonable negative samples that closely adhere to the underlying physical imaging principle.
- Proposing an unsupervised regional segmentation module to maintain regional brightness consistency, realize region-discriminate enhancement, and eliminate the dependency on semantic ground truths.
PIE casts the image enhancement task as a multi-task joint learning problem, where LLE is converted into three constraints - contrastive learning, regional brightness consistency, and feature preservation, simultaneously ensuring the quality of global/local exposure, texture, and color.
Extensive experiments on six independent datasets demonstrate that PIE surpasses state-of-the-art LLE models in terms of visual quality, no and full-referenced image quality assessment, and human subjective survey. PIE also potentially benefits downstream tasks like semantic segmentation and face detection under dark conditions.
Statystyki
Capturing images under low illumination can lead to image details loss, color under-saturation, low contrast/low dynamic range, and uneven exposure.
Existing learning-based LLE methods often train a model with strict pixel-correspondence image pairs via strong supervision, which are challenging to acquire in practice.
The quality of negative samples and the specific contrastive learning strategy significantly impact the results of LLE.
The enhancement strategies for the background and foreground should be different, but the introduction of semantic segmentation destroys the universality and flexibility of the method.
Cytaty
"PIE effectively learns from unpaired positive/negative samples and smoothly realizes non-semantic regional enhancement by incorporating physics-inspired contrastive learning and an unsupervised regional segmentation module."
"We design the Bag of Curves (BoC) solution by leveraging the Image Signal Processing (ISP) pipeline (i.e., the Gamma correction and Tone mapping) to destroy positive samples but follow the basic imaging rules to generate negative samples."
"We introduce an unsupervised regional segmentation module that uses a super-pixel segmentation to maintain regional brightness consistency and enable region-discriminate enhancement while avoiding reliance on semantic labels."