Non-aligned supervision for Real Image Dehazing
arxiv 2023

The effectiveness of our method on hazy video

Abstract

Removing haze from real-world images is challenging due to unpredictable weather conditions, resulting in misaligned hazy and clear image pairs. In this paper, we propose a non-aligned supervision framework that consists of three networks - dehazing, airlight, and transmission. In particular, we explore a non-alignment setting by utilizing a clear reference image that is not aligned with the hazy input image to supervise the dehazing network through a multi-scale reference loss that compares the features of the two images. Our setting makes it easier to collect hazy/clear image pairs in real-world environments, even under conditions of misalignment and shift views. To demonstrate this, we have created a new hazy dataset called ”Phone-Hazy”, which was captured using mobile phones in both rural and urban areas. Additionally, we present a mean and variance self-attention network to model the infinite airlight using dark channel prior as position guidance, and employ a channel attention network to estimate the three-channel transmission. Experimental results show that our framework outperforms current state-of-the-art methods in the real-world image dehazing.

Method

Overall pipeline of our non-aligned supervision framework with physical priors for the real image dehazing. It includes the mvSA and non-aligned supervision modules. mvSA can effectively estimate the infinite airlight A∞ in real scenes. Our framework is different from the supervised dehazing models as it does not require aligned ground truths.

Results

Example results on the real-world non-homogeneous smoke dataset.

Example results on the real-world dense smoke dataset.

Comparison of dehazing results on the real-world Phone-Hazy dataset (rural scenery).

Comparison of dehazing results on the real-world Phone-Hazy dataset (urban roads).

Comparison of dehazing results on the real-world RTTS dataset (wilderness and city buidings).

(a) - (c) shows our model's visual results on the Phone-Hazy dataset, while (d) - (e) shows the visualization of our model's test results on RTTS dataset.

Citation

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Acknowledgements

Thanks to Ricardo Martin-Brualla and David Salesin for their comments on the text, and to George Drettakis and Georgios Kopanas for graciously assisting us with our baseline evaluation.
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