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Prompt-based test-time real image dehazing: a novel pipeline

Zixuan Chen, Zewei He, Ziqian Lu, Xuecheng Sun, Zhe-Ming Lu

TL;DR

A novel pipeline called Prompt-based Test-Time Dehazing (PTTD) is presented to help generate visually pleasing results of real-captured hazy images during the inference phase, achieving superior performance against state-of-the-art dehazing methods in real-world scenarios.

Abstract

Existing methods attempt to improve models' generalization ability on real-world hazy images by exploring well-designed training schemes (\eg, CycleGAN, prior loss). However, most of them need very complicated training procedures to achieve satisfactory results. For the first time, we present a novel pipeline called Prompt-based Test-Time Dehazing (PTTD) to help generate visually pleasing results of real-captured hazy images during the inference phase. We experimentally observe that given a dehazing model trained on synthetic data, fine-tuning the statistics (\ie, mean and standard deviation) of encoding features is able to narrow the domain gap, boosting the performance of real image dehazing. Accordingly, we first apply a prompt generation module (PGM) to generate a visual prompt, which is the reference of appropriate statistical perturbations for mean and standard deviation. Then, we employ a feature adaptation module (FAM) into the existing dehazing models for adjusting the original statistics with the guidance of the generated prompt. PTTD is model-agnostic and can be equipped with various state-of-the-art dehazing models trained on synthetic hazy-clean pairs to tackle the real image dehazing task. Extensive experimental results demonstrate that our PTTD is effective, achieving superior performance against state-of-the-art dehazing methods in real-world scenarios. The code is available at \url{https://github.com/cecret3350/PTTD-Dehazing}.

Prompt-based test-time real image dehazing: a novel pipeline

TL;DR

A novel pipeline called Prompt-based Test-Time Dehazing (PTTD) is presented to help generate visually pleasing results of real-captured hazy images during the inference phase, achieving superior performance against state-of-the-art dehazing methods in real-world scenarios.

Abstract

Existing methods attempt to improve models' generalization ability on real-world hazy images by exploring well-designed training schemes (\eg, CycleGAN, prior loss). However, most of them need very complicated training procedures to achieve satisfactory results. For the first time, we present a novel pipeline called Prompt-based Test-Time Dehazing (PTTD) to help generate visually pleasing results of real-captured hazy images during the inference phase. We experimentally observe that given a dehazing model trained on synthetic data, fine-tuning the statistics (\ie, mean and standard deviation) of encoding features is able to narrow the domain gap, boosting the performance of real image dehazing. Accordingly, we first apply a prompt generation module (PGM) to generate a visual prompt, which is the reference of appropriate statistical perturbations for mean and standard deviation. Then, we employ a feature adaptation module (FAM) into the existing dehazing models for adjusting the original statistics with the guidance of the generated prompt. PTTD is model-agnostic and can be equipped with various state-of-the-art dehazing models trained on synthetic hazy-clean pairs to tackle the real image dehazing task. Extensive experimental results demonstrate that our PTTD is effective, achieving superior performance against state-of-the-art dehazing methods in real-world scenarios. The code is available at \url{https://github.com/cecret3350/PTTD-Dehazing}.
Paper Structure (16 sections, 3 equations, 10 figures, 4 tables, 1 algorithm)

This paper contains 16 sections, 3 equations, 10 figures, 4 tables, 1 algorithm.

Figures (10)

  • Figure 1: Different frameworks and their results on real-world hazy images. (a) Directly apply model trained on synthetic data to real hazy images (e.g., AECRNet wu2021CVPR); (b) Use synthetic and real data together to train the model and then apply it to real hazy images (e.g., PSD Chen2021CVPR, DAD Shao2020CVPR); (c) Our proposed PTTD; (d) A real hazy image; and (e-h) Processing results of state-of-the-art (SOTA) methods (AECRNet wu2021CVPR, PSD Chen2021CVPR, DAD Shao2020CVPR) and our proposed PTTD (by adopting pre-trained AECRNet wu2021CVPR). It can be observed that AECRNet-PTTD achieves very promising results.
  • Figure 2: (a) is a real hazy input; (b) is the processing result of AECRNet wu2021CVPR, which is trained on synthetic data; (c) and (d) are the results by fine-tuning the mean $\mu$; (e) and (f) are the results by fine-tuning the standard deviation $\sigma$. In this experiment, the perturbation $\Delta$ is set to a small constant, i.e., $\Delta = 0.005$.
  • Figure 3: (a) The overall architecture of our Prompt-based Test-Time Dehazing (PTTD); (b) The proposed prompt generation module (PGM).
  • Figure 4: (a) A real hazy image $x_r$; (b) A haze-free image $y_s$; (c) Prompt via direct ILN (adaIN); (d) Prompt via ILN with partition; (e) Prompt via CBILN with partition.
  • Figure 5: Dehazing results of various methods on O-HAZE. We choose AECRNet-PTTD to compare with SOTA dehazing methods. Please zoom in on screen for a better view.
  • ...and 5 more figures