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

TL;DR

This paper introduces a novel test-time pipeline called Prompt-based Test-Time Dehazing (PTTD) that enhances real-world image dehazing performance by adjusting feature statistics during inference, without complex training.

Contribution

The paper proposes a model-agnostic, test-time dehazing pipeline using prompt generation and feature adaptation to improve real image dehazing from synthetic-trained models.

Findings

PTTD outperforms state-of-the-art methods in real-world scenarios.

Feature statistic adjustment effectively narrows the domain gap.

The approach is compatible with various dehazing models.

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}.