arXiv:2607.24291eess.SPeess.IV2026-07中稿 · publication in IEE…

提出鲁棒方差稳定方法,提升无参考RAW去噪的准确性和稳定性。

RPG-VST: Robust Poisson-Gaussian Variance Stabilization for Blind RAW Denoising

  • 用学生-t分布和物理约束估计噪声参数,抗干扰更强。
  • 在六个数据集上平均提升PSNR,严重性能下降案例减少至4例以下。
  • 无需干净参考图或学习阈值,适合真实场景盲去噪应用。

广义安斯科姆变换(GAT)可将泊松-高斯(PG)RAW噪声转化为近似高斯噪声,使冻结的高斯去噪器得以处理,但其可靠性依赖于拟合的采样/读出噪声参数。在无参考单图部署中,这些参数通常从低纹理RAW统计量中估计,而这些统计量常受残余纹理、截断、坏点及读出噪声底限污染。此类污染导致对数方差残差呈现重尾分布,使得普通最小二乘法(OLS)校准方法脆弱,即便平均PSNR表现良好,仍会出现严重尾部失败。我们提出RPG-VST,一种用于盲态RAW去噪的鲁棒无参考方差稳定框架。RPG-VST利用学生-t对数方差目标函数与鲁棒分块统计量,分别对每个色彩滤波阵列(CFA)通道估计PG参数,并通过分块方差比估计稳定域噪声水平σ_z,作为可靠性信号。对于每张图像,RPG-VST根据哪种拟合方式使σ_z更接近单位方差,自动选择鲁棒拟合或传统OLS拟合,无需干净参考或学习阈值。在SID Sony SID$50$、SIDD和ELD数据集上,使用冻结的SwinIR和Restormer去噪器,RPG-VST在所有六组设置中均提升了平均PSNR;在四组中减少了严重尾部(定义为相较于直接去噪增益低于$-1$ dB的情况),其余两组保持不变。在SIDD上,提升达$+1.83/+1.92$ dB,严重尾部由$44/36$降至$7/4$。消融实验表明,σ_z门控有效防止了未加门控的鲁棒拟合在读出噪声主导的ELD捕获中出现退化。

原文摘要 · Abstract (English)

Variance stabilization with the generalized Anscombe transform (GAT) enables frozen Gaussian denoisers to process Poisson--Gaussian (PG) RAW noise, but its reliability depends on fitted shot/read-noise parameters. In blind single-image deployment, these parameters are estimated from low-texture RAW statistics that are often corrupted by residual texture, clipping, defective pixels, and read-noise floors. Such contamination yields heavy-tailed log-variance residuals, making ordinary least-squares PG calibration brittle and causing severe tail failures despite favorable average PSNR. We propose RPG-VST, a robust no-reference variance-stabilization framework for blind RAW denoising. RPG-VST estimates PG parameters separately for each color filter array (CFA) plane using a Student-$t$ log-variance objective with robust tile statistics and physical constraints. It then estimates the stabilized-domain noise level $σ_z$ from tile variance ratios and uses it as a reliability signal. For each image, RPG-VST selects the robust fit or the conventional OLS fit according to which produces $σ_z$ closer to unit variance, requiring no clean reference or learned threshold. On SID Sony SID$50$, SIDD, and ELD with frozen SwinIR and Restormer denoisers, RPG-VST improves mean PSNR in all six dataset--backbone settings. It reduces severe tails, defined as cases whose PSNR gain over Direct is below $-1$ dB, in four settings and leaves them unchanged in the other two. On SIDD, it yields $+1.83/+1.92$ dB and reduces severe tails from $44/36$ to $7/4$. Ablations show that the $σ_z$ gate prevents regressions of ungated robust fitting on read-noise-dominated ELD captures.

RAW去噪方差稳定鲁棒估计无参考

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