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Bright-Channel Retinex Enhancement with a Conditional Overdispered-Noise Analysis

Aug 2026 · 0 citations · 22 references
Computer Science Engineering

TL;DR

A training-free low-light enhancement method that combines local bright-channel illumination estimation, Retinex division, and edge-preserving denoising and obtains mean PSNR/SSIM of 17.74dB/0.739, the highest values among the evaluated with conventional methods.

Abstract

I present a training-free low-light enhancement method that combines local bright-channel illumination estimation, Retinex division, and edge-preserving denoising. For a fixed illumination estimate, a conditional Negative -Binominal psueduo-count method characterises the heteroscedastic noise amplified by division. The unconstrained reflectance ratio is the pixelwise maximum-likelihood estimate, with a boundary solution for zero-valued observations; the implemented estimate additionally applies illumination filtering and range clipping. The NB model is a diagnostic noise analysis rather than a calibrated sensor model, and the final fixed-bandwidth bilateral filter is an empirical approximation rather than the exact Bayesian solution. On the LOL-v1 dataset, the methodobtains mean PSNR/SSIM of 17.74dB/0.739, the highest values among the evaluated with conventional methods. A 400X600 image is processed at approximately 43 FPS on an Apple M2 Pro CPU.

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