Generation of High Dynamic Range Illumination from a Single Image for the Enhancement of Undesirably Illuminated Images

TL;DR

This paper introduces a single-image HDR illumination generation method that enhances poorly lit images by decomposing, scaling, and fusing illumination and reflectance components to produce visually appealing results.

Contribution

The novel algorithm generates virtual multi-exposure illuminations from one image and fuses them for improved image enhancement, with efficient computation and high-quality output.

Findings

Produces visually pleasing enhanced images

Achieves comparable objective results to traditional methods

Requires modest computational resources

Abstract

This paper presents an algorithm that enhances undesirably illuminated images by generating and fusing multi-level illuminations from a single image.The input image is first decomposed into illumination and reflectance components by using an edge-preserving smoothing filter. Then the reflectance component is scaled up to improve the image details in bright areas. The illumination component is scaled up and down to generate several illumination images that correspond to certain camera exposure values different from the original. The virtual multi-exposure illuminations are blended into an enhanced illumination, where we also propose a method to generate appropriate weight maps for the tone fusion. Finally, an enhanced image is obtained by multiplying the equalized illumination and enhanced reflectance. Experiments show that the proposed algorithm produces visually pleasing output and also yields comparable objective results to the conventional enhancement methods, while requiring modest computational loads.