Microsoft Corporation
Real-time adaptive shadow and highlight enhancement

Abstract:

An "Adaptive Exposure Corrector" performs automated real-time exposure correction of individual images or image sequences of arbitrary length. "Exposure correction" is defined herein as automated adjustments or corrections to any combination of shadows, highlights, high-frequency features, and color saturation of images. The Adaptive Exposure Corrector outputs perceptually improved images based on image ISO and camera ISO capabilities in combination with camera noise characteristics via exposure corrections by a variety of noise-aware image processing functions. An initial calibration process adapts these noise aware image processing functions to noise characteristics of particular camera models and types in combination with particular camera ISO settings. More specifically, this calibration process precomputes a Noise Aware Scaling Function (NASF) and a Color Scalar Function (CSF). The NASF and CSF are then applied to adapt various image processing functions that are subsequently applied to perform real-time noise-aware exposure corrections on images as those images are being captured.