Image Brightness Quantification for HDR

Images' brightness quantification is challenging due to the perceptual nature of brightness. In Standard Dynamic Range (SDR), the most common brightness quantification metrics are the Average Picture Level (APL) and the Frame Average Luminance Level (FALL). These metrics rely on simple image statistics and they adequately quantify SDR images' brightness. However, they fail to sufficiently characterize the High Dynamic Range (HDR) broader luminance range and larger color volume. In this work, we propose a novel HDR image brightness quantification metric that weights each pixel contribution to overall brightness based on their color intensity and location. The proposed method is computationally inexpensive, thus suitable for real time applications. Results show that the proposed method outperforms the state-of-the-art HDR brightness quantification metrics.