FMNet: Frequency-Aware Modulation Network for SDR-to-HDR Translation

High-dynamic-range (HDR) media resources that preserve high contrast and more details in shadow and highlight areas in television are becoming increasingly popular for modern display technology compared to the widely available standard-dynamic-range (SDR) media resources. However, due to the exorbitant price of HDR cameras, researchers have attempted to develop the SDR-to-HDR techniques to convert the abundant SDR media resources to the HDR versions for cost-saving. Recent SDR-to-HDR methods mostly apply the image-adaptive modulation scheme to dynamically modulate the local contrast. However, these methods often fail to properly capture the low-frequency cues, resulting in artifacts in the low-frequency regions and low visual quality. Motivated by the Discrete Cosine Transform (DCT), in this paper, we propose a Frequency-aware Modulation Network (FMNet) to enhance the contrast in a frequency-adaptive way for SDR-to-HDR translation. Specifically, we design a frequency-aware modulation block that can dynamically modulate the features according to its frequency-domain responses. This allows us to reduce the structural distortions and artifacts in the translated low-frequency regions and reconstruct high-quality HDR content in the translated results. Experimental results on the HDRTV1K dataset show that our FMNet outperforms previous methods and the perceptual quality of the generated HDR images can be largely improved. Our code is available at https://github.com/MCG-NKU/FMNet.