Impact of Downscaling On Adversarial Images

Under the sunlight, images displayed on a digital device are generally perceived to be darker than the original, which leads to a decrease in visibility. So, global luminance compensation or tone mapping adaptive to ambient lighting is required. However, global luminance compensation schemes usually have limitations in chrominance compensation as well as local contrast enhancement. This paper proposes a piece-wise linear curve (PLEC)-based image enhancement to enhance both luminance and chrominance. PLECs are regressed through deep learning. in addition, we present a local contrast enhancement scheme for further visibility improvement. Experimental results show that the proposed method outperforms a prior art in terms of subjective/objective visual quality, with significant run-time reduction.