JBE, vol. 27, no. 5, pp.812-815, September, 2022

DOI: https://doi.org/10.5909/JBE.2022.27.5.812

Image Enhancement based on Piece-wise Linear Enhancement Curves for Improved Visibility under Sunlight

Junmin Lee and Byung Cheol Song

C.A E-mail: bcsong@inha.ac.kr

Abstract:

Images displayed on a digital devices under the sunlight are generally perceived to be darker than the original images, which leads to a decrease in visibility. For better visibility, global luminance compensation or tone mapping adaptive to ambient lighting is required. However, the existing methods have limitations in chrominance compensation and are difficult to use in real world due to their heavy computational cost. To solve these problems, this paper propose a piece-wise linear curves (PLECs)-based image enhancement method to improve both luminance and chrominance. At this time, PLECs are regressed through deep learning and implemented in the form of a lookup table to real-time operation. Experimental results show that the proposed method has better visibility compared to the original image with low computational cost.

Keyword: ambient-lighting, visibility improvement, piece-wise linear curve, look up table

Reference:
[1] J. Kim, C. Son, C. Lee and Y. Ha, "Illuminant Adaptive Color Reproduction Based on Lightness Adaptation and Flare for Mobile Phone.", International Conference on Image Processing, Atlanta, GA, USA, pp. 1513-1516, 2006. doi: https://doi.org/10.1109/ICIP.2006.312570
[2] Schlick, Christophe, “Quantization Techniques for Visualization of High Dynamic Range Pictures.”, Photorealistic Rendering Techniques. Springer, Berlin, Heidelberg, Germany, pp.7-20,1995. doi: https://doi.org/10.1007/978-3-642-87825-1_2
[3] R. Mantiuk, S. Daly, and L. Kerofsky, "Display adaptive tone mapping.", ACM SIGGRAPH 2008 papers, No.68, pp.1-10, August, 2008. doi: https://doi.org/10.1145/1399504.1360667
[4] H. Su, C. Jung, S. Wang and Y. Du, "Readability Enhancement of Displayed Images Under Ambient Light," IEEE Transactions on Circuits and Systems for Video Technology, Vol. 28, No. 7, pp. 1481-1496, July 2018. doi: https://doi.org/10.1109/TCSVT.2017.2676881
[5] Jan. Bauer, “Effiziente und optimierte Darstellungen von Infor- mationen auf Grafikanzeigen im Fahrzeug: Situationsadaptive Bildaufbereitungsalgorithmen und intelligente Backlightkonzepte.”, KIT Scientific Publishing, Germany, 2013.
[6] E. Reinhard et al., “High dynamic range imaging: acquisition, display, and image-based lighting.”, Morgan Kaufmann, Burlington, Massachusetts, USA, 2010.

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