In a imaging system such as digital still camera, gamma transformation is important, because of the difference of dynamic range between natural scene and printer. We propose gamma transformation by sigmoid function adjusted by the peak position of histogram of lightness level. It is confirmed that the sigmoid transformation increases the clearness of image.
Takashi Watanabe, Yasushi Hoshino, "Gamma Transformation by Sigmoid Function in Digital Camera System" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP16), 2000, pp 678 - 681, https://doi.org/10.2352/ISSN.2169-4451.2000.16.1.art00065_2