Characterization of Error Reduction in Mobile Liquid Crystal Display Using Distinct <italic>XYZ</italic> Electro-Optical Transfer Functions for Each Channel and Interchannel Components

Abstract

Most display characterization methods, such as the gain- offset-gamma model and S-curve model, generally assume that dis- plays have two fundamental characteristics, channel-chromaticity constancy and channel independence. Consequently, based on the assumption of channel-chromaticity constancy, only one electro- optical transfer function (EOTF) is used for each channel to estab- lish the relation between the digital input values and the output lu- minance levels. Meanwhile, based on the channel-independence assumption, the channel color values are simply summed to acquire mixed color values. However, these assumptions are not so appli- cable in the case of liquid crystal-based mobile displays. Accord- ingly, modifications are required to enable the application of conven- tional display characterization methods to mobile displays. Therefore, this study proposes the modeling of distinct EOTFs in terms of the X, Y, and Z values for each channel to consider the differences among the EOTFs resulting from channel-chromaticity inconstancy. In addition, to overcome the poor additivity property among the channels due to channel interaction, the proposed method also models and uses the EOTFs of the X, Y, and Z values for the interchannel components cyan, magenta, yellow, and gray. Experimental results confirm that the mobile display color values predicted by the proposed characterization method are more accu- rate than those predicted by other characterization methods due to considering the channel-chromaticity inconstancy and/or channel dependence of the display. © 2006 Society for Imaging Science and Technology. DOI: 10.2352/J.ImagingSci.Technol.200650:4349