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Title: Adapting Michelson Contrast for use with Optical See-Through Displays
Due to the additive light model employed by current optical see-through head-mounted displays (OST-HMDs), the perceived contrast of displayed imagery is reduced with increased environment luminance, often to the point where it becomes difficult for the user to accurately distinguish the presence of visual imagery. While existing contrast models, such as Weber contrast and Michelson contrast, can be used to predict when the observer will experience difficulty distinguishing and interpreting stimuli on traditional dis-plays, these models must be adapted for use with additive displays. In this paper, we present a simplified model of luminance contrast for optical see-through displays derived from Michelson's contrast equation and demonstrate two applications of the model: informing design decisions involving the color of virtual imagery and optimizing environment light attenuation through the use of neutral density filters.  more » « less
Award ID(s):
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
2022 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct)
Page Range / eLocation ID:
409 to 410
Medium: X
Sponsoring Org:
National Science Foundation
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Fig. 3(b) shows the tunneling probability T according to the Kane two-band model in the three materials, In0.53Ga0.47As, GaAs, and GaN, following our observation of a similar electroluminescence mechanism in GaN/AlN RTDs (due to strong polarization field of wurtzite structures) [8]. The expression is Tinter = (2/9)∙exp[(-2 ∙Ug 2 ∙me)/(2h∙P∙E)], where Ug is the bandgap energy, P is the valence-to-conduction-band momentum matrix element, and E is the electric field. Values for the highest calculated internal E fields for the InGaAs and GaN are also shown, indicating that Tinter in those structures approaches values of ~10-5. As shown, a GaAs RTD would require an internal field of ~6×105 V/cm, which is rarely realized in standard GaAs RTDs, perhaps explaining why there have been few if any reports of room-temperature electroluminescence in the GaAs devices. [1] E.R. Brown,et al., Appl. Phys. Lett., vol. 58, 2291, 1991. [5] S. Sze, Physics of Semiconductor Devices, 2nd Ed. 12.2.1 (Wiley, 1981). [2] M. Feiginov et al., Appl. Phys. Lett., 99, 233506, 2011. [6] L. Coldren, Diode Lasers and Photonic Integrated Circuits, (Wiley, 1995). [3] Y. Nishida et al., Nature Sci. Reports, 9, 18125, 2019. [7] E.O. Kane, J. of Appl. Phy 32, 83 (1961). [4] P. Fakhimi, et al., 2019 DRC Conference Digest. [8] T. Growden, et al., Nature Light: Science & Applications 7, 17150 (2018). [5] S. Sze, Physics of Semiconductor Devices, 2nd Ed. 12.2.1 (Wiley, 1981). [6] L. Coldren, Diode Lasers and Photonic Integrated Circuits, (Wiley, 1995). [7] E.O. Kane, J. of Appl. Phy 32, 83 (1961). [8] T. Growden, et al., Nature Light: Science & Applications 7, 17150 (2018). 
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