In this paper, we propose a novel model for the computational color constancy, inspired by the amazing ability of the human vision system (HVS) to perceive the color of objects largely constant as the light source color changes. The proposed model imitates the color processing mechanisms in the specific level of the retina, the first stage of the HVS, from the adaptation emerging in the layers of cone photoreceptors and horizontal cells (HCs) to the color-opponent mechanism and disinhibition effect of the non-classical receptive field in the layer of retinal ganglion cells (RGCs). In particular, HC modulation provides a global color correction with cone-specific lateral gain control, and the following RGCs refine the processing with iterative adaptation until all the three opponent channels reach their stable states (i.e., obtain stable outputs). Instead of explicitly estimating the scene illuminant(s), such as most existing algorithms, our model directly removes the effect of scene illuminant. Evaluations on four commonly used color constancy data sets show that the proposed model produces competitive results in comparison with the state-of-the-art methods for the scenes under either single or multiple illuminants. The results indicate that single opponency, especially the disinhibitory effect emerging in the receptive field's subunit-structured surround of RGCs, plays an important role in removing scene illuminant(s) by inherently distinguishing the spatial structures of surfaces from extensive illuminant(s).

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A highly efficient inverted organic light emitting diode using 1.0 nm-thick ZnIx as a hole-blocking layer is developed. We fabricate devices with the configuration ITO/ZnIx (1.0 nm)/Alq3 (50 nm)/NPB (50 nm)/MoO3 (6.0 nm)/Al (100 nm). The deposition of a ZnIx layer increases the maximum luminance by two orders of magnitude from 13.4 to 3566.1 cd/m2. In addition, the maximum current efficiency and power efficiency are increased by three orders of magnitude, and the turn-on voltage to reach 1 cd/m2 decreases from 13 to 8 V. The results suggest that the electron injection efficiency is not improved by introducing a ZnIx layer. Instead, the improved device performance originates from the strong hole-blocking ability of ZnIx. This work indicates that layered materials may lead to novel applications in optoelectronic devices.