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Abstract The gamut and EOTF (Electro-Optical Transfer Function) of a display together determine its color performance. Gamut determines the range of displayable colors, and the EOTF determines the color accuracy and depth. Image reproduction often comprises two parts: the image source and the display terminal. To ensure the universality of different terminals, the image source is generally produced in a standardized gamut standard, while the terminal pursues a wider gamut and more spectacular color performance. As a widely welcomed form of display, WCGDs (Wide Color Gamut Displays) boast stunning color performance. However, certain colors in WCGDs displays are oversaturated, which is unacceptable to the human eye. This paper analyzes the oversaturation problem of WCGDs. Firstly, a display model based on EOTF and gamut parameters is established. Then the color point vector field varies with EOTF is derived and the drift of luminance and chromaticity are analyzed separately. Finally, two strategies are present to optimize the color oversaturation problem of WCGDs based on the analysis conclusions and verify its effectiveness. This paper presents a detailed analysis and possible strategy for color oversaturation in WCGDs, providing a theoretical basis for the accurate color reproduction and efficient color management of WCGDs.

Abstract In this paper, a theoretical model is presented for the display process of uniformly-arranged virtual-pixel LED displays with RGBG sub-pixel structure cells. Such displays' modulation transfer function (MTF) is derived theoretically from this model. Experiments were conducted to validate the theoretical model to measure the MTF of virtual-pixel displays and traditional real-pixel displays with a pixel pitch of 0.9 mm. A dual-line spread function measurement method is proposed, which is experimentally shown to be more effective than the conventional single-line LSF measurement method in measuring the MTF of LED displays. The rationality of the theoretical model was analyzed and compared through experiments. Furthermore, a combined subjective and objective evaluation method for the image quality of LED sub-pixel displays is proposed, which analyses the effect of LED sub-pixel multiplexing on the display clarity based on the square root integration method and achieves the subjective goal of quantifying the LED display quality. The research results reveal the theoretical and experimental aspects of virtual-pixel displays and may have practical significance for the design of high-quality LED displays.

This paper proposes a Field Programmable Gate Array (FPGA)-based control system to implement micro-light-emitting diode (micro-LED) real-time display. The control system includes the interface control, video processing, memory management, image data transmission, control signal generation and correction. Then, we implement the micro-LED real-time display via memory management. We propose the brightness correction to achieve high grey-scale and high uniformity display. The LEDs are mounted on the glass substrate prepared using low-temperature polysilicon (LTPS) technology, and then we find the 24 × 46 pixels micro-LED panel. And the control system has been successfully applied to the panel of glass-based micro-LED displays. A new grey control method is proposed in this work, which can effectively improve the refresh rate of the micro-LED displays. The high grey-scale refresh rate is 2100 Hz, and the low grey-scale refresh rate is 300 Hz. The uniformity of the panel is increased to 85% after brightness correction.