Study On The Mechanism And Key Technology Of The Wide-Gamut And Low-power Display

As the most popular interactive terminals in human's daily life,displays have been running on their way of high-speed technical progress and innovation under the basement of all the breakthroughs in several fields including chemical materials,electronic circuits,manufacturing and et al.in recent decades.In order to fulfil the audiences'strict requirements for visual experience,display devices are leading towards multi-dimensional goals including higher spatio-temporal resolution,higher dynamic range,wider gamut and lower power consumption.Especially the last two have become hotspots currently in the industry field.However,although those emerging technologies do update fast,there are always compatibility issues and image artifacts needed optimization in their preliminary stage.To solve these problems,several research of power optimization,color gamut management,visual artifacts,subjective picture quality evaluation in newly developed display technologies were studied in this thesis.The main work and conclusion of it can be summarized into five aspects as listed below:1.A high accuracy measurement system was established for recording temporal luminance response curves of displays.By purposeful software programming,the system can complete several types of measurement tasks automatically,which dramatically improves monitor measurement efficiency.Based on the response data sampled by the system metioned above,the motion blur artifact of AMLCD(Active Matrix Liquid Crystal Display)was simulated precisely.At the meantime,the overdrive lookup table was also built to improve LCD's dynamic image quality.Using the system's dual-channel measurement scheme,crosstalk phenomenon was suppressed and the stereoscopic performance of SG(Shutter Glasses)type 3D displays was promoted.2.According to the metamerism in HVS(Human visual system),an optimized design of backlight spectrum as well as color filter transmittance spectral distribution for transmissive display system was proposed based on linear programming method.This algorithm calculated the maximum theoretical luminous efficiency when the original gamut of display was kept undamaged.Its simulation results provide valuable parameter standards and reference for the light source devices in low-power backlight unit.3.The gamut shell of display in L~*a~*b~*color space was searched and recorded successfully by applying a discrete-point method.Based on that,the mapping transformation of nature images between different display gamuts was implemented and integrated in our color management tool.With the help of this tool,performance of 4 classic gamut mapping algorithms were evaluated and compared.According to the gamut mapping idea,a new gray level transformation program for RGBW devices was proposed,which can reduce the color desaturation degree and cause little distortion in achromatic situations.4.By designing subjective perceptual experiments,the image quality of several new-developed display techniques were fully evaluated and compared,including OLED(Organic Light-Emitting Diode),Local Dimming,QD(Quantum Dot),HDR(High Dynamic Range)and et al.Perception features of the above devices were described,merits and drawbacks of the corresponding technology were also analyzed to give some suggestions for the further development of next generation of display.5.The mechanism of FSC(Field Sequential Color)display,which has been a promising candidate structure of wide-gamut and low-power display system in the future,was studied deeply.By modeling the smooth pursuit eye movement,the generation procedure of CBU(Color Breakup)artifact in FSC devices was analyzed carefully.The simulation and reproduction of CBU was also achieved precisely.A perceptual experiment was conducted to investigate the thresholds of CBU visibility among different sub-field primaries.From the experimental result an anisotropy of HVS sensitivity in temporal color fusion can be inferred.This conclusion will play a pivotal role in related aspects of optical engineering including FSC display design,LED lighting system construction or even visual health protection.At last,a CBU suppression method was proposed.By intentionally bring proper motion compensation degree in each sub-field,CBU artifact can be suppressed so remarkably that subjects feel almost imperceptible of it,which in turn improve the image quality of FSC devices.