Measurement Of Critical Optical Properties For Near-eye Display Based On Imaging Light Measuring Device

With the development of display technology,VR/AR goggle,typically known as near-eye display(NED)device,has become more and more popular due to its portability,excellent user experience,wild application,etc.As the market share of near-eye display devices increases,measurement of NED has been paid more and more attention.According to investigation,NED mesurement methods/devices available have more or less drawbacks such as being able to measure only one of the optical properties,ambiguous measurement process,long measurement time consuming,high cost,etc.Thus,small-medium enterprices of NED product can only use expert judgement method to control product quality instead,which is not only time-consuming and painstaking,but also bringing hidden dangers.Therefore,this paper aims to use Ix MD as measuring device,supplemented by necessary hardware and software system,to measure several selected critical properties which most represents the optical presentation quality of NED.It’s supposed to build an automated and low-cost NED measurement system,providing fast,convenient and relatively accurate measurement for critical optical properties of NED,for reference and application.The main achivements of this paper are summarized as follows.Firstly,measurement method for critical NED optical properties based on Ix MD has been built.The whole mesurement method and process has been built for measurement of critical NED optical properties,including field of view(FOV),luminance/luminance uniformity,chromaticity/chromaticity uniformity,distortion and Michelson contrast,using Ix MD as measuring device.Also,detail information such as generation of test images and preparations before measurement has been included.These specific methods have provided clear guidance for building of the measurement system.Secondly,a hardware measurement system,combined by a head-imitation frame and a CMOS camera,has been designed and optimized.The system consists of a head-imitation frame,a binocular CMOS camera and a computer,and some optimization methods has been given.Thanks to this configuration,the measurement system is suitable for different NED devices which have various form factor,also provides convenient wearing position adjustment and alignment of NED.Thirdly,an interactive software system has been composed using Qt creator and Open CV Library.The software measurement system with visual interface has been composed using Qt creator and Open Source Computer Vision Library(Open CV).The functions include camera monitoring and capture,NED wearing position check,nine measuring position extract,measurement for critical optical properties,data storage,etc.Some key codes of the program have been given.Lastly,the accuracy,repeatability and error of the measurement system has been proved by measuring and confirmatory experiments to meet the requirements.The hardware and software system were combined into a complete measuring system for NED measurement.Experiments have been conducted to evaluate the accuracy,repeatability and sorce of error of this measuring system.According to experimental results,measuring one NED device using this system costs less than 30 min,and was easy to operate.Basically,Error of multi-measurements was less than 10%,the result was repeatable.The average error of luminance calibration was less than 3.5%,and FOV and luminance measurement has been proved relatively high accuracy.In summary,the measurement method and measurement system for measuring critical NED optical properties has been built,based on Ix MD,supplemented by necessary software and hardware system.Finally,a series of rapid,convinient and accurate methods for optical measurement of NED has been built,providing low-cost optical evaluation plans for production and sales of NED,with a great application prospect.