Research On The Optical Performance Detection Method And System Of The Helmet Display

The helmet mounted display(HMD)is a commonly used military equipment and has begun to expand into the civilian sector in recent years.The human eye will directly observe the exit image when equipped with it.Therefore,defects in its optical performance will pose a threat to the health and safety of users,with serious consequences.At present,the detection of the HMD is mostly the process inspection,and the detection process is mostly for the visual inspection of the inspection personnel using the instrument.The test results lack objectivity.Therefore,it is necessary to study the automatic optical detection equipment of the HMD.This paper first analyzes the display principle and structure of the HMD,and then develops the inspection project according to relevant standards.The automatic detection methods of optical parameters such as optical axis parallelism,relative image tilt,field of view and distortion were analyzed,and the overall detection scheme of the equipment was developed.The modules of the testing equipment were designed,the parameters of each device were determined,and the design and selection were completed.In order to achieve automatic detection of optical axis parallelism,relative image tilt,and field of view,it is necessary to obtain the posture of the cross division in the detected image and the position coordinates.The position of the crosshair is extracted by threshold segmentation,and the line resolution is obtained by hough transform fitting,thus completing the detection of the crosshair attitude.In order to achieve automatic detection of distortion,it is necessary to extract the center coordinate of the center cross and its reticle length,and the center coordinates of each edge detection cross.The coordinates of the center cross and the length of the reticle are obtained in the same manner as the above-mentioned detection items,and the center coordinates of the remaining detection crosses are located by the gray center of gravity method,and the distortion detection is completed.Finally,under the Visual Studio 2010 platform,the automatic detection software was written,and the function of detecting and saving the query detection data was realized.After the equipment was built,the test was carried out.A smart eyeglass type HMD was tested using a calibrated HMD inspection device.The results were then compared to those obtained by other traditional methods.It indicates that the device detection function is accurate and reliable.