Research on binocular alignment measurement technology of helmet mounted display

As an important evaluation specification of the helmet mounted display, binocular alignment directly affects the imaging quality of the helmet mounted display, such as the imaging distance and the imaging clarity, and then has a vital impact on the combat effectiveness of the pilot and the aircraft. The traditional detection method relies on the human eye to align the collimator for subjective interpretation, the results are often uncertain because different people have different feelings. This paper proposes an automatic measurement method of binocular alignment based on a single digital camera. This method combines the binocular images of the helmet mounted display into the same optical path by placing a turning prism at the binocular exit pupil position of the helmet mounted display, thereby achieving the purpose of synchronously collecting binocular images by using a single digital camera. Digital image processing technology realizes automatic calculation of binocular alignment indicators, which greatly improves the measurement accuracy and the measurement efficiency. This method uses a turning prism to merge the binocular images of the helmet mounted display into one optical path. The camera can collect binocular images without moving during the measurement process, so it can avoid the straightness error caused by the use of a translation stage, and finally an objective, accurate and fast measurement of binocular alignment specification is obtained. At last, this article discusses the measurement principle of the method in detail, explains the optical-mechanical structure of the binocular alignment measurement equipment in detail, and analyzes the measurement accuracy. Finally, several binocular alignment test results are compared. The test results show that this method has obvious advantages in the measurement accuracy and the measurement efficiency. It can meet the needs of fast, accurate and objective measurement of the binocular alignment of the helmet mounted display, and has the value of a wide range of applications.