Helmet-mounted display image quality evaluation system

Helmet-mounted displays (HMDs) provide essential pilotage and fire control imagery information for pilots. To maintain system integrity and readiness, there is a need to develop an image quality evaluation system for HMDs. In earlier work, a framework was proposed for an HMD system called the integrated helmet and display sighting system (IHADSS), used with the U.S. Army´s Apache helicopter. This paper describes prototype development and interface design and summarizes bench test findings using three IHADSS helmet display units (HDUs). The prototype consists of hardware (cameras, sensors, image capture/data acquisition cards, battery pack, HDU holder, moveable rack and handle, and computer) and software algorithms for image capture and analysis. Two cameras with different-size apertures are mounted in parallel on a rack facing an HDU holder. A handle allows users to position the HDU in front of the two cameras. The HMD test pattern is then captured. Sensors detect the position of the holder and whether the HDU is angled correctly in relation to the camera. Algorithms detect HDU features captured by the two cameras, including focus, orientation, displacement, field-of-view, and number of grayshades. Bench testing of three field-quality HDUs indicates that the image analysis algorithms are robust and able to detect the desired image features. Suggested future directions include development of a learning algorithm to automatically develop or revise feature specifications as the number of inspection samples increases.