Abstract: In this paper, we propose augmented reality (AR) applications for equipment maintenance. The system is based on the projection and detection of infrared markers. We use an infrared projector to project markers onto the surface of the equipment to be maintained. These markers are invisible to the human-eye, but they could be clearly identified by the infrared camera. As a proof of concept, we have implemented a prototype camera system consisting of a conventional camera (scene camera) and an infrared camera (tracking camera). The systempsilas viewpoint could be calculated and the visible image is captured simultaneously when using such a camera system. Some 3D models are overlaid on top of a video image. We demonstrate several applications of our method, including air filter replacement and gear-box maintenance for a milling machine.