Rectangular stable power-aware mobile projection on planar surfaces

Abstract

Pico projectors are becoming increasingly popular and can be used in conjunction with handheld mobile devices, portable media players, digital cameras in the foreseeable future. Mobile projection provides new opportunities realizing mobile spatial augmented reality applications. Projection from handheld devices bring in challenges of stabilizing the imagery in the persence of hand movements which entails more complex problems like keystone, zoom and jitter correction. However, no suitable software interface exists today that integrates these pico-projectors with handheld mobile devices. This paper develops the first power-efficient software methods and interface to project a rectangular, stable image from a pico-projector augmented to a handheld mobile device that can allow users to make contents legible on such devices via real-time solutions for keystone correction, zoom and jitter correction. To provide power efficient solutions in the context of mobile power-sensitive devices, we achieve the keystone correction, zoom and hand-movement stabilization mostly using data from an inertial measurement unit (IMU) while minimizing the use of less power-efficient sensor like camera. For zoom stabilization, we use a very inexpensive low power distance sensor. The camera is used only for initialization. We have developed two prototype systems to show our software interface: the first one is implemented on cellphone running Android OS; and the second one used a raspberry pi interface to the projectors.