Adaptive frame rate pattern projection for structured light 3D camera system

Structured light 3D camera systems are composed of a commercial video projector and a machine vision camera. High scan speed structured light 3D camera systems, suffers synchronization problems due to a mismatch in the projector screen refresh rate, and camera capturing speed. Commercial video projectors project with fixed refresh rate, frame rate of machine vision camera's increase or decrease with the resolution. Synchronization between projected frame and captured frame cannot be achieved through computer graphic's interface, due to limited control of hardware of computer. This paper presents a method to project structured light patterns and trigger for the camera according to camera frame rate and projector screen refresh rate. An adaptive frame rate pattern projection framework is implemented on Field Programmable Gate Array (FPGA), to achieve camera projector synchronization at any camera frame rate and projector refresh rate, which improves the accuracy of the point cloud.