An embedded system for an eye-detection sensor

Real-time eye detection is important for many HCI applications, including eye-gaze tracking, autostereoscopic displays, video conferencing, face detection, and recognition. Current commercial and research systems use software implementation and require a dedicated computer for the image-processing task—a large, expensive, and complicated-to-use solution. In order to make eye-gaze tracking ubiquitous, the system complexity, size, and price must be substantially reduced. This paper presents a hardware-based embedded system for eye detection, implemented using simple logic gates, with no CPU and no addressable frame buffers. The image-processing algorithm was redesigned to enable highly parallel, single-pass image-processing implementation. A prototype system uses a CMOS digital imaging sensor and an FPGA for the image processing. It processes 640 × 480 progressive scan frames at a 60 fps rate, and outputs a compact list of sub-pixel accurate (x, y) eyes coordinates via USB communication. Experimentation with detection of human eyes and synthetic targets are reported. This new logic design, operating at the sensor’s pixel clock, is suitable for single-chip eye detection and eye-gaze tracking sensors, thus making an important step towards mass production, low cost systems.