Extended Kalman filter based hand-shake detector for optical image stabilization using a low cost gyroscope

Abstract

Application extended Kalman filter (EKF) based hand-shake detector to an optical image stabilization (OIS) stabilized by fuzzy sliding-mode controller (FSMC) is proposed in this paper to enhance the image sharpness and stabilization rate (SR) of digital cameras. A low-cost gyroscope is used to sense the hand-shake vibration independently in dual-axis and the EKF is designed to online tune the parameters of hand-shake detector for improving the phase-shift phenomenon. The proposed EKF based handshake detector determines the time-varying hand-shake vibration and adopts a multi-rate strategy to reduce the computational load. The developed OIS system equipped with the FSMC and EKF based hand-shake detector is implemented in a fixed-point 16-bit microcontroller. The OIS performance is improved by the EKF based hand-shake detector in the target frequency range 2-12 Hz, and the best SR is -30.46 dB at 8Hz and the largest improvement is 1.82 times (dB) at 2 Hz.