Image-based optical miniaturized three-axis force sensor for cardiac catheterization

In order to determine the cause of and to treat an abnormal heart rhythm, electrophysiological studies and ablation procedures of the heart sensorized catheters are required. During catheterization, force sensors at the tip of the catheter are essential to provide quantitative information on the interacting force between the catheter tip and the heart tissue. In this paper, we are proposing a small sized, robust, and low-cost three-axis force sensor for the catheter tip. The miniaturized force sensor uses the fiber-optic technology (small sized multi-cores optical fiber and a CCD camera based on image processing to read out the forces by measuring light intensity, which are modulated as a function of the applied force. In addition, image processing techniques and a Kalman filter are used to reduce the noise of the light intensity signals. In this paper, we explain the design and fabrication of our three-axis force sensor and our approach for reducing noise levels by applying a Kalman filter model, and finally discuss the calibration procedure. Moreover, we provide an assessment of the performance of the proposed sensor.