Abstract: An antenna impedance matching design circuit includes a load circuit, a filter circuit and a matching circuit which are connected to each other. The load circuit is connected to one end of the filter circuit for connecting a near field communication chip, and the matching circuit includes a plurality of capacitors.

Abstract: A method and system for calibrating extrinsic parameters between a depth camera and a visible light camera. Acquiring depth images and visible light images of the checkerboard plane in different transformation poses; determining visible light checkerboard planes of different transformation poses in a coordinate system of the visible light camera and depth checkerboard planes of different transformation poses in a coordinate system of the depth camera; determining a rotation matrix from the coordinate system of the depth camera to the coordinate system of the visible light camera; determining a translation vector from the coordinate system of the depth camera to the coordinate system of the visible light camera; rotating and translating the coordinate system of the depth camera, so that the coordinate system of the depth camera coincides with the coordinate system of the visible light camera to complete the extrinsic calibration of the dual cameras.