title: Near-Infrared Camera Calibration for Optical Surgical Navigation.
abstract: Near-infrared optical tracking devices, which are important components of surgical navigation systems, need to be calibrated for effective tracking. The calibration results has a direct influence on the tracking accuracy of an entire system. Therefore, the study of calibration techniques is of theoretical significance and practical value. In the present work, a systematic calibration method based on movable plates is established, which analyzes existing calibration theories and implements methods using calibration reference objects. First, the distortion model of near-infrared cameras (NICs) is analyzed in the implementation of this method. Second, the calibration images from different positions and orientations are used to establish the required linear equations. The initial values of the NIC parameters are calculated with the direct linear transformation method. Finally, the accurate internal and external parameters of the NICs are obtained by conducting nonlinear optimization. Analysis results show that the relative errors of the left and right NICs in the tracking system are 0.244 and 0.282 % for the focal lengths and 0.735 and 1.111 % for the principal points, respectively. The image residuals of the left and right image sets are both less than 0.01 pixel. The standard error of the calibration result is lower than 1, and the measurement error of the tracking system is less than 0.3 mm. The experimental data show that the proposed method of calibrating NICs is effective and can generate favorable calibration results.
authors.affiliation: School of Information Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China.
authors.forename: Ken
authors.initials: K
authors.lastname: Cai
authors.affiliation: Department of Biomedical Engineering, South China University of Technology, Guangzhou, 510006, China. bmeyrq@gmail.com.
authors.forename: Rongqian
authors.initials: R
authors.lastname: Yang
authors.affiliation: Department of Biomedical Engineering, South China University of Technology, Guangzhou, 510006, China.
authors.forename: Qinyong
authors.initials: Q
authors.lastname: Lin
authors.affiliation: Department of Biomedical Engineering, South China University of Technology, Guangzhou, 510006, China.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Liu
authors.affiliation: College of Science, Guilin University of Technology, Guilin, 541004, China.
authors.forename: Huazhou
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Radiology, General Hospital of Guangzhou Military Command of PLA, Guangzhou, 510010, China.
authors.forename: Shanxing
authors.initials: S
authors.lastname: Ou
authors.affiliation: School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering, South China University of Technology, Guangzhou, 510006, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000465:Algorithms; D002138:Calibration; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation* / Q000592:standards*; D007259:Infrared Rays; D013508:Ophthalmologic Surgical Procedures / Q000295:instrumentation*
keywords: Camera calibration; Near-infrared; Optical surgical navigation