Fast C-arm projection image correction based on visual model

In view of the fact that the accuracy of computer-assisted surgery is impacted by the C-arm X-ray projection image distortion and the present distortion corrections are time-consuming, the paper proposes a visual model-based correction method for fast correction of C-arm X-ray projection distortion images. This method conducts the analysis of the sources and types of C-arm X-ray projection image distortion and treats the C-arm system calibration and projection distortion image correction as an integrate system firstly, and then, obtains the distortion parameters by using the Tsai method of visual model. Finally, the distortion images are corrected by using distortion parameters. The experimental results show that the maximum error is 8.81 pixels at 120 cm between the X-ray source to the detector. The maximum error is 9.09 pixels at 121 cm between the X-ray source to the detector. When the difference between the X-ray source to the detector is 18 mm, the result obtained by using this method is 18.11 mm and the error is 0.11 mm. The results are stable when the C-arm is at different postures. The method has the advantages of elimination of ideal image errors, simplicity in steps, and easy online usage.