title: Kinect-Based Correction of Overexposure Artifacts in Knee Imaging with C-Arm CT Systems.
abstract: Objective. To demonstrate a novel approach of compensating overexposure artifacts in CT scans of the knees without attaching any supporting appliances to the patient. C-Arm CT systems offer the opportunity to perform weight-bearing knee scans on standing patients to diagnose diseases like osteoarthritis. However, one serious issue is overexposure of the detector in regions close to the patella, which can not be tackled with common techniques. Methods. A Kinect camera is used to algorithmically remove overexposure artifacts close to the knee surface. Overexposed near-surface knee regions are corrected by extrapolating the absorption values from more reliable projection data. To achieve this, we develop a cross-calibration procedure to transform surface points from the Kinect to CT voxel coordinates. Results. Artifacts at both knee phantoms are reduced significantly in the reconstructed data and a major part of the truncated regions is restored. Conclusion. The results emphasize the feasibility of the proposed approach. The accuracy of the cross-calibration procedure can be increased to further improve correction results. Significance. The correction method can be extended to a multi-Kinect setup for use in real-world scenarios. Using depth cameras does not require prior scans and offers the possibility of a temporally synchronized correction of overexposure artifacts. To achieve this, we develop a cross-calibration procedure to transform surface points from the Kinect to CT voxel coordinates.
authors: Pattern Recognition Laboratory, Computer Science Department 5, University of Erlangen-Nuremberg, 91058 Erlangen, Germany; Department of Informatics, Technical University of Munich, 85748 Garching bei München, Germany.
authors: Johannes
authors: 0000-0002-9409-4401
authors: J
authors: Rausch
authors: Pattern Recognition Laboratory, Computer Science Department 5, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
authors: Andreas
authors: 0000-0002-9550-5284
authors: A
authors: Maier
authors: Department of Radiology, Stanford University, Stanford, CA 94305, USA.
authors: Rebecca
authors: 0000-0001-9034-9449
authors: R
authors: Fahrig
authors: Department of Radiology, Stanford University, Stanford, CA 94305, USA.
authors: Jang-Hwan
authors: JH
authors: Choi
authors: Department of Radiology, Stanford University, Stanford, CA 94305, USA.
authors: Waldo
authors: W
authors: Hinshaw
authors: Pattern Recognition Laboratory, Computer Science Department 5, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
authors: Frank
authors: 0000-0002-7553-6390
authors: F
authors: Schebesch
authors: Pattern Recognition Laboratory, Computer Science Department 5, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
authors: Sven
authors: S
authors: Haase
authors: Pattern Recognition Laboratory, Computer Science Department 5, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
authors: Jakob
authors: J
authors: Wasza
authors: Pattern Recognition Laboratory, Computer Science Department 5, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
authors: Joachim
authors: J
authors: Hornegger
authors: Department of Radiology, Stanford University, Stanford, CA 94305, USA.
authors: Christian
authors: 0000-0002-5556-5338
authors: C
authors: Riess