- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Geometric Calibration of Markerless Optical Surgical Navigation System
摘要： Background: Patient-to-image registration is required for image-guided surgical navigation, but marker-based registration is time consuming and subject to manual error. Markerless registration is an alternative solution to avoid these issues. Methods: This study designs a calibration board and proposes a geometric calibration method to calibrate the near infrared tracking and structured light components of the proposed optical surgical navigation system simultaneously. Results: A planar board and a cylinder are used to evaluate the accuracy of calibration. The mean error for the board experiment is 0.035 mm, and the diameter error for the cylinder experiment is 0.119 mm. A calibration board is reconstructed to evaluate the accuracy of the calibration, and the measured mean error is 0.012 mm. A head phantom is reconstructed and tracked by the proposed optical surgical navigation system. The tracking error is less than 0.3 mm. Conclusions: Experimental results show that the proposed method obtains high accessibility and accuracy and satisfies application requirements.
关键词： Calibration,Markerless,Structure light,Optical surgical navigation system
更新于2025-09-23 15:23:52
-
[IEEE 2019 16th China International Forum on Solid State Lighting & 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS) - Shenzhen, China (2019.11.25-2019.11.27)] 2019 16th China International Forum on Solid State Lighting & 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS) - Influence of the Charge Transfer on the Lifetime of Quantum-Dot Light-Emitting Diodes
摘要： A more natural means of communicating complex movements to a robot manipulator is where the manipulator copies the movements of human hands. This paper presents a markerless human–robot interface that incorporates Kalman ?lters (KFs) and particle ?lters (PFs) to track the posture of human hands. This method allows one operator to control dual robot manipulators by using his/her double hands without any contact devices or markers. The algorithm employs Leap Motion to determine the orientation and the position of the human hands. Although the position and the orientation of the hands can be obtained from the sensor, the measurement errors increase over time due to the noise of the devices and the tracking error. The PFs and KFs are used to estimate the position and the orientation of the human hand. Due to the limitations of the perception and the motor, a human operator cannot accomplish high-precision manipulation without any assistance. An adaptive multispace transformation is employed to assist the operator to improve the accuracy and reliability in determining the posture of the manipulator. The greatest advantage of this method is that the posture of the human hands can be estimated accurately and steadily without any assistant markers. The human-manipulator interface system was experimentally veri?ed in a laboratory, and the results indicate that such an interface can successfully control dual robot manipulators even if the operator is not an expert.
关键词： particle ?lter (PF),Kalman ?lter (KF),Human–robot interface,markerless
更新于2025-09-19 17:13:59
-
AR Enabled IoT for a Smart and Interactive Environment: A Survey and Future Directions
摘要： Accompanying the advent of wireless networking and the Internet of Things (IoT), traditional augmented reality (AR) systems to visualize virtual 3D models of the real world are evolving into smart and interactive AR related to the context of things for physical objects. We propose the integration of AR and IoT in a complementary way, making AR scalable to cover objects everywhere with an acceptable level of performance and interacting with IoT in a more intuitive manner. We identify three key components for realizing such a synergistic integration: (1) distributed and object-centric data management (including for AR services); (2) IoT object-guided tracking; (3) seamless interaction and content interoperability. We survey the current state of these respective areas and herein discuss research on issues about realizing a future smart and interactive living environment.
关键词： augmented reality,Internet of Things,interaction,IoT,markerless,tracking,AR,marker
更新于2025-09-16 10:30:52
-
Frequency response of the leap motion controller and its suitability for measuring tremor
摘要： Although tremor is one of the most common movement disorders, it is evaluated using relatively coarse clinical scales. We propose to measure tremor in clinical settings using the Leap Motion Controller (LMC), which is a markerless motion capture sensor that has a low cost, zero set-up time, and dynamic accuracy of 1.2 mm. However, the frequency response of the LMC has not been characterized, so its ability to track oscillations such as tremor is unknown. To characterize the frequency response of the LMC, we measured the position of a mannequin hand simultaneously with the LMC and a high-resolution encoder while the mannequin hand oscillated at various combinations of frequency (1–15 Hz) and amplitudes (0.01–30 mm). We calculated the magnitude ratio and phase shift of the LMC and found the bandwidth of the LMC to range from 0–3 Hz to 0–5 Hz for tremor amplitudes greater than the dynamic accuracy. This bandwidth is too small to accurately measure most tremors. However, we developed an inverse ?lter to estimate the actual tremor amplitude and phase despite the limited bandwidth. Over the combinations of frequency and amplitude mentioned above, the inverse ?lter estimated the actual tremor amplitude and phase with errors of 3% and 2%, respectively.
关键词： Markerless motion capture,Frequency response,Tremor,Leap motion controller
更新于2025-09-09 09:28:46
-
Development of a markerless tumor-tracking algorithm using prior four-dimensional cone-beam computed tomography
摘要： Respiratory motion management is a huge challenge in radiation therapy. Respiratory motion induces temporal anatomic changes that distort the tumor volume and its position. In this study, a markerless tumor-tracking algorithm was investigated by performing phase recognition during stereotactic body radiation therapy (SBRT) using four-dimensional cone-beam computer tomography (4D-CBCT) obtained at patient registration, and in-treatment cone-beam projection images. The data for 20 treatment sessions (five lung cancer patients) were selected for this study. Three of the patients were treated with conventional flattening filter (FF) beams, and the other two were treated with flattening filter-free (FFF) beams. Prior to treatment, 4D-CBCT was acquired to create the template projection images for 10 phases. In-treatment images were obtained at near real time during treatment. Template-based phase recognition was performed for 4D-CBCT re-projected templates using prior 4D-CBCT based phase recognition algorithm and was compared with the results generated by the Amsterdam Shroud (AS) technique. Visual verification technique was used for the verification of the phase recognition and AS technique at certain tumor-visible angles. Offline template matching analysis using the cross-correlation indicated that phase recognition performed using the prior 4D-CBCT and visual verification matched up to 97.5% in the case of FFF, and 95% in the case of FF, whereas the AS technique matched 83.5% with visual verification for FFF and 93% for FF. Markerless tumor tracking based on phase recognition using prior 4D-CBCT has been developed successfully. This is the first study that reports on the use of prior 4D-CBCT based on normalized cross-correlation technique for phase recognition.
关键词： markerless,phase recognition,tumor tracking,4D-CBCT
更新于2025-09-09 09:28:46