Collimating Illumination and Piezoelectric Transducer based 3D Intraoral Scanner

Furqan Ullah,박강,이건수 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

Due to the restrictions of size and volume on the 3D scanner for dental applications, it is not easy to perform non-contact profile scanning in the mouth cavity. In this paper, a piezoelectric transducer and collimating illumination based 3D intraoral scanner is presented for the measurement of tooth profiles in the mouth cavity. The phase-shifting technique is used along with an accurate calibration method for the measurement of the tooth profile. Experimental and theoretical inspection of the phase-to-coordinate relation is presented. In addition, a nonlinear system model is proposed for collimating illumination that gives a more accurate mathematical representation of the system, thus improving the shape measurement accuracy. Simulation and optical measurement results are presented to verify the feasibility and performance of the developed system.

Model Analysis of fringe-projection-based 3D Measurement Systems using Real-time 3D Virtual Scanner

Furqan Ullah(펄칸 울라),Kang Park(박강) (사)한국CDE학회 2012 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2012 No.2

This paper presents a real-time 3D virtual scanning system based on fringe projection technique. In this system, four models of 3D measurement systems are evaluated based on collimating and perspective projections. Once the intensity variations of the projected fringe pattern are captured using a perspective camera, the wrapped phase is obtained by performing the phase-shifting technique. However, the obtained phase is in the range of [-π, +π] along with discontinuities. In order to unwrap it to obtain a continuous phase map, a conventional phase-unwrapping algorithm is used. Experimental and theoretical inspection of the phase-to-coordinate relation for all four cases is presented. Nonlinear system models are proposed for the collimating projection and finally, the coordinate acquisition, reconstruction, and display processes are performed in the real-time virtual environment, and results are presented to verify the proposed approaches.

Society of CAD/CAM Engineers 2013

Furqan Ullah,Kang Park (사)한국CDE학회 2013 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2013 No.8

프린지 투영법을 이용한 실시간 3D 구강 내 스캐너의 개발

Furqan Ullah,이건수(Gunn Soo Lee),박강(Kang Park) (사)한국CDE학회 2012 한국CDE학회 논문집 Vol.17 No.3

Real-time three-dimensional shape measurement is becoming increasingly important in various fields, including medical sciences, high-technology industry, and microscale measurements. However, there are not so many 3D profile tools specially designed for specifically narrow space, for example, to scan the tooth shape of a human jaw. In this paper, a real-time 3D intraoral scanner is proposed for the measurement of tooth profile in the mouth cavity. The proposed system comprises a laser diode beam, a micro charge-coupled device, a graticule, a piezoelectric transducer, a set of optical lenses, and a polhemus device sensor. The phase-shifting technique is used along with an accurate calibration method for the measurement of the tooth profile. Experimental and theoretical inspection of the phase-to-coordinate relation is presented. In addition, a nonlinear system model is developed for collimating illumination that gives the more accurate mathematical representation of the system, thus improves the shape measurement accuracy. Experiment results are presented to verify the feasibility and performance of the developed system. The experimental results indicate that overall measurement error accuracy can be controlled within 0.4 ㎜ with a variability of ±0.01.

Development of a Surface-based Virtual Dental Sculpting Simulator with Multimodal Feedback

Furqan Ullah,박강 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

This paper presents a surface-based virtual dental sculpting simulator based on sensory modalities like visual, auditory and haptic sensation. The simulator can be used to perform different dental procedures such as grinding, drilling, or surface scrubbing, and gain experience of using various virtual dental tools of different shapes. The surface-based dental model, which is extracted from a commercial 3D dental laser scanner, is used for simulating sculpting processes at less memory cost. Large amount of triangular mesh data is contained in scanned models; therefore, a model reduction algorithm is proposed for large triangular mesh data. For the computation of repulsive force feedback, a spring-damper force model with a force filter is used. Vertex deformation method is implemented along with an enhanced bi-tri subdivision method of triangles to perform precision sculpting simulation. In order to make the mesh regular, a number of mesh refinement algorithms are performed. Finally,considering the fidelity, stability, computer efficiency, and update rate of the haptic display, it can be concluded that these multimodal realities based virtual system can generate stable simulation of material removal from a human tooth model with realistic auditory, visual, and force sensations.

Development of a Surface-based Virtual Dental Sculpting Simulator with Multimodal Feedback

Ullah, Furqan,Park, Kang Korean Society for Precision Engineering 2013 International Journal of Precision Engineering and Vol.14 No.4

This paper presents a surface-based virtual dental sculpting simulator based on sensory modalities like visual, auditory and haptic sensation. The simulator can be used to perform different dental procedures such as grinding, drilling, or surface scrubbing, and gain experience of using various virtual dental tools of different shapes. The surface-based dental model, which is extracted from a commercial 3D dental laser scanner, is used for simulating sculpting processes at less memory cost. Large amount of triangular mesh data is contained in scanned models; therefore, a model reduction algorithm is proposed for large triangular mesh data. For the computation of repulsive force feedback, a spring-damper force model with a force filter is used. Vertex deformation method is implemented along with an enhanced bi-tri subdivision method of triangles to perform precision sculpting simulation. In order to make the mesh regular, a number of mesh refinement algorithms are performed. Finally, considering the fidelity, stability, computer efficiency, and update rate of the haptic display, it can be concluded that these multimodal realities based virtual system can generate stable simulation of material removal from a human tooth model with realistic auditory, visual, and force sensations.

Virtual Dental Treatment Training System using a Haptic Device

Furqan Ullah(펄칸울라),Kang Park(박강) (사)한국CDE학회 2009 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2009 No.2

Digital Fringe Projection based Real - time 3D Shape Measurement System

Furqan Ullah,Kang Park(박강) (사)한국CDE학회 2013 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2013 No.1

We are presenting a digital fringe projection based 3D shape measurement system which is capable of performing small and large scale measurements in real-time and can be applied to various applications. The coordinates acquisition, reconstruction, and display processes are performed, simultaneously and quickly. In addition, a real-time virtual 3D scanner is developed in order to calibrate and analyze the proposed system precisely. Optical and simulation measurement results are presented to verify the feasibility and performance of the developed system.

Collimating Illumination and Piezoelectric Transducer based 3D Intraoral Scanner

Ullah, Furqan,Lee, Gun Soo,Park, Kang Korean Society for Precision Engineering 2013 International Journal of Precision Engineering and Vol.14 No.4

Due to the restrictions of size and volume on the 3D scanner for dental applications, it is not easy to perform non-contact profile scanning in the mouth cavity. In this paper, a piezoelectric transducer and collimating illumination based 3D intraoral scanner is presented for the measurement of tooth profiles in the mouth cavity. The phase-shifting technique is used along with an accurate calibration method for the measurement of the tooth profile. Experimental and theoretical inspection of the phase-to-coordinate relation is presented. In addition, a nonlinear system model is proposed for collimating illumination that gives a more accurate mathematical representation of the system, thus improving the shape measurement accuracy. Simulation and optical measurement results are presented to verify the feasibility and performance of the developed system.

Integrated Tracking and Accident Avoidance System for Mobile Robots

Irfan Ullah,Furqan Ullah,Qurban Ullah,신서용 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.6

In the intelligent transportation field, various accident avoidance techniques have been applied. One of the most common issues with these is the collision, which remains an unsolved problem. To this end, we developed a Collision Warning and Avoidance System (CWAS), which was implemented in the wheeled mobile robot. Path planning is crucial for a mobile robot to perform a given task correctly. Here, a tracking system for mobile robots that follow an object is presented. Thus, we implemented an integrated tracking system and CWAS in a mobile robot. Both systems can be activated independently. Using the CWAS, the robot is controlled through a remotely controlled device, and collision warning and avoidance functions are performed. Using the tracking system, the robot performs tasks autonomously and maintains a constant distance from the followed object. Information on the surroundings is obtained through range sensors, and the control functions are performed through the microcontroller. The front, left, and right sensors are activated to track the object, and all the sensors are used for the CWAS. The proposed system was tested using the binary logic controller and the Fuzzy Logic Controller (FLC). The efficiency of the robot was improved by increasing the smoothness of motion via the FLC, achieving accuracy in tracking and increasing the safety of the CWAS. Finally, simulations and experimental outcomes have shown the usefulness of the system.