In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research a...In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research and development,camera calibration is achieved by extracting characteristic points of the laser plane,so that the calibra- tion efficiency is improved significantly.With feedback control of its intensity,the laser is automatically adjusted for different material.A modified algorithm is presented to improve the accuracy of laser stripe extraction.The fusion of data extracted from left and right camera is completed with re-sampling technique.The scanner is integrated with a robot arm and some other machinery for on-line measurement and inspection,which provides a flexible measurement tool for reverse engineering.展开更多
An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error....An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error. The receiver is fabricated in a 0.18μm CMOS process. Measurements show that the IQ phase error can be calibrated within 1°,which satisfies the system requirement.展开更多
Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should...Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should possess uniform background and contain marker shadow only, but in fact marker images always possess nonuniform background and are contaminated by noise and unwanted anatomic information, making the extraction very difficult. A target-orientated marker shadow extraction method was proposed. With this method a proper threshold for marker image binarization can be determined.展开更多
文摘In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research and development,camera calibration is achieved by extracting characteristic points of the laser plane,so that the calibra- tion efficiency is improved significantly.With feedback control of its intensity,the laser is automatically adjusted for different material.A modified algorithm is presented to improve the accuracy of laser stripe extraction.The fusion of data extracted from left and right camera is completed with re-sampling technique.The scanner is integrated with a robot arm and some other machinery for on-line measurement and inspection,which provides a flexible measurement tool for reverse engineering.
文摘An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error. The receiver is fabricated in a 0.18μm CMOS process. Measurements show that the IQ phase error can be calibrated within 1°,which satisfies the system requirement.
基金Project of Science and Technology Committee of Shanghai Municipality (No.2528(3))
文摘Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should possess uniform background and contain marker shadow only, but in fact marker images always possess nonuniform background and are contaminated by noise and unwanted anatomic information, making the extraction very difficult. A target-orientated marker shadow extraction method was proposed. With this method a proper threshold for marker image binarization can be determined.
