Edge detection and enhancement techniques are commonly used in recognizing the edge of geologic bodies using potential field data. We present a new edge recognition technology based on the normalized vertical derivati...Edge detection and enhancement techniques are commonly used in recognizing the edge of geologic bodies using potential field data. We present a new edge recognition technology based on the normalized vertical derivative of the total horizontal derivative which has the functions of both edge detection and enhancement techniques. First, we calculate the total horizontal derivative （THDR） of the potential-field data and then compute the n-order vertical derivative （VDRn） of the THDR. For the n-order vertical derivative, the peak value of total horizontal derivative （PTHDR） is obtained using a threshold value greater than 0. This PTHDR can be used for edge detection. Second, the PTHDR value is divided by the total horizontal derivative and normalized by the maximum value. Finally, we used different kinds of numerical models to verify the effectiveness and reliability of the new edge recognition technology.展开更多
Automatic weld seam tracking technology to be used in hyperbaric underwater damaged pipeline repair welding is much more important,because of poor bevel preparation and severe working condition.A weld seam tracking sy...Automatic weld seam tracking technology to be used in hyperbaric underwater damaged pipeline repair welding is much more important,because of poor bevel preparation and severe working condition.A weld seam tracking system based on digital signal processing(DSP)passive light weld image processing technology has been established.A convenient charge coupled device(CCD)camera system was used in the high pressure environment with the help of an aperture and focus altering mechanism to guarantee overall image visibility in the scope of pressure below 0.7 MPa.The system can be used in the hyperbaric environment to pick up the real welding image of both the welding arc and the welding pool.The newly developed DSP technology was adopted to achieve the goal of system real time characteristics.An effective weld groove edge recognition technique including narrow interesting window opening,middle value wave filtering,Sobel operator weld edge detecting and edge searching in a defined narrow area was proposed to remove the guide error and system accuracy was ensured.The results of tracking simulation and real tracking application with arc striking have proved the validity and the accuracy of the mentioned system and the image processing method.展开更多
基金supported by the National Science and Technology Major Projects (2008ZX05025)the Project of National Oil and Gas Resources Strategic Constituency Survey and Evaluation of the Ministry of Land and Resources,China (XQ-2007-05)
文摘Edge detection and enhancement techniques are commonly used in recognizing the edge of geologic bodies using potential field data. We present a new edge recognition technology based on the normalized vertical derivative of the total horizontal derivative which has the functions of both edge detection and enhancement techniques. First, we calculate the total horizontal derivative （THDR） of the potential-field data and then compute the n-order vertical derivative （VDRn） of the THDR. For the n-order vertical derivative, the peak value of total horizontal derivative （PTHDR） is obtained using a threshold value greater than 0. This PTHDR can be used for edge detection. Second, the PTHDR value is divided by the total horizontal derivative and normalized by the maximum value. Finally, we used different kinds of numerical models to verify the effectiveness and reliability of the new edge recognition technology.
基金supported by National Hi-tech Research and Development Program of China(863 program,Grant No.2002AA602012)National Natural Science Foundation of China(Grant No.40776054)Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality of China
文摘Automatic weld seam tracking technology to be used in hyperbaric underwater damaged pipeline repair welding is much more important,because of poor bevel preparation and severe working condition.A weld seam tracking system based on digital signal processing(DSP)passive light weld image processing technology has been established.A convenient charge coupled device(CCD)camera system was used in the high pressure environment with the help of an aperture and focus altering mechanism to guarantee overall image visibility in the scope of pressure below 0.7 MPa.The system can be used in the hyperbaric environment to pick up the real welding image of both the welding arc and the welding pool.The newly developed DSP technology was adopted to achieve the goal of system real time characteristics.An effective weld groove edge recognition technique including narrow interesting window opening,middle value wave filtering,Sobel operator weld edge detecting and edge searching in a defined narrow area was proposed to remove the guide error and system accuracy was ensured.The results of tracking simulation and real tracking application with arc striking have proved the validity and the accuracy of the mentioned system and the image processing method.
