A mixed scheme based on Wavelet Transformation (WT) is proposed for image edge detection. The scheme combines the wavelet transform and traditional Sobel and LoG (Laplacian of Gaussian) operator edge-detection algorit...A mixed scheme based on Wavelet Transformation (WT) is proposed for image edge detection. The scheme combines the wavelet transform and traditional Sobel and LoG (Laplacian of Gaussian) operator edge-detection algorithms. The precise theory analysis is given to show that the wavelet transformation has an advantage for signal processing. Simulation results show that the new scheme is better than only using the Sobel or LoG methods. Complexity analysis is also given and the conclusion is acceptable, therefore the proposed scheme is effective for edge detection.展开更多
SHRIMP U-Pb zircon analyses for a gabbro sample from the Garzê ophiolite block yielded a mean 206Pb/238U age of 292±4 Ma, which indicated that the spread- ing time of the Garzê-Litang Tethys was most li...SHRIMP U-Pb zircon analyses for a gabbro sample from the Garzê ophiolite block yielded a mean 206Pb/238U age of 292±4 Ma, which indicated that the spread- ing time of the Garzê-Litang Tethys was most likely at the earliest Permian. Combined with previous studies, we sug- gest that the opening of the Tethys in southwest China was derived from breakup of the East Gondwanaland in the late Paleozoic.展开更多
基金Supported by the National Defence 973 project(2002HS0604,2002HS0634)
文摘A mixed scheme based on Wavelet Transformation (WT) is proposed for image edge detection. The scheme combines the wavelet transform and traditional Sobel and LoG (Laplacian of Gaussian) operator edge-detection algorithms. The precise theory analysis is given to show that the wavelet transformation has an advantage for signal processing. Simulation results show that the new scheme is better than only using the Sobel or LoG methods. Complexity analysis is also given and the conclusion is acceptable, therefore the proposed scheme is effective for edge detection.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.40472119 and 40172071)the Progranme of Excelent Young Scientists of the Ministry of Land and Resources,the Ministry of Science and Technology of the People's Republic of China(Grant No.2002CB412608)the China Geological Survey(Grant No.200313000057).
文摘SHRIMP U-Pb zircon analyses for a gabbro sample from the Garzê ophiolite block yielded a mean 206Pb/238U age of 292±4 Ma, which indicated that the spread- ing time of the Garzê-Litang Tethys was most likely at the earliest Permian. Combined with previous studies, we sug- gest that the opening of the Tethys in southwest China was derived from breakup of the East Gondwanaland in the late Paleozoic.
