The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships ...The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships between image pairs.Methods based on geometric transformation estimation usually perform affine transformation of the global image for viewpoint correction,which not only increases the time complexity but also generates a large number of redundant features.To solve this problem,this paper proposes an adaptive affine transformation model(AATM)to achieve robust image matching by dividing special regions with pixel information and employing feature extraction algorithms with different granularities.First,the input image is divided into significant and non-significant regions by an adaptive algorithm.Second,for the salient region,the feature point extraction is accelerated by optimizing the longitude angle sampling algorithm and constructing the affine invariant nonlinear scale space,introducing the Hessian integral image and box filter.Then,for the non-significant region of the weak texture scene through the uniform step sampling algorithm,a dense feature description can be obtained in the weak texture scenes,so that more robust features are extracted for both significant and non-significant regions.The results of extensive experiments on two datasets show that the AATM algorithm outperforms similar algorithms in terms of the number of correctly matched pairs,elapsed time,and root mean square error(RMSE),indicating that the AATM can obtain more robust matches in scenes with large angle tilting and scale transformations.展开更多
In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechani...In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechanical anisotropy was investigated.The results revealed that the alloy tube contains the high content(Mg1-xZnx)11Ce phase and the low content of Mg12Ce phase.These second phases are respectively incoherent and coherent with the Mg matrix,and their influence can be ignored.Additionally,the alloy tube exhibited a weak basal fiber texture,where the c-axis was aligned along the 0°∼30°tilt from TD to ED.Such a texture made the initial deformation(at 1.0%∼1.6%strain)of the three samples controlled by comparable basalslip.As deformation progressed(1.6∼9.0%strain),larger amounts of ETWs nucleated and gradually approached saturation in the three samples,re-orienting the c-axis to a 0°∼±30°deviation with respect to the loading directions.Meanwhile,the prismatic and pyramidal<c+a>slips replaced the dominant deformation progressively until fracture.Eventually,the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates,resulting in the low compressive anisotropy of the alloy tube.展开更多
基金Supported by the National Natural Science Foundation of China(No.61971162,61771186)the Natural Science Foundation of Heilongjiang Province(No.PL2024 F023)+1 种基金the Fundamental Scientific Research Funds of Heilongjiang Province(No.2022-KYYWF-1050)the Open Research Fund of National Mobile Communications Research Laboratory in Southeast University(No.2023D07).
文摘The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships between image pairs.Methods based on geometric transformation estimation usually perform affine transformation of the global image for viewpoint correction,which not only increases the time complexity but also generates a large number of redundant features.To solve this problem,this paper proposes an adaptive affine transformation model(AATM)to achieve robust image matching by dividing special regions with pixel information and employing feature extraction algorithms with different granularities.First,the input image is divided into significant and non-significant regions by an adaptive algorithm.Second,for the salient region,the feature point extraction is accelerated by optimizing the longitude angle sampling algorithm and constructing the affine invariant nonlinear scale space,introducing the Hessian integral image and box filter.Then,for the non-significant region of the weak texture scene through the uniform step sampling algorithm,a dense feature description can be obtained in the weak texture scenes,so that more robust features are extracted for both significant and non-significant regions.The results of extensive experiments on two datasets show that the AATM algorithm outperforms similar algorithms in terms of the number of correctly matched pairs,elapsed time,and root mean square error(RMSE),indicating that the AATM can obtain more robust matches in scenes with large angle tilting and scale transformations.
基金supported by the National Natural Science Foundation of China(Nos.51974082,51901037)State Key Laboratory of Baiyunobo Rare Earth Resource Research and Comprehensive Utilization(No.2021H2279)Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project 2.0 of China,No.BP0719037).
文摘In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechanical anisotropy was investigated.The results revealed that the alloy tube contains the high content(Mg1-xZnx)11Ce phase and the low content of Mg12Ce phase.These second phases are respectively incoherent and coherent with the Mg matrix,and their influence can be ignored.Additionally,the alloy tube exhibited a weak basal fiber texture,where the c-axis was aligned along the 0°∼30°tilt from TD to ED.Such a texture made the initial deformation(at 1.0%∼1.6%strain)of the three samples controlled by comparable basalslip.As deformation progressed(1.6∼9.0%strain),larger amounts of ETWs nucleated and gradually approached saturation in the three samples,re-orienting the c-axis to a 0°∼±30°deviation with respect to the loading directions.Meanwhile,the prismatic and pyramidal<c+a>slips replaced the dominant deformation progressively until fracture.Eventually,the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates,resulting in the low compressive anisotropy of the alloy tube.
