A novel tie point matching algorithm of aerial images with the assistance of airborne LiDAR point clouds and POS data is proposed Firstly,the conjugate point searching strategy used in traditional correlation coeffici...A novel tie point matching algorithm of aerial images with the assistance of airborne LiDAR point clouds and POS data is proposed Firstly,the conjugate point searching strategy used in traditional correlation coefficient matching is improved and a fast algorithm is presented.Secondly,an automatic camera boresight misalignment calibration method based on virtual ground control points is proposed,and then the searching range of image matching is adaptively determined and applied to the image matching of the entire surveying area.Test results verified that the fast correlation coefficient matching algorithm proposed in this paper can reduce approximately 25% of the matching time without the loss of matching accuracy.The camera boresight misalignment calibration method can effectively increase the accuracy of exterior orientation elements of images calculated from POS data,and thus can significantly improve the predicted position of conjugate point for tie point matching.Our proposed image matching algorithm can achieve superior matching accuracy with multi-scale,multi-view,and cross-flight aerial images.展开更多
The City of Whittlesea is in Melbourne’s north and is one of the largest municipalities in metropolitan Melbourne. The council GIS team using current aerial photos from 2017 and LiDAR (“LiDAR” stands for Light Dete...The City of Whittlesea is in Melbourne’s north and is one of the largest municipalities in metropolitan Melbourne. The council GIS team using current aerial photos from 2017 and LiDAR (“LiDAR” stands for Light Detection and Ranging) point clouds 2009 products to identify trends in urban tree canopy cover in the established suburbs of the municipality between 2009 and 2017. The tree canopy coverage was calculated for residential properties, road reservations, public land and park sites within urban parts of Bundoora, Epping, Lalor, Mill Park, Thomastown, and South Morang. From the total project area of approximately 3499 hectares a test site was selected based on an extension of one of the LIDAR data tiles (e325n5828). This project investigates only 6 meters and higher tree canopy cover within the project area. The objectives of the project were to establish a methodology to calculate the urban tree canopy coverage from LiDAR 2009 data, that can be replicated in future calculations. The calculated urban tree canopy coverage from LiDAR 2009 data is 9%, compared to 8% coverage in 2017, based on aerial photography. This estimate was compared to similar Local Governance Areas that range from 12% to 40%. A key to planning and managing urban tree canopy is first to understand the quantity, quality, tree density and distribution of the resource across the landscape. Tree inventories and urban tree canopy analyses comprise an assortment of tools, technologies, and procedures that help us understand the structure and function of our urban tree canopy. The data and information gleaned from urban tree canopy assessments enable resource professionals and policymakers to make informed decisions about ordinances, housing diversity strategy, and budgeting, future tree planting programs and reduce urban heat islands.展开更多
基金The National Natural Science Foundation of China under Grants(41171292,41322010)The National Basic Research Program of China(973 Program)(2012CB719904).
文摘A novel tie point matching algorithm of aerial images with the assistance of airborne LiDAR point clouds and POS data is proposed Firstly,the conjugate point searching strategy used in traditional correlation coefficient matching is improved and a fast algorithm is presented.Secondly,an automatic camera boresight misalignment calibration method based on virtual ground control points is proposed,and then the searching range of image matching is adaptively determined and applied to the image matching of the entire surveying area.Test results verified that the fast correlation coefficient matching algorithm proposed in this paper can reduce approximately 25% of the matching time without the loss of matching accuracy.The camera boresight misalignment calibration method can effectively increase the accuracy of exterior orientation elements of images calculated from POS data,and thus can significantly improve the predicted position of conjugate point for tie point matching.Our proposed image matching algorithm can achieve superior matching accuracy with multi-scale,multi-view,and cross-flight aerial images.
文摘The City of Whittlesea is in Melbourne’s north and is one of the largest municipalities in metropolitan Melbourne. The council GIS team using current aerial photos from 2017 and LiDAR (“LiDAR” stands for Light Detection and Ranging) point clouds 2009 products to identify trends in urban tree canopy cover in the established suburbs of the municipality between 2009 and 2017. The tree canopy coverage was calculated for residential properties, road reservations, public land and park sites within urban parts of Bundoora, Epping, Lalor, Mill Park, Thomastown, and South Morang. From the total project area of approximately 3499 hectares a test site was selected based on an extension of one of the LIDAR data tiles (e325n5828). This project investigates only 6 meters and higher tree canopy cover within the project area. The objectives of the project were to establish a methodology to calculate the urban tree canopy coverage from LiDAR 2009 data, that can be replicated in future calculations. The calculated urban tree canopy coverage from LiDAR 2009 data is 9%, compared to 8% coverage in 2017, based on aerial photography. This estimate was compared to similar Local Governance Areas that range from 12% to 40%. A key to planning and managing urban tree canopy is first to understand the quantity, quality, tree density and distribution of the resource across the landscape. Tree inventories and urban tree canopy analyses comprise an assortment of tools, technologies, and procedures that help us understand the structure and function of our urban tree canopy. The data and information gleaned from urban tree canopy assessments enable resource professionals and policymakers to make informed decisions about ordinances, housing diversity strategy, and budgeting, future tree planting programs and reduce urban heat islands.