A MODIFIED PROJECTIVE TRANSFORMATION SCHEME FOR MOSAICKING MULTI-CAMERA IMAGING SYSTEM EQUIPPED ON A LARGE PAYLOAD FIXED- WING UAS
A MODIFIED PROJECTIVE TRANSFORMATION SCHEME FOR MOSAICKING MULTI-CAMERA IMAGING SYSTEM EQUIPPED ON A LARGE PAYLOAD FIXED- WING UAS
复制标题
大有效载荷固定翼无人机镶嵌多相机成像系统改进的投影变换方案
DOI：
10.5194/isprsarchives-xl-3-w2-87-2015
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
J. Rau
中科院分区：
文献类型：
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作者：
J. Jhan;Yi Tang Li;J. Rau
近年来，无人机系统（Unmanned Aerial System，UAS）被广泛应用于测绘、灾害调查、植被监测等航空影像的采集。无人机系统是一种机动性高、操作风险低的平台，但由于无人机载荷小、作业时间短，降低了影像采集效率。在这项研究中，一个最低点和四个倾斜的消费级数码单反相机组成的多相机系统配备在一个大的有效载荷无人机，这是旨在收集大的地面覆盖图像的有效方式。视场（FOV）增加到127度，从而适合于山区灾害图像的采集。合成采集的五幅图像被配准和拼接为更大格式的虚拟图像，以减少图像的数量、后处理时间和更容易的立体绘制。该方法不采用传统的图像匹配和光束法平差估计变换参数的方法，而是标定多摄像机的IOP和ROP，并推导出用于图像拼接的改进投影变换（MPT）模型的系数。然而，由于室内环境条件的不同以及无人机的振动，室内标定的IOP和ROP存在一定的不确定性，这将导致初始MPT结果的误配准效应。剩余残差通过初始MPT结果重叠区域上的连接点匹配进行分析，其中引入位移和尺度差异并进行校正，以修改ROP和IOP，从而获得更精细的配准结果。在本实验中，经过系统误差校正后，拼接图像的内部精度优于0.5个像素。通过严格的空中三角测量，对独立相机和镶嵌图像进行了比较，其中5个控制点和9个检查点的RMSE在平面和垂直方向上分别小于5cm和10cm。实践证明，所设计的成像系统和方案具有制作大比例尺地形图的潜力。
In recent years, Unmanned Aerial System (UAS) has been applied to collect aerial images for mapping, disaster investigation, vegetation monitoring and etc. It is a higher mobility and lower risk platform for human operation, but the low payload and short operation time reduce the image collection efficiency. In this study, one nadir and four oblique consumer grade DSLR cameras composed multiple camera system is equipped on a large payload UAS, which is designed to collect large ground coverage images in an effective way. The field of view (FOV) is increased to 127 degree, which is thus suitable to collect disaster images in mountainous area. The synthetic acquired five images are registered and mosaicked as larger format virtual image for reducing the number of images, post processing time, and for easier stereo plotting. Instead of traditional image matching and applying bundle adjustment method to estimate transformation parameters, the IOPs and ROPs of multiple cameras are calibrated and derived the coefficients of modified projective transformation (MPT) model for image mosaicking. However, there are some uncertainty of indoor calibrated IOPs and ROPs since the different environment conditions as well as the vibration of UAS, which will cause misregistration effect of initial MPT results. Remaining residuals are analysed through tie points matching on overlapping area of initial MPT results, in which displacement and scale difference are introduced and corrected to modify the ROPs and IOPs for finer registration results. In this experiment, the internal accuracy of mosaic image is better than 0.5 pixels after correcting the systematic errors. Comparison between separate cameras and mosaic images through rigorous aerial triangulation are conducted, in which the RMSE of 5 control and 9 check points is less than 5 cm and 10 cm in planimetric and vertical directions, respectively, for all cases. It proves that the designed imaging system and the proposed scheme have potential to create large scale topographic map.
DOI：
10.3390/rs5041875
发表时间：
2013-04
期刊：
Remote. Sens.
影响因子：
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作者：
A. Tommaselli;M. Galo;M. V. A. Moraes;J. Marcato;C. R. Caldeira;R. Lopes
通讯作者：
A. Tommaselli;M. Galo;M. V. A. Moraes;J. Marcato;C. R. Caldeira;R. Lopes