Research On Height Estimation Method Of Architecture Based On High-Resolution SAR Image

Synthetic Aperture Radar(SAR),as an active microwave remote sensing technology,can achieve high-precision image acquisition throughout the day.However,due to the fact that most of them are two-dimensional images,the lack of target height information limits the application of SAR in urban planning,ecological monitoring,and earthquake damage assessment.Although the height information of the target can be obtained through interferometric SAR,multi-base SAR,multi-angle SAR,etc.,there are problems such as resource consumption,complex system and processing.Focusing on the task of building height estimation based on high-resolution SAR images,this thesis mainly starts from the image domain,and mainly carries out the following work on the altimetry mechanism and altimetry method involved in building height estimation.1.The SAR imaging mechanism is analyzed,the geometric characteristics and scattering characteristics of typical buildings in SAR images are revealed,and the advantages and disadvantages of traditional high-resolution SAR image building altimetry methods are compared,which lays a foundation for subsequent architectural altimetry methods based on high-resolution SAR images.2.The mapping relationship between building height and its shadow geometric features is established,and the shadow extraction method based on gray distribution distortion and shadow saliency model is studied,and the architectural shadow extraction is realized when there is distortion in the gray distribution distortion map,the proportion of shadows in the SAR image to be processed is small,or the overall gray value is low.Aiming at the problem that the shadow extraction method is affected by noise and the large amount of computation,the Gaussian smoothing and superpixel segmentation preprocessing methods are studied.Based on the above work,the architectural height inversion based on the geometric features of shadows is realized.3.The target height extraction method based on iterative simulation matching scheme was studied,and the influencing factors of height estimation were analyzed.Aiming at the incidence angle error problem introduced by the platform,an improved iterative simulation matching altimetry scheme is proposed by taking the beam incidence angle and target height as the dual search variables,which overcomes the influence of the non-ideal motion of the platform and realizes more accurate target height extraction.The above theories and methods have been verified by simulation and measured data.The results show that the proposed method can effectively estimate the height information of the building target.