Lanzhou Jiaotong University

Powerchina Northwest Engineering Corporation Limited

Haowen Yan

Jingzhong Li

Xiaomin Lu

Liming Zhang

Weifang Yang

Zufeng Li

Shuwen Yang

Xiaoning Su

Pengbo Li

Wende Li

Ben Ma

Zhixuan Miao

Haixing Shang

Xiaorong Gao

Fengshan Su

Wenjun Zhao

Shengjie Di

Mingbo Liu

Ziyi Zhang

Min Deng

Shihong Du

Zhao Zhang

Liang Wu

Min Yang

Pengbin Wang

Tao Tan

A multi-scale DEM generation method based on curvature wavelet transform is provided. The method includes following steps: obtaining a wavelet basis function and a wavelet decomposition layer number of the curvature wavelet transform, and a DEM related parameter feature information amount and an output resolution; an grid surface curvature of DEM data is acquired, and the grid surface curvature of the DEM data is decomposed and reconstructed based on the wavelet basis function and the wavelet decomposition layer number to obtain a reconstruction matrix; based on the reconstruction matrix, terrain feature points in the DEM data are extracted by taking a feature information amount as a threshold; and based on the terrain feature points in the DEM data, resampling is performed with the output resolution as resolution, so that DEM generation and synthesis are realized.

Method for multi-scale digital elevation model generation based on curvature wavelet transform

Disclosed is a graph convolution auto-encoder based method for computing road network similarity. The method includes: creating a dual graph of a road network, and giving road network space feature information to nodes of the dual graph from three aspects of global, local and connection characteristics on the basis of a relation principle between an entire structure and parts of the structure, such that a quantitative expression of a road network graph structure is obtained; aggregating and updating node feature information and structure information of a road network graph by the graph convolution auto-encoder, and forming a deep understanding of the road network, such that a coded expression of node information of the road network is obtained; and mapping a complex high-dimensional feature space to an easy-to-measure low-dimensional feature space through an average pooling operation, so as to obtain a set of feature vectors, and computing the similarity.

Graph convolution auto-encoder based multi-scale method for computing road network similarity

A method for controlling engineering projection deformation includes: calculating, based on known coordinates of an engineering key region, a change rate of a length deformation function per kilometer in a first direction caused by a height difference of the engineering key region and a change rate of the length deformation function per kilometer in the first direction caused by a distance from a central meridian of a Gaussian projection zone of the engineering key region; solving a distance between a meridian where a center of the engineering key region is located and a new central meridian; solving an elevation of a compensation projection plane; and performing comprehensive projection deformation compensation based on the elevation of the compensation projection plane and the distance between the meridian where the center of the engineering key region is located and the new central meridian, so as to realize the controlling of engineering projection deformation.

Method and device for controlling engineering projection deformation

Disclosed in the present disclosure is a commutative encryption and watermarking method based on a chaotic system and a zero watermark for vector geospatial data. According to the method, firstly, the vector geospatial data are scrambled and encrypted by using chaotic sequences generated by a composite chaotic system. Then, vector geospatial elements are randomly combined in pairs. A feature matrix is constructed according to the number of vertex coordinates of the vector geospatial elements in combinations, and the parity of the number. Finally, an XOR operation is performed on the feature matrix and the watermark image to construct a zero watermark image, and the zero watermark is constructed through invariant features of the vector geospatial data.

Commutative encryption and watermarking method based on chaotic system and zero watermark for vector geospatial data

Disclosed in the present disclosure is a classification method based on skeleton lines for building shapes. The method includes: (1) expanding a template library of buildings by combining building shape classification in architecture and building shape features in real life on the basis of inheriting advantages of a traditional template matching method; (2) avoiding influence of small depressions and protrusions of the buildings on overall shapes by constructing a least-squares template; (3) extracting the skeleton lines of the buildings and calculating feature vectors of the buildings; and (4) calculating similarity between feature vectors of skeleton lines of the buildings and skeleton lines of templates by using cosine similarity, and selecting the template with the highest similarity as a classification result of the building shapes.

Classification method based on skeleton lines for map building shapes

The disclosure provides a reversible watermarking method for the oblique photography three-dimensional models with controllable accuracy. According to the disclosure: firstly, by using the global stability of the average included angle of vertex normal vector, the feature points of the oblique photography three-dimensional model are extracted; secondly, the mapping relationship is established by the ratio of the distance between feature points and non-feature points, and the vertexes are grouped, and each group consists of a feature point corresponding to several non-feature points; finally, the spherical coordinate system is constructed by taking the feature points as the coordinate origin in grouping, and the watermark is embedded by modifying the radius of the coordinate system.

Reversible watermarking method for oblique photography three-dimensional models with controllable accuracy

Growing community of inventors

Lanzhou, China

Haowen Yan