抗尺度变换的矢量地图匹配导航方法

相比于景象匹配导航,矢量地图匹配导航具有无损变换、空间效率和时间效率高等优势。针对矢量地图匹配导航过程中实时图与基准图尺度不一致的情况,提出了一种抗尺度变换的位姿解算算法,并将其应用到矢量地图匹配导航系统中。该算法将尺度因子作为未知参数,与位姿参数一起进行估计,从而避免了尺度差异造成的位姿解算误差较大的问题。仿真结果表明,抗尺度变换的位姿解算算法用于小尺度变换下的矢量地图匹配时,经度标准差和纬度标准差均小于0.06″,航向角标准差小于0.06°。

峡谷地区GNSS网与边角网联合平差尺度一致性归算

峡谷地区布置较为集中的工程区域,短程精密测距精度总体优于GNSS测量精度,但其观测方向常存在较为严重的遮挡,需采用GNSS测量与全站仪边角测量,联合建立统一尺度的高精度工程测量控制网。采用一种基于区域GNSS与精密测距边长的尺度比估计方法,以精密测距边长为基准确定出合理的尺度比,从而实现GNSS成果与精密测距成果在尺度上的一致性,为联合平差提供了一种尺度高度一致的观测数据,使平差成果更加稳健。

Underwater Image Enhancement Based on Multi-scale Adversarial Network

In this study,an underwater image enhancement method based on multi-scale adversarial network was proposed to solve the problem of detail blur and color distortion in underwater images.Firstly,the local features of each layer were enhanced into the global features by the proposed residual dense block,which ensured that the generated images retain more details.Secondly,a multi-scale structure was adopted to extract multi-scale semantic features of the original images.Finally,the features obtained from the dual channels were fused by an adaptive fusion module to further optimize the features.The discriminant network adopted the structure of the Markov discriminator.In addition,by constructing mean square error,structural similarity,and perceived color loss function,the generated image is consistent with the reference image in structure,color,and content.The experimental results showed that the enhanced underwater image deblurring effect of the proposed algorithm was good and the problem of underwater image color bias was effectively improved.In both subjective and objective evaluation indexes,the experimental results of the proposed algorithm are better than those of the comparison algorithm.

多层次约束的矢量地图匹配导航算法

针对航空用线状目标的矢量地图匹配问题,提出了一种多层次约束的矢量地图匹配导航算法(MLC-VMMA).该算法利用差角作为线状目标的匹配特征量,依次根据距离、顺序和误差等多层次约束条件来减小可行解空间的大小,完成在具有旋转、平移、缩放变换下的矢量地图匹配.仿真结果表明,MLC-VMMA适用于小尺度缩放变换下的矢量地图匹配,具有较高的可靠性与导航精度.

基于奇异值分解的特征跟踪方法

在传统的基于模板匹配的跟踪方法中 ,均是给定一个模板 ,然后从图像中各个位置取出一个个与模板大小一致的区域进行相似性度量 ,找出与模板距离最小的一个区域作为当前模板 ,以便进行下一步的匹配跟踪工作。在景象匹配和相关跟踪过程中 ,由于所面临的大多数是变化的场景 ,实时获取的图像与预存模板之间存在比较大的差异 ,传统相关匹配方法的应用就会受到限制 ;而且在跟踪过程中 ,随时更新模板会造成跟踪性能对扰动过分敏感 ,从而产生漂移。首先拍摄目标不同角度的图像 (尽可能包含目标可能出现的所有情况 ) ,构成目标图像训练集合 ,抽取出特征矩阵 ,对它进行奇异值分解 ,构成一个关于目标的多维空间。然后再用匹配方法在全局范围搜索 ,找出目标的大致位置 ,并利用收敛方法在确定的大致位置内进行搜索 ,确定目标的仿射变换参数 。

邻图配对式运动恢复结构的欧式三维重建

传统增量式运动恢复结构重建易受到尺度变化的影响,重建出的点云存在分层现象,并且不存在量纲。通过改进重建拓扑结构和尺度迭代最近点算法,提出了一种新的欧式三维重建方法。首先,设计了两两相邻图片重建点云后并入主点云的重建拓扑结构;然后,建立了对应表,旨在找到同一世界点在新建点云和主点云下的对应三维点对;接着,结合Geman-McClure范数,提出了抗噪声的尺度迭代最近点求解算法;最后,设置地面控制点,为重建出的点云引入尺度。实验结果表明,提出方法重建出的点云比传统增量式运动恢复结构重建出的点云更精确,并且点云长度的测量绝对误差在1%~2%左右。提出方法适用于近场景物体较精确的欧式三维重建。

Macro mechanical parameters’ size effect of surrounding rock of Shuibuya project’s underground power station

Scale effect is one of the important aspects in the macro mechanical parame- ters’ research of rock mass, from a new point of view, by means of lab and field rock me- chanics test, establishment of E^Vp relation, classification of engineering rock mass, nu- merical simulation test and back analysis based on surrounding rock’s displacement monitoring results of Shuibuya Project’s underground power station, rock mass deforma- tion module’s size effect of surrounding rock of Shuibuya Project’s undegroud power sta- tion was studied. It’s shown that rock mass deformation module’s scale effect of sur- rounding rock of Shuibuya Project’s undeground power station is obvious, the rock mass deformation module to tranquilization is 20% of intact rock’s. Finally the relation between rock mass deformation modules and the scale of research was established.

Size effect on cubic and prismatic compressive strength of cement paste

A series of compression tests were conducted on 150 groups of cement paste specimens with side lengths ranging from 40 mm to 200 mm. The specimens include cube specimens and prism specimens with height to width ratio of 2. The experiment results show that size effect exists in the cubic compressive strength and prismatic compressive strength of the cement paste, and larger specimens resist less in terms of strength than smaller ones. The cubic compressive strength and the prismatic compressive strength of the specimens with side length of 200 mm are respectively about 91% and 89% of the compressive strength of the specimens with the side length of 40 mm. Water to binder ratio has a significant influence on the size effect of the compressive strengths of the cement paste. With a decrease in the water to binder ratio, the size effect is significantly enhanced. When the water to binder ratio is 0.2, the size effects of the cubic compressive strength and the prismatic compressive strength of the cement paste are 1.6 and 1.4 times stronger than those of a water to binder ratio of 0.6. Furthermore, a series of formulas are proposed to calculate the size effect of the cubic compressive strength and the prismatic compressive strength of cement paste, and the results of the size effect predicted by the formulas are in good agreement with the experiment results.

Application of analytical hierarchy process to selection of primary crusher

Selection of crusher required a great deal of design based on the mining plan and operation input. Selection of the best primary crusher from all of available primary crushers is a Multi-Criterion Decision Making （MCDM） problem, in this paper, the Analytical Hierarchy Process （AHP） method was used to selection of the best primary crusher for Golegohar Iron Mine in Iran. For this reason, gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impactor, hammer mill and feeder breaker crushers were considered as alternatives and capacity, feed size, product size, rock compressive strength, abrasion index and mobility of crusher were considered as criteria. As a result of our study, the gyvratory crusher was offered as the best primary crusher for the studied mine.