基于环形特征的卷积神经网络轮毂识别

针对实际生产中不同种类轮毂的混流生产问题,提出了一种基于环形特征的卷积神经网络轮毂识别算法。将直角坐标下的环形轮毂映射到极坐标中,归一化为标准形式的矩形,提取轮毂图像的环形特征信息,减少冗余特征产生的影响;设计了一种改进的VGG网络架构,利用深度可分离卷积打破输出通道维度与卷积核大小的联系,在不损失网络性能的同时降低了计算量,能够在实际生产中轮毂识别任务在有限的算力情况下实时进行计算;从有效性和实时性两个方面对轮毂识别算法进行评估,且通过Inception V3、SVM、KNN等模型的对比实验,验证了该算法可以实时地对轮毂自适应分类。实验表明:该方法对轮毂图像的处理精度达到99%以上,单幅图像平均处理时间降低至11.78 ms。

一种环形特征线的快速提取方法

针对三维网格模型,提出一种基于特征点评估的环形特征线快速提取方法.该方法首先利用采样点邻域的凹凸性程度确定模型特征点集;然后从环形特征线初始特征点开始进行迭代,利用主成分分析方法确定特征点的主方向并沿主方向找出新的特征点作为下一个迭代点,逐次迭代直到回到初始特征点为止;最后利用三次B样条插值这些迭代点并投影到网格模型上得到光滑的环形特征线.实验结果表明,此方法能够快速有效地提取三维网格模型上的环形特征线.

基于环形特征匹配的双目视觉里程计

针对视觉里程计中采用基本特征点匹配算法易出现误匹配现象,提出一种结合双向光流法的特征点环形匹配算法。该算法将双目图像与前后帧图像组成环形,前后帧图像采用双向金字塔光流法跟踪特征点,并剔除错误的特征点追踪结果。基本特征匹配算法通常采用快速最近邻匹配(FLANN)算法,但其结果包含很多误匹配的点对。本文提出的匹配算法不仅能剔除误匹配特征点,还能使特征点均匀分布于图像上。随后采用基于3D-2D点的P3P(Perspective-3-Point)算法结合RANSAC(Random Sample Consensus)得到初始位姿估计结果,再利用g2o(General Graph Optimization)库对位姿估计结果进一步优化。定位实验结果表明,结合双向光流法的特征点环形匹配算法具有更高的定位精度。

基于环形模板匹配的金属零件识别算法

针对在金属零件的模板匹配中,由于图像采集时零件摆放的位置和方向不同,使匹配图像中存在零件的不同侧面导致传统匹配方法准确率低的问题,提出了一种使用环形特征模板的模板匹配算法RTMM。通过一组同心圆将模板分割为几个环形区域,利用环形区域相互之间的关系作为预选区域的定位特征,在匹配图像中快速筛选出若干个预选区域;通过Sobel算子寻找各环形区域中的稳定点,根据各环形区域包含的稳定点数量筛选出能够代替整幅模板图像的环形区域;从环形区域中提取精确匹配的特征,对预选区域进行筛选,从而得到精确的匹配结果。

基于模板特征点提取的立体视觉里程计实现方法

针对传统的里程计存在精度较低和实时性较差的缺点,提出将Blob和Corner结合的模板特征点算法提取立体图像序列特征点;采用改进的绝对误差和(SAD)算法结合特征点环形匹配模型,实现特征点的精确匹配;通过位姿参数估计几何模型及三点算法的随机抽样一致性(RANSAC)迭代,精确得出车体运动的距离和方向信息。实验结果表明:基于模板特征点提取的立体视觉里程计精度高,实时性好,可为车体自动导航提供一种新途径。

回转体内部自动焊接装置总体设计

介绍了国内外有关回转体零部件内部特征(环形、纵向、横向)的成型现状,结合生产实际提出一种新型的成型方式,为后续回转体类零件批产提供基础保障。

Pollen Morphology and Ecological Significance of Nine Hygrophyte Species at Sevenstar Lake Area in the Bashang Area of Hebei Province

ObjectiveThis study aimed to investigate the morphological characteristics of pollen from nine hygrophyte species at Sevenstar Lake area in the Bashang Area （the southern edge of Inner Mongolian Plateau） of Hebei Province, as well as their ecological significance. MethodThe pollen morphology of nine hygrophyte species distributed at Seven Star Lake area was observed and studied by using an optical microscope, and morphological characteristics like size, shape, surface ornamentation were recorded. ResultsPollen grains were globose, subglobose prolate spheroidal; germination aperture had five types, namely, 3-groove, 6-groove, 3 （4）-groove, 3-colporate, 3 （4）-colporate; ektexine possessed four kinds of ornamentation： reticulate, striped, spiny, granular. Meanwhile, the environmental indication significance of these nine hygrophyte species was also discussed according to their habitats, origin and distribution. ConclusionThe study provides the basis of modern palynology for the study of ancient environment, ancient vegetation and paleoclimate.

Two New Species of Nymphulinae(Lepidoptera:Crambidae) from China

Two following new species of Nymphulinae are described: Paracymoriza convallata, sp. nov., Parapoynx candida, sp. nov. They are collected separately from Fujian and Tianjin. The photographs and the male or female genitalia of the new species are provided.

Effects of axial cyclic loading at constant confining pressures on deformational characteristics of anisotropic argillite

Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media.Considering argillite's anisotropy and inelastic deformational properties,theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves,which can be better fitted for the description of its elasticity than loading curves.Test results indicate that with the growth of accumulated plastic,strain,the apparent elastic modulus of argillite decreases in a form of exponential decay function,whereas the apparent Poisson ratio increase in a form of power equation.A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain.It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.

Ultrastructure of extrusomes in hypotrichous ciliate Pseudourostyla nova

The ultrastructure of extrusomes of the hypotrichous ciliate Pseudourostyla nova was observed in scanning and transmission electron microscopy and enzyme-cytochemistry. The results show that the distribution, morphological characteristics, morphogenesis process, and extrusive process of the extrusomes in P. nova are different from the trichocysts in Paramecium, suggesting that the extrusomes of P. nova can respond to environmental stimuli, play an important role in the defense of this species, and cannot be regarded as "trichocysts". The results also suggest that the extrusomes might be originated from the Golgi apparatus and mature in the cytoplasm; after the extrusion of mature extrusomes, the residual substance might be reabsorbed and reused by the ciliate cell via food vacuoles, and take part in material recycling of the cell.

Morphological Characteristics and Environmental Implications of Phytoliths in Topsoils from Different Vegetation Zones on Northern Slope of Changbai Mountains,China

The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline.

Monitoring and analysis of shock wave in water for underwater drilling blasting

Taking the underwater reef blasting in Gulei sea channel of Xiamen Port as an example,the forming characteristic of shock wave in water for underwater drilling blasting is analyzed.By field monitoring,the pressure of shock wave in water for different distances is attained;the major parameters such as pressure amplitude and positive action time,and the propagation attenuation rule of shock wave in water are analyzed in this paper.The results can be helpful for engineering design and construction and environmental safety assessment.

以卫星影像为底图的无人机图像自动拼接方法

针对无人机影像受成像角度倾斜、光照不均匀等影响,导致常规匹配方法拼接效果较差的问题,该文提出一种基于现有卫星影像的由粗到精无人机图像自动拼接方法。首先,在对图像进行粗匹配阶段,提出了一种基于环状描述子的尺度不变特征变换,用于解决图像间旋转和尺度的差异,较好地克服了SIFT算法描述子维度较高且计算量大的不足。其次,引入分块互信息进行精匹配,减少拼接过程中的累计误差。最后,采用该文提出算法对无人机图像进行拼接,实验结果表明,该文提出的无人机图像拼接算法在满足实时性要求的同时可以达到较高精度。