首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 671 毫秒
1.
为了使车辆快速并准确地检测出人行横道,针对车载摄像头获取的路面图像,提出了一种基于决策树参数优化的人行横道检测方法,该方法分3个步骤完成:首先,通过逆透视变换获得指定区域内的道路俯瞰图;其次,通过阈值分割提取出路面白色标线;最后根据人行横道的特征属性实现检测。其中,白色标线的提取是准确检测的基础,因此结合边缘信息与自适应阈值,改进了分割算法,并使用决策树优化分割参数。结果表明:即使在路面光照不均匀的情况下,改进后的算法分割效果显示良好,有效提高了人行横道检测率。  相似文献   

2.
冯健  马海荣  李夏 《科技信息》2013,(16):129-130
从高分辨率遥感影像中快速,有效的提取道路信息,一直是遥感学界研究的热点和难点问题。本文研究了一种基于阈值分割与数学形态学的高分辨率遥感影像道路提取算法,该算法不需人工给出道路种子点,方向等信息,在某种意义上提高了道路提取的自动化程度。提取过程是:首先利用阈值分割将遥感影像分割成包含道路信息的二值图像,然后利用数学形态学运算对二值图像进行处理,根据道路形态特征提取出道路区域。  相似文献   

3.
经典的C V模型分割算法在处理较大尺寸图像时存在需多次迭代、运算时间长的缺点。在分析图像尺寸和初始逼近图像与获得稳定解的迭代次数与运算时间的关系的基础上,提出了一种改进的基于阈值分割及快速连通域标记算法的局部C V图像分割算法,对大尺寸图像进行处理。采用OTSU算法对图像进行初步的阈值分割,再利用快速非递归连通域标记算法进行连通域的标记及图像的局部分片。对分片后的小块图像以其阈值分割的结果作为初始逼近图像采用C V算法进行分割处理。算法分析及仿真结果证实,与经典C V算法相比较,改进的算法能够以很少的迭代次数和很短的运算时间达到稳定解,能够对含有丰富轮廓细节的大尺寸图像进行快速有效的处理。  相似文献   

4.
针对含有多个目标的灰度图像提出一种基于多阈值迭代方法的图像分割算法.首先使用非线性拉伸灰度直方图,并对图像不同灰度范围使用二值掩模进行处理,在此基础上采用迭代式阈值算法反复分割的图像分割算法.实验证明,这种综合分割算法能够有效降低单阈值穷举搜索算法的计算复杂度,分割效果也比较令人满意.  相似文献   

5.
针对迭代阈值选择算法每次迭代计算灰度阈值的过程存在大量重复计算的问题,提出了基于均值累计和频次累计的快速迭代阈值选择算法。对快速迭代阈值选择算法和迭代阈值选择算法阈值计算的时间开销及图像二值化分割进行了实验分析,结果表明:文中提出的快速迭代阈值选择算法可有效的对实验图像进行二值化,该算法可显著降低迭代过程的时间开销。当图像尺寸达到10 000*10 000时,快速迭代阈值选择算法的时间消耗可降低至迭代阈值选择算法的10%,验证了快速迭代阈值算法的有效性。  相似文献   

6.
现有的Arimoto熵阈值法仅依赖于灰度直方图分布,且计算最佳阈值时需搜索整个解空间,效率不高.为此,文中提出了一种二维Arimoto灰度熵阈值分割的快速迭代算法.首先,提出了一维Arimoto灰度熵阈值选取的快速迭代算法;然后,考虑图像目标和背景的类内灰度均匀性,导出了基于灰度-平均灰度级直方图的Arimoto灰度熵阈值法,并给出了中间变量的快速递推公式;最后,提出了二维Arimoto灰度熵阈值选取的快速迭代算法,推导了相应的公式,大大减少了运算量.实验结果表明,文中所提算法运行速度快,分割性能优于现有的5种同类阈值分割算法,分割后图像中的目标完整,边缘纹理清晰,细节更为丰富.  相似文献   

7.
基于最小类内方差的快速阈值分割算法   总被引:6,自引:0,他引:6  
最小类内方差法分割图像时需要计算二次统计量,运算量大,效率不高。以减小运算量为目标,对最小类内方差的方法进行改进,提出一种基于最小类内方差的快速闪值分割算法。从图像的灰度直方图出发,推导出简单的迭代公式,然后利用基于最小类内方差的快速阈值分割算法求出阈值。该算法获取阈值速度快,实时性强,用所获取的阈值分割图像有较好的分割效果。理论分析和实验结果表明,该算法运算速度快,分割效果好,具有较高的实用价值。  相似文献   

8.
针对目前交通标线提取研究对于语义信息丰富的标线精细化分割研究不足的现状, 通过移动激光扫描数据提出了一种精细化交通标线的语义分割算法。该算法先从道路点云中提取出路面,并根据点云的强度信息将其转变为栅格图像并对其优化,通过二值化处理提取出路面标线;在此基础上根据矩形度筛选将所有标线对象粗分为两类,并采用不同的语义分割策略进行识别,最后获得了10种符号标线以及非符号标线对象的精细化语义信息。实验选取了上海8组不同区域的城市道路点云数据进行验证,结果表明该算法具有96.04 %的精度与96.92 %的召回率,综合评价指标F达到96.48 %,为高精地图提供了更加丰富的交通标线语义信息。  相似文献   

9.
基于模糊划分熵的图像阈值化分割方法因具有良好的分割性能已成为图像分割广泛应用的方法之一.但是,随其需要确定的隶属函数参数个数的增加,导致其搜索空间快速增大,不利用模糊划分熵阈值法在诸如机器视觉、目标检测等众多实时性要求较高场合的应用.提出了搜索模糊2-划分熵最佳分割阈值的快速迭代算法,使其计算复杂性从O(L3)降低为O(L).大量实验结果表明,提出的模糊划分熵阈值法所对应的快速迭代是可行的.  相似文献   

10.
针对依赖硬件设施的晶圆分割方法存在生产成本高、工艺复杂且分割效果不稳定的问题,提出以仿射迭代最近点(ICP)算法为核心的基于图像形状配准思想的晶圆分割方法。该方法采用Canny算子提取图像边缘,建立晶圆模板图像与目标图像的特征点集;对目标图像的边缘图像进行基于Hough的直线检测,得到粗略的晶圆矩形边框信息;以矩形左上角的点坐标作为匹配搜索区域的初始值进行基于仿射ICP算法的精确配准,通过晶圆产品图像与模板图像的特征匹配,实现晶圆的快速、准确分割。理论分析及实验结果表明:该方法计算复杂度较低,单独样本分割时间约为0.9s,样本分割精度明显高于其他算法,满足自动化生产线的实时在线检测需求。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号