针对ORB(oriented FAST and rotated BRIEF)在匹配多相似区域图像时误匹配率高的问题,提出一种基于余弦相似度的改进ORB算法。该算法首先通过汉明距离(Hamming distance)最近邻匹配,计算匹配特征向量的余弦相似度;其次通过梯度计算法计...针对ORB(oriented FAST and rotated BRIEF)在匹配多相似区域图像时误匹配率高的问题,提出一种基于余弦相似度的改进ORB算法。该算法首先通过汉明距离(Hamming distance)最近邻匹配,计算匹配特征向量的余弦相似度;其次通过梯度计算法计算余弦相似度的最优阈值范围;然后将汉明距离高自由度最近次近邻粗匹配结果,利用余弦相似度不变性剔除不在最优阈值范围的匹配点;最后用RANSAC算法再次精确匹配。实验结果表明:该算法能在保证匹配特征点数以及实时性的基础上,高效降低误匹配率,尤其在匹配多相似区域图像时,可将原算法产生的误匹配率降低80%左右,同时该算法还超越了原算法在图像发生视角、旋转、尺度、模糊、光照变化时的适应性。展开更多
目的探讨腹腔器官移植供、受者的ABO血型基因型的分布频率,分析移植供、受者在ABO血清型相同的基础上的基因型随机错配情况。方法肾移植受者89例、肝移植受者22例为受者组,同期86名无关随机供者为供者组。两组均采用单克隆抗体检测ABO...目的探讨腹腔器官移植供、受者的ABO血型基因型的分布频率,分析移植供、受者在ABO血清型相同的基础上的基因型随机错配情况。方法肾移植受者89例、肝移植受者22例为受者组,同期86名无关随机供者为供者组。两组均采用单克隆抗体检测ABO血清学分型,同时采用聚合酶链反应-序列特异性引物(sequence-specific prime rpolymerase chain reaction,PCR-SSP)技术测定ABO血型基因型。所用引物可识别6个ABO血型基因(O1、O2、A1、A2、B1和B3)和21个ABO血型复等位基因。计算ABO血型基因频率,并在ABO血清学分型相同的基础上,分析供、受者之间ABO基因型的错配率。结果供者组和受者组均表达出O1、O2、A1、B1、A2共5个ABO血型基因和O1O1、O1O2、O2O2、A1A1、A1O1、A1O2、A2O1、A2O2、A1B1、A2B1、B1O1、B1O2和B1B1共13个ABO血型复等位基因;与其血清学分型一致率为100%。受者组及供者组患者中ABO血型基因频率从高到低依次为:O1(38.7%比43.0%)、O2(25.7%比21.5%)、A1(17.6%比18.0%)、B1(16.0%比16.3%)、A2(1.8%比1.2%),两组的分布频率比较差异均无统计学意义(均为P>0.05)。A型和B型中的杂合子血型基因型比例均超过85%。在ABO血清学同型的基础上,供、受者ABO基因的平均随机错配率为53.1%,其中供受者O→O的错配率为47.4%,A→A的错配率为66.8%,B→B的错配率为55.1%;AB→AB的错配率为16.7%。结论受者组及供者组患者中ABO血型基因频率从高到低依次为O1、O2、A1、B1、A2。在ABO血清学分型相同的基础上,供、受者ABO基因随机错配率较高。因此,有必要检测器官移植供、受者ABO血型基因分型,这有利于供受体间进行合理的配对。展开更多
Long inverted repeats(LIRs) are evolutionarily and functionally important structures in genomes because of their involvement in RNA interference, DNA recombination, and gene duplication. Identification of LIRs is high...Long inverted repeats(LIRs) are evolutionarily and functionally important structures in genomes because of their involvement in RNA interference, DNA recombination, and gene duplication. Identification of LIRs is highly complicated when mismatches and indels between the repeats are permitted. Long inverted repeat explorer(Lirex) was developed and introduced in this report. Written in Java, Lirex provides a user-friendly interface and allows users to specify LIR searching criteria, such as length of the region, as well as pattern and size of the repeats. Recombinogenic LIRs can be selected on the basis of mismatch rate and internal spacer size from identified LIRs. Lirex, as a cross-platform tool to identify LIRs in a genome, may assist in designing following experiments to explore the function of LIRs. Our tool can identify more LIRs than other LIR searching tools. Lirex is publicly available at http://124.16.219.129/Lirex.展开更多
文摘针对ORB(oriented FAST and rotated BRIEF)在匹配多相似区域图像时误匹配率高的问题,提出一种基于余弦相似度的改进ORB算法。该算法首先通过汉明距离(Hamming distance)最近邻匹配,计算匹配特征向量的余弦相似度;其次通过梯度计算法计算余弦相似度的最优阈值范围;然后将汉明距离高自由度最近次近邻粗匹配结果,利用余弦相似度不变性剔除不在最优阈值范围的匹配点;最后用RANSAC算法再次精确匹配。实验结果表明:该算法能在保证匹配特征点数以及实时性的基础上,高效降低误匹配率,尤其在匹配多相似区域图像时,可将原算法产生的误匹配率降低80%左右,同时该算法还超越了原算法在图像发生视角、旋转、尺度、模糊、光照变化时的适应性。
文摘目的探讨腹腔器官移植供、受者的ABO血型基因型的分布频率,分析移植供、受者在ABO血清型相同的基础上的基因型随机错配情况。方法肾移植受者89例、肝移植受者22例为受者组,同期86名无关随机供者为供者组。两组均采用单克隆抗体检测ABO血清学分型,同时采用聚合酶链反应-序列特异性引物(sequence-specific prime rpolymerase chain reaction,PCR-SSP)技术测定ABO血型基因型。所用引物可识别6个ABO血型基因(O1、O2、A1、A2、B1和B3)和21个ABO血型复等位基因。计算ABO血型基因频率,并在ABO血清学分型相同的基础上,分析供、受者之间ABO基因型的错配率。结果供者组和受者组均表达出O1、O2、A1、B1、A2共5个ABO血型基因和O1O1、O1O2、O2O2、A1A1、A1O1、A1O2、A2O1、A2O2、A1B1、A2B1、B1O1、B1O2和B1B1共13个ABO血型复等位基因;与其血清学分型一致率为100%。受者组及供者组患者中ABO血型基因频率从高到低依次为:O1(38.7%比43.0%)、O2(25.7%比21.5%)、A1(17.6%比18.0%)、B1(16.0%比16.3%)、A2(1.8%比1.2%),两组的分布频率比较差异均无统计学意义(均为P>0.05)。A型和B型中的杂合子血型基因型比例均超过85%。在ABO血清学同型的基础上,供、受者ABO基因的平均随机错配率为53.1%,其中供受者O→O的错配率为47.4%,A→A的错配率为66.8%,B→B的错配率为55.1%;AB→AB的错配率为16.7%。结论受者组及供者组患者中ABO血型基因频率从高到低依次为O1、O2、A1、B1、A2。在ABO血清学分型相同的基础上,供、受者ABO基因随机错配率较高。因此,有必要检测器官移植供、受者ABO血型基因分型,这有利于供受体间进行合理的配对。
基金supported by the National Natural Science Foundation of China (Grant Nos. 41476104 and 31460001)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB06010201)+1 种基金the International Science and Technology Cooperation Project of Hainan Province, China (Grant No. KJHZ2015-22)the support from the Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences (Grant Nos. SIDSSE-BR-201303 and SIDSSE-201305)
文摘Long inverted repeats(LIRs) are evolutionarily and functionally important structures in genomes because of their involvement in RNA interference, DNA recombination, and gene duplication. Identification of LIRs is highly complicated when mismatches and indels between the repeats are permitted. Long inverted repeat explorer(Lirex) was developed and introduced in this report. Written in Java, Lirex provides a user-friendly interface and allows users to specify LIR searching criteria, such as length of the region, as well as pattern and size of the repeats. Recombinogenic LIRs can be selected on the basis of mismatch rate and internal spacer size from identified LIRs. Lirex, as a cross-platform tool to identify LIRs in a genome, may assist in designing following experiments to explore the function of LIRs. Our tool can identify more LIRs than other LIR searching tools. Lirex is publicly available at http://124.16.219.129/Lirex.
