提出基于类词包(CSBOW,Class-Specific Bag of Words)技术的有监督图像分类算法。在训练阶段,首先在每一类训练图像库中提取特征点,运用SIFT描述符形成特征区域描述符,然后根据欧氏距离对特征矢量进行K均值聚类,每一类形成若干聚类中心...提出基于类词包(CSBOW,Class-Specific Bag of Words)技术的有监督图像分类算法。在训练阶段,首先在每一类训练图像库中提取特征点,运用SIFT描述符形成特征区域描述符,然后根据欧氏距离对特征矢量进行K均值聚类,每一类形成若干聚类中心即所谓类词包。在测试阶段,首先提取测试图像的特征点,运用SIFT描述符形成若干特征矢量,然后依次计算每个特征矢量与各聚类中心的欧式距离,运用竞争投票机制决定图像的分类结果。将CSBOW技术应用到商品图像分类,实验结果证明本算法分类正确率高于传统的基于词包和SVM的图像分类算法。展开更多
Several therocephalian species,mainly represented by cranial material from the late Permian,have been reported from China in recent years.Here we describe a tiny new baurioid therocephalian,Jiucaiyuangnathus confusus ...Several therocephalian species,mainly represented by cranial material from the late Permian,have been reported from China in recent years.Here we describe a tiny new baurioid therocephalian,Jiucaiyuangnathus confusus gen.et sp.nov.,from the Jiucaiyuan Formation,Xinjiang,China.The new taxon is represented by a partial snout with occluded partial lower jaw and two postcranial skeletons.Although juvenile in stage,the new species is diagnosed by the following features:round pit in middle of lateral surface of maxilla;lacrimal contact nasal;fossa for dentary tooth on the posterior end of the premaxilla,lateral to the anterior choana;two small vertical triangular ridges extending dorsally and ventrally on the vomerine anterior portion,and bordering a thin vomerine foramen laterally;anterior projection of the lateral part of the frontal on the nasal;symphyseal region of the dentary projected anteriorly;5 upper premaxillary teeth,upper and lower canines absent,diastema between the last premaxillary upper incisor and first maxillary tooth present,no diastema separating anterior from posterior dentition in the mandible,10 maxillary teeth and 12 dentary teeth,posterior postcanine expands mesiodistally,having a main large cusps and tiny anterior and posterior accessory cusps in line;neural arches of the atlas fused by the neural spine,neural spine of the axis projected posteriorly,procoracoid foramen lies between procoracoid and scapula.Features of the dentition resembles those of the small baurioid Ericiolacerta parva from South Africa and Silphedosuchus orenburgensis from Russia.The specimens provide the rare opportunity to know in detail the postcranial skeleton of baurioids.展开更多
文摘提出基于类词包(CSBOW,Class-Specific Bag of Words)技术的有监督图像分类算法。在训练阶段,首先在每一类训练图像库中提取特征点,运用SIFT描述符形成特征区域描述符,然后根据欧氏距离对特征矢量进行K均值聚类,每一类形成若干聚类中心即所谓类词包。在测试阶段,首先提取测试图像的特征点,运用SIFT描述符形成若干特征矢量,然后依次计算每个特征矢量与各聚类中心的欧式距离,运用竞争投票机制决定图像的分类结果。将CSBOW技术应用到商品图像分类,实验结果证明本算法分类正确率高于传统的基于词包和SVM的图像分类算法。
文摘Several therocephalian species,mainly represented by cranial material from the late Permian,have been reported from China in recent years.Here we describe a tiny new baurioid therocephalian,Jiucaiyuangnathus confusus gen.et sp.nov.,from the Jiucaiyuan Formation,Xinjiang,China.The new taxon is represented by a partial snout with occluded partial lower jaw and two postcranial skeletons.Although juvenile in stage,the new species is diagnosed by the following features:round pit in middle of lateral surface of maxilla;lacrimal contact nasal;fossa for dentary tooth on the posterior end of the premaxilla,lateral to the anterior choana;two small vertical triangular ridges extending dorsally and ventrally on the vomerine anterior portion,and bordering a thin vomerine foramen laterally;anterior projection of the lateral part of the frontal on the nasal;symphyseal region of the dentary projected anteriorly;5 upper premaxillary teeth,upper and lower canines absent,diastema between the last premaxillary upper incisor and first maxillary tooth present,no diastema separating anterior from posterior dentition in the mandible,10 maxillary teeth and 12 dentary teeth,posterior postcanine expands mesiodistally,having a main large cusps and tiny anterior and posterior accessory cusps in line;neural arches of the atlas fused by the neural spine,neural spine of the axis projected posteriorly,procoracoid foramen lies between procoracoid and scapula.Features of the dentition resembles those of the small baurioid Ericiolacerta parva from South Africa and Silphedosuchus orenburgensis from Russia.The specimens provide the rare opportunity to know in detail the postcranial skeleton of baurioids.
