Fingerprint segmentation is an important step in fingerprint recognition and is usually aimed to identify non-ridge regions and unrecoverable low quality ridge regions and exclude them as background so as to reduce th...Fingerprint segmentation is an important step in fingerprint recognition and is usually aimed to identify non-ridge regions and unrecoverable low quality ridge regions and exclude them as background so as to reduce the time expenditure of image processing and avoid detecting false features. In high and in low quality ridge regions, often are some remaining ridges which are the afterimages of the previously scanned finger and are expected to be excluded from the foreground. However, existing seg-mentation methods generally do not take the case into consideration, and often, the remaining ridge regions are falsely classified as foreground by segmentation algorithm with spurious features produced erroneously including unrecoverable regions as fore-ground. This paper proposes two steps for fingerprint segmentation aimed at removing the remaining ridge region from the fore-ground. The non-ridge regions and unrecoverable low quality ridge regions are removed as background in the first step, and then the foreground produced by the first step is further analyzed for possible remove of the remaining ridge region. The proposed method proved effective in avoiding detecting false ridges and in improving minutiae detection.展开更多
Transition metal dichalcogenides are interesting candidates as photocatalysts for hydrogen evolution reaction.The MnPSe_(3)/WS_(2) heterostructure is hence studied here with first principles calculations by exploring ...Transition metal dichalcogenides are interesting candidates as photocatalysts for hydrogen evolution reaction.The MnPSe_(3)/WS_(2) heterostructure is hence studied here with first principles calculations by exploring its electronic properties under the application of an electric field.It is discovered that the band gap will decrease from the WS_(2) monolayer to the MnPSe_(3)/WS_(2) heterostructure with Perdew-Burke-Ernzerhof functional,while increase slightly when electron correlation is involved.The conduction band minimum of the heterostructure is determined by the MnPSe3 layer,while the valence band maximum is contributed by the WS_(2)layer.The band edges and band gap suggest that the heterostructure will have good photocatalytic properties for water splitting.Moreover,comparing to monolayer WS_(2),the light absorption in both the ultraviolet and visible regions will be enhanced.When an electric field is present,a linear relation is observed between the electric field and the band gap within specific range,which can thus modulate the photocatalytic performance of this heterostructure.展开更多
目的探讨弥散加权成像(DWI)/表观弥散系数(ADC)值对急性CO中毒迟发性脑病的预测价值。方法回顾性分析76例急性CO中毒患者,根据临床分为无迟发性脑病组(52例)和迟发性脑病组(24例),比较两组患者的临床特征,并分别测量苍白球、侧脑室周围...目的探讨弥散加权成像(DWI)/表观弥散系数(ADC)值对急性CO中毒迟发性脑病的预测价值。方法回顾性分析76例急性CO中毒患者,根据临床分为无迟发性脑病组(52例)和迟发性脑病组(24例),比较两组患者的临床特征,并分别测量苍白球、侧脑室周围白质区、半卵圆中心、额顶叶皮质区四个区域的平均ADC值,并与同期正常人群(20例)进行比较,通过绘制受试者工作特征曲线(receiver operating characteristic,ROC),计算曲线下面积(area under the curve,AUC)预测迟发性脑病的发生。结果76例CO患者中,DNS发生率为24例(31.6%),苍白球是最常见受累部位,占68例(89.5%),DNS组和非DNS组中,苍白球区平均ADC值分别为(0.639±0.064)×10^(-3)mm^(2)/s和(0.665±0.056)×10^(-3)mm^(2)/s,明显低于正常对照组平均ADC值分别为(0.701±0.029)×10^(-3)mm^(2)/s,三组比较差异有统计学差异(F=7.061,P=0.001),DNS组侧脑室周围白质区、半卵圆中心区、额顶叶皮质区的ADC值均低于非DNS组和正常对照组,但是无统计学差异(P=0.749,0.144,0.568)。非DNS组和DNS组的苍白球ADC值ROC曲线显示其AUC为0.636(95%CI 0.500~0.772),最佳界值为0.645×10^(-3)mm^(2)/s,敏感度为71.2%,特异度为58.3%。苍白球/丘脑的ADC比值ROC曲线显示其AUC为0.624(95%CI 0.482~0.766),其最佳界值为0.811,敏感度为63.5%,特异度为62.5%。结论苍白球的弥散受限是急性CO中毒患者的特征性表现,DWI/ADC值得测定可以作为预测迟发性脑病得敏感指标。展开更多
基金Project supported by the National Natural Science Foundation of China (No. 60373023), and the Science and Technology Research Foundation of Hunan City University (No. 20057306), China
文摘Fingerprint segmentation is an important step in fingerprint recognition and is usually aimed to identify non-ridge regions and unrecoverable low quality ridge regions and exclude them as background so as to reduce the time expenditure of image processing and avoid detecting false features. In high and in low quality ridge regions, often are some remaining ridges which are the afterimages of the previously scanned finger and are expected to be excluded from the foreground. However, existing seg-mentation methods generally do not take the case into consideration, and often, the remaining ridge regions are falsely classified as foreground by segmentation algorithm with spurious features produced erroneously including unrecoverable regions as fore-ground. This paper proposes two steps for fingerprint segmentation aimed at removing the remaining ridge region from the fore-ground. The non-ridge regions and unrecoverable low quality ridge regions are removed as background in the first step, and then the foreground produced by the first step is further analyzed for possible remove of the remaining ridge region. The proposed method proved effective in avoiding detecting false ridges and in improving minutiae detection.
基金Project(2682019CX06)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2019KY23)supported by Research Start-up Fund from the Southwest Jiaotong University,China+2 种基金Projects(20ZDYF0236,20ZDYF0490)supported by the Key R&D Projects in the Field of High and new Technology of Sichuan,ChinaProject(52072311)supported by the National Natural Science Foundation of ChinaProject(2019JDJQ0009)supported by the Outstanding Young Scientific and Technical Talents in Sichuan Province,China。
文摘Transition metal dichalcogenides are interesting candidates as photocatalysts for hydrogen evolution reaction.The MnPSe_(3)/WS_(2) heterostructure is hence studied here with first principles calculations by exploring its electronic properties under the application of an electric field.It is discovered that the band gap will decrease from the WS_(2) monolayer to the MnPSe_(3)/WS_(2) heterostructure with Perdew-Burke-Ernzerhof functional,while increase slightly when electron correlation is involved.The conduction band minimum of the heterostructure is determined by the MnPSe3 layer,while the valence band maximum is contributed by the WS_(2)layer.The band edges and band gap suggest that the heterostructure will have good photocatalytic properties for water splitting.Moreover,comparing to monolayer WS_(2),the light absorption in both the ultraviolet and visible regions will be enhanced.When an electric field is present,a linear relation is observed between the electric field and the band gap within specific range,which can thus modulate the photocatalytic performance of this heterostructure.
文摘目的探讨弥散加权成像(DWI)/表观弥散系数(ADC)值对急性CO中毒迟发性脑病的预测价值。方法回顾性分析76例急性CO中毒患者,根据临床分为无迟发性脑病组(52例)和迟发性脑病组(24例),比较两组患者的临床特征,并分别测量苍白球、侧脑室周围白质区、半卵圆中心、额顶叶皮质区四个区域的平均ADC值,并与同期正常人群(20例)进行比较,通过绘制受试者工作特征曲线(receiver operating characteristic,ROC),计算曲线下面积(area under the curve,AUC)预测迟发性脑病的发生。结果76例CO患者中,DNS发生率为24例(31.6%),苍白球是最常见受累部位,占68例(89.5%),DNS组和非DNS组中,苍白球区平均ADC值分别为(0.639±0.064)×10^(-3)mm^(2)/s和(0.665±0.056)×10^(-3)mm^(2)/s,明显低于正常对照组平均ADC值分别为(0.701±0.029)×10^(-3)mm^(2)/s,三组比较差异有统计学差异(F=7.061,P=0.001),DNS组侧脑室周围白质区、半卵圆中心区、额顶叶皮质区的ADC值均低于非DNS组和正常对照组,但是无统计学差异(P=0.749,0.144,0.568)。非DNS组和DNS组的苍白球ADC值ROC曲线显示其AUC为0.636(95%CI 0.500~0.772),最佳界值为0.645×10^(-3)mm^(2)/s,敏感度为71.2%,特异度为58.3%。苍白球/丘脑的ADC比值ROC曲线显示其AUC为0.624(95%CI 0.482~0.766),其最佳界值为0.811,敏感度为63.5%,特异度为62.5%。结论苍白球的弥散受限是急性CO中毒患者的特征性表现,DWI/ADC值得测定可以作为预测迟发性脑病得敏感指标。
