基于三维配准的面部变化检测技术

针对微整容变化检测的问题,提出一种基于改进迭代最近点算法的变化检测方法。首先采用面部数据曲率特征确定特征点,然后通过普式分析法对面部特征点集求解最小二乘函数,提高迭代最近点算法的效率。通过对面部微整形数据的测试,与经典的ICP方法相比,文中方法具有配准精度高、收敛速度快的特点。

人脸面部变化字典学习的单样本人脸识别问题

基于稀疏表达的分类识别方法(SRC)是近年来人脸识别领域的热点研究课题之一,该理论认为,可以用人脸数据库中的所有其他样本作为稀疏表达字典,并且理想状态下该样本仅与同类样本强相关.然而其对于样本数量有着较高要求,且在处理含有光照问题人脸图像时无法消除光照对数据库的影响.针对上述情况,在稀疏表达的基础上,利用随机投影和构造人脸面部变化模型来优化稀疏表达字典,提出一种新的单样本人脸识别算法.该算法在低维空间中不仅能保持原始数据的稀疏重构关系,还能提高单样本人脸识别准确率.通过AR,Yale B,Extended Yale B人脸数据库的实验证明了面部变化模型的框架和其算法的有效性.

骨性Ⅲ类错牙合患者正畸正颌联合治疗前后面部软组织变化的研究

目的探讨骨性Ⅲ类错牙合患者正畸正颌联合治疗前后面部软组织变化的特征。方法选择在江苏省口腔医院正畸科就诊的14例骨性Ⅲ类错牙合畸形的患者为研究对象,分别于正畸正颌联合治疗前、后拍摄3dMD,利用3dMD vultus软件对颌面部软组织进行重建,然后选取面部软组织有代表性的17个三维标志点并测量线距和角度,比较骨性Ⅲ类错牙合患者正畸正颌联合治疗前后的差异。结果面凸角、鼻唇角、颏唇角、上唇长度,鼻翼宽度及鼻基底宽度有统计学差异,P<0.05。结论①3dMD提供了三维测量软组织的一种方法。②骨性Ⅲ类错牙合患者正畸正颌联合治疗前后面型改善。

骨性Ⅲ类偏颌患者正颌术后面部软组织的三维变化

目的探讨骨性Ⅲ类偏颌患者正颌术前和术后不同时期面部不同区域软组织的变化。方法回顾性选择2016年10月至2019年12月于首都医科大学附属口腔医院创伤整形科接受LeFortⅠ型截骨术、下颌骨矢状劈开术和颏成形术治疗的23例骨性Ⅲ类偏颌成人患者,其中男性9例.女性14例,年龄23~30岁。所有患者分别于术前1周、术后3个月、术后6个月和术后12个月拍摄三维面像和锥形束CT。将所采集患者的面部软硬组织三维数据导入Mimics Medical和3-matic Medical软件并将其划分为27个区域,将软组织图像与硬组织根据额部进行三维重叠,软件根据重叠信息自动计算各区域的软组织体积,并分析术后不同时期各区域软组织的体积变化。通过SPSS统计软件对不同时期不同部位软组织的体积变化数据进行单因素重复测量方差分析。结果骨性Ⅲ类偏颌患者偏斜侧鼻翼旁区、上口角旁区、鼻区、上唇区、下颊部区、下[牙合]体区以及非偏斜侧颧骨区、鼻翼旁区、上颊部区、上下口角旁区软组织体积术前1周到术后3个月、6个月和12个月软组织体积均呈增加趋势(P<0.05)。术后12个月患者下唇及颏区软组织和偏斜侧下口角旁区体积均减小(P<<0.01)。术后左右侧上下口角旁区软组织的对称性变化在不同时期存在统计学差异(P<0.05)。结论骨性Ⅲ类偏颌患者双颌手术和颏成形术后面部偏斜明显改善。面下三分之一软组织术后变化明显,偏斜侧下口角旁区和下唇及颏区软组织术后变得凹陷.而偏斜侧和非偏斜侧上下口角旁、下颌体区、上唇区软组织均较术前凸出。术后左右侧上下口角旁区软组织的不同变化利于改善口周软组织的对称性。骨性Ⅲ类偏颌患者术后鼻翼旁区、鼻区软组织均发生变化,术前应告知骨Ⅲ类偏颌患者上颌骨前徙术后可能会影响鼻部外观。

成人拔牙正畸后面部软组织变化的三维研究

目的通过三维面部扫描比较正畸拔牙与非拔牙矫治后面部软组织变化的差异。方法将就诊患者正畸治疗方案分为拔牙与不拔牙两组，拔牙组12例，不拔牙组10例。矫治前后采用结构光三维照相机获取患者三维面相。采用Rapidform2006软件重叠矫治前后面相，将面部按解剖结构特点分为九个区，利用距离图示法分析面部各区的三维变化，同时应用SPSS 16.0统计软件对治疗前后组内及组间变化行统计学分析。结果两组患者在矫治中BMI指数未有显著统计学差异。根据面部变化分析：不拔牙患者具有面部增大、不变，和颊肌区、咬肌区、颏肌下区这三个变小区域，而拔牙组面部轮廓均表现为缩小或不变，不含增大区域。结论成人正畸治疗后面部软组织三维变化，无论拔牙与否，咬肌区和颊肌区均表现为缩小，眶下区和颧肌区均无明显改变，而两组在上下唇红区、口轮匝肌区、颏唇沟区的变化方向相反并有显著性差异。

人脸对齐处理对面部色泽变化的影响

对人脸识别考勤系统所获取的图像序列进行色泽变化分析,可有效获取员工的健康信息。本文利用基于Haar-like特征的人脸识别算法自动确定左眼、右眼、鼻子和嘴巴特征点位置,分别采用左右眼两点对齐法、左右眼+鼻子三点对齐法、左右眼+嘴巴三点对齐法,对图像序列进行配准处理以得到标准化图像序列,对标准化图像序列的各色彩分量进行相关函数分析,研究人脸图像序列对齐处理方法对面部色泽变化的影响。探讨能够有效减小图像序列对齐处理引起的面部色泽变化的方法,更好地保留员工自身健康变化引起的面部色泽变化,提供更为准确的健康警示信息。

Sedimentary Evolution of the Holocene Subaqueous Clinoform off the Southern Shandong Peninsula in the Western South Yellow Sea

Based on the stratigraphic sequence formed since the last glaciation and revealed by 3000 km long high-resolution shallow seismic profiles and the core QDZ03 acquired recently off the southern Shandong Peninsula, we addressed the sedimentary characteristics of a Holocene subaqueous clinoform in this paper. Integrated analyses were made on the core QDZ03, including sedimentary facies, sediment grain sizes, clay minerals, geochemistry, micro paleontology, and AMS 14 C dating. The result indicates that there exists a Holocene subaqueous clinoform, whose bottom boundary generally lies at 15–40 m below the present sea level with its depth contours roughly parallel to the coast and getting deeper seawards. The maximum thickness of the clinoform is up to 22.5 m on the coast side, and the thickness contours generally spread in a banded way along the coastline and becomes thinner towards the sea. At the mouths of some bays along the coast, the clinoform stretches in the shape of a fan and its thickness is evidently larger than that of the surrounding sediments. This clinoform came into being in the early Holocene(about 11.2 cal kyr BP) and can be divided into the lower and upper depositional units(DU 2 and DU 1, respectively). The unit DU 2, being usually less than 3 m in thickness and formed under a low sedimentation rate, is located between the bottom boundary and the Holocene maximum flooding surface(MFS), and represents the sediment of a post-glacial transgressive systems tract; whereas the unit DU 1, the main body of the clinoform, sits on the MFS, belonging to the sediment of a highstand systems tract from middle Holocene(about 7–6 cal kyr BP) to the present. The provenance of the clinoform differs from that of the typical sediments of the Yellow River and can be considered as the results of the joint contribution from both the Yellow River and the proximal coastal sediments of the Shandong Peninsula, as evidenced by the sediment geochemistry of the core. As is controlled mainly by coactions of multiple factors such as the Holocene sea-level changes, sediment supplies and coastal dynamic conditions, the development of the clinoform is genetically related with the synchronous clinoform or subaqueous deltas around the northeastern Shandong Peninsula and in the northern South Yellow Sea in the spatial distribution and sediment provenance, as previously reported, with all of them being formed from the initial stage of the Holocene up to the present.

Comparative Analysis of China Surface Air Temperature Series for the Past 100 Years

Temperature change plays a crucial role in global change sciences. In the past several decades, comprehensive find- ings have been achieved on temperature change in China for the past 100 years. Several time series have been created to illustrate the averaged surface air temperature for the country. The correlations of these series range from 0.73 to 0.97. It is also achieved in better data quality, wider spatial data coverage, improved homogeneity of time series, and enhanced reliability of findings. The results show an annual mean temperature increase by 0.78±0.27℃ per 100 years in China for the period 1906-2005. After prolonging the period till 2007, it is found that 2007 is rated as the warmest year in the past 100 years. Although all the series, except one, reflect temperature changes in the eastern part of China before the 1930s, they represent the general temperature change in most parts of the country after the 1930s.

Interannual variations of surface winds over China marginal seas

In a study of surface monsoon winds over the China marginal seas, Sun et al. （2012） use singular value decomposition method to identify regional dominant modes and analyze their interdecadal variability. This paper continues to evaluate the interannual variability of each dominant mode and its relation to various atmospheric, oceanic and land factors. The findings include： 1） The intensity of the winter monsoon over the East China Sea is highly correlated with the Siberian High intensity and anti-correlated with the latitudinal position of the Aleutian Low as well as the rainfall in eastern China, Korean Peninsula and Japan; 2） The western Pacific subtropical high is significantly correlated with the summer monsoon intensity over the East China Sea and anti-correlated with the summer monsoon over the South China Sea; 3） The winter monsoon in a broad zonal belt through the Luzon Strait is dominated by the ENSO signal, strengthening in the La Nifia phase and weakening in the E1 Nifio phase. This inverse relation exhibits interdecadal shift with a period of weak correlation in the 1980s; 4） Analysis of tidal records validates the interdecadal weakening of the East Asian summer monsoon and reveals an atmospheric bridge that conveys the ENSO signal into the South China Sea via the winter monsoon.

Interannual to decadal variation of spring sea level anomaly in the western South China Sea

Satellite observations of sea level anomalies(SLA) from January 1993 to December 2012 are used to investigate the interannual to decadal changes of the boreal spring high SLA in the western South China Sea(SCS) using the Empirical Orthogonal Function(EOF) method. We find that the SLA variability has two dominant modes. The Sea Level Changing Mode(SLCM) occurs mainly during La Ni?a years, with high SLA extension from west of Luzon to the eastern coast of Vietnam along the central basin of the SCS, and is likely induced by the increment of the ocean heat content. The Anticyclonic Eddy Mode(AEM) occurs mainly during El Ni?o years and appears to be triggered by the negative wind curl anomalies within the central SCS. In addition, the spring high SLA in the western SCS experienced a quasi-decadal change during 1993–2012; in other words, the AEM predominated during 1993–1998 and 2002–2005, while the La Ni?a-related SLCM prevailed during 1999–2001 and 2006–2012. Moreover, we suggest that the accelerated sea level rise in the SCS during 2005–2012 makes the SLCM the leading mode over the past two decades.

Single-trial ERP evidence for the three-stage scheme of facial expression processing

Using a rapid serial visual presentation paradigm, we previously showed that the average amplitudes of six event-related potential (ERP) components were affected by different categories of emotional faces. In the current study, we investigated the six discriminating components on a single-trial level to clarify whether the amplitude difference between experimental conditions results from a difference in the real variability of single-trial amplitudes or from latency jitter across trials. It is found that there were consistent amplitude differences in the single-trial P1, N170, VPP, N3, and P3 components, demonstrating that a substantial proportion of the average amplitude differences can be explained by the pure variability in amplitudes on a single-trial basis between experimental conditions. These single-trial results verified the three-stage scheme of facial expression processing beyond multitrial ERP averaging, and showed the three processing stages of "fear popup", "emotional/unemotional discrimination", and "complete separation" based on the single-trial ERP dynamics.

Causes of Lake Area Changes in Poland

The northern part of Poland is occupied by numerous lakes formed during the last glaciation as a result of the Scandinavian ice sheet. Studies carried out in the lake district areas show progressive reduction of the surface area of the lakes, which leads to their eventual disappearance. The paper discusses the degree of the observed changes and points out main natural and anthropogenic factors influencing changes of lake area in Poland, including climate change, depth of lake basins, biomass growth, deforestation, hydrotechnical works, use of fertilizers and discharge of wastewater.