Research on Several Key Technical Problems in Face Recognition Based on Manifold Learning

人脸识别作为生物特征识别的主流技术之一，是国内外研究和应用的热点。主流的人脸识别技术对光照、姿态等由于非理想采集条件或者用户不配合造成的变化鲁棒性较差。流形学习是近年来机器学习及模式识别等领域的研究热点。人脸从某种意义上来说是一种典型的流形结构，人脸数据集是由某些内在变量控制形成的非线性流形。因此，基于流形学习的人脸识别研究近年来引起了人们的广泛关注，成为该领域的热门研究课题。 本文通过仿真实验，系统分析主流线性和非线性流形学习算法在人脸识别中应用的可行性，优势及存在的问题。针对流形学习在人脸识别应用中的本征维数估计问题、测试数据的out-of-sample问题、无监督学习问题以及人脸识别技...As a dominant technology of Biometric Verification Technologies, human face recognition has become a hot research and application topic both at home and abroad. However, due to the complexity of human face structure, the diversity of illumination, face pose and facial expression, face recognition technology is universally considered a challenging study topic. In recent years, manifold learning has...学位：工学硕士院系专业：信息科学与技术学院计算机科学系_计算机软件与理论学号：2302008115321

A New Easy Fast Camera Self-Calibration Technique

本文提出了一种新的相机自标定方法,该方法要求摄像机在3个(或3个以上)不同方位摄取一个包含其内接正三角形的圆的新型标定模板的图像。首先,从模板图像中推导得到圆环点的像点坐标;然后通过得到的圆环点像点坐标,可线性求解摄像机内参数。与传统方法不同的是,该方法避免了复杂的椭圆拟合和直线拟合,降低了计算复杂度,提高了标定速度和精度,对噪声更加鲁棒。此外,该方法中的标定过程不需要模板的任何物理度量,也不要建立模板及其图像上点的对应,标定过程简单易于操作。基于模拟和真实图像的实验验证了该方法的有效性和鲁棒性。In this paper,we present a new camera calibration approach by taking three images at least of the proposed planar pattern which includes an arbitrary circle with its inscribed regular triangle under different orientations.First,the imaged circular points are derived from the images of the proposed planar pattern.And then,the camera intrinsic matrix and extrinsic matrix are determined via the obtained imaged circular points.In contrast to the conventional methods,our method avoids ellipse and line fittings.It reduces the computing complexity and it is more robust to noise.Another advantage of our method is that neither any metric measurement on the model plane,nor the point correspondences is necessary;hence the calibration process becomes extremely simple.Experiments on both synthetic data and real image data demonstrate the robustness and effectiveness of our method.国家自然科学基金资助项目(60873179);深圳市科技计划基础研究项目(JC200903180630A

环孢素治疗中重度干眼症的对照研究

【目的】观察0．2％（2g/L）环孢素滴眼液对中重度干眼症的效果。【方法】将中重度干眼症134例随机分为对照组（65例）和实验组（69例）。对照组应用10g/L羧甲基纤维素钠，4次／d，实验组应用10g/L羧甲基纤维素钠和2g／L环孢素滴眼液，4次/d。两组均连续用药1个月。用药前后均进行荧光素染色检查、泪液分泌检查（STT）、泪膜破裂时间检测（BUT）、结膜印迹细胞检查。【结果】两组比较在治疗前差异无统计学意义（P〉0．05），治疗后实验组SIT、BUT比对照组的结果有统计学意义（P〈0．01），实验组治疗前后结果比较有统计学意义（P〈0．01）。对照组的治疗前后比较差异无统计学意义（P〉0．05）。【结论】2g/L环孢素滴眼液治疗中重度干眼确有良好的效果

Research on 3D Bilinear Multidimensional Morphable Models

形变模型在计算机视觉和计算机图形学等领域均有广泛的应用.但现有形变模型的建立或依赖于不稳定的人脸图像对应光流算法,或需要大量的人机交互,而且基于随机梯度下降算法的模型匹配过程常收敛于局部最优值.针对这些缺陷,提出三维双线性多分辨率形变模型.首先基于人脸关键特征分割和网格重采样建立原始人脸的自动稠密对应;然后经紧致凸松弛将模型匹配问题转化为两个双线性规划问题,最后通过基于内点方法的全局优化算法求解.基于模拟和真实数据的实验表明:该模型在最优性、模型匹配速度、收敛性和对噪声异常点的鲁棒性优于传统的形变模型.Morphable model has widespread applications in computer vision and computer graphics.The current model construction method either depends on the unstable optical flow algorithm or it requires lots of human-machine interactions.The model matching procedure based on stochastic gradient descent algorithm often gets stuck in the local optimum.In this paper,3D bilinear multidimensional morphable models are proposed.Firstly,dense correspondences between prototypic faces are constructed by face segmentation based on key feature and the mesh resampling.And then the model matching problem is converted into two bilinear programs after tight convex relaxations.Finally,the bilinear programs are efficiently solvable by modern interior point methods.Experiments with synthetic data and real image data validate that the 3D bilinear multidimensional morphable models outperform the morphable models in optimality,model matching speed,convergence rate and robustness to noise and outliers.国家自然科学基金项目(60873179);深圳市科技计划基础研究项目(JC200903180630A);高等学校博士学科点专项科研基金(20090121110032

20个燕麦品种饲草产量和品质比较分析

适宜的品种和收获时期是燕麦饲草高产和高品质的关键因素.研究了国内外20个主要饲用燕麦品种(7个裸燕麦Avena nuda L,13个皮燕麦Avena sativa L)在河北坝上地区连续种植三个生长季(2017～2019)不同生育期饲草产量的变化规律,同时比较了不同生育期燕麦的饲草品质.结果表明:(1)从孕穗期、抽穗期、开花期、乳熟期到完熟期,20个燕麦品种饲草产量(地上生物量干重)都在逐渐增加,在完熟期达到最大值.品种坝莜18号、远杂1号、GL381饲草产量在成熟期超过12 t ha~(-1).(2)随着生育期从孕穗期到完熟期,粗蛋白含量和代谢能逐渐下降,相对饲用价值先降低后增加,拐点出现在开花期或乳熟期.综合粗蛋白含量、相对饲用价值、代谢能三个品质指标,白燕9号、青引2号、陇燕3号和KONA的饲草品质较高.(3)随着生育期从孕穗期到完熟期,饲草品质产量指标粗蛋白产量、相对饲用价值产量和代谢能产量都在逐渐增加,在完熟期达到最大值,坝莜18号、远杂1号、GL381和Haywire最高.因此,建议在河北坝上及周边相似气候区种植饲草用燕麦时,根据最大生物量和最大饲草品质产量选择适宜的品种,推荐坝莜18号、远杂1号和GL381

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements