基于HOG及在线多实例学习的目标跟踪算法

传统的基于色彩直方图或空间色彩直方图的跟踪算法在跟踪目标出现尺度变化的复杂条件下,因无法显著区分颜色相近的目标和背景,不能得到准确跟踪结果.提出基于HOG及在线多实例学习的目标跟踪算法.此算法采用HOG特征值提取方式,结合在线多实例学习技术,对目标远离场景、平移、旋转、遮挡等情况进行跟踪.实验结果表明,该算法能够对各种复杂情况下的动态目标进行有效跟踪,具有良好的鲁棒性和准确性.     

PROPERTIES OF W/Cu FGMS CONTAINING 1%TiC OR 1%La2O3 PREPARED USING GSUHP

W / Cu functionally gradient materials (FGMs) containing 1%La_2O_3 and 1%TiC were prepared using graded sintering under ultra-high pressure (GSUHP). The specimens have been found to exhibit low porosity (11.57% and 11.35%, respectively). Shearing strength of the specimens between layers is good. Moreover, the specimens have still demonstrated good performance in testing thermal-shock resistance. When power density of laser is 200MWm~(-2), the specimens have been tested for thermal-shock resistance (1000 times); the specimens that contained 1%La_2O_3 were not subjected to damage, whereas those that contained 1%TiC began to crack. Finally, effect of additives on thermal-shock resistance was also preliminarily discussed.     

混合梯度稀疏先验约束下的图像盲复原

图像盲复原旨在无参考的情况下准确估计模糊核并恢复潜在的清晰图像。现有研究成果表明,利用全变分模型对高阶图像梯度先验约束进行描述可以有效抑制复原图像中产生的阶梯效应。本文在实验观察和研究的基础上,提出了采用稀疏先验约束模型对盲复原过程进行正则化的方法,以获得更佳的图像复原效果。该方法利用图像高阶梯度的稀疏性,通过与低阶梯度相结合来构造混合梯度正则项。同时,在正则项中引入基于图像熵的自适应因子,来调节迭代优化过程中两类梯度先验的比例,以此获得更好的收敛性。仿真与实验证明,与现有图像盲复原先进方法相比,本文方法具有更优越的图像复原性能。     

Böhler Edelstahl

Böhler Edelstahl produces high performance tool and high speed steels via an optimised powder metallurgy/hot isostatic pressing route, as part of a high value special alloys portfolio.     

负压差对固体进料系统压力分布和气固两相流动规律的影响

A series of experiments on a solid feed system was performed to investigate the effects of negative pressure gradient on the gas-solid flow pattern and hydrodynamic characteristics. Based on the non-fluidized gas-solid two phase flow and particulate mechanics in the standpipe, a method for predicting the pressure of the air passing through the recycle chamber and the pressure drop through the loop seal slit in these systems is also presented. The predicted pressure profile along the negative pressure gradient from the proposed model exhibits a good agreement with the experimental data. The experimental data show that the gas flow in the standpipe is always upward in the negative pressure gradients, while the direction of gas cannot be changed by the drag force. The solid flow rate, the materiel bed height in the recycle chamber (Hf), the pressure drop across the slit (△Pg） decrease with an increasing negative pressure gradient. At a given negative pressure gradient, the superficial gas velocity through the recycle chamber of the loop seal does not affect the pressure drop in standpipe. It increases with an increasing negative pressure gradient.     

基于改进Canny算子的垃圾图像边缘检测

为提高垃圾识别分类的准确率,文中在垃圾图像预处理过程中提出了一种基于改进Canny算子的垃圾图像边缘检测方法。该方法从传统Canny算子滤波方式、梯度方向及阈值自适应3个角度实现了垃圾图像边缘检测的优化。针对Canny算子高斯滤波仅适用于高斯噪声和边缘细节易丢失的问题,采用改进的梯度倒数加权法进行滤波。针对Canny算子易检测出伪边缘的问题,通过在计算图像梯度方向的过程中增加方向梯度模板实现了边缘的精确化。同时采用最小误差法解决人工设定阈值的局限性,实现阈值自适应。实验结果表明,该方法在去噪性能和边缘细节两方面得到了改进,获得了更好的边缘检测效果,为后续垃圾图像的识别分类提供了技术保障。     

宽线性共轭梯度算法及其在盲多用户检测中的应用

本文提出了一种宽线性共轭梯度算法，分析了算法在均值意义下的收敛性，并给出了算法稳定条件。仿真表明，新算法应用于码分多址系统多址干扰抑制时的性能优于Yin（2003）及Schober（2004）所提出的算法。     

335 GHz非平衡式肖特基二极管三倍频器

基于混合集成的方式,采用对称锥形渐变线匹配结构设计了335 GHz非平衡式三倍频器。在保证单模传输的条件下,该匹配结构不仅能够固定二极管位置,而且可以增大匹配效果,解决了高频段倍频器3 dB带宽较窄的问题。实测结果表明,该倍频器在330~356 GHz频率范围内输出功率均大于5 mW。驱动功率为220 mW时,有最高输出功率11.2 mW,由它作为核心器件组成的固态太赫兹本振源,能够驱动超外差接收机中670 GHz二次谐波混频器。     

大直径大折射率差轴向梯度折射率玻璃

采用一般商用铅 硅酸盐系列玻璃,按折射率分布从低到高排列成多层堆片,在650～800℃下进行熔融/扩散,形成一种大直径(40mm×40mm×0.5mm)、大轴向梯度折射率(Δn≈±0.4)线性剖面分布的玻璃板。这种材料对光学设计提供了校正像差的附加自由度。     

12位80MHz采样率具有梯度误差补偿的CMOS电流舵D/A转换器实现

提出了一种12位80 MHz采样率具有梯度误差补偿的电流舵D/ A转换器实现电路.12位DAC采用分段式结构,其中高8位采用单位电流源温度计码DAC结构,低4位采用二进制加权电流源DAC结构,该电路中所给出的层次式对称开关序列可以较好地补偿梯度误差.该D/ A转换器采用台湾U MC 2层多晶硅、2层金属(2 P2 M) 5 V电源电压、0 .5μm CMOS工艺生产制造,其积分非线性误差小于±0 .9L SB,微分非线性误差小于±0 .6 L SB,芯片面积为1.2 7mm×0 .96 m m ,当采样率为5 0 MHz时,功耗为91.6 m W.