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101.
Xiaoming Peng Author Vitae Mohammed Bennamoun Author Vitae Author Vitae 《Pattern recognition》2011,44(3):544-558
Nose tip detection in range images is a specific facial feature detection problem that is highly important for 3D face recognition. In this paper, we propose a nose tip detection method that has the following three characteristics. First, it does not require training and does not rely on any particular model. Second, it can deal with both frontal and non-frontal poses. Finally, it is quite fast, requiring only seconds to process an image of 100-200 pixels (in both x and y dimensions) with a MATLAB implementation. A complexity analysis shows that most of the computations involved in the proposed algorithm are simple. Thus, if implemented in hardware (such as a GPU implementation), the proposed method should be able to work in real time. We tested the proposed method extensively on synthetic image data rendered by a 3D head model and real data using FRGC v2.0 data set. Experimental results show that the proposed method is robust to many scenarios that are encountered in common face recognition applications (e.g., surveillance). A high detection rate of 99.43% was obtained on FRGC v2.0 data set. Furthermore, the proposed method can be used to coarsely estimate the roll, yaw, and pitch angles of the face pose. 相似文献
102.
103.
介绍了活性氧的种类、代谢途径和测定方法,以及植物人存在的抗氧化机制、植物与病原物互作中活性氧的产生及遗传基础,重点对活性氧在植物与病原物互作中抗病信号转导、抗菌作用、膜脂氧化、细胞壁强化、植保素合成和过敏性细胞死亡等方面进行了综述。 相似文献
104.
The antioxidant -tocopherol (vitamin E), applied in a basal trunk band to the green ash tree,Fraxinus pennsylvanica var.subintergerrinia, elicited an alteration of foliar feeding byMalacosoma disstria larvae (Lepidoptera: Lasiocampidae). The bioassayed effects were dependent on the dosage of elicitor, the time after elicitation, and the position in the tree. Leaves for chemical analysis were collected from trees receiving two dosages and at two intervals after elicitation. Compounds in the ethyl acetate extractables from the ash tree leaves were separated by TLC and HPLC. TLC separations showed differences in the nonhydrolyzed extractables attributable to elicitor dosage and time after elicitation. TLC-resolved differences were also evident among acid-hydrolyzed samples. HPLC-resolved profiles revealed eight peaks in the nonhydrolyzed extractables that were quantitatively negatively correlated with larval feeding preference between elicited versus control foliage on at least one of the two sampling dates. Results from this study and other investigations reported in the literature indicate that the antioxidant-tocopherol (vitamin E) can function as an environmental-stress elicitor of alterable defensive chemistry in green ash and other plants. 相似文献
105.
106.
高纯四溴双酚A双(2,3-二溴丙基)醚合成新工艺 总被引:7,自引:0,他引:7
研究了合成阻燃剂四溴双酚A双(2,3-二溴丙基)醚的新工艺,特点是通过加入表面活性剂TABS、催化剂SB和表面活性剂A的方法,提高产品纯度和降低游离酸的含量,成品的炭化温度为295℃,纯度大于95%。 相似文献
107.
108.
《Ergonomics》2012,55(2):149-157
Distinction can be drawn between three types of letter sorting machines and these types can also be used to classify other kinds of machine and task. In one type (‘paced ’) the speed of operation is set by the machine : in another (‘ unpaced’) the speed is determined by the operator's own actions, and in a third (‘ lagged ’) the speed is determined by the operator, but a minimum time (a ‘ time lag ’) has to elapse between one operation and the next. The performance of 7 operators on a lagged letter sorting machine was observed over a period of 9 months. Records were taken of mean sorting rate, and of the distribution of sorting times. Practice effects are shown to have been continuing at the end of this period, and it is argued that the distribution of sorting times has been affected by the machine' lag. By assuming a distribution that would be expected if there were no lag, tables are presented which estimate what the sorting rate would be (a) if there were no log at all, (b) for different values of lag and (c) for different values of paced rate. 相似文献
109.
针对在超高绝缘电阻测量时,因存在衰减缓慢的时变非线性背景电流而难以快速准确测量的难题,提出一种基于非线性误差抑制算法的超高阻测量方法。首先分组交替改变测试电压极性,测量相应静电计输出信号,再根据非线性误差电流特点,采用n次多项式表示相邻n+2个分组的背景电流,构建连续n+2个分组测量的输出电压矩阵,最后通过误差抑制算法得到不含背景电流项的测量结果。实验结果表明,采用非线性误差电流抑制算法可将由固有衰减时间引起的测量过渡时间从长达数十分钟至数小时缩短到数分钟,同时提高了在10~0.1 pA极微电流条件下的超高阻测量精度,绝缘电阻测量量程可有效扩展到1016Ω量级。 相似文献
110.
本文介绍了常用的蓄电池监测方法和智能蓄电池组监测系统的应用。该系统可应用于各种蓄电池组的性能监测,综合判定蓄电池组的性能,有效地活化蓄电池的使用寿命,并能对失效的电池给以报警提示。 相似文献