为解决动态背景下运动目标检测所得目标较为微弱且目标区域离散的问题,文中提出一种动态背景下的运动目标检测算法。首先利用SURF(Speeded Up Robust Features)算法提取图像中的特征点,通过双向匹配法去除误匹配的SURF特征点对,并将特...为解决动态背景下运动目标检测所得目标较为微弱且目标区域离散的问题,文中提出一种动态背景下的运动目标检测算法。首先利用SURF(Speeded Up Robust Features)算法提取图像中的特征点,通过双向匹配法去除误匹配的SURF特征点对,并将特征点分为前景点和背景点两部分;再利用背景点计算仿射变换矩阵,以提高仿射变换矩阵的准确性,完成背景运动的补偿,消除背景运动对目标检测的影响。然后对补偿后的图像采用帧差法和形态学操作,完成对目标的初步提取。最后利用颜色、位移和位置信息对目标进行归并处理,完成运动目标的检测。实验结果表明,文中算法能够准确检测出运动目标,并且所得目标较为明显且目标区域连续。说明文中算法准确率高且具有较强的鲁棒性。展开更多
We have previously found that unilateral labyrinthectomy is accompanied by modification of hyaluronan and chondroitin sulfate proteoglycan staining in the lateral vestibular nucleus of rats and the time course of subs...We have previously found that unilateral labyrinthectomy is accompanied by modification of hyaluronan and chondroitin sulfate proteoglycan staining in the lateral vestibular nucleus of rats and the time course of subsequent reorganization of extracellular matrix assembly correlates to the restoration of impaired vestibular function. The tenascin-R has repelling effect on pathfinding during axonal growth/regrowth, and thus inhibits neural circuit repair. By using immunohistochemical method, we studied the modification of tenascin-R expression in the superior, medial, lateral, and descending vestibular nuclei of the rat following unilateral labyrin- thectomy. On postoperative day 1, tenascin-R reaction in the perineuronal nets disappeared on the side of labyrinthectomy in the superior, lateral, medial, and rostral part of the descending vestibular nuclei. On survival day 3, the staining intensity of tenascin-R reaction in perineuronal nets recovered on the operated side of the medial vestibular nucleus, whereas it was restored by the time of postoperative day 7 in the superior, lateral and rostral part of the descending vestib- ular nuclei. The staining intensity of tenascin-R reaction remained unchanged in the caudal part of the descending vestibular nucleus bilaterally. Regional differences in the modification of tena- scin-R expression presented here may be associated with different roles of individual vestibular nuclei in the compensatory processes. The decreased expression of the tenascin-R may suggest the extracellular facilitation of plastic modifications in the vestibular neural circuit after lesion of the labyrinthine receptors.展开更多
In design of flexure mechanism, diminishing the parasitic-motion is a key point to improve the accuracy. However, most of existing topics concentrate on improving the accuracy of linear-motion flexure mechanisms via c...In design of flexure mechanism, diminishing the parasitic-motion is a key point to improve the accuracy. However, most of existing topics concentrate on improving the accuracy of linear-motion flexure mechanisms via compensating the parasitic error, but few research the multi-dimensional flexure mechanisms. A general design principle and method for high-precision flexure mechanisms based on the parasitic-motion compensation is presented, and the proposed method can compensate the parasitic rotation in company with translation, or the parasitic translation in company with rotation, or both. The crucial step for the method is that the parasitic motion of a flexure mechanism is formulated and evaluated in terms of its compliance. The overall compliance matrix of a general flexure mechanism is formulated by using screw theory firstly, then the criteria for the parasitic motions is introduced by analyzing the characteristics of the resultant compliance matrix as well as with aid of the concept of instantaneous rotation center. Subsequently, a compliance-based compensation approach for reducing parasitic-motion is addressed as the most important part. The design principles and procedure are further discussed to help with improving the accuracy of flexure mechanisms, and case studies are provided to illustrate this method. Finally, an analytical verification is provided to demonstrate that the symmetry design philosophy widely used in flexure design can effectively improve accuracy in terms of the proposed method. The proposed compensation method can be well used to diminish the parasitic-motion of multi-dimensional flexure mechanisms.展开更多
文摘为解决动态背景下运动目标检测所得目标较为微弱且目标区域离散的问题,文中提出一种动态背景下的运动目标检测算法。首先利用SURF(Speeded Up Robust Features)算法提取图像中的特征点,通过双向匹配法去除误匹配的SURF特征点对,并将特征点分为前景点和背景点两部分;再利用背景点计算仿射变换矩阵,以提高仿射变换矩阵的准确性,完成背景运动的补偿,消除背景运动对目标检测的影响。然后对补偿后的图像采用帧差法和形态学操作,完成对目标的初步提取。最后利用颜色、位移和位置信息对目标进行归并处理,完成运动目标的检测。实验结果表明,文中算法能够准确检测出运动目标,并且所得目标较为明显且目标区域连续。说明文中算法准确率高且具有较强的鲁棒性。
基金supported by a grant from the Hungarian Academy of Sciences(MTA-TKI 11008)a grant from the European Union and the State of Hungarythe European Social Fund in the framework of TáMOP-4.2.4.A/2-11/1-2012-0001‘National Excellence Program’
文摘We have previously found that unilateral labyrinthectomy is accompanied by modification of hyaluronan and chondroitin sulfate proteoglycan staining in the lateral vestibular nucleus of rats and the time course of subsequent reorganization of extracellular matrix assembly correlates to the restoration of impaired vestibular function. The tenascin-R has repelling effect on pathfinding during axonal growth/regrowth, and thus inhibits neural circuit repair. By using immunohistochemical method, we studied the modification of tenascin-R expression in the superior, medial, lateral, and descending vestibular nuclei of the rat following unilateral labyrin- thectomy. On postoperative day 1, tenascin-R reaction in the perineuronal nets disappeared on the side of labyrinthectomy in the superior, lateral, medial, and rostral part of the descending vestibular nuclei. On survival day 3, the staining intensity of tenascin-R reaction in perineuronal nets recovered on the operated side of the medial vestibular nucleus, whereas it was restored by the time of postoperative day 7 in the superior, lateral and rostral part of the descending vestib- ular nuclei. The staining intensity of tenascin-R reaction remained unchanged in the caudal part of the descending vestibular nucleus bilaterally. Regional differences in the modification of tena- scin-R expression presented here may be associated with different roles of individual vestibular nuclei in the compensatory processes. The decreased expression of the tenascin-R may suggest the extracellular facilitation of plastic modifications in the vestibular neural circuit after lesion of the labyrinthine receptors.
基金Supported by National Natural Science Foundation of China(Grant No.51305022)the Fundamental Research Funds for the Central Universities,China(Grant No.FRF-TP-13-013A)National Science Foundation for Post-doctoral Scientists of China(Grant No.2012M520163)
文摘In design of flexure mechanism, diminishing the parasitic-motion is a key point to improve the accuracy. However, most of existing topics concentrate on improving the accuracy of linear-motion flexure mechanisms via compensating the parasitic error, but few research the multi-dimensional flexure mechanisms. A general design principle and method for high-precision flexure mechanisms based on the parasitic-motion compensation is presented, and the proposed method can compensate the parasitic rotation in company with translation, or the parasitic translation in company with rotation, or both. The crucial step for the method is that the parasitic motion of a flexure mechanism is formulated and evaluated in terms of its compliance. The overall compliance matrix of a general flexure mechanism is formulated by using screw theory firstly, then the criteria for the parasitic motions is introduced by analyzing the characteristics of the resultant compliance matrix as well as with aid of the concept of instantaneous rotation center. Subsequently, a compliance-based compensation approach for reducing parasitic-motion is addressed as the most important part. The design principles and procedure are further discussed to help with improving the accuracy of flexure mechanisms, and case studies are provided to illustrate this method. Finally, an analytical verification is provided to demonstrate that the symmetry design philosophy widely used in flexure design can effectively improve accuracy in terms of the proposed method. The proposed compensation method can be well used to diminish the parasitic-motion of multi-dimensional flexure mechanisms.
