211 research outputs found

    香溪河小水电的梯级开发对浮游藻类的影响

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    以香溪河干流上5个连续的小水电站为对象,于2005年10月20—22日分别对其浮游藻类和主要理化指标进行研究.结果表明:硅藻占绝对优势(95.54%),其中,线性曲壳藻(Achnanthes linearis)、披针曲壳藻椭圆变种(A.lanceolatavar.elliptica)、扁圆卵形藻(Cocconeisplacentula)为绝对优势种,其平均相对丰富度分别为23.96%、18.62%和12.48%;所有样点的平均藻类密度为6.29×105ind.L-1,最高为1.81×106ind.L-1

    洱海流域水生态分区

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    分区边界的确定是生态分区的重要步骤,但目前多数水生态分区的边界确定以定性分析、专家判断为主。本研究以洱海流域为例,建立了一套两级分区体系。该体系基于GIS技术,用子流域作为分区基本单元,并用相关分析法,定量筛选一、二级分区指标。其中,一级分区指标为高程、坡度和植被归一化指数(NDVI),二级分区指标为农田百分比和城镇百分比。通过指标图层的叠加和重分类,合并同质性子流域,从而将洱海流域划分为5个一级区和9个二级区。藻类群落分布的验证结果表明分区合理。本研究将定量分析和子流域边界应用于水生态分区,使分区边界的确定更科学,在实际管理中更具有可操作性。本研究结果为水生态分区研究提供了新的方法,为洱海流域水生态管理提供了基本管理单元

    Contour Detection Based on Compound Receptive Field

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    自然场景自动检测目标轮廓是非常困难的。该文提出了一种基于复合感受野的图像轮廓检测仿生模型。在传统的基于抑制模型的基础上引入去抑制机制,在减少背景纹理干扰的同时,保护较弱的轮廓,从而尽量保持轮廓的完整性。实验结果表明,这种仿生模型可以有效地抑制纹理边缘,减少对轮廓的破坏,提高了自然背景中轮廓检测的性能。Contour detection from natural scenes is a tough task in computer vision.This paper proposes a visual model of contour detection based on compound receptive field.By inducing dis-inhibition mechanism to traditional model that was based on inhibition mechanism,inferences are suppressed while weak edges are preserved,so that the integrity of contour is improved.Experiment results show that this approach can suppress edges due to texture,protect object contour and improve the performance of contour detection from nature scene.国家973计划项目(2007CB311005);国家863计划项目(2006AA01Z129);福建省自然科学基金(A0710020);厦门大学985二期信息创新平台项目资助课

    Moving Object Detection Algorithm in Video Sequences

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    提出一种基于前景目标分类的视频序列中运动目标检测方法。该方法在RGB空间内建立了一种新颖的背景模型;为了解决背景更新“死锁”问题,提出了像素点的跳跃度函数和稳定性函数,将前景分类为静止目标、运动目标及虚假目标;最后提出了一种基于HSV颜色信息和一阶梯度信息的混合阴影剪除算法。实验结果表明,该方法能有效分割视频场景中的运动目标并鲁棒地分离目标及其阴影区域。An efficient algorithm of detecting moving objects in video sequences was proposed.An adaptive background model was built and subsequently the background model is updated by a foreground object classification based background update algorithm which can resolve the "deadlock" problem efficiently.An improved shadow suppression algorithm which combines HSV color information with first-order image gradient information was exploited to segment shadows.Extensive experiments results on indoor and outdoor image sequences demonstrate that the proposed system can effectively detects moving objects and suppresses their shadows.国家自然科学基金资助项目(60175008);; 国家创新研究群体科学基金项目(60024301

    A bionic image filter using extended surround receptive field

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    针对图像处理的噪声平滑和对比度增强问题,提出了一种仿生图像滤波器.滤波器模拟初级视皮层自适应机制和大周边感受野(包括经典感受野、经典外周与去抑制区)3个区域之间的作用机制;引入自适应形状的核函数模拟自适应方向选择机制以平滑噪声;进而利用3个不同尺度的核函数来模拟大周边感受野的3个区域,通过3个区域的加权组合调节边缘区域的对比度.对灰度图像的处理实验表明:这种仿生图像滤波器可以有效地平滑图像噪声,增强细节特征,使图像在视觉效果上得到明显改善.De-nosing and contrast enhancement in image processing were dealt.Then a novel bionic image filter was proposed.The proposed filter simulated the spatially adaptive mechanism in primary visual cortex and the mechanism of the extended surround field(which included the classical receptive field,classical surround and dis-inhibition area).In order to smooth noises,shape adaption of kernel was introduced which simulated the spatially orientation-selective mechanism.Furthermore,three different bandwidth kernels were introduced to simulate these three areas of extended surround field and their weighted combination was used to adjust the contrast of edge regions.Experimental results on grey images show that this bionic filter is a fruitful method to smooth noise,enhance weak information and improve visual quality of image.国家重点基础研究发展计划资助项目(2007CB311005);福建省自然科学基金资助项目(A0710020);河南省教育厅自然科学基础研究计划资助项目(2007510023);河南省高等学校青年骨干教师资助计划项目;厦门大学985二期信息创新平台资助项

    Moving Object Tracking Based on Location and Confidence of Pixels

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    运动目标跟踪是视频信息处理的重要研究课题之一·首先将时间域上的中值背景建模与空间域上最小交叉熵法相结合,用于检测运动目标所在跟踪区域·在此基础上,提出了跟踪区域内基于像素的可信度与空间位置的权重函数,利用HSV色彩分布模型计算出目标模型与预测模型间的相似性,选出最优相似模型作为当前目标模型,从而实现了多目标的跟踪·实验显示,该算法计算简单,对相似目标能实现准确的跟踪,对非刚性目标的尺度变化、多目标的交叉及部分遮挡具有鲁棒性·Moving object tracking is a critical issue of image sequence processing. In this paper, a moving object tracking algorithm based on location and confidence of pixels is proposed. Firstly, the moving objects are detected by combining the median background model in temporal domain with the minimum cross-entropy in spa tial domain. Then the rectangle area of the objects are obtained, and at the sa me time an HSV color distribution model is used to measure the similarity betwe en t arget rectangles and hypothetical rectangles. In this process, a weighting func tion based on location and confidence of pixels is presented to weigh the pixel values in the rectangle area of the tracking. The experimental results show tha t the algorithm is computationally efficient and robust to scale invariant, part ial occlusion and interactions of non-rigid objects, especially similar objects .国家创新研究群体基金项目(60024301);; 国家自然科学基金项目(60175008

    Detection of Tongue's Crack Based on Adaptive Threshold

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    舌象中的裂纹是中医舌诊中的重要内容。由于拍摄条件的不同,舌象质量有较大差异,传统的阈值选取方法并不适用。文中提出一种舌象裂纹检测的自适应阈值选择方法。该方法利用舌象的l*A*b色彩特征及区域的分裂-合并,对舌象进行区域分割,自适应地选取舌中部区域的色彩值作为阈值,对整个舌象进行裂纹提取。经验证,本方案对不同的舌象能较好地提取出裂纹,实现舌象裂纹诊断的客观化。Tongue's crack is a very important part of herbalist doctor diagnosis.For the different screen conditions,there are many differences on the tongue's quality.It is not effective to use the traditional threshold extraction algorithm.In order to solve this problem,propose a new adaptive threshold algorithm.Present the segmentation of the image of tongue by using the feature on tongue in the L*a*b color space and the split-combining algorithm.Then use the threshold,which is the color value extracted automatically in the middle of the tongue, to detect the crack of the whole tongue.The experiments show that this approach is able to distill the crack effectively to different tongue images,and achieve the objectivity of the diagnosis based on the tongue's crack.国家973项目资助(2007CB311005-02

    极化液治疗急性心肌梗死研究的进展

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    极化液(gIk)作为调节代谢的一种溶液组合,最早是由SOdI-PAllArES等人提出用来保护缺血心肌的。有实验证实gIk可降低急性心肌梗死(AMI)患者死亡率,也有实验表明gIk对AMI患者毫无作用,甚至增加早期AMI患者死亡率。本文就gIk在AMI中的作用做一篇综述。国家自然科学基金资助项目(81170090);福建省自然科学杰出青年基金(2009D015);厦门市杰出青年科技人才创新计划项目(3502Z20116009);厦门市科技局科研基金(3502Z20094006

    Novel approach to SVD-based image filtering improvement

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    提出一种提高SVd滤波性能的新方法。基于奇异值分解滤波可以有效地分析水平(垂直)方向的图像特性。根据图像的局部方向,自适应地调整待滤波区域的形状,使重采样后局部区域中的边缘垂直或水平,再对局部区域进行奇异值分解滤波;所得的结果加权平均,得到信号估计值。将这一算法应用于图像去噪,实验结果表明,新方法可以有效地提高SVd的滤波性能。A novel approach to improve the filtering efficiency of a noisy image is proposed.Image filtering based on SVD favors the denoising in the line(horizontal)and column(vertical)direction.Based on this property,the new denoising method adapts shape and size of block to local orientation before performing SVD filtering.Through over-complete representation in overlap regions,the proposed method performs well in denoising and preserving image details.国家重点基础研究发展规划(973)(No.2007CB311005);福建省自然科学基金计划资助项目(No.A0710020);厦门大学985二期信息创新平台项目(No.2004-2008)---

    南水北调中线水源区溪流生态系统健康评价

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    2007年7月—2008年5月,对南水北调中线水源区丹江口水库若干入库溪流的河流水文、河流形态、河岸带、水体理化和底栖生物进行调查并应用河流健康综合评价指数进行评价。结果表明,位于上游的溪流生态系统健康状况较好,而位于城镇下游的溪流生态系统健康状况较差,主要体现在河流形态的改变、底栖藻类自养指数升高和底栖动物多样性减小。提出维持丹江口入库溪流生态系统健康的建议,除了对上游地区要进行生态环境保护外,更要对中游地区受破坏的河流形态进行恢复
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