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The morphological characteristics and the cuttlebone formation of Sepia esculenta exposed to different water temperature fluctuations were investigated under laboratory conditions. Temperature fluctuation cycles (15 cycles, 60 d in total) consisted of the following three regimes of 4 d duration: keeping water temperature in 26°C for 3 d (Group A), 2 d (Group B), 0 d (Group C, control); then keeping water temperature in 16°C for the next 1, 2, 4 d. No significant difference in the survival rate was observed between the control and temperature fluctuation groups (P>0.05). Lamellar depositions in a temperature fluctuation cycle were 2.45±0.02 for Group A, 2.00±0.02 for Group B, and 1.78±0.02 for Group C (P<0.05). The relationship between age and number of lamellas in the cuttlebone of S. esculenta under each water temperature fluctuation could be described as the linear model and the number of lamellas in the cuttlebone did not correspond to actual age. Group A had the highest cuttlebone growth index (CGI), the lowest locular index (LI), and inter-streak distances comparing with those of control group. However, the number of lamellas and LI or CGI showed a quadratic relationship for each temperature fluctuation group. In addition, temperature fluctuations caused the breakage of cuttlebone dark rings, which was considered a thermal mark. The position of the breakage in the dark rings was random. This thermal mark can be used as supplementary information for marking and releasing techniques. 相似文献
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研究伪距定位中衰减记忆无迹卡尔曼滤波(MAUKF)方法,针对衰减记忆UKF滤波器可能因衰减因子引入造成滤波精度降低、滤波收敛速度并没有得到改善的问题,本文依据预测残差的统计量,对衰减记忆UKF滤波算法进行了改进。仿真结果表明,该算法相比衰减记忆UKF算法提高了定位精度和收敛速度。 相似文献
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采用传统棋盘格进行相机标定时,标定模板旋转角度对角点排序带来较大的影响,针对此设计了一种黑白环扇圆盘标定模板,并提出了与该标定模板相应的角点识别和排序算法。新的标定模板设计中心圆为1/4缺口的黑色圆,以此来消除标定模板旋转给角点排序带来的影响。通过模板区域分割算法实现标定模板的提取;创建圆形检测器剔除Harris算法提取的伪角点;利用向量积和角点几何特性完成角点排序。实验结果表明:该标定模板及其角点识别与排序算法可以有效剔除伪角点,角点排序具有良好的旋转不变性,能够实现自动相机标定。 相似文献
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一种用于机器视觉检测的图像配准快速算法 总被引:2,自引:0,他引:2
图像配准是机器视觉检测的关键步骤之一。针对产品包装印刷质量检测,文中提出了一种新的图像配准算法。其基本思想是:首先进行图像概略匹配得到特征点的概略位置,接着进行特征点的精确检测,根据检测到的对应特征点坐标计算转换参数,最后生成配准图像。实验表明,该算法计算速度快,具有较好的精度和稳定性,适用于在线机器视觉检测等对速度要求高,而图像只有小角度旋转的情况。 相似文献
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土地资源调查利用的土地类型数据多为不同比例尺电子矢量地图,以此数据为研究基础,详细介绍了Delaunay三角网及其Voronoi多边形的特性,以及在土地数据类型中的图斑综合与点群目标综合中的算法应用,具体描述了两种算法的实现过程和试验结果,并对几种点群目标算法进行了简要分析和比对,详细介绍了实现过程;重点阐述了图斑综合算法的思想和算法的具体实现.最后以"土地利用数据库智能化自动综合系统"为例验证了算法方案的合理性和可行性. 相似文献