摘要
扫描离子电导显微镜(SICM)能够在非接触条件下获取样品表面纳米级形貌特性信息,可以在生理液态环境下实现对活体细胞等柔软样品无损成像。但是通过前期大量实验结果,发现在使用连续扫描模式时SICM扫描图像存在"拖尾"现象,导致图像失真,并限制了扫描成像速度。针对这一问题,结合SICM成像原理进行分析,得出电流逼近曲线高度非线性是产生这一现象的主要原因,并提出一种基于电流偏差补偿模型的SICM自适应控制方法。主要思想是建立电流偏差补偿模型,利用上一行扫描高度数据作为先验知识预测当前扫描点位置,并输入补偿模型得到新的电流偏差作为系统被控量。最后分别用新旧控制算法对标准栅格扫描图像进行成像效果对比,实验结果验证了该算法在一定扫描速度范围内能够有效地解决"拖尾"现象,明显减小图像失真,为进一步提高SICM系统成像质量和成像速度提供了一种有效的技术方法。
Scanning ion conductance microscopy （SICM） can be used to obtain the surface topography of the sample under non-contact conditions. It can realize the nondestructive imaging of soft samples, e. g. , living cells in physiological liquid environment. However, there is smearing phenomenon in the S1CM image when using the continuous feedback-control scanning mode which is found through a large number of experimental results. It causes the image distortion and limits the scan speed, To solve this problem, the SICM imaging principle is analyzed. It is concluded that the highly nonlinearity of the approach curve is the main reason for this phenomenon, and an adaptive control method based on current-error compensation model for SICM is proposed in this study. The main idea is to establish a current-error compensation model, predict the current scanning point position by using the scanning data of the last line as the prior knowledge, and then put it into the compensation model to calculate the new current-error as the system controlled variable. Finally, the performance of scan images for the standard grating under the new and old control algorithms is compared. The experimental results show that the new algorithm can effectively solve the smearing phenomenon at a certain degree of scanning speed and significantly reduce the image distortion. It provides an effective techniea, method to improve the image quality and imaging speed of SICM system.
作者
滕泽宇
于鹏
杨洋
杨铁
刘连庆
Teng Zeyu Yu Peng Yang Yang Yang Tie Liu Lianqing(Shenyang Institute of Automation, China Academy of Sciences, Shen yang 110016, China School of lnformation Science and Engineering, Northeastern University, Shenyang 110819, China)
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2017年第9期2258-2265,共8页
Chinese Journal of Scientific Instrument
基金
国家自然科学基金面上项目(61573341)
国家自然科学基金专项(61327014)
国家自然科学基金重点项目(61433017)资助
关键词
扫描离子电导显微镜
拖尾现象
自适应控制
补偿模型
先验知识
scanning ion conductance microscopy （SICM）
smearing phenomenon
adaptive control
compensation model
prior knowledge
