【作者】 李伟；

【导师】 闫卫平；

【作者基本信息】 大连理工大学 ， 物理电子学， 2006， 硕士

【摘要】 激光诱导荧光检测是毛细管电泳芯片的主要检测手段之一，其中又以共聚焦式检测装置的灵敏度和信噪比最高，是目前最为常用的检测手段。共聚焦光路的成像特点使得其聚焦操作难度较大，目前主要依靠操作人员手工操作，可靠性、重复性差。本文在分析国内外研究现状的基础上，设计了基于图像处理辅助聚焦的共聚焦式激光诱导荧光检测装置。 本文采用共聚焦式激光诱导荧光检测原理，设计了CCD辅助检测及光路切换装置，通过图像处理获取离焦状态及确定运动目标位置，利用电移台的移动实现自动聚焦及自动跟踪。以AT89C52单片机为核心设计了检测装置的下位机控制系统，采用Keil C语言编写程序，完成三维电控平台的控制、光路切换、高压控制、信号采集、安全保护等功能。系统可以工作在脱机和联机两种模式，脱机时用户通过键盘和LCD操作，联机时由上位机通过串行口控制。 上位机程序采用VC++编写，主要完成利用图像采集卡获取CCD图像，并进行噪声抑制、栅格化等预处理，以及图像保存、打开等常规操作。根据图像清晰度评价函数判断聚焦情况，控制Z轴电动位移台移动，采用粗调细调相结合的策略加快聚焦速度，使电泳芯片到达最佳聚焦位置。通过改进的三帧差分法计算运动目标的位置，控制X、Y轴电动位移台跟踪目标。接收下位机传送的荧光信号，并实时绘制曲线。 本文设计组建的装置能较好地完成自动聚焦、自动跟踪、荧光信号采集等任务，可以在毛细管电泳芯片研制过程中的各个阶段进行观察、测试和数据采集，为芯片的深入研究提供依据。本装置自动化程度较高，方便易用，基本达到了预期效果。更多还原

【Abstract】 Laser induced fluorescence (LIF) detection is one of the main means of Capillary Electrophoresis (CE) chip detection, in which confocal detecting device is the most commonly used means of detection for the higher sensitivity and signal-to-noise ratio (SNR). The focus operation is very diffcult for the imaging characteristic of confocal system. At present it mostly depends on manual operation, whose reliability and repeatability is poor. This paper designs a LIF detection device that can auto focus based on image processing after analyzing the related study at home and abroad.Based on confocal LIF detection principle, this paper designs a CCD aided measuring and optical switching device. After acquiring defocusing status and position of moving target by image processing, electric moving stages are driven to execute auto focusing and auto tracking. Lower computer control system based on AT89C52 microcontroller is designed and programe is written in Keil C language. The system achieves many functions, such as 3-dimensional electric moving stage control, optical switching, high voltage control, signal acquisition, security protection, etc.. It can run in off-line mode or on-line mode. Users can use keyboard and LCD to operate the device in off-line mode. It can communicate with upper computer through serial port in on-line mode.Upper computer programme is written in VC++. The functions it achieces are as follows: acquiring CCD image using image card, accomplishing image preprocessing such as noise reduction and gridding, performing routine operation such as image saving and opening. Z axis electric moving stage is driven to make CE chip focused based on the definition function value. Coarse adjustment and fine adjustment is both adopted to speed up focusing process. X axis and Y axis electric moving stages are driven to track object based on its position which is calculated by improved 3 frame difference algorithm. Fluorescence data is received and displayed as a real-time curve.The device this paper designs and builds can accomplish the task of auto focusing, auto tracking and fluorescence signal acquisition. It can watch, test and acquire data in every phase of the study of CE chip, which offers the foundation of farther study. This device basically yields the expected results for its automatization and easy using characteristic.更多还原