【作者】 何雨桐；

【导师】 孟华；

【作者基本信息】 大连理工大学 ， 测试计量技术及仪器， 2009， 硕士

【摘要】 光电式几何量测量是规则几何物体多种测量方法中应用较广的一种,特别是基于线阵CCD的光电式几何量测量由于具有结构简单,成本低等特点,广泛应用于规则几何物体的尺寸测量中。本文设计的光电式几何量测量系统采用平行光成像法对规则几何物体进行测量。系统中的平行光源用于照射物体,将物体的尺寸信息变成光信号,光线经过光接收系统投影到线阵CCD上,硬件部分对CCD输出的电信号进行滤波放大以及数据采集,经过软件处理后得到被测物体的尺寸。光源发出的平行光由LED点光源转换形成,具有大口径、高精度的特点。其直径可达40mm,最大平行度误差小于0.2度。平行光照射被测物体后,光线被线阵CCD接收。在被测物体和线阵CCD之间加入光接收系统,同时将透镜中某些曲面选用非球面结构,进一步提高了测量的精度。光学系统的设计基于基本的像差理论,采用ZEMAX软件进行优化。线阵CCD接收的光信号通过线阵CCD的光电转换后需要进行硬件处理,硬件电路实现了CCD视频信号的接收、预处理和采集,整个硬件电路的运行通过CPLD进行控制。经过硬件处理后的CCD视频信号通过USB总线送入上位机。采用EasyUSB动态库实现USB设备与PC机的通信,省去了固件程序的编写,缩短了设计周期。被测物体尺寸信息的提取通过在上位机编程实现。使用亚像元细分技术和直线拟合算法两种方法进行物体尺寸信息的提取,通过计算可求出被测物体尺寸的大小。光学系统的像差、CCD自身噪声和分辨率的局限性、硬件系统的误差和软件算法精度的有限性都会影响测量的精度,再加上外界环境等一些不确定因素的影响,测量系统误差相对较大。测量系统的软件设计应用了误差补偿的方法,提高了系统测量的精度。本文设计的光电式几何量测量系统可以实现中等尺寸物体的微米级精度测量,相对于传统的测量系统具有精度高、体积小等优点。更多还原

【Abstract】 Photoelectric geometrical parameter measuring is a kind of regular geometrical object measuring methods, and it is widely used. With simple structure and low cost, the photoelectric geometrical parameter measurement based on linear CCD is widely used in measuring regular geometrical object.In this paper, geometrical parameter measuring system based on CCD is designed. The system uses parallel-ray imaging method to measure regular geometrical object. In the measuring system, parallel light is used to irradiate object and turn the object size information into optical signals. Through the receiving system, the optical signals are projected onto CCD. Hardware component is used to filtering, amplification and data collection of the CCD output. The size of object can be available after processed by software.The parallel light is formed by LED, and has large-caliber, high-precision characteristics. Its diameter is 40mm, and the maximum error of Parallelism is less than 0.2 degree. After irradiating the object, the parallel light is received by linear CCD. By inserting a receiving system between the linear CCD and the measured object, and setting non-spherical surface for some surface of the lens, the accuracy of measuring is enhanced. The optical system is designed according to aberration theory, and optimized by ZEMAX. The optical signals received by linear CCD will be processed by hardware after photoelectric conversion. Hardware which is controlled by CPLD is used to receive, pre-process and collect the signals. After processed by hardware, the video signals of CCD are sent to the host computer through USB. EasyUSB is used to achieve the communication between USB and PC, eliminating the program of firmware and the design cycle was shortened. Through programming at host computer, the size of measured object could be extracted. Sub-pixel technology and linear fitting algorithm are both used to extract the size information of object, and the size of object can be available by calculating.There are many factors can affect the accuracy of measurement, such as the aberrations of optical system, the noise and the resolving power of CCD, the errors of hardware and the accuracy of the algorithm in software. Some uncertain factors of external environment can also make the error of measuring system relatively large. In the software part of the measuring, error compensation is used to improve the accuracy of the measurement The Photoelectric geometrical parameter measuring system designed in this paper can measure middle size object with micron-level accuracy, having high accuracy and small size advantage.更多还原