汽车仪表检测中液晶符号识别系统的设计与实现

发布时间：2018-06-24 11:40

本文选题：汽车组合仪表 + 视觉检测　；参考：《湖北工业大学》2017年硕士论文

【摘要】：随着汽车工业和电子信息技术的快速发展,汽车组合仪表的信息化程度越来越高,质量要求日趋严格。因此,汽车组合仪表在出厂前要经过严格的质量检测,但人工检测的效率和精度低,不适合自动化生产。针对目前人工检测中效率低和精度差的问题,本文利用了机器视觉领域相关的研究成果,设计了一套汽车仪表视觉检测系统。在深入研究信号驱动单元硬件设计方案和汽车仪表液晶符号的定位与识别算法后,本文完成了以下方面的工作。(1)以STM32为主控制器,采用集成式的设计方式,设计了汽车仪表信号驱动单元硬件电路和相应的软件。每种类型的信号驱动电路互相独立,并由主控制器控制其产生输出信号。主控制器首先与上位机建立通信连接,当接收到上位机发送的指令后,主控制器根据指令控制相应的驱动电路产生信号,这种集成式的设计方式大大提高了系统的稳定性和精度。(2)针对液晶显示区域的定位问题,根据液晶显示区域的特征,利用一种改进的ACSS角点检测算法,对区域进行粗略定位,再通过边缘测量算子进行精确定位。改进的ACSS算法增加了对二值边缘的筛选步骤,筛选后二值边缘的数量减少,去掉了大量的伪角点,计算量变小,与目前主流的角点检测算法相比,实验结果表明改进的ACSS算法检测速度和精度都有一定提高。(3)针对液晶符号识别问题,运用BP神经网络算法对液晶字符进行识别。首先对液晶字符进行预处理,滤除噪声干扰,提取液晶符号的二值图像,接着在垂直方向上使用投影法进行字符分割,最后使用训练好的BP网络对单个符号进行识别。实验结果表明BP网络的字符识别率高,实时性强。另外,本文还对其他液晶符号、LED指示灯和小表指针角度的识别算法进行了分析和实现,最终的识别结果达到了设计要求。通过以上工作,本文实现了汽车仪表视觉检测系统,检测系统能实时完成汽车仪表的全部功能检测,系统的拓展功能强,兼容性好,并在汽车仪表生产流水线上进行了应用,达到了预期的效果
[Abstract]:With the rapid development of automobile industry and electronic information technology, the information level of automobile combination instrument is becoming more and more high, and the quality requirement is becoming more and more strict. Therefore, the automobile combination instrument must pass through the strict quality inspection before leaving the factory, but the manual inspection efficiency and the precision are low, is not suitable for the automation production. Aiming at the problems of low efficiency and poor precision in manual inspection, a visual inspection system of automobile instrument is designed by using the related research results in the field of machine vision. After deeply studying the hardware design of the signal drive unit and the localization and recognition algorithm of the liquid crystal symbol of the automobile instrument, the following work has been accomplished in this paper. (1) the STM32 is used as the main controller and the integrated design method is adopted. The hardware circuit and corresponding software of vehicle instrument signal drive unit are designed. Each type of signal drive circuit is independent of each other and is controlled by the master controller to generate the output signal. The main controller first establishes a communication connection with the host computer. After receiving the instruction sent by the host computer, the master controller controls the corresponding driving circuit to generate the signal according to the instruction. This integrated design method greatly improves the stability and accuracy of the system. (2) aiming at the location of liquid crystal display region, according to the characteristics of liquid crystal display region, an improved ACSS corner detection algorithm is used to roughly locate the region. Then accurate location is carried out by edge measurement operator. The improved ACSS algorithm increases the screening steps of binary edges, reduces the number of binary edges, removes a large number of pseudo-corner points, and reduces the amount of calculation, compared with the current mainstream corner detection algorithm. The experimental results show that the speed and accuracy of the improved ACSS algorithm are improved. (3) to solve the problem of liquid crystal symbol recognition, BP neural network algorithm is used to recognize liquid crystal characters. First, the liquid crystal character is preprocessed, noise interference is filtered, the binary image of liquid crystal symbol is extracted, then the character is segmented by projection method in the vertical direction, and the single symbol is recognized by the trained BP neural network. The experimental results show that BP neural network has high character recognition rate and high real-time performance. In addition, this paper also analyzes and implements the recognition algorithm of LED indicator lamp and small meter pointer angle of other liquid crystal symbols, and the final recognition results meet the design requirements. Through the above work, this paper has realized the automobile instrument vision inspection system, the detection system can complete the automobile instrument all function inspection in real time, the system expansion function is strong, the compatibility is good, and has carried on the application in the automobile instrument production line. Achieved the desired effect
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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