【作者】 袁云峰；

【导师】 钟应善；

【作者基本信息】 广西大学 ， 机械电子工程， 2002， 硕士

【摘要】 溶液pH值是表征溶液酸碱度的一个重要物理化学参数，它对溶液的物理化学性质、化学反应速度、生成物的成分、性质及微生物的生长和新陈代谢等，都有很大影响，在工业过程检测控制中占有举足轻重的地位。 工业上一般使用基于电极法的工业pH计来测量溶液的pH值，虽然理论上pH计的精度很高，但由于电极法需要机理复杂的化学传感器，因电极内的电解液不断损耗而造成的累积误差、对H~+离子敏感的电极易受污染和损坏、电极的冲洗和净化而导致的电极特性的变坏以及难于在高温高压工况下进行测量等等这些缺陷常常困扰着工业企业，究其原因，主要是工业生产中恶劣的工况环境不适合使用pH计。本文从人工比色目测法出发，根据现阶段计算机技术的发展特点，提出了一种新的以机器视觉去模拟人工视觉从而检测溶液pH值的方法，用数码摄像头去拍摄pH试纸的颜色信息，形成24位真彩色图像文件，然后通过微机强大的运算功能，运用数字图像处理的相关技术，从颜色图像文件中抽取颜色特征数作为检测溶液pH值的依据。与人工比色目测法相比，它避免了因人为因素造成的主观影响，具有客观性；与pH计测试法相比，它避免了恶劣工况环境的影响，使得测量可以进行并满足一定的精度要求。 本文首先对现阶段pH值测试手段进行了综述，并在相关色度学理论和酸碱指示剂显色原理及各种测色方法方面进行了探讨，然后在系统设计方面进行了选择，绐出了一个简洁的系统方案，随后根据现有阶段计算机的硬件技术，选用性价比合适的数码摄像头组成了硬件系统，并针对相关软件进行了设计，最后以实验验证了这种基于机器视觉模拟人工视觉方法的可行性。更多还原

【Abstract】 The pH value of the solution is an important physical and chemical parameter which affects the physical and chemical properties of the solution , the velocity of chemical reaction, the composition and properties of the resultant and the growth of the microbe metabolism greatly .It plays a decisive position in detecting and controlling at industrial procedure of production.The industrial pH meter based on the electrode is usually used to measure the pH Value of the solution in industry, although it has high precision in theory, its mechanization about chemical sensor is very complicated , the loss of electrolyte in electrode causes accumulated error, the electrode sensitive with H+ ion is polluted and damaged easily, the wash and purify of the electrode ruins the characteristics of the electrode and it does not used in high temperature and high pressure. These working condition defects puzzle factories and other enterprises. Studying its causes, it is not appropriate for the adverse circumstances. Starring from artificial colorimetric ocular estimate and according to the developing characteristics of the computer technique of the present period,this article put forward a new method which measures the pH value of the solution by testing the digital color information of the pH test paper drawing from the digital image file shot by digital camera . Compared with the method of using human vision, it improves the objectivity of the result by avoiding the subjectivity of human ; Compared with the method of using electrode, it can be content with the precision but avoiding the influences of the adverse circumstance.The article firstly summarizes the measuring method of the pH value of the solution, approaches the theory about the theory of colouriry ,the mechanization of the acid and alkali color-developing agent and the method of the colour measurement, then gives a simple system design scheme, and designs the hardware system based on the present computer technique, programmes the software, finally tests and verifys the technical scheme by experiment, proves its feasibility.更多还原