基于数字图像的水位识别系统及其方法  

Digital image-based water level recognizing system and method

作　　者：徐兴[1,2,3] 洪添胜[1,2,3] 岳学军[1,2,3,4] 蔡坤[1,2,3] 黄双萍[1,2,3] 刘永鑫[1,2,3] 

机构地区：[1]华南农业大学南方农业机械与装备关键技术教育部重点实验室,广东广州510642 [2]华南农业大学国家柑橘产业技术体系机械研究室,广东广州510642 [3]华南农业大学工程学院,广东广州510642 [4]南昆士兰大学工程与测绘学院

出　　处：《排灌机械工程学报》2014年第1期33-39,共7页Journal of Drainage and Irrigation Machinery Engineering

基　　金：教育部博士点基金资助项目(20124404120002);广东高校优秀青年创新人才培育项目(LYM10035);广东省农业机械化科研项目(粤农计[2013]2号)

摘　　要：为了有效监控水情,给水利和农业生产灌溉提供及时有效的指导信息,设计了一种基于数字图像的水位识别系统.该系统将红色的球形浮标置于垂直于水面的固定杆上,水位变化引起球形浮标上下变化,所拍摄图像上浮标的相对位置也出现变化,从而可通过图像处理获得水位信息.针对所设计的水位识别系统,提出基于红色色域和球形特征的自适应球形浮标目标提取算法和球心坐标计算和校正算法,用以求得浮标球心的准确坐标位置,并通过球心坐标和水位之间的换算公式,最终计算得到当前水位高度数据.现场试验结果表明,在采用6.0×106pixel摄像头,拍摄高度为71 cm,摄像头和固定杆距离为282 cm的条件下,该系统最大测量误差为0.216 91 cm,低于国标(GB/T 50138—2010)所规定的1 cm误差.该系统无需专用昂贵的水位计或复杂的传感器技术,成本较低;以浮标为检索目标,使此法不受水温、水质、含沙量等外界干扰因素的影响,适用性更强;系统组成简单,安装方便,易于使用.In order to monitor water level efficiently and provide instantaneous and effective information for guiding water conservancy and agriculture irrigation,a digital image-based water level recognizing system was designed. In the system,a red spherical buoy was installed on a rod which was fixed vertically in water. Since the water level was derived by change in the relative position of buoy,the water level information could be specified by processing the buoy images snatched by a digital camera. For an instantaneous water level could be obtained through a conversion formula between the spherical centre coordinates and the height of water level,an adaptive spherical buoy capturing algorithm for identifying the red region and extracting the characteristics of red sphere and a calculation and correction algorithm for the sphere centre coordinates were proposed. It was shown experimentally that the maximum error in measurement was 0. 216 91 cm,which is far below 1cm error specified in the new edition of China National Standard( GB / T 50138—2010) under 6 megapixel camera,71 cm shoot height,and 282 cm distance between the camera and the fixed rod. Importantly,the system needs no expansive water level gauge or complex sensors and is subject to a relatively low cost. Additionally,the system relies on noncontact measurement only,and unnecessarily affected by interference factors,such as water temperature, quality,sediment etc. This innovative system has a simple structure,can be installed conveniently and used easily,and it has an even better feasibility in water level monitoring sector.

关 键 词：水位监测 浮球特征 球心位置 数字图像处理 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]