Design Of Online Water Meter Verification System Based On Computer Vision Technology

In the field of water supply,water meter is the most widely used measuring instrument.There are lots of manufacturers of water meter in our country,they produce a large number of water meters every year and the main products are mechanical water meter.In the production of mechanical water meter,the procedure of verification is necessary to guarantee water meter quality,when using traditional method,the operator needs to operate the verification instrument,read the number of the under-verified water meters,calculate the errors and save the results on paper.It is a hard work with low efficiency and the results are more likely affected by the operator.Though enterprises have done a lot of work to improve the level of automation of the traditional verification instruments,they could not overcome the limits of traditional method.Enterprises urgently need a new verification instrument that can truly make the verification of water meter automated.According to the water meter verification standard,an online water meter verification system based on Computer Vision Technology was designed.Based on the existing manual verification instrument,the advanced image processing technology is introduced into the water meter verification.This system is based on an industrial computer and consists of two parts,the hardware part and the software part.In the hardware part,the traditional verification instrument was upgraded,an ultrasonic water meter is used as the stand water meter,two electric control valves are selected to replace the manual valves,a temperature sensor and a pressure sensor are used for measuring the water temperature and pressure.A data acquisition card is used to control those hardware above by its analog input/output ports,digital input/output ports and count ports,the data acquisition card with PCI bus is used to communicate with the computer.In the software part,the system includes an automatic verification module and a data management module.In the automatic verification module,a Harris corner detection algorithm is proposed to extract the corner of the image,and the Hausdorff distance combined with the template matching method is used to locate the plum needle.The local adaptive threshold segmentation algorithm is used to segment the plum needle in the wet water meter,and the OSTU algorithm is used to segment the plum needle in the dry water meter.When the plum needle is located,the system selects four sampling points in each under-verified water meter,then the number of teeth of stand water meter and the under-verified water meters are counted while verifying.When the stand water meter counts to the set value,the system can automatically stop the counting and calculates the error of each under-verified water meter and judges that the under-verified water meter is qualified or not by the error.Aiming at the problem that the mechanical wet type water meters may have bubbles,this paper presents a method to eliminate the bubbles by image morphology method.In the data management module,a data management system is designed to provide some functions of data recording,analyzing,exporting,and system privilege managing.The verification work can be accomplished by the designed system automatically now,Experimental result shows that the system has a good stability,lower labor intensity,and can improve the accuracy of the results and shorten the time of verification.Therefore,this system has some wide application value.