Measuring Method On Outside Dimension For Vehicle Detecting Line

With the development of economy,more and more people own cars.But in order to earn more profits,vehicle overloading phenomenon is more and more serious,which has become a frequent cause of traffic accidents,threatening the life and property safety.In 2004,People 's Republic of China issued the national standard of "Road vehicle dimensions,axle load and quality limits" required that the outside dimension of vehicle must be measured.In 2015,the new standard of "Items and methods of motor vehicles safety technology inspection" stipulated that the outside dimension must be measured by using an automatic detector.Both of the standards are aim to increase the supervision of illegal modification on vehicles.Therefore,it is of great practical significance and research value to research the outside dimension device of vehicle.The current detecting line commonly used manual measurement such as tape,rod and other tools,which takes high labor intensity,long measuring time but has poor accuracy and low efficiency.In order to satisfy the demand of automatic detection of the outside dimension,this paper studies a non-contact measurement method based on structured light and machine vision,which realizes a speedy accurate and automatic measurement.Firstly,the thesis analyzes the non-contact measurement,selects the method of structured light according to the automatic detection requirement,and designs the hardware of the system.Secondly,based on the basic calibration principle,the thesis studies the virtual grid plane to solve the calibration relationship,and analyzes the structural light bar.At the same time,the thesis uses the extreme value method to extract the center of the structured light,and refine the light bar to determine the edge points of the vehicle to realize the dimension parameter measurement.Then,the thesis uses VC ++ to develop the software system.The software adopts the modular idea,which can accomplish the functions of hardware control,image acquisition,size calculation,result display,historical query,etc.Finally,in order to apply the method to the actual scene,the paper designs the measurement device and calibration method of large scale measurement,and verifies the design's feasibility.The thesis presents a new design method of outside the outside dimension of vehicle,which provides a new design idea for the automatic detection.This research has certain theoretical significance and application value.