Computer Vision Based Pantograph Inspection System

Pantograph is a crucial power collection apparatus in modern electric railway locomotives.Contact condition between pantograph and overhead line directly affects the quality of power collection.There are multiple factors that could impact the contact condition,causing arcing or even worse,overhead line damage.During operations of locomotives,contact plate,drag link and upper arm work consistently in a high voltage environment.Attaching physical sensors directly to high voltage components on a pantograph could be a safety hazard.Attributed to recent development of optieal sensors and visual algorithms,image processing and pattern recognition based pantograph inspection methods are widely studied and adopted.This article establishes a system that captures movement of pantograph with a high-speed camera,implements a solution for pantograph visual tracking,and verifies the validity of this system.Pantograph dynamic properties are obtained with this system,revealing components,movement properties when pantograph detachment occurs.This article takes 2 algorithms,Median Flow and Boosting,as tracking algorithm candidates.Fundamental mechanisms of these algorithms are discussed and implemented.An in-depth discussion of performance bottleneck of serial implementation structure is carried out.Aiming to overcome these bottlenecks,one shallow and one deep parallel computation architectures are designed and implemented,which are later proven to be more efficient than its serial opponent.When trying to test these tracking algorithms’ accuracy,this article pointed out that common generic performance measures have certain limitations.Some specific performance measures are proposed and a procedure to generate ground truth trajectory is developed to simulate experimental traj ectory.Eventually,this article verifies visual tracking system’s validity through these specific measures and successfully captures pantograph components’ movements.By performing spectrum analysis,dynamic properties of contact plate,drag link and upper arm is obtained.A deeper study on dynamic properties conveys further characteristics when detachment occurs.