Design And Research On The Close-range Photography Inspection System Of Straddle-type Monorail Track Beam

As a fast and convenient way to travel,urban rail transit has developed rapidly in recent years,which greatly meets the daily travel needs of residents.For straddle-type monorail rail traffic,the flatness of the track surface during construction will directly affect people's comfort when riding,so the detection of the flatness of the straddle-type monorail track surface is particularly important.For the detection of the flatness of the straddle-type monorail track surface,the traditional method is to first clean the beam surface with water to ensure that the original surface of the concrete is exposed within the inspection range,and there is no debris on the concrete surface.After the beam surface is cleaned,use a ruler to continuously measure the flatness of the beam surface along the two sides of the center line of the beam base plate,and the overlap is about 1m at a time.Obviously,this method is inefficient and has a certain degree of danger,and real-time monitoring cannot be achieved.Prior to this,some scholars used drones to detect the flatness of the track surface.Although the drones are maneuverable and flexible,they cannot meet the detection accuracy requirements.In recent years,the close-range photography technology has developed rapidly and has been widely used in many fields.Therefore,this article adopts the close-range photography measurement method to detect the flatness of the straddle type monorail track beam.The research content of the thesis is as follows:1.Researched and compared several measurement methods commonly used in track beam flatness detection,briefly introduced the development status of digital close-range photogrammetry.2.Introduce the basic theory of digital close-range photogrammetry involved in the detection of rail beam flatness,the application of non-measurement cameras,the conversion of photogrammetric coordinate system and the analytical methods in closerange photogrammetry,and the main sources of error affecting the experimental results Analysis.3.Compare several feature point extraction methods commonly used in close-range photogrammetry,and then select the appropriate center point extraction algorithm for the artificial signs commonly used in the close-range photogrammetry track beam flatness detection,thereby increasing the amount of pixel coordinates of the mark points Measurement accuracy and experimental verification on campus.4.Designed the data collection platform of the track beam close-range photography inspection system for on-site data collection,and at the same time compared and analyzed two data processing models for close-range photogrammetry,namely the beam method and the direct linear transformation method(DLT).The degree of detection is based on the direct linear transformation method,introducing additional constraints and implementing data resolution through matlab programming.Through comparative analysis,the detection results obtained by the direct linear transformation method with additional constraints have achieved the effect of beam adjustment,thus verifying that the method is feasible in the detection of track beam flatness.5.Based on the above theoretical experimental analysis,this article takes the Mengxi Road Station of Wuhu City Rail Transit Line 2 as an example,uses additional constraint DLT algorithm for data processing,and uses some high-precision total stations for some artificial feature points.Inspection,the inspection results show that this data processing method can be fully applied to the detection of track beam flatness.Therefore,the flatness detection of straddle-type monorail track beams based on close-range photogrammetry is feasible.