Method for measuring shape of general cable strand of suspension bridge based on machine vision

Abstract

The invention discloses a method for measuring the shape of a general cable strand of a suspension bridge based on machine vision. The method comprises the following steps: installing vision monitoring equipment; erecting a reference cable strand and a measurement layer cable strand of the main cable, installing light targets in the spans of the reference cable strand and the measurement layer cable strand respectively, and using visual monitoring equipment for collecting shake image data of the different light targets within preset time; analyzing and calculating the shaking image data to obtain the actual height difference between the reference cable strand and the measuring layer cable strand, namely the real-time linear data of the measuring layer cable strand; and moving the relative reference cable strand and the measurement layer cable strand upwards, and sequentially erecting the main cable strands from bottom to top through the same method. According to the method, a light target is installed in the span of a general cable strand and a reference cable strand, a visual monitoring device is used for collecting an orthographic light target image, shaking image data of the light target are analyzed, the actual space distance is converted according to the pixel distance, the height difference between the general cable strand and the reference cable strand is calculated, and then real-time line shape data of the general cable strand are obtained. And high-precision automatic measurement of the strand shape is realized.

Description

technical field [0001] The invention relates to the field of bridge engineering monitoring. More specifically, the present invention relates to a method for measuring the general cable strand shape of a suspension bridge based on machine vision. Background technique [0002] The main cable is one of the core structures of the suspension bridge. The main cable is composed of several strands, including reference strands and general strands. The absolute sag measurement method is used for positioning and installation of the reference strands, and relative sag is used for installation of the general strands. The sag measurement method is used for positioning and installation, and the erection is carried out in accordance with the principle of "as close as possible to the reference cable strand". At present, the general cable strand sag measurement is usually carried out with a level ruler and a square ruler. The device is large in size and difficult to operate. It is not suitab...

AI Technical Summary

Problems solved by technology

At present, the general cable strand sag measurement is usually carried out with a level ruler and a square ruler. The device is large in size and difficult to operate. It is not suitable for single-person measurement operations. It requires the cooperation of multiple people to complete the test, which is affected by the subjective judgment of the measurement personnel. Larger, with low accuracy and low measurement efficiency, it cannot meet the requirements of efficient and accurate installation of large-diameter main cables; In a natural environment, the vibration amplitude of the cable strands is large, and it is difficult to accurately measure the shape of the strands using conventional measuring tools such as calipers, which will also lead to the inability to complete the erection of the cable strands accurately and quickly, affecting the construction progress

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