Design And Implementation Of Level Bar Calibration System

In order to ensure the quality of the product,in the production process of the bubble level,we need to detect the product.This is mainly through image processing and other methods to detect the bubble position in the level column and calculate the distance of the bubble offset to determine whether the product is qualified.For those unqualified products,we need to correct the tilt angle of the level column.In the past,most of the bubble levels were calibrated by manual rotation of the level column.The efficiency and accuracy of the calibration are relatively low.A bubble level calibration system is now developed to improve the quality of the product.It can reduce the workload of workers,and greatly improve the automation level of the production line.In this paper,we first introduce the research background of the topic,the research status and development trend of machine vision and the research status of related industrial applications.Then,in the 2nd chapter,we introduce the hardware part of the image acquisition system and the electromechanical control system used in this application.The hardware platform of image acquisition system is built,and the selection of industrial camera,optical lens,light source and illumination mode are described.And we systematically introduced the facilities in the electromechanical control system,including servo motor,servo driver,motion control card,air cylinder,solenoid valve.Then,in the 3rd chapter,we elaborate on the positioning algorithm of the bubble.The one-dimensional edge detection algorithm is applied to find the edges of the level column,the reference lines and the bubble.And the criteria of these positioning are given.We construct an ideal elliptic edge to verify that the edge extraction algorithm can also be applied to the curved edge.We introduce the min-max normalization to make the algorithm adapt the changes of illumination and distance.We also elaborate on the ideas of Canny edge filter.We can use this edge filter to improve the accuracy of positioning.Finally,in the 4th chapter,we elaborate the algorithm to calibrate the bubble level.We elaborate on the control strategies when the bubble is between or beyond the left and right reference lines.We give a method to calculate the rotation angle of the motor when the bubble is located in the range between the left and right reference lines.And a method is given for determining the rotation direction of the motor when the bubble is located outside the range between the left and right reference lines.We also propose a new line detection algorithm,and apply this algorithm to the motor control algorithm when the bubble is outside the range between the left and right reference lines.Unlike the usual Hough transform algorithm which searches for all the possible line segments in the global scope regardless of length and width of the segments,the line detection algorithm we present can more quickly search for line segments of specific length and width.