Image detecting method for arc ruler lines of pointer instrument scale

Abstract

The invention discloses an automatic detecting method, based on images, for arc scale labels of a pointer instrument. A single digital camera is utilized to construct an image collecting system and carry out calibration, two gauge outfit images are shot under drive signals corresponding to 20% of full scale and 80% of full scale, ruler line areas and scale line areas are achieved through thresholding and morphological processing, a framework is extracted, a candidate ruler disk center is decided on projection through a frame sectioning method, the ruler disk center and the radius of the ruler lines are roughly detected and decided through a hough transform circle, the least square fit is removed and cut by two points to decide the accurate center and the radius of the ruler lines, orientation angles of the scale lines on the ruler lines are decided through a radial projection method to obtain a candidate scale base point, the obtained scale base point is decided and detected through co-domain, and results of two images are combined to obtain a final scale base point set. The detecting method can automatically detect scale positions of arc ruler lines of the pointer instrument, can be applied to automatic calibration and automatic reading of the instrument, improves reading accuracy and reduces labor intensity.

Description

technical field [0001] The invention relates to the fields of instrument automatic calibration and instrument automatic reading, in particular to an image-based automatic detection method for the scale on the circular arc scale of a pointer instrument. Background technique [0002] The pointer instrument has the advantages of simple structure and convenient use. Today, as digital instruments are widely used, pointer instruments still have a large annual output, and there are a large number of pointer instruments in various systems in use. If relying on manual work to complete the verification and calibration of new and in-use pointer instruments, the labor load will be huge, and it will be easily affected by the subjective factors of the inspectors themselves. A low-cost solution to the verification and calibration of pointer instruments is an automatic instrument verification and calibration method based on image processing and machine vision. In addition, the computer re...

AI Technical Summary

Problems solved by technology

These methods are either too simple to apply to occasions where there is unevenness in the scale spacing, resulting in large systematic errors in automatic readings; or the methods are more cumbersome and the reliability is also reduced

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