Image processing method for reading pointer type instrument indication value

Abstract

An image processing method for reading pointer type instrument indication value includes that: any three scale marks are selected on an instrument indicator dial digital image, corresponding points dividing the scale mark into the same proportion are selected on the selected scale marks, and a circle including three corresponding points is drawn; the pointer of the instrument and the scale mark atthe left side of the pointer are identified, and the intersection point of the pointer and the circle and the intersection point of the scale mark at the left side of the pointer and the circle are obtained; and the indication value of the pointer of the instrument is calculated according to the two intersection points. The method can accurately obtain the positions of the pointer and the scale mark at the left side of the pointer, can avoid indication value calculation deviation caused by camera lens distortion, uneven indicator dial scale marks or no coincidence of the fixed point of the pointer and the center of the circle and improves the efficiency and accuracy of reading indication value of pointer type instrument.

Description

technical field [0001] The invention relates to the field of reading display values ​​of measuring instruments, in particular to an image processing method for reading display values ​​of pointer instruments. Background technique [0002] At present, the reading of the indication value of the scale line dial pointer instrument is generally read by human eyes, and the indication value of the instrument is estimated and read by human eyes recognizing the relative position of the pointer and the scale line and the absolute position of the scale line. This method is labor intensive, inefficient and less accurate. [0003] In order to solve such problems, an automatic reading system for instrument indication values ​​based on machine vision testing technology has been developed, which uses machine vision to replace human eyes to automatically read the indication values ​​​​of scale line dial pointer instruments. For example, the patent No. ZL200520093025.7 and the patent name "D...

AI Technical Summary

Problems solved by technology

For example, the patent No. ZL200520093025.7 and the patent name "Digital Readout Device for Analog Pressure Gauge" discloses a device that uses machine vision instead of human eyes to automatically digitally read analog pressure indication values, but the inventive device The method can not realize the accurate identification of the position of the meter pointer and the scale line, and the "angle method" is adopted when the calculator indicates the value, that is, the angle between the pointer and the zero scale line is first identified, and then the calculator indicates the value. The device has the problem of indication calculation deviation caused by the distortion of the camera lens and the uneven scale of the dial; in addition, when the scale line is uneven or the center of the circle passing through the scale line of the dial is different from the fixed point of the pointer due to the manufacturing process of the instrument. When coincidence, the instrument representation value obtained by "angle method" is very inaccurate

In the patent No. ZL02262023.0, the patent name is "Automatic Verification Device for Dial Indicator Dial Indicator", a method for automatically reading the indication value of the dial indicator (belonging to the pointer instrument) is disclosed. The indication method also adopts the "angle method", and there is a similar deviation problem in the indication calculation

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