Image-processing-based automatic reading number recognition method of pointer type instrument

Abstract

The invention provides an image-processing-based automatic reading number recognition method of a pointer type instrument. Image preprocessing is carried out to determine the position of a dial platepreliminarily; a straight line segment of the dial plate area is extracted based on a straight line detection algorithm, scale lines are screened based on spatial distribution characteristics of dialscale lines, and the center point of the dial plate is located precisely by using least squares fitting; and according to center projection features of the scale lines, the position of the main scaleline is determined for standby. According to the invention, the edge lines of the two sides of the pointer are detected by using Hough transform and the intersection point of the edge lines is connected with the center of the dial plate to form a connecting line as the straight line of the pointer, so that the extraction precision of the pointer position is improved. With the character recognitiontechnology, the scale value of the dial plate is recognized automatically, the reading number corresponding to the main scale line is determined, and then the number indicated by the pointer is calculated according to indication numbers of the main scale lines at the left side and the right side of the pointer as well as angles and distances between the main scale lines at the left side and the right side of the pointer and the pointer ling segment, so that the accuracy and robustness are improved and the application scene of the algorithm is extended.

Description

technical field [0001] The invention relates to the technical field of pointer reading, in particular to an image processing-based automatic recognition method for pointer meter readings. technical background [0002] As a traditional measuring instrument, the pointer meter is still widely used in industrial production because of its simple structure, low price, stable and reliable work, etc. Commonly used pointer instruments include barometers, thermometers, pressure gauges, etc. Pointer instruments require a large number of workers to perform manual readings during calibration and use. The accuracy of manual readings depends on people's subjective consciousness and is easily affected by various factors such as environment and fatigue. In order to improve efficiency and accuracy and avoid long-term observation and operation of staff in high-risk and toxic environments, researchers have proposed a variety of automatic reading methods for pointer instruments. The existing ...

AI Technical Summary

Problems solved by technology

From the examples given, the invention uses an industrial camera to acquire images, and is also used for automatic reading of a specific pointer instrument in a fixed scene. The collected image instrument is just in the most suitable installation direction for reading, and it is also necessary to know the instrument in advance. Prior information such as range and accuracy is not suitable for the mobility requirements of multi-instrument inspection tasks in factories

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