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Proceedings Paper

Machine vision for automatic calibration of analog display instruments
Author(s): Robert Sablatnig; C. Hansen
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Paper Abstract

This paper presents a general process for an automatic reading of analog instruments. The calibration of analog watermeters serves for a demonstration of this algorithm. Reading a measuring instrument means detecting the position of scales and pointers in the intensity image in order to determine the value displayed by the measuring instrument. The reading process involves the detection of its boundaries, scales, pointers and lettering elements by using pattern recognition algorithms and a-priori information about the geometry and the elements of the meter. First, a validation for the correct type has to be done by checking the actual, detected elements with the elements defined in the type-description. Following the determination of the indicated measurement value, the intensity image of the watermeter is compressed and stored to ensure a given quality standard by protocolling each measurement step. The calibration process consists of five reading phases. A series of watermeters of the same type is calibrated in one run with water quality measurement. The outlined automated approach to the problem is faster, more reliable, stable and cheaper than the manual reading and checking of the meters performed now. Results concerning time, accuracy and reliability are given at the end of the paper.

Paper Details

Date Published: 27 March 1995
PDF: 11 pages
Proc. SPIE 2423, Machine Vision Applications in Industrial Inspection III, (27 March 1995); doi: 10.1117/12.205522
Show Author Affiliations
Robert Sablatnig, Technische Univ. Wien (Austria)
C. Hansen, Technische Univ. Wien (Austria)


Published in SPIE Proceedings Vol. 2423:
Machine Vision Applications in Industrial Inspection III
Frederick Y. Wu; Stephen S. Wilson, Editor(s)

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