Researches On Information Collection System Of Dial Instrument

Dial instrument is an indispensable tool in signal measurement for its widely use in industrial measurement and controlling. Its low cost, reading stabilization, need no extra power supply put it in an irreplaceable position in the digital age. It requires regular complicated checks in order to guarantee accurate reading, which accounts for the necessity to have a deeper insight into automatic checking.At domestic and abroad, there're some research results and mature processing to make machine vision applicable to checking system. However, many technological obstacles and insufficient researches in the dial image processing with high-accuracy and large dial explains why this essay has realistic value.Here are the outlines for the dissertation:1.Establishment of checking system:This dissertation analyzes automatic controlling in the selection of program-controlled data source and camera in system. Image acquisition is accomplished through 1300K-pixel camera which is free for driver and Opencv which is a open source software in VC platform. Remote controlling is completed by Angilent E364A digital controlling standard source and GPIB standardized programming.2.Fixed & segmentation of pointer instrument:According to acquired instrument image's feature,we find that the pointer instrument surface significantly different from other parts. So we determine the segmentation threshold by OTSU. Then we cut the Pointer instrument surface from other directions by horizontal & vertical projection.3.Preprocessing of pointer instrument image:There are mainly two parts:Firstly, to eliminate ill effects from MSR lighting in large image collection by homomorphic filtering calculation. This can increase contrast in between background setting and target image. Secondly, separation between pointer area and character instruction area is based on fitted circle parameter.And it's a separation with sobel operator edge extracting, elaboration and tracking in specific to the circular arc range of the pointer instrument image poiter area and circle in variance Hough Transform fitting pointer area.4.Study on reading values of pointer instrument:Clear binary image of calibration region comes out from number and mirror plate region elimination after double binarilizations including overall and partial binarilization. Here introduces a new reading method:To fix on every calibration's slope by arc which center is the rotate center and intersects with arc. And to figure out readings by comparing pointer's slope and all calibrations' slopes after treatment and find the pointer.This system has certain practical value. It achieves image capturing & preprocessing and reading the value of pointer instrument automatically. This system uses WINDOWS VC++ platform for programming.