Research On The Optical Quality Examination Of Commodity Barcode On Machine Vision

Commodity barcode is a kind of data carrier which plays a key role in the process of commodity circulation.In order to ensure the barcode printed quality,the National Standardization Management departments promulgate the quality inspection standards of commodity barcode which used for relevant agencies detecting the quality of commodity barcode in accordance with the standards.At present,the domestic commodity barcode quality detection method is the combination of artificial and detecting instrument,the detection links are more and slow,the detection range are limited.In view of this,this paper proposed a method of using machine vision technique detect the printing quality of commodity barcode,which effectively improving the correctness and efficiency of detection.The commodity barcode symbol print quality inspection standards(GB/T 18348-2008)specified that the commodity barcode quality testing projects in a total of 14 items,including structure size characteristic parameters(Z size,left and white space zone width,bar high,bar width and character height),optical properties(the highest and minimum reflectance,reflectance ratio,symbol contrast,the minimum edge contrast,modulation ratio and defect)and the barcode symbol conformance.Because this topic was responsible for two people,this paper aiming at the seven optical properties parameters and the symbol conformance,based on machine vision method to detect the optical quality and symbol conformance of barcode.Firstly,according to the actual size range of commodity barcode designed collection device,and the collected barcode image was graying,binary pretreatment to reduce the amount of information.Then,designed a set of algorithm which including selecting the image center area,edge detection,Hough transform,angle measurement,interpolation rotation and projection aiming to positing the barcode area and segmentation.Then,according to the national standard "comprehensive classification method" to detect the optical properties of the segmentation of barcode symbol area,calculate the optical characteristics parameters and determine the optical quality grade of barcode.Finally,by the method of similar edge distance measurement for decoding barcode,by the template matching method for character recognition of the barcode digital area,and compare the results of the decoding with character reading to determine the barcode symbol consistency.This experiment from the Shaanxi province barcode quality supervision and inspection station extracted 100 barcode samples,through detection and analysis,this system assessed the optical quality grade and the conformance of barcode symbol of barcode were consistent with the detection results.Meanwhile,greatly reducing the detection time,improving the detection efficiency,the user interface is convenient and simple which achieves a better detection result.