Author Affiliations
Department of Information and Control Engineering, Shenyang Urban Construction University, Shenyang, Liaoning 110167, Chinashow less
Fig. 1. Architectural diagram of machine-vision based detection system
Fig. 2. Flow chart of defect detection algorithm
Fig. 3. Binary images. (a) T1 threshold image; (b) T2 threshold image
Fig. 4. Picture of packing bag
Fig. 5. Platform for experimental testing
Fig. 6. Standard setting module
Fig. 7. Location setting module
Fig. 8. Partial detection results of defect classification. (a) Qualified image; (b) continuous bag (over length); (c) continuous bag (over width); (d) motion of packaging layout; (e) dimension error; (f) foreign matter on packages
No. | Condition | Defect classification |
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1 | L>Lup or W>Wup | Defect 1: continuous bag | 2 | L>Lup or L<Llow or W>Wup or W<Wlow | Defect 2: dimension error(over length or over width) | 3 | θ<θT | Defect 3: foreign matteron packages | 4 | O⊄M | Defect 4: motion ofpackaging layout |
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Table 1. Feature and defect matching
Classification | Detection |
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Defectnumber | Qualifiednumber |
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Actual | Defect number | PT | NF | Qualified number | PF | NT |
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Table 2. Confusion matrix
Category | Proposedmethod | Templatematching | Manualdetection |
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Defect | Qualified | Defect | Qualified | Defect | Qualified |
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Defect | 195 | 5 | 178 | 22 | 186 | 14 | Qualified | 6 | 294 | 25 | 275 | 16 | 284 |
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Table 3. Confusion matrices for different detection methods
Method | True positiverate /% | True negativerate /% | Accuracy /% |
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Proposed method | 97.5 | 98 | 97.8 | Template matching | 89 | 91.7 | 90.6 | Manual detection | 93 | 94.7 | 94 |
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Table 4. True positive rates, true negative rates, and accuracy of different detection methods
No. | Defecttype | Sample | Successnumber | Missingnumber | Wrongnumber | Missingrate /% | Errorrate /% | Positiverate /% |
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1 | Continuous bag | 200 | 199 | 0 | 1 | 0 | 0.5 | 99.5 | 2 | Dimension error | 200 | 199 | 0 | 1 | 0 | 0.5 | 99.5 | 3 | Foreign matter on packages | 200 | 195 | 1 | 4 | 0.5 | 2.0 | 97.5 | 4 | Motion of packaging layout | 200 | 197 | 0 | 3 | 0 | 1.5 | 98.5 | | Total | 800 | 790 | 1 | 9 | 0.125 | 1.125 | 98.75 |
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Table 5. Test of classification results