Journal of Jilin University(Engineering and Technology Edition) ›› 2024, Vol. 54 ›› Issue (7): 2072-2079.doi: 10.13229/j.cnki.jdxbgxb.20230150

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An character recognition network for imprint character

Xin-dong YOU(),Lei GUO,Jing HAN(),Xue-qiang LYU   

  1. Beijing Key Laboratory of Internet Culture and Digital Communication,Beijing Information Science and Technology University,Beijing 100101,China
  • Received:2023-02-21 Online:2024-07-01 Published:2024-08-05
  • Contact: Jing HAN E-mail:youxindong7895@126.com;hanjing@bistu.edu.cn

Abstract:

The imprint characters on the surface of the workpiece are uneven, rusty, and weathered, which the traditional character recognition methods hard to achieve satisfactory results. This paper regards the characters recognition task as a particular detection problem and designs a two-stage recognition network according to its characteristics: location and classification network. The location newtork uses the anchor-free method to extract the region of interest of characters, which effectively solves the problem of character region extraction. The classification network uses the Feature Decoupled Convolution Block and the Structural Re-parameterization technology, which can significantly improve the classification accuracy without any extra parameter. The transferring learning is used to solve the small sample problem and imbalance problem in the training stage. The experimental results on the self-built bolt dataset and the SynthText dataset show that the algorithm can achieve overall accuracies of 98% and 92%, respectively, which is superior to the compared algorithms.

Key words: imprint character, character recognition, anchor-free, small sample, object detection

CLC Number: 

  • TP391

Fig.1

Location network structure"

Fig.2

Label generation"

Fig.3

Classification network using training strategy of cross-domain transfer learning"

Fig.4

Feature decoupling convolution module"

Fig.5

Cross-domain migration learning strategy"

Fig.6

Location and classification data set"

Table 1

Character positioning index"

数据集算法准确率召回率F1
自建螺栓数据集Faster R-CNN0.9750.9620.969
YOLOv50.9790.9700.974
CenterNet0.9800.9490.964
RetinaNet0.9430.9060.924
本文0.9960.9970.996
SynthText数据集Faster R-CNN0.9550.9370.946
YOLOv50.9620.9390.950
CenterNet0.9450.9200.932
RetinaNet0.8980.8860.891
本文0.9730.9630.968

Table 2

FD Block comparison test results"

数据集算 法基线准确率替换后准确率基线帧率/(帧·s-1替换后帧率/(帧·s-1
自建螺栓数据集VGG160.9630.974112.7113.9
ResNet500.9750.98195.195.8
SynthText数据集VGG160.9150.922184.8186.3
ResNet500.9230.932148.5149.1

Table 3

Improvement of cross-domain migration"

跨域迁移
自建螺栓数据集0.9810.990
SynthText数据集0.9320.949

Table 4

Comparison of different algorithm experiments"

算法准确率召回率F1
Faster R-CNN0.9470.9340.941
YOLOv50.9670.9560.962
CenterNet0.9610.9310.946
RetinaNet0.9230.8870.905
本文0.9850.9860.985

Table 5

Comparison of different algorithm experiments"

算法准确率召回率F1
Faster R-CNN0.9040.8870.895
YOLOv50.9150.8930.903
CenterNet0.8770.8640.870
RetinaNet0.8430.8270.835
本文0.9230.9140.918

Fig.7

Effect display"

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