Journal of Forensic Medicine ›› 2022, Vol. 38 ›› Issue (1): 31-39.DOI: 10.12116/j.issn.1004-5619.2021.411001

Special Issue: 水中尸体研究专题

• Original Articles • Previous Articles     Next Articles

Comparison among Four Deep Learning Image Classification Algorithms in AI-based Diatom Test

Yong-zheng ZHU1,2(), Ji ZHANG2(), Qi CHENG2,3, Hui-xiao YU2,4, Kai-fei DENG2, Jian-hua ZHANG2, Zhi-qiang QIN2, Jian ZHAO5, Jun-hong SUN1(), Ping HUANG1,2()   

  1. 1.School of Forensic Medicine, Shanxi Medical University, Taiyuan 030001, China
    2.Shanghai Key Laboratory of Forensic Medicine, Key Laboratory of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai 200063, China
    3.Department of Forensic Medicine, Guizhou Medical University, Guiyang 550000, China
    4.Department of Forensic Medicine, Xuzhou Medical University, Xuzhou 221004, Jiangsu Province, China
    5.Guangzhou Forensic Science Institute & Key Laboratory of Forensic Pathology, Ministry of Public Security, Guangzhou 510442, China
  • Received:2021-10-04 Online:2022-02-25 Published:2022-02-28
  • Contact: Jun-hong SUN,Ping HUANG

Abstract: Objective

To select four algorithms with relatively balanced complexity and accuracy among deep learning image classification algorithms for automatic diatom recognition, and to explore the most suitable classification algorithm for diatom recognition to provide data reference for automatic diatom testing research in forensic medicine.

Methods

The “diatom” and “background” small sample size data set (20 000 images) of digestive fluid smear of corpse lung tissue in water were built to train, validate and test four convolutional neural network (CNN) models, including VGG16, ResNet50, InceptionV3 and Inception-ResNet-V2. The receiver operating characteristic curve (ROC) of subjects and confusion matrixes were drawn, recall rate, precision rate, specificity, accuracy rate and F1 score were calculated, and the performance of each model was systematically evaluated.

Results

The InceptionV3 model achieved much better results than the other three models with a balanced recall rate of 89.80%, a precision rate of 92.58%. The VGG16 and Inception-ResNet-V2 had similar diatom recognition performance. Although the performance of diatom recall and precision detection could not be balanced, the recognition ability was acceptable. ResNet50 had the lowest diatom recognition performance, with a recall rate of 55.35%. In terms of feature extraction, the four models all extracted the features of diatom and background and mainly focused on diatom region as the main identification basis.

Conclusion

Including the Inception-dependent model, which has stronger directivity and targeting in feature extraction of diatom. The InceptionV3 achieved the best performance on diatom identification and feature extraction compared to the other three models. The InceptionV3 is more suitable for daily forensic diatom examination.

Key words: forensic pathology, artificial intelligence, drowning, deep learning, diatom test, convolutional neural network

CLC Number: