SkinNet-INIO: Multiclass Skin Lesion Localization and Classification Using Fusion-Assisted Deep Neural Networks and Improved Nature-Inspired Optimization Algorithm

Abstract

Background: Using artificial intelligence (AI) with the concept of a deep learning-based automated computer-aided diagnosis (CAD) system has shown improved performance for skin lesion classification. Although deep convolutional neural networks (DCNNs) have significantly improved many image classification tasks, it is still difficult to accurately classify skin lesions because of a lack of training data, inter-class similarity, intra-class variation, and the inability to concentrate on semantically significant lesion parts. Innovations: To address these issues, we proposed an automated deep learning and best feature selection framework for multiclass skin lesion classification in dermoscopy images. The proposed framework performs a preprocessing step at the initial step for contrast enhancement using a new technique that is based on dark channel haze and top-bottom filtering. Three pre-trained deep learning models are fine-tuned in the next step and trained using the transfer learning concept. In the fine-tuning process, we added and removed a few additional layers to lessen the parameters and later selected the hyperparameters using a genetic algorithm (GA) instead of manual assignment. The purpose of hyperparameter selection using GA is to improve the learning performance. After that, the deeper layer is selected for each network and deep features are extracted. The extracted deep features are fused using a novel serial correlation-based approach. This technique reduces the feature vector length to the serial-based approach, but there is little redundant information. We proposed an improved anti-Lion optimization algorithm for the best feature selection to address this issue. The selected features are finally classified using machine learning algorithms. Main Results: The experimental process was conducted using two publicly available datasets, ISIC2018 and ISIC2019. Employing these datasets, we obtained an accuracy of 96.1 and 99.9%, respectively. Comparison was also conducted with state-of-the-art techniques and shows the proposed framework improved accuracy. Conclusions: The proposed framework successfully enhances the contrast of the cancer region. Moreover, the selection of hyperparameters using the automated techniques improved the learning process of the proposed framework. The proposed fusion and improved version of the selection process maintains the best accuracy and shorten the computational time.

Keywords: deep learning; feature selection; features fusion; hyperparameters selection; image processing; machine learning; skin cancer.

Figure 1

Categories of skin lesions: (a) melanoma; (b) actinic keratosis; (c) basal cell carcinoma; (d) Merkel cell carcinoma; (e) melanocytic nevus/mole; (f) squamous cell carcinoma [20].

Figure 2

Illustration of the proposed methodology for skin lesion classification.

Figure 3

Visual results of hybrid contrast enhancement. (A) Original images; (B) enhanced images after applying the proposed approach.

Figure 4

Augmentation process such as Flip LR and Flip UD.

Figure 5

Architecture of DarkNet19 model.

Figure 6

Architecture of ResNet18 model [49].

Figure 7

Architecture of InceptionV3 model [49]. * sign in employed for such kind of figures.

Figure 8

Process of transfer learning for feature extraction of skin cancer.

Figure 9

Confusion matrix of Quadratic SVM for augmented ISIC2018 dataset.

Figure 10

Confusion matrix of Quadratic SVM for augmented ISIC2018 dataset.

Figure 11

Confusion matrix of Quadratic SVM for augmented ISIC2019 dataset.

Figure 12

Confusion matrix of Quadratic SVM for augmented ISIC2019 dataset using proposed feature selection technique.