目前的三维模型分类方法均是对初始姿态已经对齐的数据集进行分类,但是在实际应用中,三维模型的姿态是未知的,非对齐的三维模型将导致分类准确率急剧下降.本文提出了一种新的三维模型分类方法,适用于模型姿态对齐和非对齐两种情况.该方法采用图卷积神经网络(Graph Convolutional neural Network,GCN)学习视图间的空间关系,将预先设置好的相机位置作为图结构中的顶点,并通过时序特征提取网络以及注意力网络进一步提升GCN的运算效果,从而完成三维模型的分类.实验表明,该方法在ModelNet10和ModelNet40数据集上进行实验,在三维模型姿态对齐的情况下,分类准确率分别高达99.3％和97.4％,远高于现有方法.在三维模型姿态非对齐的情况下,也有较高的分类准确率.

Zero-shot learning (ZSL) strives to classify unseen categories for which no data is available during training.At present, among generative methods, zero-shot learning based on joint generative model VAEGAN is a research hotspot.On this basis, we propose a zero-shot image classification method based on Discriminator Feedback VAEGAN (DF-VAEGAN).This method introduces a feedback module in the discriminator part, which can improve the overall performance of the model in the training stage.In the feature generation stage, it can be combined with the generator to jointly improve the quality of feature generation.Finally, the classifier is trained through high quality synthetic features to improve classification accuracy.The method also reconstructs attribute features through the decoder and uses a cycle consistency loss to ensure semantic consistency of the generated feature.Experiments on ZSL and generalized zero-shot learning (GZSL) show that our method outperforms existing methods on five classical datasets, effectively enhancing the quality of feature synthesis and reducing the goal of between categories in the zero-shot image classification task.

Zero-shot learning (ZSL) aims to classify samples of unseen categories for which no training data is available. At present, the VAEGAN framework which combines Generative Adversarial Networks (GAN) with Variational Auto-Encoder (VAE) has achieved good performance in zero-shot image classification. Based on the VAEGAN, we propose a new zero-shot image classification method named Enhanced VAEGAN (E-VAEGAN). Firstly, we design a feature alignment module to align visual features and attribute features. Then, the aligned features are fused with the hidden layer features of the encoder to improve output features of the encoder. Secondly, the triplet loss is applied during the encoder training, which further increases the discriminability of features. Finally, the hidden layer features of the discriminator are input into a transform module and then fed back to the generator, which improves the quality of the generated fake samples. The originality of this paper is that we design a new E-VAEGAN which employs the feature alignment module, triplet loss and transform module to reduce the ambiguity between categories and make the generated fake features similar to the real features. Experiments show that our method outperforms the compared methods on five zero-shot learning benchmarks.

The integration of view-based 3D model classification and deep learning can effectively improve the classification accuracy. However, current methods consider that the views from different viewpoints of 3D model with same category belong to the same category and ignore the view differences, which makes it difficult for the classifier to learn a reasonable classification surface. To solve this problem, a 3D model classification method based on deep neural network is proposed. The multiple viewpoint groups are set evenly around the 3D model in this method, and the view classifier for each viewpoint group is trained for fully mining the deep information of the 3D model in different viewpoint groups. These classifiers share a feature extraction network, but have their own classification network. In order to extract the discriminative view features, the attention mechanism is added to the feature extraction network; In order to model the views of the non-viewpoint group, additional classes are added to the classification network. In the classification stage, a view selection strategy is first proposed, which can use a small number of views to classify the 3D model and improve classification efficiency. Then a classification strategy is proposed to achieve reliable 3D model classification through classification view. Experimental results on ModelNet10 and ModelNet40 show that the classification accuracy can reach up to 93.6% and 91.0% with only 3 views.