The prevalence of long-tailed distributions in real-world data often results in classification models favoring the dominant classes, neglecting the less frequent ones. Current approaches address the issues in long-tailed image classification by rebalancing data, optimizing weights, and augmenting information. However, these methods often struggle to balance the performance between dominant and minority classes because of inadequate representation learning of the latter. To address these problems, we introduce descriptional words into images as cross-modal privileged information and propose a cross-modal enhanced method for long-tailed image classification, referred to as CMLTNet. CMLTNet improves the learning of intra-class similarity of tail-class representations by cross-modal alignment and captures the difference between the head and tail classes in semantic space by cross-modal inference. After fusing the above information, CMLTNet achieved an overall performance that was better than those of benchmark long-tailed and cross-modal learning methods on the long-tailed cross-modal datasets, NUS-WIDE and VireoFood-172. The effectiveness of the proposed modules was further studied through ablation experiments. In a case study of feature distribution, the proposed model was better in learning representations of tail classes, and in the experiments on model attention, CMLTNet has the potential to help learn some rare concepts in the tail class through mapping to the semantic space.

The interaction between light and materials is key to physically-based realistic rendering. However, it is also complex to analyze, especially when the materials contain a large number of details and thus exhibit "glinty" visual effects. Recent methods of producing glinty appearance are expected to be important in next-generation computer graphics. We provide here a comprehensive survey on recent glinty appearance rendering. We start with a definition of glinty appearance based on microfacet theory, and then summarize research works in terms of representation and practical rendering. We have implemented typical methods using our unified platform and compare them in terms of visual effects, rendering speed, and memory consumption. Finally, we briefly discuss limitations and future research directions. We hope our analysis, implementations, and comparisons will provide insight for readers hoping to choose suitable methods for applications, or carry out research.