# Generation and frame characteristics of predefined evenly-distributed class centroids for pattern classification

arXiv: https://arxiv.org/abs/2105.00401 · HTML: https://mlsanity.com/paper/2105.00401/

## Key facts

- Cited by 3 papers in the map (data through 14 Oct 2026).
- Builds on 10 of its 25 references that are in the map.
- First posted on arXiv 2 May 2021.

## Builds on (most cited first, 10 of 10)

- [Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks](https://mlsanity.com/paper/1506.01497/) (2015)
- [DeepLab: Semantic Image Segmentation with Deep Convolutional Nets, Atrous Convolution, and Fully Connected CRFs](https://mlsanity.com/paper/1606.00915/) (2016)
- [SphereFace: Deep Hypersphere Embedding for Face Recognition](https://mlsanity.com/paper/1704.08063/) (2017)
- [Learning Deconvolution Network for Semantic Segmentation](https://mlsanity.com/paper/1505.04366/) (2015)
- [Additive Margin Softmax for Face Verification](https://mlsanity.com/paper/1801.05599/) (2018)
- [A New Loss Function for CNN Classifier Based on Pre-defined Evenly-Distributed Class Centroids](https://mlsanity.com/paper/1904.06008/) (2019)
- [A Classification Supervised Auto-Encoder Based on Predefined Evenly-Distributed Class Centroids](https://mlsanity.com/paper/1902.00220/) (2019)
- [An Image Clustering Auto-Encoder Based on Predefined Evenly-Distributed Class Centroids and MMD Distance](https://mlsanity.com/paper/1906.03905/) (2019)
- [The FaceChannel: A Fast & Furious Deep Neural Network for Facial Expression Recognition](https://mlsanity.com/paper/2009.07635/) (2020)
- [Semi-supervised learning method based on predefined evenly-distributed class centroids](https://mlsanity.com/paper/2001.04092/) (2020)

## Built on by (most cited first, 3 of 3)

- [Effective Out-of-Distribution Detection in Classifier Based on PEDCC-Loss](https://mlsanity.com/paper/2204.04665/) (2022)
- [A Softmax-free Loss Function Based on Predefined Optimal-distribution of Latent Features for Deep Learning Classifier](https://mlsanity.com/paper/2111.15449/) (2021)
- [Out-of-distribution detection based on subspace projection of high-dimensional features output by the last convolutional layer](https://mlsanity.com/paper/2405.01662/) (2024)

## Abstract (arXiv)

Predefined evenly-distributed class centroids (PEDCC) can be widely used in models and algorithms of pattern classification, such as CNN classifiers, classification autoencoders, clustering, and semi-supervised learning, etc. Its basic idea is to predefine the class centers, which are evenly-distributed on the unit hypersphere in feature space, to maximize the inter-class distance. The previous method of generating PEDCC uses an iterative algorithm based on a charge model, that is, the initial values of various centers (charge positions) are randomly set from the normal distribution, and the charge positions are updated iteratively with the help of the repulsive force between charges of the same polarity. The class centers generated by the algorithm will produce some errors with the theoretically evenly-distributed points, and the generation time will be longer. This paper takes advantage of regular polyhedron in high-dimensional space and the evenly distribution of points on the n dimensional hypersphere to generate PEDCC mathematically. Then, we discussed the basic and extensive characteristics of the frames formed by PEDCC. Finally, experiments show that new algorithm is not only faster than the iterative method, but also more accurate in position. The mathematical analysis and experimental results of this paper can provide a theoretical tool for using PEDCC to solve the key problems in the field of pattern recognition, such as interpretable supervised/unsupervised learning, incremental learning, uncertainty analysis and so on.