Few-Shot Class-Incremental Learning via Training-Free Prototype
  Calibration
Qi-Wei Wang Da-Wei Zhou Yi-Kai Zhang De-Chuan Zhan Han-Jia Ye
Real-world scenarios are usually accompanied by continuously appearing
classes with scare labeled samples, which require the machine learning model to
incrementally learn new classes and maintain the knowledge of base classes. In
this Few-Shot Class-Incremental Learning (FSCIL) scenario, existing methods
either introduce extra learnable components or rely on a frozen feature
extractor to mitigate catastrophic forgetting and overfitting problems.
However, we find a tendency for existing methods to misclassify the samples of
new classes into base classes, which leads to the poor performance of new
classes. In other words, the strong discriminability of base classes distracts
the classification of new classes. To figure out this intriguing phenomenon, we
observe that although the feature extractor is only trained on base classes, it
can surprisingly represent the semantic similarity between the base and unseen
new classes. Building upon these analyses, we propose a simple yet effective
Training-frEE calibratioN (TEEN) strategy to enhance the discriminability of
new classes by fusing the new prototypes (i.e., mean features of a class) with
weighted base prototypes. In addition to standard benchmarks in FSCIL, TEEN
demonstrates remarkable performance and consistent improvements over baseline
methods in the few-shot learning scenario. Code is available at:
https://github.com/wangkiw/TEEN