HIERARCHICAL FEATURE FUSION TRANSFORMER FOR NO-REFERENCE IMAGE QUALITY ASSESSMENT

Recently, increasing interest has been drawn in Transformer-based models for No-reference Image Quality Assessment (NR-IQA), especially for the hybrid approach. The hybrid approach tend to apply Transformer to aggregate quality information from feature maps extracted by Convolutional Neural Networks (CNN). However, existing methods cannot fully utilize the information of hierarchical features extracted by the deep neural network, resulting in the limited performance of image quality evaluation. In this work, we propose a novel Hierarchical Feature Fusion Transformer for NR-IQA (HiFFTiq), which is able to effectively exploit complementary strengths of features extracted by different layers. Further, we propose a new Uniform Partition Pooling (UPP) which can reduce the resolution of input features via uniform partitions and can well retain the quality-related information compared to the traditional pooling method Sliding Window Pooling (SWP). The results of experiment demonstrate that HiFFTiq leads to improvements of performance over the state-of-the-art methods on three large scale NR-IQA datasets.