Split-Conv: A Resource-efficient Compression Method for Image Quality Assessment Models

Yiming Zhang, Xiongkuo Min, Guangtao Zhai

Abstract: Blind Image Quality Assessment (BIQA) models based on deep neural networks (DNNs) have achieved state-of-the-art performance recently. However, the heavyweight architecture makes them hard to deploy on resource-constrained devices. Filter pruning is one of the most effective ways to compress the DNN model. However, most pruning methods need complete retraining after pruning which is too resource-consuming for IQA models with complex training processes. In this paper, we propose a resource-efficient structural pruning method for IQA models called Split-Conv, where the model only needs to be retrained on small IQA databases. Specifically, we split convolutional layers into sub-convolutional kernels and decorators, which can measure the importance of convolutional channels more precisely, thus reducing the requirement for retraining conditions. The experiments on several IQA models demonstrate the effectiveness of our IQA model pruning approach. For instance, DBCNN, StairIQA, and HyperIQA’s performances can be kept at the baseline level when 50% parameters are pruned with the model being retrained on the authentically distort IQA database containing only 586 images, and the performances of StairIQA and HyperIQA on KonIQ-10k database are still acceptable after 80% of the parameters have been pruned. Besides, due to Split-Conv’s capability to identify the important, useless, and harmful filters, the performances of some BIQA models can even be boosted after model compression with a proper pruning ratio.