DTMNet: A Discrete Tchebichef Moments-based Deep Neural Network for Multi-focus Image Fusion

Compared with traditional methods, the deep learning-based multi-focus image fusion methods can effectively improve the performance of image fusion tasks. However, the existing deep learning-based methods encounter a common issue of a large number of parameters, which leads to the deep learning models with high time complexity and low fusion efficiency. To address this issue, we propose a novel discrete Tchebichef moment-based Deep neural network, termed as DTMNet, for multi-focus image fusion. The proposed DTMNet is an end-to-end deep neural network with only one convolutional layer and three fully connected layers. The convolutional layer is fixed with DTM co-efficients (DTMConv) to extract high/low-frequency information without learning parameters effectively. The three fully connected layers have learnable parameters for feature classification. Therefore, the proposed DTMNet for multi-focus image fusion has a small number of parameters (0.01M paras vs. 4.93M paras of regular CNN) and high computational efficiency (0.32s vs. 79.09s by regular CNN to fuse an image). In addition, a large-scale multi-focus image dataset is synthesized for training and verifying the deep learning model. Experimental results on three public datasets demonstrate that the proposed method is competitive with or even outperforms the state-of-the-art multi-focus image fusion methods in terms of subjective visual perception and objective evaluation metrics.