Demosaicking and denoising are very important tasks among various processing steps of Image signal processor (ISP) because they are essential and process raw data obtained from sensors. Convolutional Neural Network (CNN) based Joint Demosaicking and denoising methods simultaneously process Demosaicking, and denoising using a single network are also proposed. Although existing CNN based methods showed excellent performance, the high-frequency details of the image were still not well restored, and a network structure for learning focused on that part was not be proposed. To solve this problem, we proposed a network structure that learns features from multi-resolution feature maps after downsampling without data loss by applying Discrete Wavelet Transform (DWT) to CNN. Moreover, this paper proposed a network structure that pays attention to the high frequency of an image using the channel attention technique and a loss function that reduces the loss in the frequency domain.
The proposed methods are high-efficiency methods that show high-performance improvement compared to required parameters or memory. In addition, the performance of the proposed method achieved the highest PSRN and SSIM compared with existing methods and showed a result of well reconstructing high-frequency details such as edges when comparing reconstructed images.
