1. INTRODUCTION
Defocus blurring is a common phenomenon in the cameras, especially when taking photos with the mobile phone. It always brings many disadvantages, such as image quality degradation and bad performance of computer vision tasks. In order to restore the blurred image to clarity, researchers have done a lot of excellent works [1], [2], [3], [4], [5]. Researchers proposed the two-stage approaches in the initial phase of study. First, generating defocus blurring map. Then, removing defocus blurring according to the blurring map. However, the two-stage methods heavily rely on the accuracy of defocus blurring map, which limits the performance of deblurring.