Directional high-pass filter for blurry image analysis

High-frequency energy distributions are important characteristics of blurry images. In this paper, directional high-pass filters are proposed to analyze blurry images. Firstly, we show that the proposed directional high-pass filters can effectively estimate the motion direction of motion blurred images. A closed-form solution for motion direction estimation is derived. It achieves a higher estimation accuracy and is also faster than previous methods. Secondly, the paper suggests two important applications of the directional high-frequency energy analysis. It can be employed to identify out-of-focus blur and motion blur, and to detect motion blurred regions in observed images. Experiments on both synthetic and real blurred images are conducted. Encouraging results demonstrate the efficacy of the proposed methods.

► Directional high-pass filter is proposed to analyze blurry images.
► Accurately identify motion direction of motion blurred images.
► The algorithm is robust to image noise.
► Effectively identify out-of-focus blur and detect motion blurred regions.