Abstract: A method for detecting streak noises in a digital image including the following steps is provided. Firstly, an exposure value of a camera is decreased, and a digital image is captured under exposure with a homogeneous background light source by the camera. Secondly, a circular region of interest (ROI) is extracted from the digital image. Next, projection values of the circular ROI corresponding to a plurality of rotation angles are calculated. Then, the projection values are respectively converted into amplitudes of the rotation angles. Afterwards, a maximum amplitude is found from the amplitudes. Finally, the maximum amplitude is compared with a threshold value to judge whether a streak noise exists in the digital image.