A new approach to depth range detection by producing depth-dependent blurring effect

This paper presents a new method for detecting the depth range of a scene from two differently focused images. This method first generates three images with differently emphasized blur using linear filtering of the two acquired images for more depth-sensitive estimation. In this point, this method is different from conventional approaches. The discrete Fourier transform of the ratio between the generated images is then introduced as a criterion of the depth range. Finally, through the thresholding process of the criterion according to its correspondence to the depth on the basis of the imaging model, the depth range is estimated in five depth steps. Experiments for synthesized and real images are performed to test the proposed method