In this paper, we propose an out-of-focus blur estimation using isotropic step responses and its application to image restoration. The proposed algorithm can make in-focused image by using only digital image processing techniques, and it required neither infrared light or ultrasound nor focusing lens assembly operated by electrically powered movement of focusing lens.To increase accuracy in estimating the Point-spread-function (PSF) of the defocus image, the proposed algorithm finds true and linear edges by using Canny edge detector, which is optimal edge detector and has good localization, estimates the step response across the edge for each pixel, computes the one-dimensional step response by averaging the step responses, estimates the two-dimensional PSF from the averaged step response, and finally provides in-focused image by image restoration filter based on the estimated PSF.There is a limit of the amount of out-of-focus, which can be recovered by the proposed algorithm. Moreover, the proposed algorithm is operating under assumption that an input image contains at least one piece-wise linear boundary between an object and background. In spite of above-mentioned limitations, the proposed algorithm can make acceptable quality of focused image by using only digital image processing.

No abstract

We propose a very simple scalable video coding (SVC) system based on the H.264 baseline profile codec. The proposed SVC algorithm can offer three levels of the temporal and spatial scalability -QVGA@15fps, QVGA@30fps, and VGA@30fps. The proposed system achieves the temporal scalability by encoding every other picture as the nonreference P-picture, so that the base layer codec dealing with the QVGA@15fps sequence is fully-compatible with the satellite-digital multimedia broadcasting (S-DMB) system in Korea. In addition, the same decoder can reconstruct the QVGA@30fps sequence when it receives the bits representing the non-reference pictures. For the spatial enhancement layer, the encoder follows the standard H.264 baseline profile except the inter-layer intra prediction. To reduce the computational burden of the encoder, the enhancement layer encoder may skip the motion estimation procedure by interpolating the motion field with that of the base layer. Simulation results show that the proposed system yields less then about 12% of loss in the reconstruction picture quality compared with the anchor H.264 JM encoder. The proposed SVC system still has a room for improvement of coding efficiency by trading with the computational complexity, so that lots of further works are required.