Sustav za adaptivno postprocesiranje videosignala

Inclusion of the latest research work to a real life applications and achieving adaptive video signal postprocessing is a complex and timely task. The proposed framework breaks the filtering process into several distinct phases and enables a researcher to move at a faster pace by narrowing the scope of the research and enabling seamless integration of this work into inherently adaptive filtering process. Some of the benefits of this modular and adaptive framework have been presented on the example of the MPEG-4 postprocessing improvements.Uključivanje najnovijih istraživačkih dostignuća u svakodnevne primjene i postizanje adaptivnog postprocesiranja videosignala zahtjevan je zadatak za koji je potrebno mnogo vremena. Predloženi sustav dijeli postupak filtriranja u nekoliko jasno odvojenih faza te na taj način sužava opseg svakog pojedinog istraživanja. Time je omogućena jednostavna integracija novih dostignuća u inherentno adaptivan proces filtriranja, što omogućava osjetno brži napredak u istraživanju. Neke prednosti ovog modularnog i adaptivnog sustava prikazane su na primjeru poboljšanja procesa postprocesiranja videosignala kodiranog prema MPEG-4 normi

Transform Domain-Based Perceptual Detection and Reduction of Blocking Artifacts

In this paper, provide a simple and effective method for measuring blocking artefacts with an ideal 2-D step function in this study. First, a basic edge detection technique for measuring blocking artefacts is proposed. The ideal 2-D step function is chosen based on the presence of blocking artefacts in the edge image. The blocking artefact reduction algorithm in frequency domain is designed to extract all of the parameters required to detect the presence of blocking artefacts and replace the optimal step function with a ramp function by replacing the coefficient of the first row of horizontal blocks with the coefficient of the shifted block. The proposed strategy was tested on various standard benchmark photos and found to increase the perceptual quality of JPEG compressed images after blocking artefact removal with the proposed method

Deblocking of block-transform compressed images using weighted sums of symmetrically aligned pixels

A new class of related algorithms for deblocking block-transform compressed images and video sequences is proposed in this paper. The algorithms apply weighted sums on pixel quar-tets, which are symmetrically aligned with respect to block boundaries. The basic weights, which are aimed at very low bitrate images, are obtained from a2-Dfunction which obeys prede ned constraints. Using these weights on images compressed at higher bitrates pro-duces a deblocked image which contains blurred false edges near real edges. We refer to this phenomenon as the ghosting e ect. In order to prevent itsoccurrences, the weights of pixels, which belong to non-monotone areas, are modi ed by dividing each pixel's weight by a prede ned factor called a grade. This scheme is referred to as weight adaptation by grad-ing (WABG). Better deblocking of monotone areas is achieved by applying three iterations of the WABG scheme on such areas followed by a fourth iteration which is applied on the rest of the image. We refer to this scheme as deblocking frames of variable size (DFOVS). DFOVS automatically adapts itself to the activity ofeachblock. This new class of algorithms produces very good subjective results and PSNR results which are competitive relative to available state-of-the-art methods