11 February 2009 Robust measurement of the blocking artefact
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Proceedings Volume 7245, Image Processing: Algorithms and Systems VII; 72450K (2009); doi: 10.1117/12.805726
Event: IS&T/SPIE Electronic Imaging, 2009, San Jose, California, United States
A method is presented to measure the intensity of the blocking artefact in compressed pictures or video frames. First, a way is devised to artificially introduce pure blocking, which closely resembles the real one subsequent to JPEG compression. Then a modified no-reference measurement is proposed that requires less computations than other formerly presented methods, permits to take into account the whole image or frame area, and is not affected by interlaced video. Some first experiments indicate that the measured values relate closely to the introduced blockiness effect. The robustness of the metric to the influence of other typical JPEG artefacts is also checked. Further, the effect on blockiness of some enhancement strategies is measured. Pictures enhanced with methods introducing the most severe blockiness are found to have the highest value of the proposed metric. Finally the problem of blockiness measurement in video sequences is addressed. In this case the blocking grid is no longer regular. In fact, blocks of different size could be used in encoding, and single blocks could be shifted in referenced (P and B) frames due to motion compensation. A method is devised for grid detection.
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Giovanni Ramponi, Leonardo Abate, "Robust measurement of the blocking artefact", Proc. SPIE 7245, Image Processing: Algorithms and Systems VII, 72450K (11 February 2009); doi: 10.1117/12.805726; https://doi.org/10.1117/12.805726


Image compression

Image enhancement

Image quality

Image processing

Video compression

Computer programming

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