Zusammenfassung
Objective quality assessment of lossy image compression codecs is
an important part of the recent call of the JPEG for Advanced
Image Coding. The target of the AIC ad-hoc group is twofold: First, to
receive state-of-the-art still image codecs and to propose suitable
technology for standardization; and second, to study objective image
quality metrics to evaluate the performance of such codes. Even tthough the
performance of an objective metric is defined by how well it predicts the
outcome of a subjective assessment, one can also study the usefulness of a
metric in a non-traditional way indirectly, namely by measuring the
subjective quality improvement of a codec that has been optimized for a
specific objective metric. This approach shall be demonstrated here on the
recently proposed HDPhoto formathdphoto introduced by Microsoft and
a SSIM-tunedssim version of it by one of the authors. We compare these two
implementations with JPEGjpeg in two variations and a visual and
PSNR optimal JPEG2000part1 implementation. To this end, we use
subjective and objective tests based on the multiscale SSIM and a new DCT
based metric.
Nutzer
