The purpose of this page is to make available one subjective quality assessment from IRCCyN/IVC. The experiment was conducted in our lab in normalized conditions.
Content
5 original grayscale images, 210 distorted images were generated from noise addition in 6 different frequency (Fourier) sub-bands of various frequency range, with 7 embedding strengths.
Details on the spreadsheet.
Marked images are entitled "Marked_boats_X_Y.bmp", where 'X' stands for the embedding sub band index in a Perceptual Channel Decomposition (PCD), splitting the Fourier frequency stectrum into 17 overlapping sub-bands, see the paper referenced at the bottom of the page for further details on the perceptual decomposition (the PCD is depicted on the figure below where every sub-band is indexed) and 'Y' is the embedding strength. A Gaussian noise was independently modulated within one PCD sub band, and spread over the whole sub-band.
Only subbands number 2, 3, 6, 7, 12 and 13 (see index on Figure 1) were used during this experiment.
Figure 1. Perceptual Channel Decomposition with indexed sub-bands.
The purpose of this experiment was to highlight the incoherencies of objective quality metrics when distortions occur in a different frequency range. Subjective evaluations were made at viewing distance of 6 times the screen height using a DSIS (Double Stimulus Impairment Scale) method with 5 categories and 7 observers. Distortions for each processing and each image have been optimised in order to uniformly cover the subjective scale.
Download
Download the
IVC-FourierSB database (52 MB zip file)
A Microsoft Excel spreadsheet, giving all subjective quality scores is
included in the above archive.
Dissemination
This database was used in
M. Carosi, V. Pankajakshan, F. Autrusseau, "Toward a simplified perceptual quality metric for watermarking applications", Proceedings of the SPIE Electronic Imaging, conf. 7542, January 2010, San Jose, CA, USA.