TID2008 is intended for evaluation of full-reference image visual quality assessment metrics. TID2008 allows estimating how a given metric corresponds to mean human perception. For example, in accordance with TID2008, Spearman correlation between the metric PSNR (Peak Signal to Noise Ratio) and mean human perception (MOS, Mean Opinion Score) is 0.525.The TID2008 contains 25 reference images and 1700 distorted images (25 reference images x 17 types of distortions x 4 levels of distortions). Reference images are obtained by cropping fromKodak Lossless True Color Image Suite.All images are saved in database in Bitmap format without any compression. File names are organized in such a manner that they indicate a number of the reference image, then a number of distortion's type, and, finally, a number of distortion's level: "iXX_YY_Z.bmp".The file "mos.txt" contains the Mean Opinion Score for each distorted image. The MOS was obtained from the results of 838 experiments carried out by observers from three countries: Finland, Italy, and Ukraine (251 experiments have been carried out in Finland, 150 in Italy, and 437 in Ukraine). Totally, the 838 observers have performed 256428 comparisons of visual quality of distorted images or 512856 evaluations of relative visual quality in image pairs. Higer value of MOS (0 - minimal, 9 - maximal, MSE of each score is 0.019) corresponds to higer visual quality of the image.In case of publishing results obtained by means of TID2008 please refer to one of the following papers:(full description of TID2008)N. Ponomarenko, V. Lukin, A. Zelensky, K. Egiazarian, M. Carli, F. Battisti, "TID2008 - A Database for Evaluation of Full-Reference Visual Quality Assessment Metrics", Advances of Modern Radioelectronics, Vol. 10, pp. 30-45, 2009. [PDF](a short description of TID2008)N. Ponomarenko, F. Battisti, K. Egiazarian, J. Astola, V. Lukin "Metrics performance comparison for color image database", Fourth international workshop on video processing and quality metrics for consumer electronics, Scottsdale, Arizona, USA. Jan. 14-16, 2009, 6 p. [PDF]