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• [P513] Subjective Image Quality Assessment: A Method Based on Signal Detection Theory
  Author(s): Yurong He, Yuming Xuan, Wenfeng Chen, Xiaolan Fu
  
  

  Abstract
  In the field of image quality assessment, to develop computerized/objective methods whose evaluations are in close agreement with human judgments becomes the main tasks. However, accurate evaluation of human's subjective judgments is still a problem, which also leads to that the inconsistent results between computerized/objective and subjective assessment are doubtful. Tradition methods based on mean opinion score (MOS) were not accurate enough, especially for images of minor changes or distortions. The present study tried to apply signal detection theory (SDT) in the field of image quality assessment, since SDT is particularly useful in measuring the way we make decisions under conditions of uncertainty. The results of three psychophysics experiments, in which images of different watermarking strengths were used as stimuli, showed that the SDT-based method was especially useful to detect the small loss of fidelity of images. This conclusion was supported by the higher correlation between the sensitivity score, P(A), with several computerized/objective QA indexes, such as PSNR, VIF and SSIM. Detecting subtle changes of images might involve some unknown implicit mechanisms for participants did not perform well enough in full-reference framework which allowing direct comparisons of the changed image to the original one.

  
   

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