Quality assessment of visual information masked by orthogonal matrices with symmetries

An approach for evaluating the quality of one-sided and two-sided matrix masking is proposed, based on an analysis of the two-dimensional correlation coefficient and the pixel-wise correlation of the masked image. The results obtained allow for a numerical assessment of masking quality when using matrices with varying structures. It is demonstrated experimentally that, in cases where the dimensions of the masking matrix cannot be made equal to those of the original image, a threshold value for the twodimensional correlation coefficient can be set, not exceeding 0.5 — at which an acceptable masking quality is ensured, and not exceeding 0.2 — at which, for each image class, an external observer cannot extract useful information from the masked image.