Deciding on the minimum changes in images of a human face under conditions of indeterminacy

The research problem consisted of using the following methods of neuroiconics: digital image processing, functional magnetic-resonance tomography (fMRT) of brain activity, and psychophysical methods to determine under conditions of indeterminacy the minimum information needed to recognize faces with different intensities of the facial expression. Indeterminacy was exemplified at the semantic level by a pattern of weak facial manifestations of emotions that bear a strong emotional burden and at the physical level by noise of various intensities imposed upon the image. Difference-recognition thresholds were established as a result of analyzing this research, and it was shown that there is correlation between the number of altered pixels in the test images and the correct answers of the observers. Thus, the number of altered pixels in the test images of faces being compared is proportional to the correct answers when a decision is being made in the psychophysical studies and to the number of altered voxels in the images being compared in maps of the brain responses from the data of the fMRT studies. (C) 2017 Optical Society of America