This antiface is virtual image generated by a computer. The software begins by identifying your unique facial metrics from a data set of photos. Then it generates a 3D representation of your face called your "identity average."
The computer compares the metrics of your identity average with those of the population average. Then it generates a new face with opposite metrics. So if you have a narrow forehead, your antiface will have a wide forehead. If your eyes point up in the outer corners, the eyes of your antiface will point down. If you have a bit of a frown, your antiface will have a bit of a smile.
R. Jenkins and A. M. Burton, the scientists who worked on this study, were unsure whether using metrics alone to make an antiface would generate a plausible photographic face. "It was not obvious in advance that this would be the case," they said.
Further, they observed that "psychologically relevant dimensions such as sex and emotional expression are reversed by this process (female becomes male; sullen becomes cheery), even though these dimensions are not explicitly coded at any stage. In addition, all aspects of the physical appearance of the face take on the opposite valence, so that dark complexion becomes light complexion, upturned nose becomes downturned nose, etc."
They also discovered that, because of the effects of accommodation, if you look long enough at an antiface and then switch to a looking at an average face, even the average face will take on qualities of the individual in question.
You can generate an antiface across the gender mean to output a same-sex antiface. Or you can use the data to render an opposite-sex version of your face. Or you can use it to create an opposite-sex antiface. The photo shows Paul McCartney's face taken through all those permutations.
Being able to look at an antiface would be an aid to portrait painters or caricaturists, because it makes clear what is unique about a given face.
More about Antifaces R. Jenkins and A. M. Burton