prosthetic knowledge

a - the original 
b - areas of interest
c - foveal and perifoveal visions

Jean Paul Courchia proposes the idea of the “opsieme”, a visual unit equivalent to the ‘phoneme’ and ‘graphemes’ used to deconstruct sounds and text: 

According to cognitive neuroscientist Stanislas Dehaene, recognizing letters and their combinations — called graphemes — and then creating an interface between what’s written and what’s articulated (phonological awareness) is the way to gain access to the lexicon that we use to communicate. If we indeed pay attention to the basic elements that compose the written sentence, we find letters, syllables and words. However, the smallest significant element of the sentence is probably the grapheme, since the whole understanding process derives from it. The grapheme is the written equivalent of the oral phoneme. It is comprised of the smallest group of letters making a phoneme. For example, in French, the phoneme [o] has several graphemes : o, au, and eau. Unlike a letter, a grapheme represents better the phonology of a language, or what a language sounds like. The French language counts 130 graphemes.

Does this same concept apply to a painting or an image ? Just like in the reading process, the image undergoes several mutations between the retina and the sensory areas of the cerebral cortex, whereby the basic components of the image (forms, colors, orientation of the lines) are dissected first and then transmitted to the visual areas. It is only then that the image is reconstructed, and that it will be confronted against other known representations that are stored in our memory for an identification of the present image. Dismantling, reassembly and identification are the three steps in the process of the visual representation, whether artistic or natural …

… Fixation can be equated with the time necessary to identify the smallest significant visual unit in an image. Just as a phoneme is the smallest articulated unit, and a grapheme is the smallest written unit, we suggest opsieme as a designation for the smallest significant visual unit : « opsie » – from the Greek ops, opsis, which means eye, vision and « eme », suffix which signifies basic unit.

You can read the whole piece here