Harmonic analysis in the visual pathway of the higher mammals.

Resumen

The most recent findings of Campbell and coworkers show that in the visual system of some vertebrates a sort of spatial frequency selectivity is present, as well as a selectivity to the orientation of a sinusoidal grating. On these bases, the visual pathway as an optical data processing system is studied. The existence of "spatial tuned networks" is postulated and the equation that accounts for such a network is presented as well as the desing of the neural net that can achieve such a function. This net performs spatial integrals and weight factor multiplication, operations widely admitted for such networks. The optimum pattern for testing this selective process is presented, pointing out that orientational selectivity could easily be explained in terms of the spectral analysis that is verifield in the visual pathway. If spectral analysis is being made in this field it can be thought that it is also possible that, under certain conditions, the characteristic operations of a linear system such as spatial filtering, correlation, etc. are carried out. These operations can be formulated by means of integral transforms, whose kernel depends on the particular operation performed. These operations can be supported in the visual pathway by the fact that this has a layered structure which is specially suitable for this activity.