To examine the contribution of granurality of film, structure of photographic paper surface and of mesh to the image transmission, the concept of carrier is introduced into the spatial fre-quency spectrum space. According to the signal carrying ability, the carriers are classified into five canonical forms in spatial frequency domain by the aid of the group theory, and spatial fre-quency spectra of objects and image signals are investigated. It becomes clear that the spectral plane can be utilized most effectively by the application of Hartley's law of the communication engineering to a two dimentional space when the anisotropy of spatial frequency distribution of the objects and the type of the image transmission carriers are considered. This proves that the silk-surface of photographic paper has a band-limiting characteristic and that the customary orien-tation of meshes in printing and of target mesh of image orthicon is correct. Furthermore, it is made clear that the use of spatial anisotropic optical filters improves the signal to noise ratio of above 6 db of TV or photographic images and also that, if the skew-scanning method is used, the band compression of TV signals by about 30% will become possible.
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