Recent Contribution to the Study of Photographic Granularity

Paper presented by Mr. A. E. Saunders at a Symposium on “Photographic Granularity” organized by the Science Committee of the Royal Photographic Society on 30 Nov.-I Dec. 1967. in London.

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* Present address: I.B.M. Ireland Ltd., 28 Fitzwilliam Place, Dublin 2, Ireland.

Abstract

Photographic granularity is well represented by the autocorrelation function and the Wiener spectrum of transmittance deviation; between the various experimental and theoretical forms of these functions exists a set of relations in which Fourier, Hankel and Abel transformations appear. A new statistical model is given: it expresses the influence of grain clumping and mottle on the shape of the Wiener spectrum. The measurement of the Wiener spectrum leads to sampling problems and integral equations; the numerical resolution of these integral equations is shown to be possible by two different methods. A weighted integration synthesizes the information given by the Wiener spectrum: this leads to an objective evaluation of graininess.

Notes

Paper presented by Mr. A. E. Saunders at a Symposium on “Photographic Granularity” organized by the Science Committee of the Royal Photographic Society on 30 Nov.-I Dec. 1967. in London.

* Present address: I.B.M. Ireland Ltd., 28 Fitzwilliam Place, Dublin 2, Ireland.