Abstract

The rms granularity values normally produced by an optical scanner are in terms of semispecular instrument density. It is shown that these semispecular values can be converted to a diffuse density basis by dividing by a quantity q that is defined as the ratio of the instrument density of the sample to the diffuse density. The q factor has been measured by two methods, one of which is convenient for use in the routine measurement of diffuse granularity with existing equipment. It has been found that, except at very low density levels, the q of a given material varies only slightly as the diffuse density changes. It does, however, increase significantly as the numerical aperture of the optical system decreases. When a range of samples is measured, maximum values of q occur at moderate values of sample granularity.

© 1970 Optical Society of America

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References

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  1. J. H. Altman, Appl. Opt. 3, 35 (1964).
    [CrossRef]
  2. C. S. McCamy, Phot. Sci. Eng. 10, 314 (1966).
  3. C. Tuttle, J. W. McFarlane, J. Soc. Motion Picture Television Engrs. 15, 345 (1930).
  4. G. A. Boutry, in Proceedings of the Ninth International Photographic Congress (Editions Rev. d’Optique, Paris, 1936), p. 484.
  5. C. E. K. Mees, The Theory of the Photographic Process (Macmillan Book Company, New York, 1942), pp. 850–851.

1966

C. S. McCamy, Phot. Sci. Eng. 10, 314 (1966).

1964

1930

C. Tuttle, J. W. McFarlane, J. Soc. Motion Picture Television Engrs. 15, 345 (1930).

Altman, J. H.

Boutry, G. A.

G. A. Boutry, in Proceedings of the Ninth International Photographic Congress (Editions Rev. d’Optique, Paris, 1936), p. 484.

McCamy, C. S.

C. S. McCamy, Phot. Sci. Eng. 10, 314 (1966).

McFarlane, J. W.

C. Tuttle, J. W. McFarlane, J. Soc. Motion Picture Television Engrs. 15, 345 (1930).

Mees, C. E. K.

C. E. K. Mees, The Theory of the Photographic Process (Macmillan Book Company, New York, 1942), pp. 850–851.

Tuttle, C.

C. Tuttle, J. W. McFarlane, J. Soc. Motion Picture Television Engrs. 15, 345 (1930).

Appl. Opt.

J. Soc. Motion Picture Television Engrs.

C. Tuttle, J. W. McFarlane, J. Soc. Motion Picture Television Engrs. 15, 345 (1930).

Phot. Sci. Eng.

C. S. McCamy, Phot. Sci. Eng. 10, 314 (1966).

Other

G. A. Boutry, in Proceedings of the Ninth International Photographic Congress (Editions Rev. d’Optique, Paris, 1936), p. 484.

C. E. K. Mees, The Theory of the Photographic Process (Macmillan Book Company, New York, 1942), pp. 850–851.

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Figures (4)

Fig. 1
Fig. 1

Schematic of optical system used to measure the q factor. A, source; D, diffuser; E, photocell; L1 and L2, interchangeable objectives. When the sample is placed in plane B, the system measures instrument density; in plane C, it measures totally diffuse density.

Fig. 2
Fig. 2

Variation of q factor with net diffuse density, for a typical sample.

Fig. 3
Fig. 3

Variation of q factor with the numerical aperture of the illuminating and collection objectives.

Fig. 4
Fig. 4

Variation of q factor with diffuse rms granularity for several samples, and for system numerical apertures of 0.10, 0.25, and 0.40.

Equations (2)

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σ ( D * ) = q × σ ( D ) ,
y = m D * + b ,

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