As mentioned in previous chapters film grain noise is signal dependent.
It is a limiting factor especially for images with high magnification.
A special film qrain noise restoration technique into which sigd haze. In an
experiment McGlamery (1967) characterized turbulence by a shift in-
variant psf. The result showed that a significant improvement of the
degraded image can be obtained by processing the image if the optical
transfer function of the turbulence is known. It is, however, im-
possible to know the psf for particular aerial images. In such cases
the psf must be determinated a posteriori from the degraded image
itself.
ACKNOWLEDGEMENT
The author wishes to thank his colleagues at the Departement of Photo-
grammetry , The Royal Institute of Technology in Stockholm who have made
contributions to this project, especially Dr Hans Hauska for his
valuable advice and help in reviewing this report. The author would
also like to thank Dan Rosenholm for the ideas that led to this study,
Ed Dauphin for help with the language and Dr Johan Philip for valuable
advices in connection with this project.
The work reported here was supported by the Swedish Board for Technical
Development, grant no. 84-3324.
REFERENCES
Andrews, H.C., Hunt, BR. 1977. Digital Image Restoration, Prentice-
Hall, Englewood Cliffs, New Jersey.
Andrews, H.C., 1975. "Tuo Dimensional Transforms" in Picture Processing
and Digital Filtering, Huang, T.S., Ed., Springer-Verlag, New York.
Bjerhammar, À., 1973. Theory of errors and generalized matrix inverses,
Elsevier Scientific Publishing Company, Amsterdam.
Bracewell, R., 1965. The Fourier Transform and Its Applications,
McGraw-Hill Book Company, New York.
Castleman, K.R., 1979. Digital Image Processing, Prentice-Hall,
Englewood Cliffs, New Jersey.
Ehlers, M., 1982. Increase in Correlation Accuracy of Remote Sensing
Imagery by Digital Filtering, Photogrammetric Engineering and Remote
Sensing, vol.48, no.3, March, 415-420
Frieden, B.R., 1975. "Image Enhancement and Restoration” in Picture
Processing and Digital Filtering, Huang, T.S.o; Ede, Springer-Verlag,
New York.
- 235.7
