QC 351 A7 no. 85 / A technique is described for suppressing unwanted
grain noise in scanned and digitized photographic images.
The technique employs the rms granularity statistics of the
film to divide, or quantize, the density range of the
digital image into distinguishable ranges of density. For
Eastman Kodak type 3414 film, the rms granularity
statistics determined indicate constant Selwyn granularity
for the range of scanning spot diameters from approximately
16 to 4 micrometers, and this result agrees with Kodak data
for a 48 micrometer diameter spot. For spots from 16 to 4
micrometers diameter, the rms granularity is also determined
to be a function of the square root of diffuse density. The
number of distinguishable density levels, required to sup-
press the grain noise of the digitally processed image, is
found to be directly related to the scanning spot diameter.
Finally, evaluation of the resulting digitally processed
images indicates that subjective image quality is directly
related to the spatial resolution of the image. That is,
with the grain noise suppressed, subjective quality is
improved by scanning the original image with a smaller
diameter spot.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/621692 |
| Date | 12 1900 |
| Creators | Hoffman, Robert Stocking, 1944- |
| Publisher | Optical Sciences Center, University of Arizona (Tucson, Arizona) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | Technical Report |
| Rights | Copyright © Arizona Board of Regents |
| Relation | Optical Sciences Technical Report 85 |
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