Increased Detectivity By Low Gamma Processing

Allan Shepp; William Kammerer

doi:10.1117/12.946793

1 April 1969 Increased Detectivity By Low Gamma Processing

Allan Shepp, William Kammerer

Proceedings Volume 0016, Image Information Recovery; (1969) https://doi.org/10.1117/12.946793
Event: Image Information Recovery, 1968, Philadelphia, United States

Abstract

Here and in other laboratories it has been observed that films exposed to subjects of an extended brightness range, processed in low gamma developers, show imagery of improved resolution and reduced flare in the normally overexposed region, and of generally improved visual fidelity over most of the exposure range, compared to the same exposure processed in a high gamma more active developer, although with a loss of toe speed and perhaps of pictoral quality. It has been generally assumed that since high gamma processing increases the contrast of the final image, it would not be possible to obtain improved imagery from low gamma processing. We explain the improved imagery of low gamma development in part by the effects of reduced density and increased contrast in the high exposure region, but principally by the fact that low gamma development leads to lower granularity and increased detectivity over most of the exposure range, compared to higher gamma development. We review detectivity and quantum efficiency theory and show that the ratio Rel d = y/σ (D, A) as a function of exposure, is the detectivity parameter of interest, since the ratio of Rel d for any two conditions of processing is the ratio of quantum efficiencies and of detectivities.

Citation Download Citation

Allan Shepp and William Kammerer "Increased Detectivity By Low Gamma Processing", Proc. SPIE 0016, Image Information Recovery, (1 April 1969); https://doi.org/10.1117/12.946793

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Image processing

Interference (communication)

Photography

Photons

Quantum efficiency

Standards development

Chromium

Show All Keywords

Keywords/Phrases

Search In:

Publication Years