Mr. Andrew J. Stokes Profile

Andrew J. Stokes

Associate Research Physicist at US Air Force

SPIE Involvement:

Author

Publications (1)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 2 May 2009 Paper

Increasing mid-frequency contrast in sparse aperture optical imaging systems

Andrew Stokes, Bradley Duncan, Matthew Dierking, Nicholas Miller

Proc. SPIE. 7323, Laser Radar Technology and Applications XIV

KEYWORDS: Signal to noise ratio, Optical imaging, Optical transfer functions, Point spread functions, Imaging systems, Spatial frequencies, Signal attenuation, Image resolution, Numerical simulations, Modulation transfer functions

Read Abstract +

Sparse aperture imaging systems are capable of producing high resolution images while maintaining an overall light collection area that is small with respect to a fully filled aperture yielding the same resolution. However, conventional sparse aperture systems pay the penalty of reduced contrast at mid-band spatial frequencies. The modulation transfer function (MTF), or normalized autocorrelation, provides a quantative measure of both the resolution and contrast of an optical imaging system. Numerical MTF calculations were thus used to examine mid-band contrast recovery through the systematic increase of autocorrelation redundancy in a Golay-9 sparse array. In a Golay-9 sparse aperture arrangement, three sets of three sub-apertures can be shown to lie at unique radii from the center of the array. In order to increase the mid-frequency contrast we then have two options. The first, and most influential, is to increase the size of the sub-apertures located at the intermediate radius from the array origin. This directly increases autocorrelation redundancy at mid-band frequencies. The second option, though less effective, is to increase the relative mid-band frequency response by attenuating the outer most sub-apertures. We will demonstrate that by increasing the diameters of the mid-radii sub-apertures, mid-band contrast can be increased by over 45%, compared to uniform sub-aperture diameter arrays. We will also demonstrate that attenuating the outer most sub-apertures can further increase mid-band contrast recovery, but only by less than 1%. The effects on array fill factor will also be discussed.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print format on SPIE.org.

PERSONAL SIGN IN
Full access may be available with your subscription

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Institutional Access:

PURCHASE THIS CONTENT

INTERESTED IN A FREE CORPORATE TRIAL?

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:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years