Measuring the modulation transfer function of an imaging spectrometer with rooflines of opportunity

Paul W. Nugent; Joseph A. Shaw; Michael R. Kehoe; Casey W. Smith; Thomas S. Moon; Rand C. Swanson

doi:10.1117/1.3497051

1 October 2010 Measuring the modulation transfer function of an imaging spectrometer with rooflines of opportunity

Paul W. Nugent, Joseph A. Shaw, Michael R. Kehoe, Casey W. Smith, Thomas S. Moon, Rand C. Swanson

Author Affiliations +

Optical Engineering, Vol. 49, Issue 10, 103201 (October 2010). https://doi.org/10.1117/1.3497051

Abstract

Measuring the modulation transfer function (MTF) of digital imagers focused at or near infinity in laboratory or field settings presents difficulties because the optical path is longer than a typical laboratory. Also, digital imagers can be hindered by low-resolution detectors, resulting in the resolution of the optics surpassing that of the detector. We measure the MTF for a short-wave infrared hyperspectral imager developed by Resonon, Inc., of Bozeman, Montana, which exhibits both characteristics. These difficulties are overcome with a technique that uses images of building rooflines in an oversampled, tilted knife-edge-based MTF measurement. The dark rooftops backlit by a uniformly cloudy sky provide the high-contrast edges required to perform knife-edge MTF measurements. The MTF response is measured at five wavelengths across the imager's spectral band: 1085, 1178, 1292, 1548, and 1629 nm. The MTF also is observed at various distances from the roof to investigate performance change with distance. Optimum imaging is observed at a distance of 150 m, potentially a result of imperfect infinity focus and atmospheric turbulence. In a laboratory validation of the MTF algorithm using a monochrome visible imager, the roofline MTF results are similar to results from point-source and sine-card MTF measurements.

©(2010) Society of Photo-Optical Instrumentation Engineers (SPIE)

Citation Download Citation

Paul W. Nugent, Joseph A. Shaw, Michael R. Kehoe, Casey W. Smith, Thomas S. Moon, and Rand C. Swanson "Measuring the modulation transfer function of an imaging spectrometer with rooflines of opportunity," Optical Engineering 49(10), 103201 (1 October 2010). https://doi.org/10.1117/1.3497051

Published: 1 October 2010

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