Advanced pushbroom hyperspectral LWIR imagers

Hannu Holma; Timo Hyvärinen; Jarmo Lehtomaa; Harri Karjalainen; Risto Jaskari

doi:10.1117/12.818557

28 April 2009 Advanced pushbroom hyperspectral LWIR imagers

Hannu Holma, Timo Hyvärinen, Jarmo Lehtomaa, Harri Karjalainen, Risto Jaskari

Proceedings Volume 7319, Next-Generation Spectroscopic Technologies II; 731907 (2009) https://doi.org/10.1117/12.818557
Event: SPIE Defense, Security, and Sensing, 2009, Orlando, Florida, United States

Abstract

Performance studies and instrument designs for hyperspectral pushbroom imagers in thermal wavelength region are introduced. The studies involve imaging systems based on both MCT and microbolometer detector. All the systems employ pushbroom imaging spectrograph with transmission grating and on-axis optics. The aim of the work was to design high performance instruments with good image quality and compact size for various application requirements. A big challenge in realizing these goals without considerable cooling of the whole instrument is to control the instrument radiation from all the surfaces of the instrument itself. This challenge is even bigger in hyperspectral instruments, where the optical power from the target is spread spectrally over tens of pixels, but the instrument radiation is not dispersed. Without any suppression, the instrument radiation can overwhelm the radiation from the target by 1000 times. In the first imager design, BMC-technique (background monitoring on-chip), background suppression and temperature stabilization have been combined with cryo-cooled MCT-detector. The performance of a very compact hyperspectral imager with 84 spectral bands and 384 spatial samples has been studied and NESR of 18 mW/(m²srμm) at 10 μm wavelength for 300 K target has been achieved. This leads to SNR of 580. These results are based on a simulation model. The second version of the imager with an uncooled microbolometer detector and optics in ambient temperature aims at imaging targets at higher temperatures or with illumination. Heater rods with ellipsoidal reflectors can be used to illuminate the swath line of the hyperspectral imager on a target or sample, like drill core in mineralogical analysis. Performance characteristics for microbolometer version have been experimentally verified.

Citation Download Citation

Hannu Holma, Timo Hyvärinen, Jarmo Lehtomaa, Harri Karjalainen, and Risto Jaskari "Advanced pushbroom hyperspectral LWIR imagers", Proc. SPIE 7319, Next-Generation Spectroscopic Technologies II, 731907 (28 April 2009); https://doi.org/10.1117/12.818557

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