A Deep-Focus Attachment For A Far-Focus Thermal Imager System

F. J. J. Clarke

doi:10.1117/12.951963

1 May 1986 A Deep-Focus Attachment For A Far-Focus Thermal Imager System

F. J. J. Clarke

Proceedings Volume 0590, Infrared Technology and Applications; (1986) https://doi.org/10.1117/12.951963
Event: 1985 International Technical Symposium/Europe, 1985, Cannes, France

Abstract

A supplementary infrared optical system has been developed at the National Physical Laboratory (NPL) to attach to a far-focus wide-angle telescope supplied for use with a TICM II thermal imager. It uses just two germanium lenses, of 75 mm and 90 mm diameter, and allows object distances from infinity down to 0.27 m. When combined with the high quality telescope and the scanner optics, the complete system has no discernible field curvature at any working distance, an important requirement for the NPL application of measuring the spatial distribution of emissivity of extended flat surfaces. The geometrical MTF data computed for 32 combinations of object distance, field angle and aperture plane show that under most conditions the effect of aberrations is significantly less than that of diffraction. In fact spatial resolution is ultimately limited by the diffusion spread in the detector, and the performance of the optical system is always fully adequate for the 512 x 512 pixel image processing involved.

Citation Download Citation

F. J. J. Clarke "A Deep-Focus Attachment For A Far-Focus Thermal Imager System", Proc. SPIE 0590, Infrared Technology and Applications, (1 May 1986); https://doi.org/10.1117/12.951963

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