Lenses for staring-array point-source detection sensors must maintain good signal-to-noise ratio (SNR) over fields of view often exceeding 100 degrees. Such lenses typically have f-θ distortion to provide constant solid angle sampling in object space. While the relative illumination calculation is often used to describe flux transfer from a Lambertian extended object for imaging applications, maximizing SNR for point-source detection depends primarily on maximizing collected irradiance at the entrance pupil, the shape of which can vary dramatically over field. We illustrate this field-dependent SNR calculation with an example lens and outline the calculations needed to derive a simple aberration-based expression for the field dependence of point-source SNR.
Long-range airborne full-motion-video systems require large apertures to maximize multiple aspects of system
performance, including spatial resolution and sensitivity. As systems push to larger apertures for increased resolution
and standoff range, both mounting constraints and atmospheric effects limit their effectiveness. This paper considers two
questions: first, under what atmospheric and spectral conditions does it make sense to have a larger aperture; second,
what types of optical systems can best exploit movement-constrained mounting? We briefly explore high-level
atmospheric considerations in determining sensor aperture size for various spectral bands, following with a comparison
of the swept-volume-to-aperture ratio of Ritchey-Chrétien and three-mirror-anastigmat optical systems.
As airborne EOIR imaging systems strive to achieve high-NIIRS full motion video (FMV) from longer and longer standoff ranges, the challenges behind conceptualizing, designing, and fielding such systems grows significantly. We present a heuristic framework for dissecting the "goodness" of an FMV multispectral sensor and look at the various components behind what makes a high-resolution sensor. Combining spatial, temporal, spectral, and "signal" resolution with system footprint size/weight/power (SWaP) metrics allows deterministic tradeoffs between optical systems as well as system architectures. We present example trade studies of optical architectures from disparate application fields in various SWaP-constrained environments for long-range imaging and evaluating how system parameters are intrinsically linked.
Performance models for infrared imaging systems require image quality parameters; optical design engineers need image quality design goals; systems engineers develop image quality allocations to test imaging systems against. It is a challenge to maintain consistency and traceability amongst the various expressions of image quality. We present a method and parametric tool for generating and managing expressions of image quality during the system modeling, requirements specification, design, and testing phases of an imaging system design and development project.
Staring infrared imagers have multiple surfaces within the integrated Dewar assembly which contribute to non-traditional
Narcissus artifacts. Static non-uniformity correction is insufficient to remove dynamic Narcissus artifacts
caused by moving focus or zoom groups. Dynamic Narcissus artifacts often manifest as rings apparent to the human eye,
although they may lie near the noise floor of the imager. Moreover, strong field curvature of the Narcissus can
complicate diagnosis using paraxial methods. We compare a simple pupil ghost metric to traditional Narcissus metrics
and present an experimental case study illustrating how the metric can be used during optimization to eliminate the
effect.
We present the definition, design, and construction of a 3.3X continuous-zoom short-wave infrared (SWIR) telephoto
lens. Compared to visible and mid-wave infrared lenses, defining the appropriate lens requirements of short-wave lenses
have some different trade-offs in terms of balancing radiometry and optimum focal plane sampling. In addition, the
design process of optimizing a visible zoom design form of given first-order properties to work in the SWIR band
reveals some challenges in glass selection and subsequent aberration balancing. A comparison of the actual measured
MTF performance of a prototype lens shows reasonable performance compared to the design.
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 or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
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.