Sophie Thétas

Demonstration of an infrared microcamera inspired by Xenos peckii vision

We present an original and compact optical system inspired by the unusual eyes of a Strepsipteran insect called Xenos peckii. It is designed for a field of view of 30 degrees and is composed of multiple telescopes. An array of prisms of various angles is placed in front of these telescopes in order to set a different field of view for each channel. This type of camera operates in the [3-5 microm] spectral bandwidth and is entirely integrated in a Dewar in order to maximize its compactness. Experimental images are presented to validate this design.

In situ optical testing of infrared lenses for high-performance cameras.

We propose to evaluate infrared lenses with a dedicated analyzer having the same mechanical interface as the usual cameras. The proposed analysis is based on a wavefront measurement and allows a diagnostic of possible internal defects of the analyzed lens. The infrared lens analyzer described is constituted with a quadriwave lateral shearing interferometer and works with a blackbody light. We describe the response of this interferometer and an innovative method to obtain the wavefront under test. We finally present the experimental analysis of long-wavelength infrared lenses and the particular case of a modified lens that generates a large spherical aberration.

MULTICAM: a miniature cryogenic camera for infrared detection

There is an emerging demand for compact infrared instruments, imagers and/or spectrometers, integrated on ground or air vehicles for spatial and spectral data collection. To reach this goal, technological barriers have already been overcome, leading to the development of infrared focal plane arrays (IRFPAs) for high-performance applications (megapixel format, bispectral technology) but also for low-cost and high-volume manufacturing (technology of uncooled micro-bolometers). The next step is to reduce the optics and make it compatible with the successful IRFPAs fabrication technology. This paper presents MULTICAM, a small cryogenic infrared camera. This optical system is composed of multi-level arrays of microlenses integrated in the cryostat and inspired from invertebrate compound eyes. First experimental results will be presented.

SYSIPHE: focus on SIELETERS, the medium and longwave infrared spectral imaging instrument

Sysiphe is an airborne hyperspectral imaging system, result of a cooperation between France (Onera and DGA) and Norway (NEO and FFI). It is a unique system by its spatial sampling -0.5m with a 500m swath at a ground height of 2000m- combined with its wide spectral coverage -from 0.4μm to 11.5μm in the atmospheric transmission bands. Its infrared component, named Sieleters, consists in two high étendue imaging static Fourier transform spectrometers, one for the midwave infrared and one for the longwave infrared. These two imaging spectrometers have very close design, since both are made of a Michelson interferometer, a refractive imaging system, and a large IRFPA (1016x440 pixels). Moreover, both are cryogenic and mounted on their own stabilization platform which allows at once to actively control and independently measure the line of sigh. These data are useful to reconstruct and to georeference the spectral image from the raw interferometric images. Sysiphe first flight occurred in September, 2013.

Results from the first flight campaign of Sieleters, an airborne infrared Imaging Fourier Transform Spectrometer

Sieleters is an airborne MWIR and LWIR imaging Fourier Transform Spectrometer developed at Onera. The first flight campaign was led at the end of 2013. Experimental results are presented, including a comparison with simulated data.

SYSIPHE, airborne hyperspectral system: Focus on the SIELETERS thermal hyperspectral imaging instrument

The SYSIPHE system is the state of the art airborne hyperspectral imaging system developed in European cooperation. With a unique wide spectral range and a fine spatial resolution, its aim is to validate and quantify the information potential of hyperspectral imaging in military, security and environment applications. The first section of the paper recalls the architecture of the project. The second one describes the SIELETERS sensors, their implementation onboard the platform and the data processing chain. The last section gives illustrations on the work in progress.

Sieleters, an airbone Imaging Static Fourier Transform Spectrometer: design and preliminary laboratory results

Sieleters is an airborne hyperspectral imager, composed of two cryogenic instruments (MWIR and LWIR), both based on a static interferometer. Its first flight is expected for June, 2013. We present design details and preliminary laboratory results.

Conception of a Stationary Fourier Transform Infrared Spectroradiometer for Field Measurements of Radiance and Emissivity

An infrared spectroradiometer is being developed to make field measurements of radiance and emissivity of terrestrial surface materials. The instrument, entirely cooled, is a stationary Fourier transform spectrometer.