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The Hyperspectral Imaging Spectroradiometer MR-i for High Radiometric Accuracy

The Hyperspectral Imaging Spectroradiometer MR-i for High Radiometric Accuracy

With more than four decades of innovation and being recognized as a global leader in spectroscopy, ABB is expanding its line of remote sensing products with a launch of new FT-IR hyperspectral imaging spectroradiometer, which operates in the infrared.

Based on the MR-Series, MR-i provides accurate spectral, temporal (rapid scanning), radiometric, and spatial information of infrared targets.

The hyperspectral MR Series of spectroradiometers are made up of a FTIR Michelson interferometer configured with dual output ports used to cover the LWIR and the MWIR + SWIR spectral range simultaneously.

Features

  • High spectral resolution, (1 cm-1) corresponding to a filter radiometer with more than 9000 channels
  • Broad spectral range (1 - 15 µm), covering LWIR to NIR
  • High NESR sensitivity, allowing characterization of weak signal in short time periods
  • High radiometric accuracy and stability of response over a broad dynamic range
  • High time resolution through fast scanning allows measurement of the evolution of quickly varying target signatures
  • High reliability: Compact and portable for easy deployment in airborne operation and field operation
  • High dynamic range and signal-to-noise ratio
  • High spatial resolution with extended FOV homogeneity, resulting in better accuracy regardless of where the target is in the FOV

MR-i Technology

While standard mono-pixel FT-IR spectroradiometers provide unique performance such as improved sensitivity over the instrument field of view (FOV) and higher spectral resolution, multi-pixel FT-IR hyperspectral imagers now expand potentials in infrared characterization. They provide accurate spatial characterization of a target’s signature by spatially resolving the necessary characteristics over the observed scene.

The data captured is further exploited by combining the spatial and spectral information of the scene. Consequently, an FT-IR imaging spectroradiometer has the unique capability of generating 3D images (2D images with spectral bands in the Z axis) offering a spectrum with every pixel of the observed scene.

Spectral Coverage

Wide Spectral Range

A single instrument is used to cover the three key atmospheric windows from 1.5 to 14 µm, extending the range of potential applications, from infrared characterization to gas detection.

The MR-i imaging spectroradiometer is comprised of a dual input and output ports Fourier Transform Infrared (FTIR) Michelson interferometer.

The 4-port configuration enables simultaneous acquisition of data from two complementary cryogenic detectors (MCT and InSb) to cover the short- to the long-wave spectral range (LWIR, MWIR and SWIR) for optimum SNR out of every measurement.

The two detectors are fully independent from each other and have their own filter holder, field stop aperture wheel, and lenses so each detector can be optimized for the best performance.

  • The FTIR technology enables the equivalent up to 9000 spectral bands per spectrum
  • 2 – 15 µm [667 – 5,000 cm-1] with optional extension to 1 µm [10,000 cm-1] available

Characteristics

Dual-camera configuration

The MR-i is the first commercially available FT-IR hyperspectral imaging spectoradiometer capable of providing dual-camera operation, covering the LWIR and MWIR of the electromagnetic spectrum simultaneously.

The MR-i 4-port interferometer can contain a mixture of two different types of camera modules (LWIR/MWIR) to extend the instrument spectral range coverage or a combination of two identical camera modules (MWIR/MWIR) to extend the instrument dynamic range.

This unique feature enables the MR-i to simultaneously acquire and perfectly synchronize the data of two interchangeable camera modules, making the device adaptable to numerous measurement scenarios.

The MR-i configuration with two detection modules is like combining the functions of two imaging spectroradiometers in a single device, providing the following benefits:

  • Ease of operation using one user interface
  • Perfect synchronization of both cameras
  • Easily interchangeable modules and fully adjustable settings
  • Lower acquisition cost
  • Lower maintenance costs

Sensitivity / Extended Dynamic Range

Some applications, such as targeting an infrared signature, often involve simultaneous measurements of high and low intensity emission sources that are randomly dispersed over the mapped scene. The signal-to-noise performance of each detection module is influenced by the integration time of the camera.

Setting the integration time in respect to the energy level of the hot pixels will impact the signal-to-noise performance of the cold pixels in the scene negatively. However, pre-setting the integration time for utmost signal-to-noise performance of the cold pixels will produce saturation on the hot pixels.

The MR-i provides an unparalleled sensitivity for the characterization of a target’s infrared signature. With both ports equipped with detector modules covering the same spectral range (LWIR-LWIR or MWIR-MWIR), they can each be set to different integration time or gains to expand the dynamic range of the instrument. This significantly enhances the faintest and brightest regions of the observed scene.

Fast Scanning Data Acquisition Rate

The MR-i is the fastest commercially available FT-IR imaging spectroradiometer ever developed. It produces the highest datacube measurement rate on the market. This instrument is provided with state-of-the-art camera modules that can offer the maximum frame measurement rate available, and is ideal for the characterization of rapidly evolving and fast moving targets.

The combination of both camera modules in a single instrument produces an unparalleled measurement rate and provides the perfect combination of spectral coverage, spatial resolution, dynamic range, and time resolution performance ever seen on a COTS FT-IR imaging spectroradiometer instrument.

Differential Optical Subtraction

The MR-i can be configured with a linear array multi-pixel sensor optimized for differential acquisition in the VLWIR (cut off near 14 µm). In order to set up this configuration, the instrument is provided with a dual-input telescope that can perform optical background subtraction.

The resulting signal is the differential between the spectral radiance entering each input port, removing the clutter impact of the background. This particular configuration has been set up to support scientific research related to stand-off detection and discovery of chemical agent threats.

Modular / Self-Configurable Instrument

The MR-i can be adapted to various applications. Its user-configurable modular architecture provides users with the flexibility to adapt the instrument to the characteristics of a particular measurement scenario. Users can easily reconfigure the MR-i without requiring re-calibration or factory reworks by simply exchanging or combining different detection modules or input telescopes.

Applications

FT-IR Spectroradiometry Applications

  • Military infrared target characterization
  • Chemical agents signature measurements
  • Scientific research
  • Imaging
  • Industrial emission monitoring

From scientific research to deployable operational solutions, Fourier Transform Infrared (FT-IR) spectroradiometry has been established as an ideal technology to develop and enhance various military applications. For the defense industry, FT-IR spectroradiometry is used for:

  • Characterization of thermal emission signatures of aircraft engines
  • Camouflage system development and thermal signature optimization
  • Classifying fugitive emissions for forming infrared signature databases
  • Remote sensing of battlefield conditions for developing different deployable reconnaissance solutions
  • Development, analysis and improvement of IR decoy emission spectra and latest counter-measure systems
  • Classifying battlespace detonations, including bomb-hit detonation, missile launches, and muzzle flash

Heritage of two decades of imaging FTS projects at ABB

  • Civil Security: Surveillance and security
  • Defense: Troops and strategic resources protection
  • Environment: Detection and identification of pollutants

This innovative and powerful technique expands engineering modeling applications. It is also used to enhance various kinds of IR emitting sources. FT-IR imaging spectroradiometers offer vital information for modeling IR emitted source of energy and observing the spatial evolution of the radiance.

The combination of the imaging spectroradiometer radiance measurement with retrieval algorithms enables different atmospheric applications to be mapped, such as:

  • Atmospheric composition analysis
  • Meteorological turbulence sounding
  • Stand-off detection and monitoring of a chemical cloud

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