Since 2010 Onera works on the characterization of the nightglow radiation for night-vision applications in moonless conditions. This radiation is mainly due to the deexcitation of hydroxyl molecules in the upper atmosphere (~87km). It is present in the visible range and reaches its maximum value in the short wavelength infrared bands between 1.4 and 1.8μm (Meinel bands). Although few energy reaches the ground, this radiation is emitted over the whole sky and therefore may be an interesting additional light source for night vision systems in moonless or cloudy sky conditions. Moreover, observation of the nocturnal sky in the short wave infrared band gives access to dynamic processes studies, these processes perturbing emission of radiation. In this paper, we present works carried out at Onera about observation and modelling of nightglow radiation.
In this paper, we report the development of low flux short wavelength infrared radio-imaging
systems to study the radiance due to nightglow emission. This radiation is mainly due to the desexcitation of
hydroxyl molecules in the upper atmosphere. It is present in the visible range and reaches its maximum
value (at ground level) in the short wavelength infrared band between 1.4 and 1.8μm. The nightglow may be
an interesting additional light source for night vision systems in moonless or cloudy sky conditions. In this
paper, we describe the experimental setup and present first results of the measurement campaigns that we
performed at the Observatoire de Haute-Provence in France and at the European Southern Observatory site
of La Silla in Chile.
Generally available satellite images, e. g. from the MODIS sensor, provide data in spectral bands, which are suitable for
remote sensing applications and earth surface observations. However, for some applications different bands as well as
specific cloud formations for a certain region may be of interest, thus making the simulation of background data
essential. Therefore, the software MATISSE ("Advanced Modeling of the Earth for Environment and Scenes
Simulation") proved to be the appropriate tool. MATISSE is an infrared background scene generator developed by
ONERA for computing natural background spectral radiance images including atmosphere, sea, land and high and low
altitude clouds. In order to validate the model, comparisons with MODIS satellite data have been carried out using
images in available spectral bands. The investigations comprised selected surface structures like sea, desert, lowland
(dry) and highlands (humid). In general, the results on radiance images show a good correlation between MODIS image
and the MATISSE-simulation.
This paper focuses on comparing results between simulated MATISSE radiance images and the MODIS observations.
Based on this, possible sources of error and the limits of the model are discussed.
MATISSE (Advanced Modeling of the Earth for Environment and Scenes Simulation) is an infrared background scene
generator developed for computing natural background spectral radiance images. The code also provides atmospheric
radiatives quantities along lines of sight. Spectral bandwidth ranges from 0.4 to 14 μm. Natural backgrounds include
atmosphere, sea, land and high and low altitude clouds. The new version MATISSE-v2.0, released this year, has been
designed to treat spatial multi resolution in the generated images in order to be able to reach metric spatial variability in
pixels footprints. Moreover, MATISSE-v2.0 includes a new sea surface radiance model (water waves and surface optical
properties) which depends on wind speed, wind direction and fetch value. Preliminary validations using radiometric
measurements have been conducted concerning sea radiances and give promising results. In order to go further in the
validation process of MATISSE-v2.0, comparisons with MODIS satellite images have been led. The results of
comparing the simulated MATISSE images radiances with the MODIS observations show that the code is performing
well. This paper gives a description of MATISSE-v2.0 new functionalities and focus on first results on comparison
between MATISSE/MODIS images radiances.
We improve the validation of the sea surface infrared optical properties multiresolution model implemented in
MATISSE-v2.0, in the 1D case, by comparison with a reference model using a sub-millimeter discretization of
the surface. A set of numerical tests is made for various wind speeds, resolutions and realizations of the sea
surface. The tests show a good agreement between the results except for grazing angles, where the influence of
inner and mutual multiple reflections and adjacent shadowing has still to be investigated.
MATISSE which acronym means Advanced Modeling of the Earth for Environment and Scenes Simulation is an
infrared background scene generator developed by Onera since the mid 1990'. MATISSE main goal is to compute
radiance images of natural backgrounds and radiative quantities such as local illumination, spectral transmission, and
spectral radiance along lines of sight.
The new version MATISSE-v2.0 has been completed during the first quarter of 2010 and the public version is going to
be released in few weeks. This latest version uses a multi resolution spatial scheme in order to treat the natural
backgrounds with spatial footprint from kilometre sizes (satellite viewing) down to metric sizes. Up to now, this spatial
scheme has been used in order to generate infrared images of sea surface. The new sea surface model (water waves and
surface optical properties) has been partially validated by using a specific Mediterranean campaign. MATISSE-v2.0 is
also accompanied with a new set of GUI (graphical user interface) in order to help the user in defining its computational
case. The code is also designed in order to be interfaced with other applications.
Our presentation will be devoted to a description of MATISSE-v2.0 new features, with examples of sea surface scenes
exemplifying the new code functionalities.
The MIRAMER field campaign took place in the Mediterranean Sea during May 2008, both ground-based and on board
an oceanographic ship. Radiometric datasets along with the associated environmental measurements have been collected
in various environmental and observation conditions. It is dedicated to the validation of the sea surface optical properties
model implemented in the MATISSE-v2.0 code.
This analytical sea surface optical properties model in the infrared band is described. It allows the introduction of multiresolution
in the simulated field-of-view answering the need in computed images including any observational
configurations. It is valid for fully-developed seas, includes shadowing and hiding functions but not breaking and foam
nor multiple reflections.
First comparisons between simulations and measurements are presented in this paper.
MATISSE is a background scene generator developed for the computation of natural background spectral radiance
images and useful atmospheric radiatives quantities (radiance and transmission along a line of sight, local illumination,
solar irradiance ...). The spectral bandwidth ranges from 0.4 to 14 μm. Natural backgrounds include atmosphere (taking
into account spatial variability), low and high altitude clouds, sea and land. The current version MATISSE-v1.5 can be
run on SUN and IBM workstations as well as on PC under Windows and Linux environment. An IHM developed under
Java environment is also implemented.
MATISSE-v2.0 recovers all the MATISSE-v1.5 functionalities, and includes a new sea surface radiance model
depending on wind speed, wind direction and the fetch value. The release of this new version in planned for April 2009.
This paper gives a description of MATISSE-v1.5 and MATISSE-v2.0 and shows preliminary comparison results
between generated images and measured images during the MIRAMER campaign, which hold in May 2008 in the
Mediterranean Sea.
The SE-WORKBENCH workshop, also called CHORALE (French acceptation for "simulated Optronic Acoustic Radar
battlefield") is used by the French DGA (MoD) and several other Defense organizations and companies all around the
World to perform multi-sensors simulations. CHORALE enables the user to create virtual and realistic multi spectral 3D
scenes that may contain several types of target, and then generate the physical signal received by a sensor, typically an
IR sensor.
The SE-WORKBENCH can be used either as a collection of software modules through dedicated GUIs or as an API
made of a large number of specialized toolkits.
The SE-WORKBENCH is made of several functional block: one for geometrically and physically modeling the terrain
and the targets, one for building the simulation scenario and one for rendering the synthetic environment, both in real and
non real time.
Among the modules that the modeling block is composed of, SE-ATMOSPHERE is used to simulate the atmospheric
conditions of a Synthetic Environment and then to integrate the impact of these conditions on a scene. This software
product generates an exploitable physical atmosphere by the SE WORKBENCH tools generating spectral images. It
relies on several external radiative transfer models such as MODTRAN V4.2 in the current version.
MATISSE [4,5] is a background scene generator developed for the computation of natural background spectral radiance
images and useful atmospheric radiative quantities (radiance and transmission along a line of sight, local illumination,
solar irradiance ...). Backgrounds include atmosphere, low and high altitude clouds, sea and land. A particular
characteristic of the code is its ability to take into account atmospheric spatial variability (temperatures, mixing ratio, etc)
along each line of sight. An Application Programming Interface (API) is included to facilitate its use in conjunction with
external codes.
MATISSE is currently considered as a new external radiative transfer model to be integrated in SE-ATMOSPHERE as a
complement to MODTRAN. Compared to the latter which is used as a whole MATISSE can be used step by step and
modularly as an API: this can avoid to pre compute large atmospheric parameters tables as it is done currently with
MODTRAN. The use of MATISSE will also enable a real coupling between the ray tracing process of the SEWORKBENCH
and the radiative transfer model of MATISSE. This will lead to the improvement of the link between a
general atmospheric model and a specific 3D terrain.
The paper will demonstrate the advantages for the SE WORKEBNCH of using MATISSE as a new atmospheric code,
but also for computing the radiative properties of the sea surface.
An analytical sea surface optical properties model in the infrared band is described. It allows the introduction of multiresolution
in the simulated field-of-view answering the need in computed images including any observational
configurations. It is valid for fully-developed seas, includes shadowing and hiding functions but not breaking and foam
nor multiple reflections.
For the model validation purposes, the MIRAMER field campaign took place in the Mediterranean sea during May 2008,
both ground-based and on board an oceanographic ship. Radiometric datasets along with the associated environmental
measurements have been collected in various environmental and observation conditions. First campaign results are
presented in this paper.
The purpose of this paper is to take into account the spatial variability of a wind-roughened sea surface from 1-meter to
large scale including sub-metric variability. An analytical model of infrared sea surface optical properties based on a
statistical approach is proposed. We introduce a new two-scale model consisting in superimposing the small scale
variability (smaller than the pixel footprint) to the large scale one. The analytical expressions given in literature are
extended to account for any slope mean vector-value and covariance matrix, and the statistical properties are determined
for the resolution required by the observational configuration.
Verifications of the physical validity of this new approach are presented. They globally show a good agreement. A bias is
observed at grazing angles, mainly explained by the fact that the multiple reflections are ignored.
Our model has also been implemented for the generation of synthetic sea surface radiance images, showing its ability to
produce good quality ocean scenes in various contextual conditions.
An analytical model of infrared sea surface optical properties is developed to access to statistical radiative characteristics of a wind-roughened water surface. Any surface size, i.e. that contains or not all the statistical information of the stochastic process governing the sea surface, can be considered. This model deals with the problem of multi-resolution in a sensor field of view. Model validation has been conducted in 1D by comparison with a reference code and in 2D by comparisons with optical properties measurements and with validated 1D cross sections.
This paper concerns the presentation of the MATISSE-v1.4 code whose main functionality is computation of spectral or integrated natural background radiance images. The spectral bandwidth ranges from 765 to 3300 cm-1 (3 to 13 μm) with a 5 cm-1 resolution. Natural backgrounds include the atmosphere, low and high altitude clouds, sea and land. The most particular functionality of the code is to take into account atmospheric spatial variability quantities (temperatures, mixing ratio, etc) along each line of sight of the image. In addition to image generation capacity, the code computes atmospheric radiance and transmission along a line of sight with the same spectral characteristics as in imaging mode. In this case, atmospheric refraction effects and radiation from high or low altitude clouds can be taken into account. A high spectral resolution mode is also available to propagate radiation from a high temperature medium in the same atmospheric state as that used for the image generation. Moreover, an Application Programming Interface (API) is included to facilitate its use in conjunction with external codes. In comparison with the previous version, the main improvement of MATISSE-v1.4 concerns the line of sight mode, the possibility to use a user atmospheric profile and computations in the Maritime Boundary Layer. This paper describes the range of functionalities of MATISSE-v1.4 as well as future developments.
This paper presents the MATISSE-v1.4 code whose main functionality is to compute spectral or integrated natural background radiance images. The spectral bandwidth extends from 765 to 3300 cm-1 (3 to 13 μm) with a 5 cm-1 resolution. Natural backgrounds include the atmosphere, low and high altitude clouds, sea and land. The most particular functionality of the code is to take into account atmospheric spatial variability quantities (temperatures, mixing ratio, etc) along each line of sight of the image. In addition to image generation capacity, the code computes atmospheric radiance and transmission along a line of sight with the same spectral characteristics as in imaging mode. In this case atmospheric refraction effects and radiation from high or low altitude clouds can be taken into account. A high spectral resolution mode is also available to propagate radiation from a high temperature medium in the same atmospheric state as that used for the image generation. Finally, an Application Programming Interface (API) is included to facilitate its use in conjunction with external codes. This paper describes the range of functionalities of MATISSE-v1.4 whose release is planned for April 2006. Future developments are also presented.
In this paper we present MATISSE 1.1 a new background scene generator, whose goal is to compute spectral or integrated radiance images of natural background, as well as the transmission of a hot gas signature.
The spectral bandwidth for this version of the code is from 750 to 3300 cm-1 (3 to 13 μm) with a 5 cm-1 resolution. Gaseous absorption is computed by a Correlated K model. The spatial variability of atmospheric quantities (temperatures and mixing ratios, among others) is taken into account, using variable profiles along the line of sight.
Natural backgrounds include the atmospheric background, low altitude clouds and the Earth ground. The radiation models used are designed for observation at low spatial resolution of clouds and soils, so a texture model was developed to increase the high spatial resolution rendering in the metric range.
Intermediate outputs of the code deliver radiance and transmission restricted to a single line of sight, in which case atmospheric refraction effects are taken into account. Along this line of sight the transmission can also be computed using a line-by-line model, which is useful to propagate the radiation emitted by a hot gas source (fires, aircraft or missile plume).
MATISSE 1.1 was released in June 2002, so this paper is devoted to a presentation of the first results obtained with the code and some validation tests.
MATISSE is a new atmospheric radiative transfer code currently under development at Onera. Its purpose is to compute background radiance images by taking into account atmospheric, cloud and ground radiation and the variability of atmospheric properties. Propagation is calculated using a Correlated K model (CK) developed at Onera. The spectral range is between 3 to 13 micrometers with a resolution of 5 cm-1. Weather forecast outputs and aerosol climatology are used as inputs to account for spatial variability of atmospheric properties in radiance computations. Partial stratocumulus cloud cover can be generated and the radiation computations use Independent Pixel Approximation (IPA) and Bidirectional Reflectivity Distribution Functions (BRDF). Ground emission and reflectance are computed from spectral emissivities, BRDF and a simple thermal model for the local ground temperature. Databases include a Digital Terrain Elevation (DTED) and a land use database with 30' spatial resolution. Texture models are used to add realistic ground and cloud clutter down to 10 meter resolution. A line-by-line model is included to compute the spectral intensity propagated from high temperature exhaust plumes. Refraction effects are computed, but only along one single line of sight.
Airborne measurement of stratus is being carried out by ONERA in order to validate NUALUM cloud simulation. The cloud top is measured by a circular variable filter cryogenic spectrometer SICAP. Two observation zenith angles are tested and the azimuth angle is variable. In situ liquid water content (LWC) measurement in performed by a Johnson Williams probe and compared with meteorological sounding. The liquid water content has been valuated inside a layer from 200m to 600m altitude. Mean LWC is equal to 0.3g/m3. Those values are typical of a stratus. The NUALUM cloud radiative transfer code has been developed at ONERA. The optical properties are computed by MIE theory. NUALUM includes the DISORT code to compute the multiple scattering in the cloud, by the mean of the discrete ordinates method. Spectral measurements show great variations of the radiation according to the azimuth angle when the wavelength is less than 4 micrometers . In this range of wavelength, radiation provides from solar reflection which is very sensitive to the scattering angle. Above 4 micrometers , thermal radiance increases. A good correlation is observed between the shape of the phase function of cloud particles and the radiance variation with scattering angle. NUALUM is in agreement with the stratus spectral measurements. During the experiment, sea spectral measurements have also been carried out. Solar reflection on the sea surface of the sea is specular and only occurs for low scattering angles.
A new model of radiative transfer in a cloudy atmosphere NUALUM has been developed at ONERA. NUALUM uses
the Discrete Ordinates Method. This code includes multiple scattering in clouds and takes into account the azimuthal
distribution of radiation. NUALUM allows geometry and microphysics of the cloud to be varied (particle size, concentration,
top and bottom altitude).
The parameterization of a cumulus cloud with NUALUM is compared with airborne measurements performed by
ONERA and CELAR: circularvariable filter cryogenic spectrometer SICAP (1.5-5.5 j.tm) and airborne infrared camera CIRAP
(3-5 pm and 8-12 tm) aim at the same point of the cloud top. The observation azimuthal angle is variable.
SICAP spectral measurements show great variations of the radiation with the azimuthal angle which are in agreement
with NUALUM simulations. The correlation between the infrared radiation images CIRAP and mean calculated radiation is
satisfactory.
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