Orthorectification of helicopter-borne high resolution experimental burn observation from infra red handheld imagers

To pursue the development and validation of coupled fire-atmosphere models, the wildland fire modeling community needs validation data sets with scenarios where fire-induced winds influence fire front behavior, and with high temporal and spatial resolution. Helicopter-borne infrared thermal cameras have the potential to monitor landscape-scale wildland fires at a high resolution during experimental burns. To extract valuable information from those observations, three-step image processing is required: (a) Orthorectification to warp raw images on a fixed coordinate system grid, (b) segmentation to delineate the fire front location out of the orthorectified images, and (c) computation of fire behavior metrics such as the rate of spread from the time-evolving fire front location. This work is dedicated to the first orthorectification step, and presents a series of algorithms that are designed to process handheld helicopter-borne thermal images collected during savannah experimental burns. The novelty in the approach lies on its recursive design, which does not require the presence of fixed ground control points, hence relaxing the constraint on field of view coverage and helping the acquisition of high-frequency observations. For four burns ranging from four to eight hectares, long-wave and mid infra red images were collected at 1 and 3 Hz, respectively, and orthorectified at a high spatial resolution (<1 m) with an absolute accuracy estimated to be lower than 4 m. Subsequent computation of fire radiative power is discussed with comparison to concurrent space-borne measurementsPeer ReviewedPostprint (published version

Data Validation and Case Studies using the TET-1 Thermal Infrared Satellite System

Based on the DLR satellite system BIRD; launched and operated in the early 2000, the TET system has been launched in 2012 as part of the FireBird satellite constellation. The constellation will consist of two satellites, the second one to be launched in second half of 2015. Acquired imagery is processed and archived by DLR and will be publicly available. For this purpose, a processing chain has been implemented converting raw data (level 0 product) to geo-annotated at-sensor radiance (level 1b). Further data products can be derived, e.g. information on brightness temperature, fire radiative power, and surface emissivity. Other processing levels, as atmospherically corrected reflectance could also be produced

The Generalized Processing Chain for BIRD and FireBIRD Mission

The FireBIRD mission has been designed to detect and monitor dynamic high temperature events, such as wild fires or volcano eruptions. In order to provide calibrated and geo-referenced data in near real time to users, a ground processing system is going to be established and deployed in the downstream chain in the national ground segment in Neustrelitz. The ground processing system consists of the Payload System Management (PSM) and one or more Instrument Processing Facility (IPFs). Due to the experimental nature of small satellite missions the components of the ground system have been often specific solutions. The design of the FireBIRD ground segment uses a modular design with separate control and payload data interfaces. For data interfaces abstract data descriptions are used in order to achieve a mission independent design to a large extend. A design constraint is to separate processing control components from data processing components as far as possible. The goal is to achieve extendibility and reusability of the processing components as well as portability of the IPF to other systems and migration for future missions

Remote Sensing Analysis Framework for Maritime Surveillance Application

Synthetic Aperture Radar (SAR) and high (HR) and very high (VHR) resolution optical satellite images are valuable sources of information for maritime situational awareness. The objective of the Maritime Security Lab Analysis Framework is to develop and integrate applications to support operational services based on those SAR and optical satellite images in near real time (NRT). In the frame of maritime surveillance services based on satellite images, the German Remote Sensing Data Center (DFD), part of the German Aerospace Center (DLR), established a framework to support automated NRT processing of huge amounts of image data from different satellite missions provided by a network of ground stations and service providers. Developed at DLRs Maritime Safety and Security Lab Neustrelitz, the Processing Framework is intended to support operational maritime surveillance value adding services. Main com-ponents are the Processing System Management (PSM), embedded thematic processors and the Graphical User Interface (GUI). The presentation will describe the overall workflow of data handling, the inter-faces and the operator GUI, which was implemented for operational use at DLRs Ground Station Neustrelitz

In-Orbit Geometric Calibration of Firebird's Infrared Line Cameras

The German Aerospace Center (DLR) has developed and launched two small satellites (TET-1 and BIROS) as part of the FireBIRD mission. Both are capable to detect and observe fire related high temperature events (HTE) from space with infrared cameras. To enable a quick localization of the fires direct georeferencing of the images is required. Therefore the camera geometry measurements with laboratory set-up on ground have to be verified and validated using real data takes. This is achieved using ground control points (GCPs), identifiable in all spectral bands, allowing the investigations of the whole processing chain used for georeferencing. It is shown how the accuracy of direct georeferencing was significantly improved by means of in-orbit calibration using GCPs and how the workflow for processing and reprocessing was developed

Results on verification and validation of OOV-TET1 multi-spectral camera observations within the FireBIRD project

Since November 2014, the OOV-TET1 Satellite is operated by DLR as part of the FireBIRD mission. Within the project the multispectral camera payload (MSC) became the mainly operated experiment. Its spectral and geometrical characteristics are designed to detect and observe high temperature events, especially wildfires, active volcanoes, which require a large temporal and radiometrical dynamic range and good spatial resolution. In order to detect, to discriminate and to characterize occurrences of sides with temperatures around 1000 K, but limited spatial extend, the camera system is equipped with spectral bands in near, mid, and thermal infrared as well as in visible range, having a ground resolution of 160m. This makes the instruments sensitive for remote sensing of events with thermal features in normal temperature range. Such topics are underground coal fires, thermal anomalies, observation of sea surface temperatures etc

The DLR FireBIRD Mission - A Technological Experiment for Operational Wildfire Monitoring

The FireBIRD mission is a constellation of two small satellites designed and developed by DLR Optical Systems in Berlin-Adlershof with contributions from other Institutes of DLR. The first satellite TET-1 was launched in 2012 from Baikonur, the second satellite BIROS was launched in 2016 from Satish Dhawan Space Centre (India). The mission is inherited from the BIRD satellite operated from 2001 to 2004 [1]. Both satellites host a number of technological experiments, of which the main payload common to both satellites is the multispectral camera system (MSC) with spectral channels in the visible (VIS), medium infrared (MWIR) and thermal or long wave infrared (LWIR) designed to detect and observe high temperature events

Neue Projekte im DLR Neustrelitz – Motivation für zukünftige Archivierung

Presentation of new Projects of DLR Neustrelitz and their resulting requirements for archiving of large data massiv

Persistent Hot Spot Detection and Characterisation Using SLSTR

Gas flaring is a disposal process widely used in the oil extraction and processing industry. It consists in the burning of unwanted gas at the tip of a stack and due to its thermal characteristic and the thermal emission it is possible to observe and to quantify it from space. Spaceborne observations allows us to collect information across regions and hence to provide a base for estimation of emissions on global scale. We have successfully adapted the Visible Infrared Imaging Radiometer Suite (VIIRS) Nightfire algorithm for the detection and characterisation of persistent hot spots, including gas flares, to the Sea and Land Surface Temperature Radiometer (SLSTR) observations on-board the Sentinel-3 satellites. A hot event at temperatures typical of a gas flare will produce a local maximum in the night-time readings of the shortwave and mid-infrared (SWIR and MIR) channels of SLSTR. The SWIR band centered at 1.61 &mu;m is closest to the expected spectral radiance maximum and serves as the primary detection band. The hot source is characterised in terms of temperature and area by fitting the sum of two Planck curves, one for the hot source and another for the background, to the radiances from all the available SWIR, MIR and thermal infra-red channels of SLSTR. The flaring radiative power is calculated from the gas flare temperature and area. Our algorithm differs from the original VIIRS Nightfire algorithm in three key aspects: (1) It uses a granule-based contextual thresholding to detect hot pixels, being independent of the number of hot sources present and their intensity. (2) It analyses entire clusters of hot source detections instead of individual pixels. This is arguably a more comprehensive use of the available information. (3) The co-registration errors between hot source clusters in the different spectral bands are calculated and corrected. This also contributes to the SLSTR instrument validation. Cross-comparisons of the new gas flare characterisation with temporally close observations by the higher resolution German FireBIRD TET-1 small satellite and with the Nightfire product based on VIIRS on-board the Suomi-NPP satellite show general agreement for an individual flaring site in Siberia and for several flaring regions around the world. Small systematic differences to VIIRS Nightfire are nevertheless apparent. Based on the hot spot characterisation, gas flares can be identified and flared gas volumes and pollutant emissions can be calculated with previously published methods