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What's New in ENVI SARscape 5.6.2

Key Highlights of ENVI SARscape 5.6.2

  • Enhanced-DPSVI: Enhanced Dual Polarization SAR Vegetation Index (EDPSVI) using Co-Pol coherence and Dual-Pol intensity data.
  • SBAS: Automatic refinement and reflattening, GCPs are now optional and not required.
  • Time Series Classification: Automatic classification of the displacement time series according to phenomenological and parametrical analyses.
  • Ship Detection: The Ship Detection workflow has been enhanced by adding new tools and new features to enrich the outcomes.
  • Coherence Matrix Viewer: Enables the literal analysis of the coherence behaviors in time series

New Missons, Tools and Sensor Support

GACOS
Import Generic Atmospheric Correction Online Service to improve the Atmospheric Correction within Interferometry and Interferometric Stacking processing (http://www.gacos.net/).

From left to right: Original wrapped interferogram; GACOS model; wrapped interferogram with GACOS model applied; wrapped interferogram with the application of the GACOS model + height correlated atmospheric phase distortion filter.

UAVSAR
Import JPL UAVSAR SLC airborne images, in L-Band, freely available at https://uavsar.jpl.nasa.gov/. It is important to note that, so far, ENVI SARscape 5.6.2 enables only the processing of amplitude images.

UAVSAR data courtesy of NASA/JPL-Caltech

ECMWF Era5 Download
Query and download (mainly) meteorological data provided by the European Center Medium Weather Forecast (ECMWF), which is publicly available and procedurally accessible through a dedicated Web-API (http://apps.ecmwf.int/datasets/) that interacts with their databases. This tool uses the "ERA5" dataset, which contains global reanalysis data from January 1979 to present computed each hour and with a granularity of about 30km.

2 metre temperature parameter over Italy and Mediterranean Sea

Import SIDD
Import of SIDD data format is now available (export SIDD was previously available). SIDD files are geocoded/calibrated 8 bit data, with a scaling transformation between the original calibrated values and the 0-255 range. SIDD files are mainly used to produce final output information for reporting/informative goals: due to this aspect, any further processing is very limited.

 

HISEA-1 by Spacety
Preliminary support of the data acquired by the HISEA-1 C-Band SAR satellite, made by Spacety. The supported products are:

  • SP SLC Spotlight Mode. Slant Range, Single-Look, Complex Products (SLC).
  • SM SLC Stripmap Mode. Slant Range, Single-Look, Complex Products (SLC).
  • NS SLC Narrow ScanSAR Mode.
  • ES SLC Extra ScanSAR Mode.
 

StriX by Synspective
Preliminary support of the data acquired by the StriX X-Band satellite by Synspective. The supported products are SLC Stripmap and Sliding Spotlight.

SBAS in ENVI Tasks – Automatic Processing

A new set of ENVI SARscape tasks enables the automatic execution of the SBAS processing chain, allowing the monitoring of the temporal evolution of surface deformations.

Enhanced Dual Polarization SAR Vegetation Index

Compute an Enhanced Dual Polarization SAR Vegetation Index (EDPSVI) using Dual-Pol data. It estimates the land cover based on the amount of vegetation.

Example of EDPSVI output, this sequence shows how the vegetation density and distribution changes across the year.


 

Ship Detection – Coastline Extraction

Extract a series of shape files containing the coastline detected in the input images, grouped by tide height.

Coastline extraction, different color lines refer to the coastline according to the different tide levels.

DEM extraction with reference height – Images characterized by large areas of sea water can be subjected to geocoding issues due to the different elevation of the sea level within the geoid and the ellipsoid models. This tool is specifically dedicated to geocode intensity SAR data characterized by the presence of sea water.

The increased geocoding precision retrieves the ellipsoidal height by subtracting the geoid component. The main tool that takes advantage of this new features is Ship Detection.


 

Ship Detection – AIS (Automatic Identification System) Matching and Annotation

The Generate Annotations Ships tool associates a user-specified name to each detected target. It uses the shape file generated by the SAR AIS Matching tool as input.


 

Generate Annotations Raster

Enables the automatic generation of annotations, in the ENVI view, of the geocoded files derived from the following tools:

  • Geocoding and Radiometric Calibration
  • Phase to Height Conversion and Geocoding
  • Phase to Displacement Conversion and Geocoding
  • SBAS - Geocoding
  • PS - Geocoding
  • Ship Detection
  • SAR AIS Matching


 

Other General Tools

Shape Tiler
This tool is used to cut one or multiple shapefiles into tiles of regular size and alignment.

Mosaic Sentinel-1
Mosaic Sentinel-1 Slant Range or Ground Range (e.g. not geocoded) SAR products (_slc_list, _gr) that have been independently imported in ENVI SARscape along the same orbit and with the same viewing geometry.

This functionality is intended to generate a single file, in the original SAR viewing geometry, from a set of independently imported frames. Although this is intended for Slant Range products, it is also suitable for Ground Range data. Data belonging to acquisitions with different time or track are automatically grouped and mosaiced separately.

Displacement Time Series Classification

Phenomenological Analysis – Fits the SBAS raster deformation time series using an external temporal phenomenological magnitude (i.e.: M= temperature, rain, etc).

Parametrical Analysis – Fits the SBAS raster deformation time series using three analytical displacement models (linear, quadratic and sinusoidal).

Both techniques retrieve the best fitting coefficients and its RMS for each pixel in the time series. These coefficients represent different characteristics of the displacement such as speed, acceleration, oscillation amplitude and frequency. These results can be then used to perform a displacement classification using the Classification panel.

Classification – Generate a displacement classification based on the goodness of fitting according to the Akaike criterion. Each class of the classification identifies the areas that better fit the model.

Displacement classification map. The different colors repreent the best fitting trend for a specific criteria.

 

Displacement time series VS temperature time series.


 

Ship Detection – Classification

Identified ships are classified with a neural network trained on Sentinel-1 data when the input image is polarized VV with a resolution of 10 meters (pixel spacing in range and azimuth). The result of such classification (a vector of probabilities) is saved in the output shape file with a column for each ship type recognized by the neural network.

SAR AIS Matching – Compensation of the doppler effect (moving targets) improves the matching between AIS signal and the detected radar target.


 

Coherence Matrix Viewer

Displays the coherence images in a matrix format where the row and columns represent the dates considered for the coherence computation.

  • Used to analyze the coherence behavior in time series (e.g. Target Detection or growing season for crop monitoring).
  • Facilitates the configuration of SBAS parameters (e.g. Connection Graph filtering parameters, First and Second inversion parameters).

Coherence matrix on the left relevant to the area within the red box; Coherence image on the right


 

Intensity Single Image Workflow

Generate the geocoded filtered image by executing the following processing sequence in a single iteration:

  • Import SAR Data.
  • Multilooking.
  • Single Image Filtering.
  • Geocoding and Radiometric Calibration.


 

Coherence CCD Time Line & Power Workflow

Generate geocoded power and coherence images by executing the following processing sequence in a single iteration:

  • Import Generic SAR Data.
  • Multitemporal Coherence (Time Line).
  • Coherence Geocoding.
  • Powers Geocoding.
  • Color Composite Generation.

Many Other Improvements

Persistent Scatterers

  • Atmospherical pattern removal through the use of external data (http://www.gacos.net/).
  • Speedup interferometry, first inversion and second inversion.

SBAS

  • Automatic refinement and reflattening, GCPs are now optional and not required.
  • Atmospherical pattern removal through the use of external data (GACOS).
  • Topography‐related atmospherical pattern removal based on unwrapped interferograms (to be used in case of strong topographic variations and stratified atmosphere).
  • Mask areas in layover/shadowing from interferograms.
  • Other masks available to remove low coherence areas.
  • Speed-up refinement and interferometry (multiple parallel unwrapping, parallel k factor computation).

Point Cloud DEM Fusion
Point Cloud Dem Fusion and gridding renewal, which also includes Point Cloud Registration for fusion, Point Cloud Filtering and Interpolation Distance Constraint.

Multilooking
Multilooking option available for Ground Range data.

Single Image Filtering
Automatic ENL (Equivalent Number of Looks) calculation and artifacts removal improvement (Lee and Refinement Lee).

Gamma and Gaussian Filtering
Automatic ENL (Equivalent Number of Looks) calculation.

Interferometric Multilooking
Multilooking option available for all of the interferometric output files.

Palsar2 Spotlight Interferometry
The ALOS Palsar2 spotlight data can now be used for interferometric purposes.

Sentinel-1

  • Generate a .txt file named ''*_progress.txt'' whenever the software is stopped or crashes during the import phase. If the user uploads the ''*_progress.txt'' file during the new import process; the software will import only those files that were not imported before the stop event.
  • Import Sentinel-1 data from a zip folder to reduce the disk usage.

RCM
Import SLC Spotlight data.

Ship Detection – Coastline Mask
Upload a land mask shapefile list to retrieve the best coastline for the input image considering tide height information.

Atmospheric Phase Delay Correction

  • Atmospherical pattern removal through the use of external data (GACOS).
  • Topography‐related atmospherical pattern removal based on unwrapped interferograms (to be used in case of strong topographic variations and stratified atmosphere).

New Tasks

  • [SARsImportSpacetyFormat] Import Spacety
  • [SARsImportSynspectiveStrixFormat] Import Synspective
  • [SARsImportSidd] Import SIDD
  • [SARsToolEra5Download] Download ERA5
  • [SARsImportUavsarFormat] Import UAVSAR
  • [SARsImportGacos] Import GACOS
  • [SARsToolsDEMExtractionReferenceHeight] Reference Height DEM
  • [SARsWF_ToolsGenericFilterSingleImage] Intensity Single Image Workflow
  • [SARsBasicFeEDPSVI] Enhanced DPSVI
  • [SARsToolCoastlineExtraction] Coastline Extraction
  • [SARsstackingUtilityTSAModeling] Process TS Parametrical Analysis
  • [SARsstackingUtilityTSPModeling] Process TS Phenomenological Analysis
  • SARsstackingUtilityTSclassification] Process TS Classification
  • [SARscapeDataToAnnotation] Annotation Creation
  • [SARsShapeToTile] Convert point shapes to tiles
  • [SARsToolsSentinel1Mosaic] Sentinel-1 Ground-Slant Range mosaic
  • [SARsInSARStackSBASGenerateConnectionGraph] Index SBAS Generate Connection Graph
  • [SARsInSARStackSBASGeocode] SBAS Geocoding
  • [SARsInSARStackSBASInterferogramGeneration] SBAS Interferogram Generation and Unwrapping
  • [SARsInSARStackSBASInversionStep1] SBAS Inversion Step1
  • [SARsInSARStackSBASInversionStep2] SBAS Inversion Step2
  • [SARsInsarMultilooking] Insar Multilooking