ReSe Applications Schläpfer provides atmospheric correction software for remote sensing images.

ATCOR® - Code Comparison

 
Overview | Examples | Alternatives | Documentation | ATCOR-2/3 | ATCOR-4
 

The table below gives an overview of the features of the ATCOR packages as distributed through ReSe (ATCOR-IDL) in comparison to current alternative codes, as available on the market:

Feature:
ATCOR-IDL (ReSe)
ATCOR Workflow for Imagine (Geosystems)
ATCOR (Geomatica)
FLAASH (ENVI /SSI)
System Features
Supported Operating Systems
Windows, Linux, MacOSX
Windows
Windows, Linux
Windows, Linux
Base Software
none 1)
Erdas Imagine
PCI Geomatica
ENVI
Airborne
yes (A-4)
no
no
yes
Satellite
yes (A-23)
yes
yes
yes
Hyperspectral
yes 3)
no
limited
yes
Ultraspectral (<2 nm) 2)
limited 3)
no
limited
yes
Extreme Tilt Angles 2)
no
no
no
yes
Batch Processing
yes
yes
yes
no
Workflow Integration
no
yes
yes
no
Correction Features
Terrain Correction
yes
yes
yes
no
Variable Visibility
yes
yes
yes
yes
Aerosol Type Detection
yes
yes
no
no
Adjacency Effect
yes
yes
yes
yes
Water Vapor Retrieval
yes 4)
yes
no
yes
Haze Removal
yes
yes
limited
no
Cirrus Cloud Removal
yes
yes
no
no
Cloud Shadow Removal
yes
no
no
no
Preview of Spectra
yes
no
yes
no
Inflight Calibration
no
(one target)
no
no
Normalize to Nadir View (Wide FOV)
yes
no
no
no
Physical Observer BRDF Correction
yes
no
no
no
Spectral Polishing
yes 5)
no
no
yes 5)
Spectral Calibration
yes
no
no
yes
Spectral Smile Correction
yes
no
no
no
Empirical Line Correction
yes
no
yes
yes (ENVI)
Thermal Region Features
Surface Temperature
yes
yes (Landsat7)
yes (Landsat7)
yes (ENVI)
Surface Emissivity
yes
no
yes
yes (ENVI)
Rugged Terrain Features
Terrain Height (DEM)
yes
yes
yes
no
DEM illumination Effects
yes
yes
yes
no
Empirical BRDF Illumination Correction
yes
yes
no
no

Notes and Remarks:

1) ATCOR from ReSe runs on the free IDL Virtual Machine.

2) It's a true advantage of FLAASH that sensor-specific LUTs can be calculated directly through Modtran®. This feature is particularly well suited for sensors at tilted angular conditions with large tilt angles. Also, 'ultraspectral' sensors having resolutions below 2nm are not ideally sampled in the ATCOR LUT. On the other hand, our experience has shown that 99% of all currently relevant data acquisitions are within the range which is covered by the ATCOR pre-calculated LUTs.

Note: The ATCOR LUTs are based on the accurate scaled DISORT (8 streams) multiple scattering option in atmospheric window regions and the accurate correlated-k algorithm in absorption regions. A variable spectral wavenumber resolution in MODTRAN is employed to achieve a constant wavelength resolution of 0.4 nm in the LUTs.

3) The IDL version of ATCOR supports the inclusion of new (user defined) sensors. A resampling tool contained within ATCOR allows interpolation of virtually any multispectral or hyperspectral sensor from the database (at 0.4 nm resolution). Inaccuracies due to this interpolation become only relevant at spectral resolutions below 2 nm.

4) ATCOR uses the latest release of Modtran®5 (v5.4) and its LUTs are based on the HITRAN atlas of 2013 - a version which to our knowledge corrects earlier problems in the water vapor absorption bands. We will include any newer version of Modtran® as soon as it is available.

5) The spectral polishing features within FLAASH and ENVI are very sophisticated. ATCOR also offers such features.

An independent comparison was published by Eyal Ben-Dor (2005) and indicates that the performance of ATCOR compares very well with other products available on the market, see: E. Ben-Dor, B. C. Kindel, and K. P. K1, "A comparison between six model-based methods to retrieve surface reflectance and water vapor content from hyperspectral data: A case study using synthetic AVIRIS data," presented at International Conference on Optics & Optoelectronics - ICOL 2005, Dehradun, India, 2005.

As ATCOR is continuously improved, we would be happy to participate in independent validation exercises and we would offer free time-limited licenses for such purposes.