Remote Sensing Software for
Image Data Processing

DROACOR-Method

 

DROACOR: Overview | Method | Features | Compare | Screenshots

 

Processing Principles

Details about the DROACOR method can be found on: www.droacor.com

The concepts and key features of DROACOR have been published here:

D. Schläpfer, C. Popp, and R. Richter, “DRONE DATA ATMOSPHERIC CORRECTION CONCEPT FOR MULTI- AND HYPERSPECTRAL IMAGERY – THE DROACOR MODEL,” ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol. XLIII-B3-2020, pp. 473–478, 2020, doi: 10.5194/isprs-archives-xliii-b3-2020-473-2020.

D. Schläpfer, R. Richter, C. Popp, and P. Nygren, “DROACOR REFLECTANCE RETRIEVAL FOR HYPERSPECTRAL MINERAL EXPLORATION USING A GROUND-BASED ROTATING PLATFORM,” Int Archives Photogrammetry Remote Sens Spatial Information Sci, vol. XLIII-B3-2021, pp. 209–214, 2021, doi: 10.5194/isprs-archives-xliii-b3-2021-209-2021.

D. Schläpfer, R. Richter, C. Popp, and P. Nygren, “DROACOR®-THERMAL: AUTOMATED TEMPERATURE / EMISSIVITY RETRIEVAL FOR DRONE BASED HYPERSPECTRAL IMAGING DATA,” Int. Arch. Photogramm., Remote Sens. Spat. Inf. Sci., vol. XLIII-B3-2022, pp. 429–434, 2022, doi: 10.5194/isprs-archives-xliii-b3-2022-429-2022.

D. Schläpfer, J. Raebsamen, C. Popp, R. Richter, S. A. Trim and M. Vögtli, "Droacor Topographic Correction Method with Adaptive Diffuse Irradiance Based Shadow Correction," IGARSS 2023 - 2023 IEEE International Geoscience and Remote Sensing Symposium, Pasadena, CA, USA, 2023, pp. 7332-7335, doi: 10.1109/IGARSS52108.2023.10283017.

 

Differences between DROACOR and ATCOR-4

DROACOR and ATCOR are both valid solutions of the physical inversion process for atmospheric correction. They share mostly the same physics but some differences should be considered:

Major differences are:

• a different physical formulation of the adjacency effects: DROACOR accounts for the close range situation for adjacency effects above the sensor; ATCOR calculates adjacency between sensor and ground.
• different treatments of spatial variablitiy of aerosol, water vapor: DROACOR uses constant values per scene, whereas ATCOR considers spatial variability.
• for imaging spectroscopy, DROACOR includes on-the-fly spectral re-calibration, LUT resampling, and atmospheric transmittance adjustment - features not available in ATCOR-4
• topographic correction in ATCOR is done as part of the atmospheric correction process (with more options and cross-talk effects) whereas in DROACOR it is done after flat terrain apparent reflectance retrieval.
• options for haze and cirrus cloud correction are only available ATCOR
• the aerosol model is constant for DROACOR while the angstrom coefficient is tuned based on dark target analysis, while ATCOR uses predefined aerosol models.
• a different underlying radiative transfer code (MODRAN for ATCOR, LibRadtran for DROACOR) - note that the impact is well below the 1% level of accuracy according to our tests.

Use DROACOR:

• if dealing with UAV based data flown below 1.5 km above ground
• for very high spatial resolutions (down to the cm range)
• if time to learn the software use is limited
• for large sets of image data do process
• for fast and efficient automatic reflectance retrieval
• .. and if your sensor is supported by DROACOR.

Use ATCOR:

• for satellites (in any case)
• for airborne data with flight altitudes above 2km above ground
• when doing large scale analysis over terrain
• if working in steep terrain
• if you want to have the ability of flexible parameter configurations (for scientific analysis)
• for processing of experimental/singular (non-standard) sensor systems.

NOTE: between 1 and 2 km above ground, both software packages may be used.