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Image Processing 

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High-quality UAV remote sensing provides a new scientific tool which, itself, needs research.  AggieAir has developed processes, field protocols, and sensor packages in the absence of industry standards. As a result, AggieAir’s protocols and practices have led to precise, accurate, and innovative research in orthorectification and radiometric calibration in visual and near infrared imagery.

 

Orthorectification 

Orthorectification combines UAV flight imagery into a single image with high accuracy of the geolocation and reflectance for each pixel and each spectral band scientifically calibrated. AggieAir employs orthorectification software that uses photogrammetry and pattern recognition technology to ensure the highest possible quality data products.

Proper design and installation of a ground control network is critical in ensuring the accuracy in orthorectification. AggieAir reports geopositional accuracy measures of its imagery for every mission and has published comparative research on orthorectification accuracy as measured against independently acquired lidar data. 

 

Orthorectification Sample

Radiometric Calibration of Imagery in the Visual & Near Infrared Ranges

Radiometric calibration translates digital/integer pixel values for each wavelength in each image into meaningful scientific data which measures the energy reflected in each spectral band from photographed surfaces. Calibration allows researchers to quantify more than simple measures of areas and lengths. AggieAir researchers have developed and published protocols to correct for vignetting and accurately calculate reflectance using a wide array of data including measurement of incident light and environmental attenuation factors in the air column. 

AggieAir continues to refine and advance radiometric calibration research to address challenges presented by greater flight distances and duration over increasingly challenging geography. 

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Visual Image Calibration

Radiometric Calibration of Infrared Imagery  

A frequent challenge of UAV remote sensing is acquiring consistent high-quality estimations of surface temperatures using microbolometer infrared cameras, which are highly sensitive to atmospheric attenuation in infrared ranges. AggieAir researchers have developed scientifically based calibration software that relies on field protocols and on-baord environmental sensors to compensate for these calibration challenges and create consistent, high-quality thermal data.  

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Near Infrared Visuals