The MAPIR T3-R50 Diffuse Reflectance Calibration Ground Target Package contains a series of 4 reflectance targets with known reflectance curves.  UNLIKE drone “sunlight sensors” this target allows users to obtain accurately repeatable calibrated images through the seasons and in differing weather / lighting conditions.  This target can be used for calibrating images with Mapir and any other brand of multispectral camera. A larger T3-R125 target is also available.

Before commencing a crop mapping survey cameras should capture an image of the entire target.  This can then be used to help calibrate images captured in the image processing software.

 We therefore highly recommend that you purchase the Mapir Camera Reflectance Calibration Target to complete your system.  

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$499.50 ( $599.40 including VAT)

Product Description

UNLIKE drone “sunlight sensors” the MAPIR T3-R50 Diffuse Reflectance Calibration Ground Target allows users to obtain accurately repeatable calibrated images through the seasons and in differing weather / lighting conditions.  Before commencing a crop mapping survey cameras should capture an image of the entire target.  This can then be used to help calibrate images captured in the image processing software.  This target is suitable for Mapir and other multi-spectral cameras and we highly recommend that you purchase this Mapir Camera Reflectance Calibration Target to complete your system.  

The MAPIR T3-R50 Diffuse Reflectance Calibration Ground Target Package contains a series of 4 ground targets composed of a felt-like material that have known reflectance curves. It can be captured from any angle with your camera thanks to similar total and diffuse reflection properties.  Each of the four targets is 50mm x 50mm and are kept in a protective case with bubble level and three tripod mounting points. A larger T3-R125 target is also available.

To use this target users should capture a full image (with no shadows on the entire target area) of the target with each camera before each flight.  These images can then be used with Mapir’s post processing software or any other software to calibrate the index image pixel values.  This will improve the normalisation of your surveys over time and locations. Contact SeeSense for the full tutorial containing detailed links and information.

Caution: The material used for the targets is similar to felt and thus must be kept debris-free to perform correctly.  It is recommended to hold your drone over the target or taking off away from it and then hovering overhead in order to reduce the amount of debris that could potentially land on the target.  The best working distance to capture the image depends on the angle of view.  The target material’s diffuse properties means that you do not need to worry about camera orientation to get good results.  The detection pattern (fiducial) is also much lower in resolution making detecting in our post processing software much easier, even with images having high noise (typically near-infrared wavelengths).  Reflective measurements were made using multiple Shimadzu spectrophotometers incorporating an integrating sphere.

By using Mapir’s Mapir Camera Control (MCC) software you can select the photo of this target taken before your survey, the fiducial pattern will be auto-detected and the reflectance value of each target will be calculated and applied to each of your images. The resulting individual images will then be calibrated and you can generate your ortho-mosaic in the software of your choosing.  You can also calibrate the entire ortho, or groups of orthos.  Using the Viewer tab in MCC you can calculate the rastor/index images (for example NDVI) and then apply your color map (lut).