Mapir Camera Reflectance Calibration Ground Target

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The MAPIR Camera Reflectance Calibration Ground Target Package contains a series of 4 ground targets composed of a felt-like material that have known reflectance curves.  Before commencing a survey all the Mapir 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.  

 MAPIR – MAPPING THE INVISIBLE

280.00 ( 336.00 including VAT)

Product Description

In order to correctly utilise the MAPIR range of multispectral imaging cameras it is essential to ensure that the images are correctly calibrated for use with image processing software.  We therefore highly recommend that you purchase the Mapir Camera Reflectance Calibration Target to complete your system.  

The Mapir Camera Reflectance Calibration Ground Target Package contains 4 ground targets that each have known reflectance curves.  The target material is composed of a felt-like material mounted to a plastic substrate.  It can be captured from any angle with your camera thanks to similar total and diffuse reflection properties.

To use this target, before each flight take a photo using each camera of the entire open reflectance calibration target with the targets facing straight up (with no shadows on the entire target area).  These images can then be used with Mapir’s post processing software (contact SeeSense for detailed links and information) and then calibrate the index image pixel values.  This will improve the normalisation of your surveys over time and locations. Contact SeeSense for the full tutorial.

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.  A hovering height of around 3-5 metres is recommended while trying to keep the target in the centre of the camera’s 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).

Ground Sample Distance 3 – 5 metres
Weight 630 grammes
Dimensions Open 320 x 510 x 14 mm
Closed 320 x 255 x 14 mm

 

  • 4 x ‘felt-like’ target
  • Lower resolution fiducial (detection) pattern

Calibration target for multispectral imaging

Mapir Camera Reflectance Calibration Target

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