Diffuse Reflectance Standard Calibration Target Package
(T4-R50)
MAPIR offers our compact and durable Diffuse Reflectance Standard Calibration Target Package (T4-R50), which contains 4 reference standard targets of known reflectance. Diffuse and total reflectance percent measurements from 250-2500nm were made using multiple Shimadzu spectrophotometers incorporating an integrating sphere. The lambertian reflectance panels can be captured from any angle thanks to similar diffuse and total reflection properties, though capturing straight-on is recommended. Our computer vision software automatically finds the QR symbol in the target images and calculates the pixel to reflectance relationship using the known target material reflectance (data download here).
The reflectance targets are composed of a felt-like sheet material adhered to a plastic substrate. Care should be taken to ensure the targets are debris-free to produce the best calibration results, often a puff of air is all that is needed to clean them. The target's housing is made of durable polypropylene plastic and the QR fiducial pattern material is a UV durable, laminated label.
| Package Model | Reference Target Dimensions |
Recommended Capture Distance (Survey3W) |
Recommended Capture Distance (Survey3N) |
| T4-R50 | 2.0" x 2.0" (50 x 50 mm) | 8 in - 16 ft (0.2 - 5.0 m) | 20 in - 40 ft (0.5 - 12.0 m) |
| T4-R125 | 5.0" x 5.0" (125 x 125 mm) | 20 in - 33 ft (0.5 - 10.0 m) |
40 in - 105 ft (1.0 - 32.0 m)
|
The green outer case of the T4-R50 is impact resistant, crushproof, dustproof and IP67 waterproof (IP67 rating = waterproof to a depth of 1 meter for 30 minutes when latched). It's polypropylene plastic resists chemicals while protecting the internals from moisture. The large hinged clasp latches the halves securely. Twisting the black circular lock fastens the clasp to the case, and there are 2 additional keys included to further lock it. A hole for a carabiner or other clip is available on one of the shorter ends (see drawing).
The small black brackets on each side allow future accessories to be attached (coming soon).
To use the target, simply capture a photo of the entire open package, making sure the QR side and the 4 target side are visible. Try to make sure no harsh/dark shadows intrude on the white outer perimeter of the QR label, rotating the target as needed. Full capturing tutorial here.
Using our MAPIR Camera Control (MCC) or MAPIR Cloud software you can provide photos of this target package and the QR fiducial pattern should be automatically detected, regardless of 3D pose. The pixel values from the targets will be measured and calibration formulas will be calculated. The reflectance calibration will then be applied to the remainder of your images until a new target image is found (depends on MCC recalibration setting value). An unlimited number of target images can be used to correct your images for reflectance over time and across various lighting environments (i.e. cloudy days). In order to fully calibrate the images for reflectance you will need the log from our ambient light sensors (DAQ-A-SD). Using the Analyze tab in MCC you can calculate the raster/index images (for example NDVI) and then apply a color map (LUT).
Automatic Target Pixel Sampling At Any Angle
Specifications:
Total Closed Dimensions: 9.5" x 5.8" x 2.8" (24.13 x 14.73 x 7.11 cm)
Total Open Dimensions: 9.5" x 11.3" x 1.9" (24.13 x 28.70 x 4.83 cm)
Each Target: 2.0" x 2.0" (50 x 50 mm)
Weight: 1.42 lbs ( 645g)
Buoyancy: 3 lbs
Weight Capacity: 10 lbs
100% MADE IN THE USA
IP67 Waterproof
Impact resistant
Compliant with airline ATA-300 / TSA compliant specifications
Made to MIL-STD 810F Standards
UPC: 00815120021381
Included:
(1pc) Diffuse Reflectance Standard Calibration Target Package (T4-R50), containing 4 measured reflectance standard targets and an identification QR label.
(2pcs) Plastic locking keys
Accessories
Tripod Clip Adapter
Easily attach the T4-R50 to a tripod (1/4-20) using our Tripod Clip Adapter (T4-R50). The clip securely attaches to the target housing and is easily removed with thumb tabs. No tools are required to attach the T4-R50 green housing to the black tripod clip adapter.
