NDVI UAV SUPPORT

Camera Settings for using NDVI

You should try to keep the following as your basic settings for mapping NDVI.

Set your camera to Manual.

  • ISO: 100 (to reduce image noise)

  • Shutter: 200 or faster (increase shutter speed if images are overexposed)

  • White Balance: Sunny or cloudy if overcast.

 

You can make small adjustments to fine-tune the area you are mapping.

Use file: DNG raw then process to TIFF-JPG later.

 

Note:

If your images are not focusing properly, be sure and check your camera's ISO and shutter settings. Near-infrared light is sensitive to your normal camera settings which would normally have an IR blocking filter in it.

RGB Sensor Camera 3 Channels for using NDVI

 

Standard NDVI mapping: CVI-6

RGN (Red+Green+NIR):

  • Red Image Channel = Red Light

  • Green Image Channel = Green Light

  • Blue Image Channel = NIR (Near Infrared)

 

Enhanced NDVI mapping: NDVI-7, AG-7 

NGB (NIR+Green+Blue):

  • Red Image Channel = NIR (Near Infrared Red Edge)

  • Green Image Channel = Green Light

  • Blue Image Channel = Blue Light

 

Normal Color Mapping

RGB (Red+Green+Blue):

  • Red Image Channel = Red Light

  • Green Image Channel = Green Light

  • Blue Image Channel = Blue Light

 

Full Spectrum Mapping

RGBN (Red+Green+Blue+NIR):

  • Red Image Channel = Red Light

  • Green Image Channel = Green Light

  • Blue Image Channel = Blue Light

  • Near Infrared = 1100nm

Enhanced NDVI mapping

NIR (NIR):

  • Red Image Channel = NIR (Near Infrared)

  • Green Image Channel = Not Used

  • Blue Image Channel = Not Used

Multi-spectral Radiometric Calibration Target

The radiation that is reflected from any subject under observation varies with factors that are independent of that subject.   These include properties of the atmosphere, the time of day they were imaged, latitude, etc.  If the multi-spectral imaging system does not take these factors into account during image processing, the wavelengths reflected by a subject that is represented in the image will differ from those that would be represented under other more nominal conditions.  Multi-spectral Ground Calibration Targets help users standardize the representation of the reflected radiation from a given subject under varying light conditions.

 

Multi-spectral Ground Calibration Targets provide a relatively flat response to incident radiation throughout the VIS-NIR wavelengths monitored by Tetracam cameras.  Placed in the camera’s field of view, the known reflectance values of a Multi-spectral Ground Calibration Target may be used as a standard to provide calibration correction factors.  These enable Tetracam systems to compensate for lighting conditions that would otherwise skew image results.  Precisely positioned Ground Calibration Targets may also be used to help geo-reference image mosaics.  In addition, these targets may be used to correlate imaging results obtained from a variety of different remote sensing systems. 

NDVI Mapping setting for using Drone Deploy

Please select the right color band order that is specific to the filter in your camera.

You can choose the appropriate filter under Plant Health by clicking the histogram to select the right color band order that is specific to the filter in the camera.

 

 

Filter Type

Below are the list of band orders available:

https://support.dronedeploy.com/docs/ndvi-band-order

  • RGB (Red, Green, Blue)

  • NGB (Near Infrared, Green, Blue)

  • RGN (Red, Green, Near Infrared)

For our cameras, choose RGN for (CVI-6) or NGB for (NDVI-8/NDVI-7/AG-7)

 

Algorithm

Select: NDVI

Spectral bands

The wavelengths are approximate; exact values depend on the particular satellite's instruments:

  • Blue, 450-515..520 nm, is used for atmosphere and deep water imaging and can reach depths up to 150 feet (50 m) in clear water.

  • Green, 515..520-590..600 nm, is used for imaging vegetation and deepwater structures, up to 90 feet (30 m) in clear water.

  • Red, 600..630-680..690 nm, is used for imaging man-made objects, in water up to 30 feet (9 m) deep, soil, and vegetation.

  • Near-infrared (NIR), 750-900 nm, is used primarily for imaging vegetation.

  • Mid-infrared (MIR), 1550-1750 nm, is used for imaging vegetation, soil moisture content, and some forest fires.

  • Far-infrared (FIR), 2080-2350 nm, is used for imaging soil, moisture, geological features, silicates, clays, and fires.

  • Thermal infrared, 10400-12500 nm, uses emitted instead of reflected radiation to image geological structures, thermal differences in water currents, fires, and for night studies.

  • Radar and related technologies are useful for mapping terrain and for detecting various objects.

 

Spectral band usage

Further information: False-color

For different purposes, different combinations of spectral bands can be used. They are usually represented by red, green, and blue channels. Mapping of bands to colors depends on the purpose of the image and the personal preferences of the analysts. Thermal infrared is often omitted from consideration due to poor spatial resolution, except for special purposes.

  • True-color uses only red, green, and blue channels, mapped to their respective colors. As a plain color photograph, it is good for analyzing man-made objects and is easy to understand for beginner analysts.

  • Green-red-infrared, where the blue channel is replaced with near infrared, is used for vegetation, which is highly reflective in near IR; it then shows as blue. This combination is often used to detect vegetation and camouflage.

  • Blue-NIR-MIR, where the blue channel uses visible blue, green uses NIR (so vegetation stays green), and MIR is shown as red. Such images allow the water depth, vegetation coverage, soil moisture content, and the presence of fires to be seen, all in a single image.

Many other combinations are in use. NIR is often shown as red, causing vegetation-covered areas to appear red.

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