Normal, healthy plants absorb visible blue and red light and reflect green visible light. This is why they appear green to our eyes. In addition to reflecting green visible light, plants also reflect Near-Infrared (NIR), as this type of light isn’t actively used for photosynthesis. When a plant is diseased or weak, reflection of NIR is greatly diminished. Since red light is being absorbed the same as it would be for a healthy plant, a mathematical algorithm can calculate the difference in what is being reflected across an area of crops.
By taking the ratio of red and near infrared bands from a remotely-sensed image, an index of vegetation “greeness” can be defined. NDVI is calculated on a per-pixel basis as the normalized difference between the red and near infrared bands of an image.
Once graded and processed, it becomes evident which crops are flourishing and which are in distress or need attention.
Hummingbird Aerial Surveys uses a special camera that detects Near-Infrared wavelengths as well as regular red wavelengths and comparisons are made resulting in a “normalized difference” through post-processing of the images.
NDVI Information can be utilized to determine:
Nitrogen Management Solutions
Insect and pest plant diagnostics
Plant disease diagnosis
Develop harvest plan based on vigor
There are many ways in which NDVI data can be captured, from satellite imagery to manned aircraft. An unmanned aerial vehicle (UAV) is the best way to retrieve the highest quality imagery. The low altitude and precision flying gives you the best coverage, resolution and accuracy.
The UAVs flight path is pre-programmed (by virtue of flight mission software) beforehand, ensuring the best coverage, suitable imagery overlap, and resolution is taken into account. The flight path is loaded into the UAVs autopilot system which will fully autonomously fly the UAV over this path.
After the flight mission is completed and all imagery is captured, the data is then processed and the NDVI data can is extracted.