Information from infrared aerial video and images
The digital cameras on Aerial Whidbey (AW) drones provide a variety of information through high-quality video clips and snapshot images in RGB values (Red-Green-Blue, or human-sensible wavelengths).
However if you need essential information about the presence, absence, or health of plants including grasses, shrubs and trees, you will want infrared video and images to reveal information that you can't easily see. An infrared camera is also ideal for highlighting the extent of flooded areas and other bodies of water (standing, seasonal, or event-triggered).
Aerial Whidbey uses a special 16 megapixel NDVI Red+NIR camera to highlight:
the species, health and soil-holding ability of current vegetation on a steep bluff or low bank
layers of bare dirt or rocks that are exposed to weathering, or prone to slippage/slumping
the presence of noxious weeds among crops and other preferred vegetation
the extent of forest canopy damage from tree infestations
the health of naturally-occurring and landscaped plants along a shoreline
the extent of seasonal flooding in areas that may or may not be designated as wetland
the extent of flooding triggered by human or natural alteration of an adjacent property
the extent of flooding caused by an unusual weather event
areas being eroded by rain run-off, springs or seepage.
An AW operator can guide a drone with an infrared camera to any altitude up to 400 feet while aiming the camera at a bluff, bank, beach, forest, field or other terrain. You have the option to hold a small display to watch what the camera is recording in real-time, and to request the operator to position the drone's camera close to specific areas.
Alternatively, you can request a programmed, comprehensive scan flight that records video and/or snapshot images of areas of your property (and adjacent properties, subject to appropriate clearances). The drone can fly in a vertical, oblique or horizontal "lawnmower" pattern while many overlapping images are recorded that are used to develop highly-detailed composite images. If needed for property drainage assessment or a terraforming project, the collection of images can be used to develop 3D digital elevation models.
Below is one of several examples of the value of infrared media. Compare the infrared image to the RGB image of an area on the face of a steep bluff. Notice the jagged line in both images, suggesting that a large chunk of land is about to slide further down the bluff, leaving bare earth exposed to further erosion. The green, healthy plants appear in shades of bright lavender (the dead or dying plants appear as red to black). We don't know exactly when, but there is a high probability of a future slide. In this case, there are no homes near the top of this bluff property. This kind of detailed information cannot be easily or safely obtained from the beach, from a boat or from the top of the bluff. A hovering drone, under tight control by the operator, is ideal for close examination of bluffs and other areas that are difficult to access. Below the first two images is another example.
When is the best time to get an infrared video, or an informative collection of infrared images?
a) Over a bluff with many trees below the top of the bluff: Bare areas, areas with water seepage, and the condition of undergrowth is most evident in winter after most of the leaves have fallen and before the leaves appear in Spring, especially leaves on the taller trees. A drone flight in winter, followed by a flight over the same path and with the same camera angles in mid-Spring, will provide the most information about the overall state of the bluff.
b) Over a bluff with few trees below the top of the bluff: Information about bare areas, areas with water seepage, and any dead or dying plants can be obtained at any time of year after the typical native grasses, shrubs and other plants have leafed out in the Spring.
c) Over fields or wetlands at risk for occurrences of noxious weeds: When a property owner is concerned about the presence of noxious weeds, or noxious weeds have been reported to the Washington State Noxious Weed Control Board, a horizontal scan by drone of 10-20 acres per flight can be done to help identify infested areas and direct eradication efforts. Depending on the species, noxious weeds can be identified in low-level videos or snapshots. Infrared video tends to suppress visual clutter so that noxious weeds are easier to identify.
d) Over wetlands and other property prone to continual, seasonal or storm-related flooding: Wetland or other designated kinds of areas can be documented from the air to establish typical patterns of flooding, which enables discussions about mitigating problems or exploring development opportunities. The extent of current water bodies and current vegetation can be readily seen in infrared videos and images. Water is indicated by black color. Plants with visible green portions are indicated by shades of lavender. A progression of videos/images from Fall through mid-Spring can provide substantial visual evidence. As always, AW can program the drone to fly the same path as often as needed, which makes it easier to compare media recorded on different dates.
e) Over forest canopies: The impact of some kinds of tree infestation can be quickly assessed by drone. A collection of infrared images, stitched together to form a composite image, provides a fast way to estimate the extent of damage. Living trees will be indicated in lavender color. The locations of damaged trees can be identified when the composite image is orthorectified by using visual ground control points, sufficient to direct tree removal or other efforts.
f) Over a bluff before, during and after remediation to prevent further erosion: Aerial Whidbey recently scanned a steep bluff that had become infested with blackberry plants that are not good for erosion control. (Tip to homeowners: Avoid throwing grass and other plant clippings over the edge of your bluff!) After a follow-up scan in the Spring, this homeowner will have a progression of visual documentation about the remediation project. In the example below:
St. John's Wort (a good erosion control plant) is on the left,
the bright red area is bare earth where invasive blackberry plants have been removed, and
on the right side are blackberry plants on an adjacent property.
How is my landscape watering system working? Is it broken somewhere? Some new plants in the image below have not survived. (Puget Sound seawater is shown in black in the lower-left corner.)
How can I prove the shape and extent of wetlands or non-wetlands on my property? Surface water appears as black in AW's infrared videos and images. A progression of videos/images from Fall through mid-Spring can provide substantial visual evidence. AW can program a drone to fly the same path as often as needed, which makes it easier to compare media recorded on different dates. Infrared images from a programmed drone flight can be used to develop 3D digital elevation models, enabling a property owner to evaluate risk mitigation or development options. The image below is of an area near a golf course. The black strip in the lower-right is a wet, paved path. A dirt walking/running path is shown from upper-right to lower-left.
Let's say that you wanted to count the number of kelp bulbs that are floating at the moment within an area of sea water on the surface of Puget Sound. Easier to do with the infrared image.
Sometimes infrared images are more attractive than informative! Here's a few examples:
Over Deer Lagoon on a very calm day in Winter
View from Scatchett Head to the Olympic Mountains.