LEARN ABOUT HOW DRONES CAN BE USED FOR ALMOST ANY APPLICATION
It's becoming a bit cliche but it's still true. People are finding new uses for drones every day. Here are a few practical uses for drones that you may not have heard of.
Crop and Pasture Health Monitoring
NDVI (Normalised Difference Vegetation Index) relies on the basic principle that vegetation reflects different amounts of electromagnetic radiation depending on the amount of stress it is under. The reflected frequencies can be filtered and measured to find the relative stress of the plant being imaged.
When a plant is healthy, it reflects more near infra-red light (light that is between the red and infra-red frequencies) than it does light in the visual spectrum. This is because any light of a wavelength above approximately 700 nanometers cannot be used by the plant for photosynthesis. Light above this wavelength only serves to heat up the plant, so it is in the plant's best interest to reflect as much near infra-red light as possible.
Traditionally, aerial NDVI imaging was either done by satellite or plane. Both of these methods had their own pros and cons. Satellite could only take images at a very low resolution and planes were very expensive to operate.
With the rise of cheaper and more technologically advanced drones, specially modified NDVI cameras could be fitted to image vegetation more cheaply and accurately than traditional methods. The NDVI camera uses a filter that blocks out all light except for that in specific visible and near infra-red bands.
The amount of light captured in each of these bands is then used to calculate the NDVI ratio of the plant. Generally speaking, when the plant is not absorbing light in the near infra-red frequency when compared to the visible bands (green and red normally), this is a sign that the plant is healthy. When the opposite is true, this can be a sign that the plant is under stress and is not at it's maximum health.
Causes of plant stress can range from incorrect soil pH levels, a lack of correct fertiliser, pest or disease, excessive heat, frost or a lack of water.
When used correctly, NDVI imaging data can give very useful insights and perspectives that cannot be obtained at ground level or with imaging in the visual spectrum. It is usually very easy to see the areas of stress relative to the healthy areas.
However, NDVI is not the only measure of plant health, it is merely one part of the many different measurements and indexes needed to comprehensively assess a plant's health. For example, NDVI images can be affected by different soil types, moisture levels, cloud cover and sensor differences to name a few. That's why it is important to not rely solely on NDVI for assessing plant health.
Real Estate has benefited hugely from the recent boom in drone use. Aerial imaging of property is no longer the domain of aviation companies with manned planes fitted with specialist cameras. Now anyone with $1000 can buy a drone fitted with an accurate GPS, a high-resolution camera and FPV capabilities and commercially operate in the real estate photography field.
Recent CASA laws have made entering this field in Australia even easier by allowing people to commercially operate drones weighing less than 2kg without an RePL (Remote Pilots Licence). Caution should be taken when hiring unlicensed drone operators however, as they are often not insured and not aware of many aviation laws and safety precautions needed to safely operate a drone. If an accident happens and the pilot is uninsured, there may be no compensation for damage to property or injury to others.
Unlicensed pilots are also restricted in the heights, locations and times that they can legally operate. A licensed pilot can make special applications to CASA to:
- Fly above 120m (400ft) above ground level
- Fly at night
- Fly in restricted airspace
AT Aerial Services is fully licensed and insured. We conduct flights safely and legally, and can apply to CASA for special permissions that other cannot.
A surprising and fun use for drones has emerged in the form of drone racing. Major cities are now seeing events dedicated solely to the competitive sport, and like most sports, competitors are making serious money with their skills.
The racing drones are usually small, lightweight drones with a front mounted camera that allows the pilot to fly in FPV (First Person View). This means that the pilot is essentially seeing what the drone is seeing.
Competitors must navigate their drone through obstacles around a set course, all whilst travelling at speeds of 80km/h and up.
Cheaper drones have also opened up possibilities in the film making industry. Flowing aerial shots that used to be taken by crane or plane can now be replicated with the the same quality by drones costing a fraction of the price. This has allowed filmmakers with limited budgets to include more aerial shots that may have been unfeasible previously.
Usually people think about what sensors can be placed on a drone to capture data, but there are plenty of uses for drones with no imaging capabilities at all.
One of these uses is bird scaring. Owners of vineyards, crops or orchards often have to contend with animals (usually of the avian variety) destroying their produce. Drones fitted with loudspeakers have successfully been used to scare birds away from these crops with resorting to lethal means.
When there is a buildup in the number of pest animals, it is sometimes decided to reduce their numbers to limit damage to the surrounding environment or to maintain a sustainable population.
Traditionally this is done by hunters manually walking a given area in search of the pest animals. This is sometimes an inefficient and unreliable way to find pest animals, as the hunters may not be able to locate the pest animal mob on the allotted day.
Drones are being used to scout areas and direct hunters to pest animal locations using both visual and thermal sensors. This saves time, money and effort and minimises disruption to the area.
Drones are not all about mapping and data collection, they can be used for creating beautiful images that would otherwise not be possible from ground level. A large proportion of drones sold will never be used for practical purposes, but instead will be used as an extension of the traditional camera. Many examples of drone photo art can be seen on image sharing websites such Instagram and Flickr.
Drones are finding uses in more and more aspects of mining operations. Some of the ways drones are being utilised for mining operators are:
- Mapping areas of interest and estimate potential yields
- Measuring volumes of ore or rubble to be moved
- Remotely analysing soil compositions
- Inspecting plant and equipment
- Detecting unusual erosion or water leakage
- Monitoring site security
Transport of Goods
Businesses like Amazon, UPS and Domino's Pizza have publicly stated their interest in using drone for delivering their goods, ranging from pizzas to books. If drone deliveries becomes a reality, they will create benefit customers by making deliveries of small items faster and cheaper.
But drones are also being used to deliver less frivolous items. Projects such as The Little Ripper are using drones to drop flotation devices to swimmers in need, while others are delivering medical supplies to people in remote or inaccessible locations.
Using lidar and photogrammetry, combined with accurate GPS systems, drones are becoming more effective at creating highly accurate and cost effective images over large areas. These images can then be processed and used to create elevation and contour maps, 3D models, volumetric measurements and surface models.
By creating these maps, one can then use them for purposes such as:
- Mining exploration
- Flood modelling
- Urban planning
- Property boundary maps
- Erosion mapping
Shortly after a disaster occurs, one of the biggest challenges is assessing the scale and magnitude of the affected areas. As lives and property can be lost due to delays, it is important to do this quickly and efficiently so that resources can be allocated and access paths can be identified.
Drones are increasingly being used to assess damage caused by wind, flooding, fires, earthquakes, terrorist attacks and other natural and unnatural disasters.
Emergency services are quickly adopting drones into their arsenal due to their ability to remotely transmit valuable data in hazardous situations.
Urban firefighters are increasing using thermal cameras to quickly assess the areas of most concern in structure fires, while rural departments are using thermal imaging to find hot spots that may have not been fully extinguished by earlier sweeps.
Thermal cameras are also being used for search and rescue situations. Because people generate heat, they can be easily spotted amongst thick bush and scrub. Drones can quickly search huge areas of inaccessible terrain that would otherwise take a lot of man hours and organisation to achieve.
Police in the US are being issued with drones so that they can assess potentially dangerous situations remotely and without the use of expensive and noisy helicopters.
Using a combination of NDVI, multispectral or hyperspectral imaging and smart agricultural equipment, crops and pastures can be imaged, processed and selectively treated on the same day.
The drone images are first stitched together and converted into VRA (Variable Rate Application) maps, which divides the area into discrete chunks. These chunks are then classified according to the level of stress present in the chunk area.
This data is then uploaded to the smart farm equipment (sprayer, irrigator etc) which then applies fertiliser, pesticide or water in varying amounts depending on the particular needs of the chunk.
This increases efficiency for the farmers as they are not wasting money by applying resources to areas that don't require them.
When property is damaged, an insurance assessor must be sent out to physically inspect the amount of damage. If the roof of your house got damaged in a hailstorm, an assessor would have to drive to your house, climb up on his ladder and then look at the damage with his own eyes. He would then do this for the other 1000 homes in your area. As you can imagine, this would quickly overwhelm the insurance company, and lead to long wait times for customers.
This may soon be a thing of the past, as even cheap drones can now take images of a sufficient quality to conduct visual inspections. A local drone operator could be hired and sent to image multiple addresses. He could then send the assessor his photos via email, without the assessor ever leaving the office.
Checking stock and water
Time is precious when you're a farmer. Those who farm large properties (1000's of acres) can find a lot of their time is spent just checking stock and assets. Drones can now help farmers save time by automatically flying predetermined routes and taking images of fences, water troughs and stock, which can be viewed at any time from home.
It seems if it can be attached to a drone, it will be. Small, battery powered seeders can be attached to drones for remote seeding of pastures and crops. These seeders can only carry a couple of kilograms of seed, but as drone prices decrease it may become practical to hire or buy a swarm of small seeding drones. The seeders can then be swapped for other payloads such as sprayers or bird scarers.
The defence industry was one of the original users and developers of drones. Once drones became technologically feasible to build reliably and cheaply, they became a great way to reduce the risks posed to human pilots who would otherwise be flying in potentially dangerous environments. As the technology improves, drones began taking on more traditional military aircraft roles, like surveillance.
Even though drones started out as flying sensors in the sky, the aim was always to equip them with weapons and carry out attacks, with the first official "kill" occurring on the 7th of October, 2001. Thousands of people have now been killed by Unmanned Combat Aerial Vehicles (UCAVs), with that number increasing yearly.
Figures are not definite, but it is estimated that hundreds, if not thousands of civilians have also been killed by drone strikes.
A lot of sensor and measurement technology is in the process of being made cheaper, lighter and smaller. Drones are a major beneficiary of this technological advancement and new hardware is constantly being fitted to drones to further increase their usefulness. This is an overview of just a few different sensors that you can find in use on drones today.
Modern drones can be equipped with all kind of sensors, not just regular cameras. These sensors can measure wavelengths of light that the human eye can not see, wavelengths that objects are constantly absorbing and reflecting.
Because each object reflects light in different ways, we can measure it and use it to tell us more about the nature of the objects.
A standard camera like that used in your smartphone operates similarly to the human eye. Both are sensitive to 3 visible bands of light. These are three primary colours (Red, Green and Blue) from which all other colours are created. Visual sensors are by far the most common payload attached to drones today.
Digital camera and smartphone tech is constantly feeding into drones, giving them higher resolution, higher frame rates, wider dynamic range and less power consumption. The DJI Phanton 4 Pro, a popular consumer drones, comes with a camera capable of 4K 60fps video and 20 megapixel stills.
AT Aerial Services offers high-resolution visual imaging and video as part of our range of services.
By measuring how plants absorb and reflect different wavelengths of light, we can guess a plant's health by calculating the ratio between the reflected wavelengths of a given plant. Generally, plants tend to reflect NIR (Near Infra-Red) and green light and absorb red light when they're healthy.
This is the basis of NDVI (Normalised Difference Vegetation Index) imaging. The sensor measures these wavelengths over a given area, the data is then processed and analysed to detect where there are areas of plant stress.
AT Aerial Services is able to offer NDVI Imaging using our specially modified drone/camera to map plant stress and health.
These work on the same principal as visual and NDVI sensors, but can measure a greater range of wavelengths. Visual sensors primarily measure 3 different bands of light, whereas Multispectral sensors can measure up to 10 distinct bands. The higher amount of bands can be used to more specifically search for specific wavelengths emitted by a certain type of plant fungal disease for example.
Hyperspectral imaging is the ultimate in accuracy and specificity when it comes to drones. It measures thousands of individual bands to get a complete image of an object or area.
Every item has its own "spectral signature" that it emits, from metals and oils, to plants, soils and even diseases. This means that if you know the spectral signature of a certain object, you than then filter you images only to show the object of interest.
Currently, hyperspectral sensors are very expensive and not commonly found on drones, but this is changing as the technology advances. Some products by Precision Hawk and Corning are now bringing hyperspectral imaging to the mainstream.
Thermal cameras are one of the most exciting sensors you can put on a drone. They image in the long-infrared band which means that they can "see" thermal emissions and temperature differences not visible to the naked eye.
Thermal camera technology is rapidly becoming cheaper, higher quality and more accessible by the day. They are still expensive due to the special construction methods used to manufacture them, as well as government restrictions. Companies like FLIR and DroneBase are constantly releasing new products at lower prices.
At it's most basic, LIDAR units emit brief laser pulses and measure the amount of time it takes for each pulse to reflect back to the on-board sensor. This is similar to RADAR, but instead of using wavelengths in the radio spectrum, it uses light around the visible spectrum to detect surfaces. This method gives a very accurate and high resolution image of the area being scanned. This is good for accurate terrain scanning and mapping, and is also the technology used in self-driving cars, as well as fields like astronomy and meteorology.
Once again, this is a developing technology that is becoming more common on drones, but the cost of super-accurate LIDAR is still relatively high.
Air Quality Sensors
Drones can do more than just see, they can also smell! That's right, drones can be fitted with air-quality and chemical sensors to remotely monitor particles and molecules in the air. This can be combined with GPS data to take comprehensive and accurate surveys of things like pollution, odour or gasses. Laser based dust sensors can also be fitted to count particles in the air. Companies like Scentroid are leading the way in developing drones for these purposes.