Choosing the Right Mapping Drone for Your Business Part II: Aerial Imaging and Cameras
Understand the Different Types of Drone Cameras and Imagery Available for Your Business
Drones make it possible to capture various types of imagery across the light spectrum. But that doesn’t mean every drone comes ready to meet the challenges of your business off the shelf.
In order to capture the right types of data you may need to purchase additional sensors, cameras, or hardware components. If you’ve read part one of this series and still have questions about aerial imagery and cameras, then this post is for you.
In this post, we’ll walk through the various types of imagery you’re able to capture using a drone, and help you understand the types of cameras you should purchase to meet your business needs. Let’s get started.
Using cameras and sensors attached to a drone, you can capture different types of light across the electromagnetic spectrum. From visible light, to thermal infrared imagery, it’s important to understand the different types of imagery and their industry uses. While construction or surveying users may only require a standard camera, an Ag user may require a near infrared (NIR) camera to evaluate crop health. The illustration below explains where the different types of imagery fall on the electromagnetic spectrum.
Visible Spectrum (RGB)
This is the most common type of imagery captured. RGB images are generally used in surveying, mapping and GIS missions where a high-definition surface model or 3D point cloud are required. This type of image is produced using the digital camera sensor that comes with most drones available on the market today, and is the color spectrum people are most used to viewing in standard photographs.
Near Infrared (NIR)
NIR imagery is most frequently used in precision agriculture in order to calculate plant vegetation health. NIR has the highest level of reflectance of the light bands. NIR-capable cameras make it possible to identify the reflectance of light from vegetation, which strongly correlates with the level of chlorophyll present in the plant. Plants with more chlorophyll reflect a higher amount of NIR light than unhealthy plants, making it possible to identify plants in poor health.
Thermal imagery is used across a variety of industries and use cases ranging from agriculture, to construction, to inspection, and surveying. This type of imagery detects heat signatures from the environment to identify the range of temperature present in an image. This can help identify “hot spots” in images in order to inspect roofs, roadways, and even identify wet spots from irrigation in crop fields.
Cameras make it possible to capture imagery across the electromagnetic spectrum. Now that you have an understanding of the various types of imagery at your disposal, let’s discuss the different cameras that make it possible to capture image data. Most drone models come with a camera off the shelf, but you may need to invest in additional camera accessories to support your business use case. Let’s explore the different types of cameras on the market.
RGB — or standard — cameras capture Red, Green, and Blue light. This is the camera type that comes stock with most drone models. These are multipurpose photo and video cameras that can be used to make high-definition 2D orthomosaic maps as well as 3D models for any industry. Additionally, they can be paired with plant health algorithms such as the Visible Atmospherically Resistant Index (VARI) to assess plant health and crop stress in precision agriculture use cases.
When considering the right RGB camera for mapping we recommend the following best practices:
Buy the highest quality camera you can afford
Higher quality camera sensors produce higher resolution photos with greater pixel density, which means you get more accurate maps. What exactly does resolution have to do with map accuracy? Put simply, increasing the resolution of an image decreases its ground sampling distance (GSD), or in other words, it reduces the space between individual pixels in an image. Because drone mapping software like DroneDeploy processes maps by taking a series of individual images and matching the common points between them, the more common points that can be matched, the higher the accuracy of the map. An image with a more pixels contains more information, which means there is a greater probability of matching common points. We recommend purchasing a drone with a 12.3-megapixel camera or higher for drone mapping projects.
Buy a camera with a mechanical shutter
Many out-of-the-box drone cameras use a rolling shutter. This means that the camera records each frame line-by-line from top to bottom. When taking videos or photographs, this helps reduce motion blur. However, it can also sometimes cause what’s known as “rolling shutter effect,” where surfaces in a photograph appear warped because the camera-object relation changed before the full image was recorded. An image that is warped in this way makes it difficult for drone mapping software to match points on a map, which negatively affects the map’s accuracy. Purchasing a drone camera with a mechanical shutter helps solve this problem, because the sensor records all of the lines of the frame nearly simultaneously, rather than line-by-line.
Learn more about producing accurate drone maps with RGB cameras in our recent blog post.
Near Infrared (NIR) Cameras
There are two main types of NIR cameras: Modified RGB cameras for Near Infrared and Multispectral Cameras. These cameras are generally used in precision agriculture to determine crop variability using plant health algorithms such as the Normalized Difference Vegetation Index (NDVI). They tend to be more expensive than RGB models because they are able to capture additional bands of light, but there are a wide variety of options available on the market to choose from. Let’s take a closer look.
RGB Cameras Modified for Near Infrared (NIR)
Modified cameras are fitted with a filter to capture some combination of Near Infrared, Red, Green, and Blue light depending on the model.
Multispectral cameras capture Red, Green, and Near Infrared light.
RGB cameras modified with NIR filters and multispectral cameras deliver high performance and accurate (absolute) NDVI imagery, but they require substantially higher investment than standard RGB cameras. Quality NIR-capable cameras can cost anywhere from $1,200 on the lower end, to $7,000 on the high end.
When considering the right modified RGB or Multispectral camera for mapping we recommend the following best practices:
While many aftermarket camera conversions for DJI cameras are available, image quality is inconsistent across manufacturers, meaning some may lead to poor map quality (see our documentation for a full explanation). We recommend getting quality control samples and a warranty from your hardware vendor prior to any purchase.
Learn more about using modified RGB and Multispectral cameras for precision agriculture in our online guide to identifying crop variability with drones.
Thermal, or thermographic cameras, usually detect radiation in the long-infrared range of the electromagnetic spectrum and produce images of that radiation, called thermograms. These cameras are most commonly used in inspection across industries ranging from construction to transportation, to public safety.
Conclusion: Pick the Right Camera for the Job
You want to be sure you choose the right camera for the job. Before purchasing a drone, camera, or any other hardware accessories, make sure you have a clear understanding of your business needs.
If you’re in agriculture, we recommend you start simple with an RGB camera and move up from there to more expensive NIR-capable cameras if you need it. Many of our Ag customers report that RGB cameras deliver the capabilities to help them around the farm. But you may need an RGB camera modified for NIR or a multispectral camera, it depends on what type of data you’re looking for — especially if you’re an agronomist. Read more in our online guide to detecting crop variability.
If you’re in construction, surveying, oil & gas, or mining, you’ll most likely want to purchase an RGB camera. Though, certain use cases may require a thermal camera for inspections of buildings, roadways, or pipelines. Know your requirements and purchase a camera that can deliver the results you’re looking for.
Before we sign off, here are a few more pieces of parting wisdom to help you make a solid choice on your next drone — and camera — for aerial mapping.
It’s Not Always About the Megapixels
If you’re familiar with any one camera spec, it’s probably the megapixel rating. A higher amount of megapixels is often associated with a better camera. But this isn’t always the case — especially when it comes to drone mapping. While having a decent amount of megapixels is important (we recommend 12.3 MP or higher), it’s only one piece of the puzzle. You’ll also want to consider the size of the camera sensor, which can make a big difference in the outcome of your photos. And ultimately your drone maps and 3D models.
Sensors: Bigger is Better
When it comes to choosing a mapping camera for your drone, pick the one with a larger sensor size. Choosing a larger sensor (e.g. 1” CMOS sensor) will result in a higher quality map when processing images on the DroneDeploy platform.
You Don’t Have to Spend a Fortune
If you’re new to the world of drone mapping, it’s easy to get sticker shock when you see the price of some newer drone models. Have no fear. You don’t need to break the bank to get a good mapping drone or camera. Consider the DJI Phantom 4 Pro, for example. It’s an affordable drone model that packs a punch. Coming in at just $1,500, this bird will allow you to produce beautiful maps and models to meet the needs of many industries such as construction, agriculture, and surveying.
Where to Learn More
If you haven’t already, read part one of this series and learn the factors to consider when choosing a drone model for your business. We break down the pros and cons of both multi-rotor and fixed wing drones.
We spoke about leveraging drones in precision agriculture to assess crop health using both RGB and NIR cameras. Read more about using these cameras to detect variability in your fields by reading our full guide.
Still have questions? Download our 2017 Drone Buyer’s Guide today to get a complete perspective on the factors that are important to choosing the right mapping drone for your business.
Get Started with DroneDeploy
Want to learn how DroneDeploy can help your business? Visit www.dronedeploy.com to start your free trial or request a consultation with one of our team members. The DroneDeploy mobile application is available for free download for both iOS and Android devices.