Industry
Modern technologies provide various solutions to the industry. In addition to transforming the way manufacturing processes occur, they also provide new routes and paths of execution. Aerial photogrammetry is one of them. But what is aerial photogrammetry? Before understanding this concept, it is important to know more about aerial photography, which is the basis of the idea. One of the key points in this is the use of unmanned aerial vehicles ( UAVs ). Or, as we know them today, the famous drones, which can be operated remotely. Drones or UAVs are becoming increasingly accessible and popular to both individuals and organizations. Currently, they serve several purposes; here, we will focus on the ability of drones to capture images while flying over a certain location, and how this contributes to the industry. Remote operation, in fact, is the root of both these processes. In this article, we will further explore both concepts. READ ALSO: • What is process optimization?
• What is artificial vision?
• What is digital image processing?
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What is aerial photography?
Aerial photogrammetry is a technique that uses aerial photographs to measure and map the shapes, dimensions, and positions of objects in space. This practice relies on carefully calibrated cameras, which can be installed on different platforms such as airplanes, drones, and even satellites. From these images, precise information can be obtained, allowing for the creation of maps and three-dimensional models that reflect the reality of the terrain. Historically, aerial photogrammetry began to gain prominence in the 19th century, with the first aerial photographs taken by pioneers like Gaspard-Félix Tournachon in 1858. Since then, technological evolution has allowed this technique to become increasingly accessible and precise, especially with the advent of drones, which revolutionized aerial data collection. The applications of aerial photogrammetry are vast and include areas such as surveying, civil construction, precision agriculture, archaeology, and environmental monitoring. It provides an efficient way to capture large volumes of data quickly and cost-effectively, enabling assertive diagnoses and improvements in planning and execution processes. Additionally, aerial photogrammetry generates products such as orthophotomaps - georeferenced images that offer precise information about an area of interest. This combination of reduced costs, data collection efficiency, and detailed analytical capability makes aerial photogrammetry an essential tool for professionals in various disciplines. Aerial images are one of the most common forms of remote sensing, which is the measurement of the characteristics of a certain place from a distance. Photographic images are a great way to provide data and applications within different types of industries. However, they are not as precise, which is why they have a limit that makes it necessary to integrate them into a photogrammetry model.
Types of aerial photogrammetry
Aerial photogrammetry can be classified into different types, depending on the methods used and specific applications. This categorization allows for the selection of the most appropriate approach to meet the needs of the project in question. Aerial Photogrammetry: This is the most common type and involves capturing aerial images from platforms such as airplanes and drones. Photos are taken at specific angles to ensure every area of the ground is covered, enabling three-dimensional modeling and precise measurement of objects and terrain. Terrestrial Photogrammetry: Unlike aerial, this approach is conducted from the ground. Cameras mounted on tripods or mobile equipment capture images of specific objects or terrain. It is especially useful in areas where aerial access is limited or where close-up detail is required. Digital Photogrammetry: With the evolution of technology, digital photogrammetry has gained prominence, utilizing specialized software to process and analyze collected data. This technique allows for the extraction of measurements and the construction of 3D models with high precision from digital images. Analog Photogrammetry: Although less common today, analog photogrammetry was the traditional method, which used film to capture aerial images. Despite being an older approach, it is still used in some historical or specific contexts. Space Photogrammetry: This type involves capturing images from satellites or other space platforms, allowing for the efficient and comprehensive analysis of large geographical areas. These different types of aerial photogrammetry enable a wide range of applications, providing valuable information for areas such as cartography, environmental monitoring, and urban development. In addition to these, there are two broad categories in aerial photogrammetry: metric photogrammetry and interpretive photogrammetry.
Differences between metric and interpretative photogrammetry
Metric photogrammetry uses coordinate points on features to visualize an object with almost completely exact measurements. Interpretative photogrammetry, on the other hand, takes a photo and adds topography using indicators such as shapes, shadows, and patterns in the image, instead of coordinates. While metric photogrammetry is more precise, interpretative photogrammetry can be sufficient to achieve results in various situations. In both cases, computer software is used to combine images and create a 3D model with precision.
Drones surpass “traditional aerial photogrammetry”
Photogrammetry is a process that involves capturing multiple images of an object, using trigonometry to create high-resolution 2D or 3D digitized models, from which precise measurements can be deduced. Depending on the scale of the project, a model made with photogrammetry can require from a few hundred to up to thousands of separate images. These models are topographic in nature, meaning they represent the physical dimensions and characteristics of the area with impressive accuracy. Furthermore, these models can be rotated or zoomed in on. Since they are created entirely through images captured by a UAV, they display every photographic detail present in those photos. Before aerial photogrammetry, land surveying was done using equipment such as magnetic compasses, drafting tables, barometers, and measuring tapes, among other more modern tools like the theodolite, total station, and more recently with the use of GPS to determine topography. Today, photogrammetry can be conducted with a mix of different devices, such as drones, airplanes, and helicopters. Thanks to technological advancements and price reductions, drones have become the primary equipment for image production.
Applications of aerial photogrammetry
Aerial photogrammetry is a versatile tool that finds diverse applications in various fields, benefiting professionals and institutions in their activities. One of the most traditional applications is in the creation of detailed topographic maps. Aerial images allow for the collection of precise data on relief, vegetation, and infrastructure, facilitating the creation of updated maps. In the field of precision agriculture, farmers use aerial photogrammetry to monitor crop health, optimize the use of inputs, and improve soil management. Through images captured by drones, it is possible to identify areas with specific needs, promoting more sustainable and efficient agricultural practices. Another important use is in urban planning. Aerial photogrammetry provides crucial information for the development and management of cities, being used in the planning of new infrastructure, land use analysis, and environmental impact assessment, which helps in making informed decisions. Furthermore, the technique is fundamental for environmental monitoring, allowing for the tracking of changes in the environment, such as deforestation, erosion, and contamination of water resources. With the regular capture of aerial images, it is possible to observe trends and changes over time, contributing to conservation. In archaeology, aerial photogrammetry assists in the identification of sites and structures hidden under vegetation, helping researchers to map and preserve cultural heritage effectively. Lastly, in the construction industry, it is widely used for monitoring works, tracking progress, and verifying compliance with projects, ensuring correct execution and within the stipulated deadlines. These applications demonstrate the importance of aerial photogrammetry as an effective tool for spatial data collection and analysis across multiple sectors, contributing to sustainable development and efficient resource management.
Image production in action
In photogrammetry, the use of some software will be necessary. Here, we will exemplify how the process could occur. Let's start with a drone camera taking a photo. In this photo, what we actually see are several points of light, which coexist to form the image that our eyes detect. Each point of light is created by a ray that extends from the object being photographed to the camera, through the lens, and then to the surface of the image (the film or chip). When photogrammetry software begins to create models of the images, it also needs information such as the position and angles of the camera, as well as the focal length, pixel size, and lens distortion. When using a drone to take aerial photos for photogrammetry purposes, it is important to obtain several images of the same region. This is because the software may need to calculate the positions of objects in the photographs by comparing them with the positions in other photographs. Finding the same 3D point in multiple images is a process of point matching; in turn, triangulation uses multiple photographs to process these points in 3D space. This matching can be done manually or automatically.
Conclusion
Using aerial photogrammetry can save time and money when compared to traditional surveying methods. This means that mapping drones are a good investment, both for land surveyors and the people who hire these professionals. In addition to the drone, the use of software capable of performing photogrammetry is essential to obtain the benefits of this process, being yet another way that technology has contributed to modern industry. Therefore, Pix Force is able to provide technologies for the production and interpretation of images with different types of capture, including aerial photogrammetry. Do you want to know our work? Get in touch with us!
Fabio Caraça
Fábio Caraça is the Chief Growth Officer at Pix Force. He leads Pix Force's transformation into a scalable SaaS operation, combining strategic vision, culture, and high-impact execution.
