aerial image of a lake to highlight the comparison between 3d scanning vs. photogrammetry

3D Scanning vs. Photogrammetry

Paul Tice3D Laser Scanning Leave a Comment

In today’s rapidly evolving AEC industry, technological advancements continue to redefine how we approach design, documentation, and project management.

Two powerful tools that have gained significant traction are 3D scanning and photogrammetry. These cutting-edge techniques have revolutionized the way we capture real-world data and create precise digital representations.

3D laser scanning and photogrammetry share the common goal of transforming physical reality into accurate digital models. However, they employ different approaches to achieve this goal.

What’s the difference between 3D scanning vs. photogrammetry? There are a few key differences, from the basic principles behind each method and their respective strengths and limitations. Know these things, and you’ll be able to make informed decisions about integrating these technologies into your projects.

If you’re in AEC and you want to know if you should choose 3D scanning or photogrammetry for your next project, you’re in the right place. Read on to explore how they work, the applications, and how you can apply this information in the field.

Why Use Either 3D Scanning or Photogrammetry?

Both 3D laser scanning and photogrammetry bring a myriad of benefits to the table, and let’s just say they’re the superheroes of data capture.

First up, we have their unmatched accuracy, which is simply mind-blowing. These technologies have the power to capture the tiniest details with precision, making sure every nook and cranny of the subject is faithfully represented.

Imagine having the ability to create architectural plans, preserve historical artifacts, or reconstruct accident scenes with sharp accuracy. That’s the level of precision we’re talking about.

These techniques aren’t just accurate, they’re also lightning-fast. You can collect a ton of useful data in a short amount of time compared to traditional methods of data capture.

The length of time it takes to capture an entire project depends on the complexity of the project. Rest assured, you can trust that the turnaround time is pretty fast.

Think about it, what used to take days or even weeks using traditional methods, can now be done in a fraction of the time. This speed is a total game-changer, allowing professionals to streamline their workflows and deliver results with superhero-like efficiency.

And here’s the cherry on top: non-invasive data collection. Say goodbye to the days of poking, prodding, invading personal space, or disrupting delicate structures. With 3D laser scanning and photogrammetry, objects, and spaces can be captured without causing any harm or making alterations.

This is especially valuable when dealing with delicate or sensitive subjects like ancient artifacts or fragile natural environments. These technologies respect the sanctity of what they capture, leaving no trace and keeping everything intact.

So, whether you’re in the realm of architecture, archaeology, or forensic investigation, 3D laser scanning, and photogrammetry have your back. They deliver jaw-dropping accuracy, speed up your workflow, and do it all while being as gentle as a warm summer breeze.

Photogrammetry and 3D Laser Scanning: How Do They Compare?

Photogrammetry and 3D laser scanning are like the dynamic duo of 3D modeling, but they each have their own unique superpowers. Let’s uncover their secrets, shall we?

First up, we have 3D laser scanning, the laser-wielding hero. Armed with a laser scanner, it shoots out laser beams and measures the time it takes for them to bounce back from objects or scenes. This laser-driven approach captures millions of data points, resulting in a precise 3D representation.

It’s the go-to choice for capturing intricate details with surgical precision. This makes it perfect for architectural and engineering projects and topographic surveys. Laser scanning can even venture into the nooks and crannies of hidden or hard-to-reach areas, ensuring nothing escapes its comprehensive documentation.

On the other side, we have photogrammetry, the versatile chameleon. It takes a different approach, using multiple photographs taken from various angles. Through the magic of specialized software, these photos are stitched together to create a 3D model.

What makes photogrammetry a favorite among the cost-conscious is its simplicity and accessibility. You can use everyday cameras, even your mobile phone, and software like the Matterport app to capture images and create 3D tours. It’s perfect for real estate, property management, and construction progress photos.

But every hero has its kryptonite. 3D laser scanning can be a bit time-consuming – even if it is considerably faster than ever before – and pricey due to the specialized equipment and expertise required. Plus, it may struggle with capturing detailed textures and colors accurately.

Photogrammetry, on the other hand, is a stickler for good lighting and still subjects. Poor lighting conditions, moving targets, or reflective surfaces can throw off its accuracy.

How Does 3D Laser Scanning Work?

How does 3D laser scanning work? We’ve got three main principles to explore: laser triangulation, phase-shift, and time-of-flight scanning.

Laser triangulation involves shooting a laser beam at an object and capturing its reflection with a camera. You can determine the distance and shape of the surface by analyzing the angles and positions of the laser beam. It’s like playing laser tag but with highly accurate measurements.

Time-of-flight scanning measures the time it takes for a laser beam to travel to an object and bounce back. This method is especially handy for larger projects and outdoor scenes, where we need to cover more ground.

Phase-shift laser scanning is like time-of-flight but goes a step further by also measuring the phase, or the position, of the laser waves (think amplitude or sinusoidal waves) when they return. This additional information allows for more precise measurements and helps create highly detailed 3D models of the scanned objects. The range of phase-shift scanners is less than time-of-flight scanners however.

Now that we’ve covered the principles, let’s talk about the different types of 3D laser scanners out there, starting with line scanners. These scanners project a laser line onto the object and capture its shape. They’re fantastic at capturing intricate details, making them the superheroes of manufacturing and quality control.

Next is the area scanner, also known as the 3D laser camera, or just 3D laser scanner, as the industry calls it. These devices emit a laser grid or pattern onto the object and use their camera superpowers to capture the reflected light. By analyzing the laser grid’s moves, they reconstruct the 3D shape of the object. They’re like the magicians of the scanning world, making architectural wonders, forensic puzzles, and archaeological treasures come to life.

So, whether you’re aiming for precision or exploring the vastness of landscapes, 3D laser scanning has got you covered. It’s like a high-tech adventure, where lasers and cameras team up to create mind-blowing 3D models.

How Does Photogrammetry Work?

Photogrammetry is like a magical art that turns ordinary photographs into incredible 3D models. Let’s take a look at how it works.

It all starts with stereo vision, which is a fancy way of saying that our eyes perceive depth by comparing the views from our left and right peepers.

Similarly, photogrammetry relies on multiple photographs taken from different angles. Specialized software analyzes these photos and finds common features. Then it calculates the distances and positions, transforming them into a detailed 3D representation. It’s like taking a bunch of puzzle pieces and assembling them into a virtual space.

This process of analyzing features, calculating camera positions, and estimating the 3D position of objects for the eventual 3D reconstruction of the object is called Structure-from-Motion (SfM). This is another important concept to learn in photogrammetry.

Now, let’s talk about software. There are various options out there, catering to beginners and seasoned pros alike.

For those just starting their photogrammetry adventure, user-friendly tools like Pix4D and Agisoft Metashape are like trusty sidekicks, guiding you through the process with their automated features.

But if you’re a seasoned pro seeking full control and precision, CapturingReality, ContextCapture, and 3DF Zephyr are your go-to superheroes. They may have a steeper learning curve, but their advanced capabilities are worth the effort.

To unleash the true power of photogrammetry, you need to follow some best practices.  If you want to capture the highest quality images, be sure to use high-resolution images, find the perfect lighting (usually flat, polarized, or diffused light), and ensure proper overlap between shots.

Other best practices are to calibrate your camera, use precise camera positions or ground control points, and continuously refine your process. It takes a while to master the process, so be patient with yourself.

Once you understand the principles of stereo vision and Structure-from-Motion, explore different software options, and follow best practices, you’ll become a photogrammetry pro in no time.

Choosing Between 3D Laser Scanning and Photogrammetry

You might have the task of choosing between these two reality capture technologies for your next project. The answer does depend completely on the scope of the project and what you need to do with the data collected. Here are a few things to consider as you weigh your options.

Speed vs. Precision: A Race Against Time

When time is of the essence, 3D laser scanning zooms ahead, capturing millions of data points in record time. Its lightning-fast data collection, especially with mobile laser scanners, makes it ideal for efficiently scanning complex scenes or objects. However, keep in mind that processing the laser scan data can take a bit longer.

On the other hand, photogrammetry takes a more leisurely approach. It strolls along, meticulously analyzing a series of photographs to reconstruct the 3D world. While it may require more time for image acquisition and processing, sometimes requiring thousands of overlapping photos for larger projects, recent advancements have made it faster and more accurate than ever.

Accuracy and Detail: Precision Strikes

If your project demands unwavering accuracy and detailed geometry, 3D laser scanning is the worthy champion.

Laser scanning excels in architectural documentation, engineering analysis, and archaeological adventures. However, bear in mind that laser scanning may require specialized training and equipment to unleash its full potential.

Cost-Effectiveness and Creativity: The Budget Hero

Looking for a visually captivating experience without breaking the bank? Enter photogrammetry, the cost-effective option with a flair for creativity.

Whether you use your phone or a high-end digital camera, you can capture a series of photographs from different angles. Photogrammetry shines in virtual tours, realistic visualizations, and exploring cultural heritage sites from the comfort of your desk.

3D Scanning vs. Photogrammetry: Embrace the Power of Choice

In the dynamic world of AEC, you have the remarkable opportunity to harness the power of choice between two extraordinary technologies: 3D scanning vs. photogrammetry.

Choosing between 3D laser scanning and photogrammetry ultimately comes down to your project’s needs, your budget, and the availability and expertise of your team.

You can always turn to the expertise of ToPa 3D to handle data capture for you, whether you need 3D laser scanning or photogrammetry. Contact us today to find out more.

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