A 101 on LiDAR in Reality Capture

If you’re not a seasoned reality capture practitioner, you just might enjoy a brief but jam-packed Reality Capture 101.

You know Albert Einstein, likely for a few reasons:

Maybe E=mc^2 and the theory of relativity.

Or, crazy hair that looks like he tested a new theory of electromagnetism…on himself.

Maybe his Nobel Prize, his pacifism, or his immigration to the United States after escaping Nazi Germany?

What most people don’t know is that in the early 1900s, an idea of our beloved bed-headed physicist would later give birth to one of the most valuable inventions of the 20th century – the laser. That’s right, Einstein is the origin story behind you checking out at the grocery store via barcode scanner, neverending fun with your cat, CDs & DVDs, and a cop being able to ask if you knew how fast you were going – because she sure as heck did.
Cat playing with a laser pointer
Albert Einstein, letting cats down since the 1900s. Image credit Katzenworld.
The laser would be parlayed into LiDAR (Light Detection and Ranging) & laser scanning, and dozens of industries worldwide would be practically born anew; such a radical way to capture and analyze our world had barely been envisioned, much less manifested.

Why is it so radical? Why is it so favored in reality capture? In this 30,000-foot view, we’ll serve up all that, plus how LiDAR works, relevant terminology & whether LiDAR is interchangeable with “laser scanning”, how it compares to other forms of reality capture, advice for implementation, and some fun future predictions. Saddle up!

How Does LiDAR Work?

Lasers capture millions of data points to determine the shape, size, distance, and surface characteristics of objects or environments. Emitted laser beams bounce off surfaces and return to the scanner. The time it takes for that to happen informs the distance to each point on the object’s surface.

Best practices typically entail getting multiple scans from different positions and angles, so as to comprehensively capture the object or environment.

Types of LiDAR, Terminology, and Laser Scanning

LiDAR is often used interchangeably – sometimes mistakenly – with the term “laser scanning” depending on the specific goals and context of the job.

LiDAR is the tech withina laser scanner, and that tech has myriad applications. For example, a LiDAR system mounted to a grounded vehicle would be called mobile LiDAR; LiDAR on flying vehicles goes by aerial LiDAR.
Aerial photogrammetry and drone-based LiDAR for surveying missions
Hello aerial LiDAR, courtesy of a UAV (unmanned aerial vehicle). Image credit OnyxScan.
LiDAR on a stationary setup – think tripod – is typically referred to as a terrestrial scanner.

In most conversations, terrestrial scanner = laser scanner. When you hear “laser scanner”, think stationary, or easy to walk with (as in, a terrestrial scanner on a tripod can still be moved from one side of the factory floor to the other, but when operating, it ain’t going anywhere.)

Regarding ease while walking, you’ll commonly hear “mobile scanner” in conversation. Note the “scanner” part, not “LiDAR” as mentioned just before the photo above. For Mobile LiDAR, think grounded vehicles. For mobile scanning, think backpack or on foot.

The video below is a terrific example of this subtle disparity, as you will see the LiDAR functionality in a laser scanner within a short, informative clip.

Completing Reality Capture: Point Clouds, 3D, and Scan-to-BIM

Once the LiDAR data has been collected, its millions of measurement points collectively form a point cloud. This digital representation is when the project play can really begin, as you’re able to visualize, measure, map, classify, and design.

And that’s before conversion to a 3D model, which can be used in an even wider array of applications.
Point cloud of city buildings
Point clouds; a golden ticket to the imminent wave of “smart cities.” Image credit nFrames.
3D modeling involves taking those millions of individual data points captured by the LiDAR sensor and algorithmically connecting them into a cohesive 3D mesh or surface. Note that “Scan-to-BIM” is a mighty common expression in the space, with BIM standing for Building Information Modeling. Soak up the 101 treatment on that and VDC (Virtual Design & Construction) here.

LiDAR vs. Other Types of Reality Capture

Although a medley of reality capture methods exists, as of 2024, three stand tall: LiDAR, photogrammetry, and 360-degree cameras. Let’s dissect the pros and cons of LiDAR as compared to the latter two, to help you crystallize when you should opt for what.

Pros of LiDAR for Reality Capture:

      • Accuracy Right up Einstein’s alley, LiDAR is like a light-based microscope, able to snag supremely accurate 3D point cloud data, often with sub-centimeter precision. This makes LiDAR well-suited for applications requiring detailed, dimensionally-accurate models.
      • Range and Coverage Nothing holds a candle to LiDAR for capturing large scale data; sensors can capture over long ranges, up to hundreds of meters, while maintaining a wide field of view.
Laser scanner line of sight representation
Even when battling blind-spit riddled terrain, the efficiency of LiDAR has no equal. Image credit LiDARUSA.
      • All-Weather Capability Watching someone with a camera look for the right light, can be like watching someone metal detect with a LEGO product. Most LiDAR systems, on the other hand, are practically impervious to the effects of poor lighting and mildly inclement weather.
      • Vegetation Penetration In actually tell you about, or at least hint toward, so much of our world we can’t see. Its uncanny capability to partially penetrate vegetation, provides data on the underlying terrain and objects occluded by foliage. We’re soon going to cover some use cases, but you can’t miss how LiDAR helped uncover an ancient Maya metropolis.
Cons of LiDAR for Reality Capture:

      • Price Tags While the ability of top-shelf sensors can drop jaws, there’s no denying the hardware’s hefty cost potential. You can blow past $10,000 quicker than you can say “scan” – but it’s not required, especially if just starting out!
Google search results for selection of laser scanning available for purchase
The upfront costs can be huge, sure. But the big picture savings are titanic. Image credit Reality Capture Network.
      • Complexity It’s not that photogrammetry & 360-degree cameras are simple, but LiDAR life can be downright difficult and frustrating, particularly early in your learning curve. Preparing and operating a LiDAR system requires technical proficiency and patience, while the data processing and 3D modeling workflows are markedly more intricate.

      • Limited Texture Know those National Geographic photo contests? Yeah…there aren’t LiDAR ones the following month for a reason. LiDAR prioritizes geometric information and often lacks the rich color and texture detail that can be obtained from photographic imagery.

      • Copious Data Volume Depending on the project, LiDAR point clouds can be colossal. This can require specialized software and cutting-edge hardware for processing and managing the data.

Industries and Use Cases for LiDAR Use

This list is by no means exhaustive, nor could it be, as industries are starting or increasing LiDAR adoption with profound regularity. But it is a showcase of prominent LiDAR spaces.

AEC (Architecture, Engineering, Construction) loves LiDAR for its signature accuracy, helping forge highly detailed 3D models of buildings, infrastructure, and construction sites. This enables virtual walkthroughs, progress monitoring, and precise as-built documentation.

Surveying & Mapping trust LiDAR’s expansive range and coverage for large-scale terrain mapping, topographic surveys, and the creation of highly accurate 3D maps.

Transportation’s roads, bridges, railways, and other transportation assets can be modeled for planning, maintenance, and autonomous vehicle applications.

Historic Preservation banks on the precision of LiDAR scanning for the meticulous documentation and digital preservation of culturally significant architecture and archaeological sites.
Students survey the outside of the Newtown Rosenwald School
Preparing to scan a historic 1912 school for African Americans. Image credit Dan Addison University of Virginia Communications .
Public Safety & Emergency Response officials know that their community is better off, when their first responders are better prepared and informed. Cue LiDAR, and its accurate 3D models of buildings, terrain, and hazardous environments to enhance situational awareness and response planning.

Industrial Inspection has seen wild strides thanks to high-res LiDAR scans, aiding inspections and monitoring the condition of critical infrastructure like bridges, dams, and power plants.

Manufacturing wants ease, and LiDAR grants it with advanced quality control, dimensional inspection, and reverse engineering of complex industrial parts and products.

Virtual & Augmented Reality are only as good as one element – immersion. LiDAR-based 3D models and their granular detail are a dynamo for creating immersive, true-to-life VR/AR experiences and simulations.

Advice for LiDAR Use in Reality Capture

For every ounce of power LiDAR possesses, it holds just as many in complexity. Here are some key tips to consider to maximize your workflows, time, and bottom line.

Practice Patience For every professional who saw their output explode thanks to LiDAR, there’s one who forfeited early on due to initial frustration, and consequently swore off the tech for good. If dipping your toes in the water feels daunting, great! Make it a toenail. After that…

Be Methodical in Your LiDAR Choice Not all LiDAR sensors are created equal. Evaluate your specific needs: required range, resolution, accuracy, and portability to select the optimal LiDAR system for your use case.

Develop a Robust Workflow Establish a streamlined process for LiDAR data collection, processing, and 3D model generation. This could involve using specialized software, automation scripts, and quality assurance checkpoints.
workflow for integrating terrestrial laser scanning and GIS techniques for scanning lichen populations
A basic workflow for terrestrial scanning (and GIS) of lichen populations. Image credit ResearchGate.
Over-Plan Data Capture Carefully map out your LiDAR scanning routes and positions to ensure comprehensive coverage while minimizing time and effort. Consider factors like line-of-sight, occlusions, and environmental conditions.

Commit to Thorough Maintenance LiDAR can have car-like prices, and demands car-like maintenance. To maintain optimal data integrity, protect sensitive components from damage and monitor sensor performance over time.

Coach ‘Em Up! Ensure your staff has the necessary skills and knowledge to operate LiDAR equipment, process the data, and create high-quality 3D deliverables. And however patient you were with yourself, double it for your crew.

Relentlessly Document and Organize Meticulous record keeping of your LiDAR projects, including metadata, processing steps, and quality control measures, will streamline future work and ease collaboration.

The Future of LiDAR Within Reality Capture

Einstein himself could not have foreseen what would come of his idea – so we surely can’t see what 2150 looks like.

But we know the road there is oozing growth. As LiDAR’s evolution continues, expect to see it reshape the very way we digitize and interact with the physical world around us.

Just imagine a future where LiDAR sensors are cheaper and ubiquitous – seamlessly integrated into our cars, our devices, our infrastructure. This proliferation of more affordable, high-performance LiDAR will unlock new frontiers for reality capture, allowing us to map our surroundings with accuracy and detail once thought impossible.

But the true magic will happen when we start fusing LiDAR data with other advanced sensing modalities. By blending precise 3D geometry with rich color, texture, and contextual information, we will be able to generate digital twins of the real world that are indistinguishable from reality.
Digital twins of cars
Digital twins, making our world go vroom vroom. Image credit Digital Twin Consortium.
This fusion of technologies will empower a growing number of industries – from construction and infrastructure management to urban planning and environmental monitoring. No longer will we be constrained by the limitations of outdated surveying techniques. Instead, LiDAR-based reality capture will become an essential tool for understanding and interacting with our world in the most novel of ways.

Heck, there could even be a Nobel Prize claimed in the field!

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