[New Video] What is Metrology?

07 June 2023 · 4 min read

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What do you think of when you hear the word Metrology?

If you pictured industrial environments with lasers being used to measure precise dimensions, you wouldn’t be wrong. But the scope of Metrology is actually much wider than the narrow, manufacturing-based definition we tend to apply to it. Metrology is very simply, the science of measurement. And we took a deeper look at what that means and the wide-ranging effects it has on our daily lives. Watch below or click here to learn more: https://bit.ly/39uO7gY

Read the Full Video Transcript Below

What if you lived in a world where you couldn’t measure anything? How would you know when to wake up? How would you build something, whether it’s a treehouse in your backyard or an airplane in a factory? How would you know if you’re about to run out of gas? Some measurements we do without thinking because we do them all the time, while others must be taken carefully and precisely. But how do we know how to measure those things to begin with? That’s metrology. And what would a world without metrology actually look like? Let’s take a look.

The word Metrology is usually associated with a high-level field of study that applies to the production and assembly of some of the most delicate and important manufacturing projects. But Metrology is actually a very simple concept (although some might say deceptively so). In fact, we all use some of the fundamentals of Metrology in our daily lives. So, what is Metrology? What are its basic principles, and how do we use it every day?

Put simply, Metrology is the science of measurement. And while high-end modern metrology is used to push the accuracies and definitions of its equipment below the limit of visibility to meet tolerance demands, even the simplest measurement tool in your home is a piece of metrology equipment if it has the three basic components of metrology: unit, measurement, and comparison.

The most fundamental piece of Metrology is the unit. In order to measure something, you must have a way to express how much of the substance there is. Laser Trackers would be useless if the definition of a millimeter changed from one day to the next. For mass, we use the Metric and Imperial systems. For time, we use seconds, minutes, hours, days, and years. For electric current, we use amps and volts. Each one of these units gives us the ability to break a measured substance into evenly sized pieces that we can evaluate.

The second part of Metrology is the ability to measure these units in a real setting. The definition of a micron is wonderful, but impractical unless we have devices that can capture a distance that small. Whether they are Laser Trackers inspecting airplane wings or temperature gauges on a superconductor, metrology equipment must be able to accurately differentiate between the smallest units it is called to measure.

Lastly, Metrology equipment must be able to apply the measured amount to some kind of reference standard. Often, this relates directly back to the unit of measurement, like a Laser Tracker showing the absolute distance of measured X, Y, and Z values, but this can also be when the tracker shows that value in reference to the CAD model and indicates the +/- difference between the two values. Reference standards can also be used to calibrate Metrology equipment and make sure they are maintaining accuracy.

But these are the kinds of high-level examples of Metrology that so often make it seem like an inaccessible field. I told you that we all use these elements of metrology in our daily lives. And if you look, you start to see the three fundamentals of Metrology everywhere. Take for instance, a measuring cup.

It may look simple, but this is one of the purest distillations of metrology equipment you can find. Using the units ounces, cups, and milliliters, it measures the amount of a substance poured into it with direct visual reference lines showing if the cup has too much, too little, or just the right amount inside. And because measuring cups are machined to exact dimensions, their reference points are unchanging and never need to be calibrated.

Tools like these are everywhere in our lives, from the thermostats in our houses to the battery indicators on laptops and tablets to the bar showing how much time is left in this video. And we understand the information these tools give us because of Metrology.

See, Metrology didn’t invent measurements. The study of Metrology has only been around since the 18th Century, but humans have needed to measure things for tens of thousands of years. Before Metrology, measurement was a Wild West where Frontier America, Ancient Rome, and Imperial China all created different definitions of how long their miles were.

Metrology is the story of us developing the discipline to define the way we measure things and standardize the units and equipment, so that measurements taken between rooms or continents would all mean the same thing. In other words, Metrology is why this bartender knows the difference between a pint and a shot glass. I’ll just have a water.

When you consider all the ways Metrology impacts our daily lives, it makes you wonder: what would that world without Metrology today look like?

The definitions and standardization created by Metrology has fueled industrial breakthroughs that have allowed for production and assembly of manufacturing projects on scales and intricacies that we could never have dreamed of hundreds of years ago. But they’ve also had a very direct impact on our daily lives. Gas is sold in standard units. We know how many of those units our car’s tank can hold. We know how far we’ve driven since we last filled up, and we have a gauge in the car that says how much gas is left. And all of that information combined means [The car roars past Daniel, apparently full of gas and possibly enveloping him in a cloud of dust] we’re much less likely to run out of gas on the road.

radar vs lidar vs ladar

 – Radar

Radar (Radio Detection and Ranging) emits microwave pulses and measures the time for echoes to return. Because radio waves have long wavelengths, radar devices can detect objects at great distances and through fog, rain or dust. They are widely used in aviation, weather monitoring and speed‑enforcement. Radar systems provide a long range but lower spatial resolution compared with LiDAR . This lower resolution arises from the larger wavelength and beam divergence; as a result radar cannot pinpoint features smaller than several centimetres.

(source:wevolver.com)

 – LiDAR

LiDAR (Light Detection and Ranging) uses pulsed laser light to measure distance. Because it operates at optical wavelengths, LiDAR can produce very high‑resolution 3D point clouds. It is the backbone of autonomous vehicles and aerial mapping. LiDAR systems generally have a shorter to medium range but offer high spatial resolution, enabling detailed 3D mapping

LiDAR’s ability to capture millions of points quickly makes it ideal for applications such as autonomous driving and surveying. For manufacturing metrology, LiDAR is useful for creating digital twins of large objects or structures. However, typical LiDAR accuracy (millimetre to sub‑millimetre) is not sufficient for tight‑tolerance inspections that require micron‑level precision. Therefore, LiDAR still falls short for high‑precision metrology in aerospace and automotive manufacturing.

– Laser Radar

Laser radar is often used to describe high‑precision laser time‑of‑flight systems. It uses a narrow, focused laser beam and measures not only the time of flight but also the angles of the incoming beam to compute precise coordinates. Laser radar systems can achieve micron‑level precision but typically operate over shorter ranges and at slower scanning speeds compared with LiDAR. Laser radar system steers a focused beam, reading the return signal directly from the object without a retroreflector, and is engineered to provide precise, industrial measurements with tolerances of thousandths or even tenths of thousandths of an inch. However, the speed of data collection is sacrificed for resolution—laser radar scans smaller areas more slowly to achieve high accuracy

(source:eastcoastmetrology.com)

– LADAR (Dynamic 9D LADAR by API)

LADAR (Laser Detection And Ranging) is sometimes used interchangeably with LiDAR, but API’s Dynamic 9D LADAR is a novel system that blends interferometry with laser scanning. LADAR is an interferometry‑based non‑contact measurement system that provides fast and accurate data acquisition. It overcomes several limitations of conventional measurement methods by delivering micron‑level resolution and eliminating issues such as limited accuracy, slow data acquisition speeds and sensitivity to surface reflectivity. LADAR technology uses fast data acquisition to deliver rapid, real‑time data collection, significantly reducing measurement and analysis time compared with traditional methods. It also functions effectively in noisy production environments and at various incident angles. The technology delivers rapid, real‑time data collection, making it suitable for in‑line production measurements where conventional laser radar is too slow.

To learn more about how LADAR can preform in line inspection, click here.

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