Which 3D Scanner is right for you? Handheld vs Stationary/Mounted

March 2, 2018

 

 

You’ve heard all the benefits of 3D Scanning and you’re planning on using this technology on your next project. Maybe you’re trying to Reverse Engineer items that no longer have CAD data available. Maybe you’re using it for metrology and quality control in your production environment. Maybe you’re trying to digitize and archive existing items, much like the Smithsonian Museum uses the technology. Whatever you’re looking to do, there’s a 3D Scanner that will work best for you and your project.

 

Unfortunately, as you may have already noticed, you’re faced with an overwhelming number of 3D Scanning choices and technologies. Do I want Laser or White Light? What brand to choose? Do I want a Handheld Scanner or a Mounted Scanner?

 

The latter question what we hope to answer in the following blog post.

 

While there is a wide number of different scanning technologies available, for the purpose of this comparison we will focus on Structured Light Scanners due to their affordability and ease of use.

 

How does each technology work?

 

Tripod-Mounted 3D Scanners

 

 

The aptly-named Tripod Scanners function by mounting both the cameras to capture the data, and 

 

a device to project a pattern on the object that the camera sees (the projector). These two devices are mounted in a fixed location—whether it be a tripod, or a full camera rig--and this gives the scanner a reference point by operating at set distance from the object. 

 

The object to be scanned is placed in front of the camera and projector rig. The projector displays an image (usually a series of lines and patterns), across the object which the camera is programmed to interpret and convert into scan data.

 

As the patterns and lines are projected across the object, the lines will bend and distort. The software knows how to interpret the bent and distorted lines and create a cloud of points.Because the projector and camera distance are fixed, it’s easy for the software to know whereabouts the camera and projector are relative to the object.

 

This is why table top scanners tend to have the advantage when it comes to accuracy. The downside is that you will need a means to move the object around in front of the scan setup, so you are able to scan all sides of the object. You can either move the object manually by picking it up and rotating it, or some scanners offer the use of a Turntable. Once a scan is taken from each side and angle, they are stitched together to form one full solid 3D model.

 

Handheld 3D Scanners

 

The operation of the handheld scanners are very similar to the tripod mounted 3D Scanner, you have structured light patterns being projected onto the object being scanned, and a camera that interprets and captures data points based on how that structured light distorts across the object.

 

However, the one key difference is that the camera and projector aren’t on a set point; rather, they are mounted to handheld device (often with a screen), and the device is hovered around the object to capture it from all of the angles. The scanner often take multiple scans per second and averages the data capture points.

 

These scanners, in most situations tend to be a little easier to operate and maneuver. Which brings us to our first point...

 

 

 

 

Ease of Use

 

Winner: Handheld 3D Scanners

 

Handheld 3D scanning is the obvious choice if you want to pick up a device and start scanning immediately. You can get accurate results, and if you’re using a device such as the Thor3D Drake, you can get a live preview of your scan on the built-in screen as the Drake captures the model.

 

Mounted Scanners can be a bit more tricky to get to hard to reach places and getting to odd angles on the object. While it can do most of what the handheld scanner can do, there’s some scenarios that will be very difficult to capture with a mounted scanners.

 

Alternatively, if accuracy is your primary objective, you will have a much easier time achieving that accuracy with a mounted scanner when compared to a Handheld.

 

 

Accuracy

 

Winner: Mounted 3D Scanners

 

When you’re comparing the same type of technology (in our case, structured light scanning), the mounted option will almost always be more accurate than it’s handheld counterpart. Additionally, if you’re scanning multiple objects quickly, with similar sizes and parameters, the mounted option will be much faster than the handheld.

 

The difference in the scanner’s quality is directly related to the way in which it functions. Mounted 3D scanners take a series of images in one snapshot and consolidates the average to generate one scan. Handheld 3D scanners using structured-light technology take one shot per frame (equivalent to one scan) and then the user moves the scanner to take another scan. It’s similar to comparing a still image taken from a camera versus a frame taken from a video recording. The former will get you better quality than the latter. The scan quality is still great for a handheld 3D scanner, but typically the Mounted 3D scanner provides slightly better results when comparing scanners that are similar in price point.

 

However, it’s important to remember that a majority of applications don’t require the high quality that the Mounted 3D Scanners provide. There are other factors such as portability and ease of use that might be more important to you. But, if you are using it for reverse engineering, 3D visualization, or quality inspection where accuracy is crucial, a Mounted 3D scanner is the perfect place to start.

 

 

Portability

 

Winner: Handheld 3D Scanners

 

Handheld scanners are by definition, portable. This isn’t to say that you can’t transport tripod-mounted scanners easily, but you’ll have to pack it up and set up at your scanning site when you get there, which can add a few extra minutes to the job.

 

Additionally, there's some Handheld scanners that have an on-board computer and battery built-in, making them a truly portable solution you can take anywhere. Mounted scanners, on the other hand, will often require to be tethered to a computer or laptop during scanning. This has the advantage of giving you more computing power during your scan, but makes the process more cumbersome.

 

 

A handheld scanner such as the Thor3D Drake is completely portable. It weighs around two kilos, is hand-held and comes equipped with a built-in touch screen, battery and an on-board computer. This means you can take it on a plane, a train and out to a heritage site in the desert and easily digitize any object away from the office and those often-hard-to-find electrical outlets. The battery life is approximately 1.5 hours (of non-stop scanning) and a complementary carrying bag is included in the price. So you are good to go!

 

 

Automation

 

Winner: Mounted 3D Scanners

 

 

 

If you’re looking to process a lot of similar sized objects quickly, Mounted Scanners are the way to go. Rather than having to move the camera around the object each time you scan an object, you can utilize a turntable that automatically rotates and scans your object at pre-programmed intervals.

 

You place your first object on the Turntable, start scanning, and the turntable automatically rotates the object, takes a scan, and then rotates again for the next scan... and so on. The software then stitches all these scans together automatically and give you your final 3D model. This is the best method to set up a hands-off automated workflow. It’s no surprise that you’ll see those in quality control and metrology environments gravitating towards Mounted 3D Scanners.

 

 

Scanning Envelope

 

Winner: Both… depending on the size of the object

 

Generally, the rule of thumb is that stationary scanners work best for objects less than 24” x 24” x 24”. While scanning larger objects is not impossible, you’re going to run into some issues and the difficulty of capturing and stitching your scans together increases dramatically. Handheld scanners excel at scanning large objects such as cars and motorcycles, larger statues or parts of buildings.

 

We know that Tripod Mounted 3D scanners are more accurate scanning objects under a certain size. They can achieve this accuracy by utilizing an adjustable field of view (FOV). Depending on the object size you’re looking to scan, the scanner’s cameras and lenses can be moved to different mounting positions to optimize settings and environment for the 3D Scan.

 

 

Field of view (FOV) is the observable area that a 3D scanner can capture a 3D scan at a certain distance. The HDI Advance 3D scanner excels in this area by offering many field of view options as well as a macro 3D scanner for tiny objects. Handheld 3D scanners often have a fixed FOV so it is restricted to the object size it can scan while retaining its accuracy. The Drake 3D Scanner, however, has a clever way to address this issue. By giving you the option to purchase 3 different attachable "heads" with different Fields of View. One for small objects (the "mini" head), one for medium-sized objects (the "midi" head), and one for scanning large objects (the "maxi" head). This gives you the option to have an adjustable field of view on a single handheld scanner.

 

Using the HDI Advance 3D scanner as an example, if a drastically smaller field of view is required to scan an object such as small turbine blade, screw, or small insect with high precision accuracy, the scanner is flexible to be converted into a macro scanner. All you need is to use an add-on accessory kit without the need to purchase an entirely new system. If you need to scan objects that vary in a range of sizes, stationary 3D scanners might be the most cost-effective solution for your needs.

 

A standard HDI Advance 3D scanner is transformed into a macro 3D scanner for scanning small parts.

 

 

 

 

Which one should you buy?

 

This guide is just a starting point! Your next step is to book a demonstration or request a FREE assessment of your project or manufacturing environment. Canadian Additive Manufacturing Solutions’ primary mission is to assist those in making the best possible choices for their project. We will point you in the right direction… even if it’s not a product we carry. Additionally, we have partnerships with companies that provide laser and high-end scanning solutions, so we can accomodate most 3D Scanning requests. And you can rest assured that if you decide to purchase equipment that we offer training to get you up-to-speed and scanning like a pro!

 

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