What Size And Type Of Objects Can You Scan?

We can scan anything from a tooth to trains, lorries, planes, buildings and a lot of items in between. For instance:

  • Castings are often scanned for dimensional verification or reverse engineering (creating data from a physical object).
  • Vehicles are scanned for the design and manufacture of body styling kits where companies need to understand the shape of the car ‘as is’ to be able to create the new parts.
  • Electronic equipment is scanned to add new parts to the device or retrofit.
  • Body panels for re-manufacture.
  • Humans are scanned for medical reasons and to create maquettes.
  • Film props to bring into CGI.
  • Virtual and Augmented reality.
  • Clay models of items to bring them into a 3D world for tooling or scaling up and down perhaps for 3D printing.

Is A Hand Held Scanner As Accurate As A Static Camera System?

Generally speaking, fixed or tripod mounted scanners have the advantage when it comes to accuracy as everything is static in most cases. Static cameras generally provide higher levels of repeatability and measurement uncertainty.

That said, some of the more recent hand-held scanners on the market use markers and calibration artifacts to overcome some of these issue.

3D Quote System

What Is ‘Resolution’?

Resolution is the sharpness of the detail that you can capture. If you have a part with very fine detail, you need to use a higher resolution camera with a small measuring volume.

If you use say a 12 mega pixel camera with a 1 metre measuring volume, the resolution will be considerably lower than using a 12 mega pixel camera with a 100mm measuring volume. This is because the ‘point to point’ resolution is much lower and consequently, the data is sharper.

‘Point to point’ resolution is defined by a grid of points that is created by the camera when an image is taken – this is controlled by the optics within the scanner.

Is It Best To Scan Everything At A High Resolution?

No. If you scan at a resolution that is much higher than needed i.e the part is fairly smooth with not much detail, the result will be a very large dataset which, then needs more post processing and computing power further downstream.

What Happens If I Scan At Too Low A Resolution?

Too low and you can miss key features that you are trying to capture. The trick is to use a resolution and measuring volume that allows for the detail to be captured with the largest volume to maximise the scanning efficiency.

Does The Level Of Detail Captured Vary Between A Hand Held Scanner And A Fixed Scanner?

‘Detail’ is impacted by the ‘resolution’ of the scanner. Generally speaking, high-end static scanners have higher resolution cameras. Hence the ‘point-to-point’ spacing is smaller, giving higher level of detail capture.

Why Use Hand Held Scanners Rather Than Fixed Scanners?

Hand held scanners are very portabl. Therefore, if you need to work in confined areas or where access is limited, they are ideal. Additionally, the set up time is very quick and moving equipment from location to location very easy.

Can A Hand Held Scanner Be Mounted Onto A Tripod To Make It Static?

Yes. Most scanners have a standard tripod mounting in them allowing them to be fixed to a tripod or robot etc. This is very useful when measuring repeat parts where, having the scanner still can be beneficial dependent on the geometry. You do have to be careful as one of the major advantages of a hand-held scanner are the ability to measure difficult areas. So, using a tripod can limit this benefit and therefore, is not a good approach for all parts.

Some Scanners Use Markers And Some Don’t – Why?

Most high-end metrology scanners use markers. The markers are recognised by the scanner algorithm. By accurately measuring the mid-point of each marker, the scanner patches can be located accurately.

A lot of scanner software uses very complex algorithms that analyse the scan data. It can very accurately position patches by free matching the data during scanning. This has the advantage of not requiring the time of adding/removing markers/cost of markers. But, the trade off can be accuracy if scanning for very high accuracy applications.

Do We Need To Always Spray Items White For Scanning?

Absolutely not! If a part is highly reflective/gloss black for example, there is too much reflection and the cameras cannot see the surface being measured. This would be similar to taking a photo of a shiny surface in the sun – you get over exposed data. In these instances, a scanning spray is very beneficial.

Historically, these scanning sprays needed to be removed and it was very difficult to do so from certain surfaces. Such as, car interiors, stitching and textured surfaces. In the last couple of years, scanning sprays that disappear after scanning have been introduced.

These allow the scan data to be vastly improved. In addition, there is no need for cleaning as they completely evaporate after use. Consequently, this makes the scanning process much cleaner which has benefits for the equipment and the environment around the equipment. In some cases (AESUB), they do not contain Titanium Oxide which has health benefits for the technician as well.
If a surface is matt or a light colour, in most instances, scanning spray is not required.

What Is Photogrammetry?

Using markers also enables the use of photogrammetry, which people use for measuring large parts and/or measuring parts where accuracy is paramount. The photogrammetry is a process that allows a series of images to be captured by the scanning device or a 3rd party camera with calibrated scaling information being introduced. This allows the images to be very accurately positioned.

The scaling information (scale bars) are normally factory calibrated to certify the accuracy. The can usually be re-certified on an annual basis or to fit in with your internal quality system requirements.

Why Are Some Scanners Hundreds Of Pounds And Other’s Tens Of Thousands Of Pounds?

There is a huge amount of research and development that goes into developing 3D scanning equipment. The cheaper scanners on the market do not tend to have traceable certification. The more expensive, industrial grade 3D scanners are usually fully certified with traceable certification. This is usually a pre-requisite in many industries. For instance, aerospace, automotive, nuclear, consumer electronics to name a few.

The optics within the more expensive scanners are normally much higher quality to ensure accuracy. Repeatability is a key requirement for a lot of scanning applications and hardware. Additionally, this is far better with the more industrial and more expensive scanners. As well as, the measurement uncertainty which essentially provides verified number. Therefore, giving confidence in the scanners’ ability to measure an object repeatably within known parameters of uncertainty.