The iNSIde View | North Star Imaging

The iNSIde View

North Star Imaging Blog


Optimizing Defect Detectability

Nate DeRoo

Inspection Services Lab Technician

Setting up a computed tomography scan can be a complicated task when trying to optimize defect detectability. There are many parameters that can be adjusted, and many of them have a direct or inverse relationship with other parameters for your scan. Optimizing these parameters can frequently be a process of trial and error, but if you consider the following you can help reduce some of the time spent optimizing your technique. The first thing to consider is the size of the defects and or features that you would like to image. This will have a very large impact on the technique that you use. Ideally you will…

Industrial Micro-Computed Tomography Uncovering History

Aymeric Beau

Inspection Services Lab Manager

Industrial Micro-Computed Tomography for archaeologists, arts experts, museums and more.  A very powerful and non-destructive technique to examine the inside of an object in 3 dimensions.The increase in capabilities of CT has led to industrial CT scanners being used more often and in more ways than ever before.Within the different worldwide NSI Inspection Service labs, we have seen a tremendous growth of CT scanning requests coming from various industries…

Computed Tomography Inspection of Additive Manufactured Components

Pat Carlson

Applications and Training Specialist - Level III

Rapidly expanding into production manufacturing, additive manufacturing (AM) has gained incredible interest in all industry facets. From aerospace applications to simple one off consumer home builds, this technology has immense versatility and use. In additive manufacturing, objects are built by adding layer upon layer of material. With all of these materials in use and knowing that many of these components will be created for critical end use applications in aerospace, medical, or automotive industries to name a few. The challenge becomes; how does the manufacturer inspect these products to ensure safety and…

Taking 3D X-ray Inspection to a New Dimension - 4D CT

Matt Zachman

Inspection Services Lab Technician

You may be wondering what 4D Computed Tomography (CT) is and how does it differ from 3D CT? With 3D CT you will generate a 3D volume of your sample that you are able to rotate, slice through it and adjust your histogram. 4D CT will give you the same benefits as 3D CT, but with the added bonus of motion and time. Sample motion can be captured by either two different scanning techniques, static or dynamic.Static 4D CTStatic 4D CT is the method of creating 4D CT by acquiring multiple CT scans. This is a lot like stop motion animation where a scene is captured and then slight movements…

Advantages of Using Advanced Scanning Styles (Vortex, Subpix, and Mosaix)

Anthony Talberg

Technical Trainer

Standard cone beam scanning is sufficient for many applications, but what about the applications where you cannot fit the part in a single detectors view? Physical size of a sample can be a limitation when trying to achieve a given resolution, or you may be dealing with artifact issues. All of these limitations are the reason that NSI has developed advanced scanning styles to overcome issues you may run into when a challenging application comes in.Vortex scanning is a commonly used scanning style by our NSI experts when a sample is very tall in one direction, such as a baseball bat. When looking for measurement…

New Guy to NDT

Ross Johnson

Sales Representative

My name is Ross Johnson and I am the “New Guy” to NDT. Now when I say “new” I mean BRAND NEW. After college I started a woodworking business and for a few years I built everything and anything from skateboards to banjo necks. I had jobs in machine shops running Bridgeport’s and lathes and then I moved into Product Development. My time in Quality Control was always limited to comparators, CMM and gages. And because there were never any requirements for non-destructive testing in our industry, I never learned about the different types of NDT. My first experience with X-ray was the X-ray I had of my broken pinky…


Guy Tolley & Sheng Yue

UK Sales and Inspection Services

X-ray micro computed tomography (micro-CT) is a powerful tool for material characterization as it can non-destructively and non-invasively image the internal structure of an object. This enables the wide range of characterization and inspection applications in the areas of biomedical, aerospace, automotive, and many more.With the recent development of novel reconstruction algorithms, we can not only image the object in 3D but also record how its structure is varying over a period (i.e. 4D imaging, as a software add-on offered by NSI).In a typical computed tomography (CT) set-up, a micro-CT image is generated…

Should I scan my whole sample or just a local area?

Shaun Coughlin

Inspection Services Lab Technician

Before choosing an area to scan on your sample you must first have an idea of what you are looking for, because you will need enough resolution to see the area you are interested in. If you have a sample with a 40 micrometer defect, you’ll want to have multiple pixels to represent that defect. Often times the defect size in the sample is not known, but an estimate based on your sample knowledge is very helpful in this process. If your full sample size is 2 inches by 2 inches and you are using a 127 micrometer pixel pitch panel, you can expect to achieve around 7.5X magnification, giving you an estimated…

How many projections do I need for my CT Scan?

Nate DeRoo

Inspection Services Lab Technician

When determining the number of projections you need for your CT scan you must first know some information about the sample that you are scanning. Samples with complex geometry will require more projections than samples with simple geometry. The reason for this is that if the sample has a flat surface we must get a projection during the CT scan that lines up with that flat surface in order for us to get a reconstruction that shows that surface as flat. If you do not get a projection that shows the flat surface in the scan, you will see that surface as bowed or curved slightly in the reconstruction. If the sample that…

Optimizing Image Signal to Noise Ratio Using Frame Averaging

Brett Muehlhauser

R&D Technical Fellow - ASNT Level III

When performing Digital Radiography and Computed Tomography, a common issue all of us deal with is the balancing of exposure time and signal to noise ratio (SNR). SNR simply compares the level of the desired signal to the level of the undesirable background noise within an image. SNR is therefore the result of dividing the average (mean) signal by the variation (standard deviation)