The iNSIde View

North Star Imaging Blog

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)

Computed Tomography, The Modern Engineer’s Multi-Tool

Derek Watkins

President & Chief Engineer, Nth-Level, LLC

In today’s competitive global market, engineers are faced with the ever growing challenge of balancing the functionality, complexity, reliability, safety, aesthetics and cost of a product’s design while bringing it to market faster than anyone has done before. Digital radiography (DR) and Computed Tomography (CT) give the modern engineer tools like no other. Analysis, reverse engineering, model building and communication all benefit from DR &CT X-ray technology.

Aerospace Suppliers Entering the World of Digital Radiography

Pat Carlson

Applications and Training Specialist - Level III

As aerospace suppliers enter into the world of digital radiography, there may be some obstacles with customer approvals. Receiving customer approvals for production using digital X-ray can be easier when following this recommended path. The scenario of transitioning from film based radiography to a digital radiography system has been recently seen as the chicken or the egg. Which one came first? Since the mid 2000’s suppliers have questioned investing in capital equipment. How can the supplier invest in capital equipment unless an…

Did you think film would be history by 2008?

Seth Taylor

Business Unit Manager

When I first began working at NSI in 1998, I clearly remember one of my first visits to a testing laboratory in Wisconsin. That particular company was interested in converting their X-ray film systems to digital detector technology-based systems. Nearly all of their radiography work involved the inspection of castings for voids and shrink, making the utilization of a digital detector very practical with the opportunity to show a great savings in a short term. At the time, the technology had just been released and I really knew very little about digital technology in general; my father-in-law had just purchased a digital…

Key Variables For Contrast Sensitivity

Wes Wren

Sales Manager

There are a number of variables that contribute to improved contrast sensitivity in a sample:1. FACTOR: SAMPLE THICKNESS- Sample thickness is a vital part in determining what the contrast sensitivity will be. When acquiring two data sets of the same material, and scanning them at the same resolutions, it is clear that the thinner sample shows better contrast sensitivity on a similar void then the thicker sample. 2. FACTOR: MATERIAL DENSITY- Density of material is a key factor in determining whether the contrast…

NSI Technology Used for Composites Analysis

Julien Noel

General Manager – NSI Europe

Composite is a very popular material for many different applications, such as Aerospace, Automotive, and Structural constructions. It is usually lighter, stronger, and in most cases less expensive than traditional material. A good example is the Boeing 787 Dreamliner which is the first passenger airplane to use composite materials as the primary material in the construction of its airframe.The tricky part with composite is the inspection. The structure is so complex – usually Fiber-reinforced polymers, or carbon-fiber reinforced plastic, or glass-reinforced carbon, etc – that it makes it difficult to inspect…

7 Frequently Asked Questions about CT Scanning

Ben Connors

Inspection Services Manager

 1.       Can I scan my part? To answer this we need to ensure we are focused and optimized in the right areas by digging deeper in to the goals of the project.  First, we review the physical size of the sample, because smaller samples and more localized areas of interest will yield higher resolution data sets. Systems can be as small as desktop and as large as a walk in vault, each…

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