Pyramid Image Quality Indicator
manufacturing
Pyramid Image Quality Indicator (GSC-TOPS-250)
A scalable, inexpensive tool and methodology to ascertain real life computed tomography system performance for a wide range of industrial applications
Overview
Image quality indicators (IQIs) and known defect standards for industrial 2D x-ray radiography have been used in practice for many years. However, universally accepted standards for 3D x-ray, also known as computed tomography (CT), do not currently exist. Customary IQI devices for 2D radiography are typically flat; however, since CT data is inherently volumetric, flat objects offer an unrealistic basis for a standard. Many known CT IQIs are known as disc phantoms and intended for medical inspection purposes or defines resolution based on the modulation transfer function calculated across the exterior edge of a round coupon. While this may be sufficient for an indirect and relative assessment, the image sharpness of the exterior edge may be not representative of interior boundaries and only serves as an indirect measure. These IQIs are also not ideal for capturing actual system performance under real life, application-defined settings. For industrial applications of CT, an IQI should be able to accommodate a much broader range of possible scan settings. The Pyramid Image Quality Indicator is designed specifically for CT data and which can be modified to accommodate a wide range of applications.
The Technology
The Pyramid Image Quality Indicator is based on the shape of a tall, 4-sided pyramid. Each side of the pyramid has a pair of vertical trenches which draw closer to each other and get narrower as they approach the tip of the pyramid. Inside the pyramid is a hollowed out conical section which may contain internal features for determining resolution or inserts that can be used for measuring contrast sensitivity. The system can be economically 3D printed and then coated, if need be, with high x-ray absorbing material. When a CT system operator is scanning a part, a specific method for that part which might include a large number of variables such as x-ray voltage, detector-to-source spacing, pixel size, etc. This established method will result in an effective level of detail for the resulting scan. The IQI is used to measure that level of detail. The operator may follow up the scan of the part with an identical scan of the IQI, which will allow a realistic measurement of parameters, like effective resolution or contrast sensitivity.
The interior of the Pyramid IQI uses a 3D variant suited for 3D CT scan data tools, known as penetrameters. These penetrameters are a solid disc of material. A stack of discs of different diameters would accommodate a range of different thicknesses. The Pyramid IQI can be easily scaled for either larger or smaller parts. It can also be 3D printed using either plastic or metal additive manufacturing. This allows an end-user to match the material density of the IQI to that of the actual part.
Benefits
- Easily scalable for size requirements
- Cost-effective
Applications
- Non-destructive evaluation
- Manufacturing quality control
- Medical x-ray equipment manufacturing
Similar Results
X-Ray Crack Detectability
NASAs software technology uses an Image Quality Indicator (IQI)-based model that can predict whether cracks of a certain size can be detected, as well as a model that can provide appropriate conditions to optimize x-ray crack detection setup. Because this modeling software can predict minimum crack sizes that can be detected by a particular X-ray radiography testing setup, users can test various setups until the desired crack detection capabilities are achieved (predicted) by the modeling system.
These flaw size parameter models use a set of measured inputs, including thickness sensitivity, detector modulation transfer function, detector signal response function, and other setup geometry parameters, to predict the minimum crack sizes detectable by the testing setup and X-ray angle limits for detecting such flaws.
Current X-ray methods provide adequate control for detection of volumetric flaws but do not provide a high probability of detection (POD), and crack detection sensitivity cannot be verified for reliable detection. This results in reduced confidence in terms of crack detection. Given that these cracks, if undetected, can cause catastrophic failure in various systems (e.g., pressure vessels, etc.), verifying that X-ray radiography systems used for NDE can detect such cracks is of the utmost importance in many applications.
X-Ray Diffraction Method to Detect Defects in Cubic Semiconductor (100) Wafers
This technology is a method of using x-ray diffraction (XRD) to evaluate the concentration of crystal structure defects, and thus the quality, of cubic (100)-oriented semiconductor wafers. Developed to enhance NASA's capabilities in fabricating chips for aeronautics applications, the method supplants existing methods that not only destroy the wafer in question, but can take as long as a day to determine the quality of a single wafer. The approach can be used with any commonly used semiconductor, including silicon, SiGe, GaAs and others, in a cubic (100) orientation, which covers at least 90% of commercial wafers. It can also be used to evaluate the quality of epi layers deposited on wafer substrates, and of ingots before they are sliced into wafers.
Digital Beamforming Interferometry
NASA Goddard Space Flight Center (GSFC) has developed a new approach that uses a single phased array antenna and a single pass configuration to generate interferograms, known as Digital Beamforming Interferometry. A digital beamforming radar system allows the implementation of non-conventional radar techniques, known as Digital Beamforming Synthetic Aperture Radar Multi-mode Operation (DBSAR).
DBSAR is an L-Band airborne radar that combines advanced radar technology with the ability to implement multimode remote sensing techniques, including several variations of SAR, scatterometry over multiple beams, and an altimeter mode. The Multiple channel data acquired with a digital beamformer systems allows the synthesis of beams over separate areas of the antenna, effectively dividing the single antenna into two antennas. The InSAR technique is then achieved by generating interferograms from images collected with each of the antennas. Since the technique is performed on the data, it allows for synthesizing beams in different directions (or look angles) and performs interferometry over large areas.
Digital Beamforming Interferometry has potential in many areas of radar applications. For example, NASA GSFC innovators developed the first P-Band Digital Beamforming Polarimetric Interferometric SAR Instrument to measure ecosystem structure, biomass, and surface water.
Robotic Inspection System for Fluid Infrastructures
The Robotic Inspection System improves the inspection of deep sea structures such as offshore storage cells/tanks, pipelines, and other subsea exploration applications. Generally, oil platforms are comprised of pipelines and/or subsea storage cells. These storage cells not only provide a stable base for the platform, they provide intermediate storage and separation capability for oil. Surveying these structures to examine the contents is often required when the platforms are being decommissioned. The Robotic Inspection System provides a device and method for imaging the inside of the cells, which includes hardware and software components. The device is able to move through interconnected pipes, even making 90 degree turns with minimal power. The Robotic Inspection System is able to display 3-dimentional range data from 2-dimensional information. This inspection method and device could significantly reduce the cost of decommissioning cells. The device has the capability to map interior volume, interrogate integrity of cell fill lines, display real-time video and sonar, and with future development possibly sample sediment or oil.
Miniaturized High-Speed Modulated X-Ray Source (MXS)
The MXS produces electrons by shining UV light from an LED onto a photocathode material such as magnesium. The electrons are then accelerated across several kV and into a chosen target material; deceleration produces X-rays characteristic of the target. The MXS uses an electron multiplier for high X-ray production efficiency.
The MXS is more compact, rugged, and power-efficient than standard X-ray sources. It can be manufactured using commercially available components and 3D printed housing, resulting in a low cost to manufacture. Unlike traditional X-ray sources, the MXS does not require a filament or vacuum and cooling systems. Most importantly, enabling rapid and arbitrary modulation allows using X-rays in the time domain, a new dimension to X-ray applications.
