scholarly journals Mean-Subtraction Method for De-Shadowing of Tail Artifacts in Cerebral OCTA Images: A Proof of Concept

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2024
Author(s):  
Woo June Choi ◽  
Bjorn Paulson ◽  
Sungwook Yu ◽  
Ruikang K. Wang ◽  
Jun Ki Kim
Keyword(s):  
Three Dimensional ◽  
Volumetric Analysis ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Vascular Networks ◽  
Simple Method ◽  
Small Vessels ◽  
Vascular Morphology ◽  
Brain Vasculature ◽  
Large Vessels

When imaging brain vasculature with optical coherence tomography angiography (OCTA), volumetric analysis of cortical vascular networks in OCTA datasets is frequently challenging due to the presence of artifacts, which appear as multiple-scattering tails beneath superficial large vessels in OCTA images. These tails shadow underlying small vessels, making the assessment of vascular morphology in the deep cortex difficult. In this work, we introduce an image processing technique based on mean subtraction of the depth profile that can effectively reduce these tails to better reveal small hidden vessels compared to the current tail removal approach. With the improved vascular image quality, we demonstrate that this simple method can provide better visualization of three-dimensional vascular network topology for quantitative cerebrovascular studies.

Analysis of Insole Geometry and Deformity by Using a Three-Dimensional Image Processing Technique: A Preliminary Study

2019 ◽  
Vol 109 (2) ◽  
pp. 98-107
Author(s):  
Kit-lun Yick ◽  
Wai-ting Lo ◽  
Sun-pui Ng ◽  
Joanne Yip ◽  
Hung-hei Kwan ◽  
...  
Keyword(s):  
Image Processing ◽  
Cross Sections ◽  
Plantar Pressure ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Diabetic Patients ◽  
Clinical Practices ◽  
Cross Sectional ◽  
Orthotic Treatment

Background: Accurate representation of the insole geometry is crucial for the development and performance evaluation of foot orthoses designed to redistribute plantar pressure, especially for diabetic patients. Methods: Considering the limitations in the type of equipment and space available in clinical practices, this study adopted a simple portable three-dimensional (3-D) desktop scanner to evaluate the 3-D geometry of an orthotic insole and the corresponding deformities after the insole has been worn. The shape of the insole structure along horizontal cross sections is defined with 3-D scanning and image processing. Accompanied by an in-shoe pressure measurement system, plantar pressure distribution in four foot regions (hallux, metatarsal heads, midfoot, and heel) is analyzed and evaluated for insole deformity. Results: Insole deformities are quantified across the four foot regions. The hallux region tends to show the greatest changes in shape geometry (17%–50%) compared with the other foot regions after 2 months of insole wear. As a result of insole deformities, plantar peak pressures change considerably (–4.3% to +69.5%) during the course of treatment. Conclusions: Changes in shape geometry of the insoles could be objectively quantified with 3-D scanning techniques and image processing. This investigation finds that, in general, the design of orthotic insoles may not be adequate for diabetic individuals with similar foot problems. The drastic changes in the insole shape geometry and cross-sectional areas during orthotic treatment may reduce insole fit and conformity. An inadequate insole design may also affect plantar pressure reduction. The approach proposed herein, therefore, allows for objective quantification of insole shape geometry, which results in effective and optimal orthotic treatment.

A Visualization Study of Abrasive Flow Variation in Abrasive Air Jets

2013 ◽  
Vol 652-654 ◽  
pp. 2123-2128
Author(s):  
Jing Ming Fan ◽  
Jun Wang
Keyword(s):  
Flow Rate ◽  
Three Dimensional ◽  
Processing Technique ◽  
Air Pressure ◽  
Image Processing Technique ◽  
Rate Variation ◽  
Efficient Technology ◽  
Air Jets ◽  
Abrasive Jet Machining ◽  
Micro Structures

Abrasive jet machining is an efficient technology for the fabrication of three dimensional micro structures on brittle materials. In abrasive jet machining, the variation or fluctuation in the amount of abrasive supply has a significant effect on the quality of the machined structures. An image processing technique is employed in this study to study the abrasive flow rate variation, in which abrasive jet pictures are captured at different moments by a Particle Image Velocimetry technology and then processed using Labview Vision Assistant and MATLAB. It shows that the abrasive flow rate fluctuates with time under the jetting conditions considered. The abrasive flow from larger nozzles or at smaller air pressures shows more profound fluctuation. Although the abrasive flow fluctuation from smaller nozzles remains almost constant when the air pressure is changed, for larger nozzles, the magnitude of the fluctuation gradually decreases as the air pressure is increased.

Detection of System Compromise in Additive Manufacturing Using Video Motion Magnification

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Sakthi Kumar Arul Prakash ◽  
Tobias Mahan ◽  
Glen Williams ◽  
Christopher McComb ◽  
Jessica Menold ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Low Cost ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Cyber Attack ◽  
Printing Process ◽  
Phase Variations ◽  
Spatio Temporal ◽  
Motion Magnification

Abstract Three-dimensional printing systems have expanded the access to low cost, rapid methods for attaining physical prototypes or products. However, a cyber attack, system error, or operator error on a 3D-printing system may result in catastrophic situations, ranging from complete product failure, to small types of defects which weaken the structural integrity of the product. Such defects can be introduced early-on via solid models or through G-codes for printer movements at a later stage. Previous works have studied the use of image classifiers to predict defects in real-time and offline. However, a major restriction in the functionality of these methods is the availability of a dataset capturing diverse attacks on printed entities or the printing process. This paper introduces an image processing technique that analyzes the amplitude and phase variations of the print head platform arising through induced system manipulations. The method uses an image sequence of the printing process to perform an offline spatio-temporal video decomposition to amplify changes attributable to a change in system parameters. The authors hypothesize that a change in the amplitude envelope and instantaneous phase response as a result of a change in the end-effector translational instructions to be correlated with an AM system compromise. Two case studies are presented, one verifies the hypothesis with statistical evidence in support of the method while the other studies the effectiveness of a conventional tensile test to identify system compromise. The method has the potential to enhance the robustness of cyber-physical systems such as 3D printers.

STRESS-STRAIN RELATIONSHIP OF ZR55AL10NI5CU30 METALLIC GLASS ANALYZED BY 3D IMAGES ON SPHERICAL INDENTS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2453-2458 ◽  
Author(s):  
YUN-HEE LEE ◽  
JONG SEO PARK ◽  
HAE MOO LEE ◽  
SEUNG HOON NAHM
Keyword(s):  
Metallic Glass ◽  
Metallic Glasses ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Polished Surface ◽  
Flow Properties ◽  
Stress Strain ◽  
Strain Relationship ◽  
Relationship Of

Mechanically polished surface of Zr 55 Al 10 Ni 5 Cu 30 metallic glass was indented with a rigid ball 0.5 mm in diameter and its corresponding load-depth curve was recorded automatically. Although a stress-strain relationship beneath the indenter can be analyzed from the raw indentation curve, the current analysis developed for crystalline solids can mislead erroneous properties because it does not consider significant material pile-ups in amorphous metallic glasses. Thus, we proposed a novel indent image processing technique for characterizing the contact and flow properties in the metallic glasses; the contact area was measured by differentiating a three-dimensional indent morphology digitized by a surface profiler and a surface-stretching strain was newly defined in order to estimate the flow properties. Finally, the work-hardening index estimated was about 0.05, comparable with the typical value measured from uniaxial compression in the Zr -based metallic glass.

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