B. Venkatraman

Automated recognition of ROIs for breast thermograms of lateral view-a pilot study

Abstract This research study proposes an automated region of interest (ROI) for breast thermograms by considering lateral view as well as the frontal view of the breasts. The lateral view helps in contralateral comparison between the different quadrants of the breast and thus ensuring the analysis of the whole breast region including the lymph nodes and armpit areas. The proposed research involves in analysis of normal, lactating and fibro adenoma breast thermograms from a specific ethnic group located in the southern part of India. An optimized anisotropic diffusion filter is applied to preserve the vascular patterns inside the breast regions which appear to be significant edges in the thermal images. Then level set algorithm without re-initialization selects the contour boundary covering maximum area of the breast regions and segments along the canny detected edges which is enhanced through anisotropic diffusion filter. The resultant ROI helps the clinical specialist to conclude the nature of the biomarkers whether normal or abnormal at the preliminary screening level. Experimental simulation result shows maximum similarity (ρ > 0.05) within the 95% confidence interval of correlation between the segmented and reference images. It can be concluded that the proposed automated ROIs confirm the suitability for clinical validation.

A comparison between finite element modeling and various thermographic non-destructive testing techniques for the quantification of the thermal integrity of macro-brush plasma facing components used in a tokamak

The plasma facing components (PFCs) inside a tokamak are typically exposed to extremely high heat flux of the order of MW/m(2). The brazing quality between the plasma facing materials (PFMs) and the heat sink will determine the structural integrity and hence the effective service life of these PFCs. Suitable non-destructive testing (NDT) techniques for the pre-qualification of these components are thus essential to evaluate their structural integrity at various stages of their service life. Macro-brush type mockups of prototype PFCs with graphite as PFM have been inspected for their brazing quality using different active Infrared (IR)-thermographic NDT techniques. The results obtained from these techniques are compared and discussed. The brazing quality was quantified by establishing a comparison between the experimental results and the results from Finite Element Analysis (FEA). The percentage of contact between the PFM and the substrate was varied in FEA. FEA results when compared with experiments shows that tiles have different amounts of contact with the substrate ranging between 10% and 80%.

Evaluation of Corrosion Detection in Reinforced Concrete using Infrared Thermography

Corrosion of reinforcing steel and other embedded metals is the leading cause of deterioration in reinforced concrete strucutres. The steel corrosion products ,occupies a greater volume than the steel. This expansion creates tensile stresses in the concrete, which can eventually cause cracking, delamination, and spalling of cover concrete ,leading to further degradation. Corrosion of steel in concrete is an electrochemical process, which takes place as a result of the formation of a corrosion cell. Exposure of reinforced concrete to chloride ions in an aggressive environment is the primary cause of premature corrosion of steel reinforcement. Corrosion loss consumes considerable portion of the budget of the country by way of either restoration measures or reconstruction. By monitoring the structures for corrosion performance and taking suitable measures at the appropriate time could effect enormous saving. This paper studies application of lock in thermography for detection of corrosion in reinforced bars and developed crack at various depth due to the accelerated corrosion in reinforced bar. http://dx.doi.org/10.21611/qirt.2015.0150

NDE measurements for understanding of performance: A few case studies on engineering components, human health and cultural heritage

Life cycle management involves a seamless integration of materials, design, analysis, production, manufacturing, and degradation plus, a wide variety of disciplines relating to surveillance and characterisation with adequate feedback and control. Science and technology of non-destructive evaluation (NDE) links all these domains and disciplines together in a seamless and robust manner. A number of research programs on NDE science and technology have evolved during the last four decades world over including the one at Indira Gandhi Centre for Atomic Research, Kalpakkam, initiated and nurtured by the first author. Many engineering and technology challenges pertaining to fast spectrum reactors have been successfully solved by this Centre through development of innovative sensors, procedures and coupled with strong basic science and modeling approaches. These technologies have also been selectively applied in gaining insights of human health and cultural heritage. This paper highlights some of the innovative N...