• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.131-140
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• 2002

Chemically amplified deep UV(CA-DUV) resists are typically based on a combination of an acid labile polymer and a photoacid generator(PAG) but acid amplification type photoresist is formulated by addition of the acid amplifiers to chemically amplified resist system(CAPs). We developed acid amplifiers base on cyclohexanediol such as 1-methacryloyloxy-4-tosyloxy cyclohexane(MTC) and poly(MTC$_{10}$-co-tBMA$_{90}$)(P-1) to enhance photosensitivity. P-1 is a copolymer of tert-butyl methacrylate and MTC as a positive working photoresist based on polymeric acid amplifier in order to enhance photosensitivity and simplify the process of fomulating a photoresist. P-1 exhibited 2X higher photosensitivity compared with PtBMA. The acid amplifiers showed reasonable thermal stability for resist processing temperature and higher photosensitivity compared with chemically amplified resist.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.3
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• pp.193-199
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• 2015

Active thermography techniques have the capability of inspecting a broad range simultaneously. By evaluating the phase difference between the defected area and the healthy area, the technique indicates the qualitative location and size of the defect. Previously, the development of the defect detection method used a variety of materials and the test specimen was done. In this study, the proposed technique of lock-in is verified with artificial specimens that have different size and depth of subsurface defects. Finally, the defect detection capability was evaluated using comparisons of the phase image and the amplitude image according to the size and depth of defects.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.2
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• pp.75-83
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• 2017

In this paper, we investigate the capacity of the lock-in infrared thermography technique for the evaluation of non-uniform top layers of a silicon carbide coating with a nickel based superalloy sample. The method utilized a multilayer heat transfer model to analyze the surface temperature response. The modelling of the sample was done in ANSYS. The sample consists of three layers, namely, the metal substrate, bond coat and top coat. A sinusoidal heating at different excitation frequencies was imposed upon the top layer of the sample according to the experimental procedures. The thermal response of the excited surface was recorded, and the phase angle image was computed by Fourier transform using the image processing software, MATLAB and Thermofit Pro. The correlation between the coating thickness and phase angle was established for each excitation frequency. The most appropriate excitation frequency was found to be 0.05 Hz. The method demonstrated potential in the evaluation of coating thickness and it was successfully applied to measure the non-uniform top layers ranging from 0.05 mm to 1 mm with an accuracy of 0.000002 mm to 0.045 mm.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.55-61
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• 2009

The wall thinning defect of nuclear power pipe is mainly occurred by the affect of the flow accelerated corrosion (FAC) of fluid. This type of defect becomes the cause of damage or destruction of in carbon steel pipes. Therefore, it is very important to measure defect which is existed not only on the welding part but also on the whole field of pipe. This study use dual-beam Shearography, which can measure the out-of-plane deformation and the in-plane deformation by using another illuminated laser beam and simple image processing technique. And this study proposes Infrared thermography, which is a two-dimensional non-contact nondestructive evaluation that can detect internal defects from the thermal distribution by the inspection of infrared light radiated from the object surface. In this paper, defect of nuclear power pipe were, measured using dual-beam shearography and infrared thermography, quantitatively evaluated by the analysis of phase map and thermal image pattern.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.5
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• pp.341-348
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• 2015

Active infrared thermography methods have been known to possess good fault detection capabilities for the detection of defects in materials compared to the conventional passive thermal infrared imaging techniques. However, the reliability of the technique has been under scrutiny. This paper proposes the lock-in thermography technique for the detection and estimation of artificial subsurface defect size and depth with uncertainty measurement.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.6
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• pp.609-620
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• 2002

It is well known that during tensile testing, a part of the mechanical work done on the specimen is transformed into heat energy. However, the ultimate temperature rise and the rate of temperature rise is related to the nature of the material, conditions of the test and also to the deformation behaviour of the material during loading. The recent advances in infrared sensors and image/data processing techniques enable observation and quantitative analysis of the heat energy dissipated during such tensile tests. In this study, infrared imaging technique has been used to characterise the tensile deformation in AISI type 316 nuclear grade stainless steel. Apart from identifying the different stages during tensile deformation, the technique provided an accurate full-field temperature image by which the point and time of strain localization could be identified. The technique makes it possible to visualise the region of deformation and failure and also predict the exact region of fracture in advance. The effect of thermal gradients on plastic flow in the case of interrupted straining revealed that the interruption of strain and restraining at a lower strain rate not only delays the growth of the temperature gradient, but the temperature rise per unit strain decreases. The technique is a potential NDE tool that can be used for on-line detection of thermal gradients developed during extrusion and metal forming process which can be used for ensuring uniform distribution of plastic strain.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.129-136
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• 2020

In this paper, we propose a thermal imagery-based object detection algorithm for low-light level nighttime surveillance system. Many features selected by Haar-like feature selection algorithm and existing Adaboost algorithm are often vulnerable to noise and problems with similar or overlapping feature set for learning samples. It also removes noise from the feature set from the surveillance image of the low-light night environment, and implements it using the lightweight extended Haar feature and adaboost learning algorithm to enable fast and efficient real-time feature selection. Experiments use extended Haar feature points to recognize non-predictive objects with motion in nighttime low-light environments. The Adaboost learning algorithm with video frame 800*600 thermal image as input is implemented with CUDA 9.0 platform for simulation. As a result, the results of object detection confirmed that the success rate was about 90% or more, and the processing speed was about 30% faster than the computational results obtained through histogram equalization operations in general images.

• Korean Journal of Human Ecology
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• v.19 no.6
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• pp.1045-1052
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• 2010

Effects of the ease of pattern on the thermal conditions of clothing were investigated through the measurement of clothing surface temperatures using infrared thermography. Four vests with different pattern ease were worn by five male subjects. Surface temperature distribution on the clothing were then examined using a thermogram to view thermo-regulating characteristics affected by the ease of pattern. Representative surface temperatures were calculated based on the percentage of the surface area within a certain temperature range and the midpoint value of the corresponding area. Representative surface temperatures matches well to the thermal insulation value measured by thermal manikin. Results indicated that representative surface temperature could be a useful quantitative value if some simple calculations were to be used alongside accurate image processing.

• Journal of Applied Reliability
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• v.9 no.2
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• pp.149-163
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• 2009

This paper intends to suggest a design to reduce the thermal load of a hand-carried ultrasound (HCU) system, with the aim of increasing the product life. To design ways to reduce the heat load, the surface temperatures of key parts of an HCU system were measured as the 4 system cooling fans, which have a direct relation to the system life, were operated normally. When the derating rate of 80% was applied while the fans of the HCU system were operated abnormally, it was observed that the key image processing parts exceeded the surface temperature (TC) with consideration to derating. Since the part surface temperature did not exceed the derated level when the regulated voltage was derated from 12V to 9V, it is expected to lower the operating voltage of the fans to 9V to increase the fan and HCU system lifetime by 1.8 times.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.251-257
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• 2015

This work presents modelling and simulation of a readout integrated circuit (ROIC) design considering pair-wise serial configuration along with thermal modeling of an uncooled microbolometer array. A fully differential approach is used at the input stage in order to reduce fixed pattern noise due to the process variation and self-heating-related issues. Each pair of microbolometers is pulse-biased such that they both fall under the same self-heating point along the self-heating trend line. A ${\pm}10%$ process variation is considered. The proposed design is simulated with a reference input image consisting of an array of $127{\times}92$ pixels. This configuration uses only one unity gain differential amplifier along with a single 14-bit analog-to-digital converter in order to minimize the dynamic range requirement of the ROIC.