• Journal of the Korean Society for Nondestructive Testing
• /
• v.33 no.4
• /
• pp.382-387
• /
• 2013

• Journal of the Korean Society for Nondestructive Testing
• /
• v.32 no.3
• /
• pp.302-306
• /
• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1307-1308
• /
• 2011

• Proceedings of the Korean Institute of Landscape Architecture Conference
• /
• 2022.10a
• /
• pp.36-37
• /
• 2022

• Journal of Broadcast Engineering
• /
• v.19 no.1
• /
• pp.109-117
• /
• 2014

This paper presents a superresolution restoration technique that can restore high-resolution images from differently blurred low resolution images rather than using the motion information between low-resolution images. In order to restore the super-resolution image the rotatable aperture mask lens system is proposed. The proposed technique does not need to estimate point spread function at each frame. In addition, it does not require image registration because there is no global translational motion between low resolution images. By using a rotatable rectangular aperture, two consecutive captured images provide sufficiently exclusive information for superresolution. Therefore, the proposed method can reduce the registration error between the low-resolution image as well as the calculation amount for superresolution restoration. The existing lens system of the camera can be extended to obtain a superresolution image by only adding an rotatable rectangular aperture mask. Finally, in order to verify the performance of the proposed system, experimental results are performed. By comparing with the existing superresolution methods, the proposed method showed the significant improvements in the sense of spatial resolution.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.4
• /
• pp.443-446
• /
• 2013

An infrared thermography technique can be used to inspect a large area simultaneously and to detect defects such as cracks or delaminations in real time. Infrared thermography is a technique in which visual images are formed from the infrared range from subjects according to their thermal radiation. The molecules of all objects are disturbed by heat, and the molecular motion becomes more active when the temperature rises and less active when the temperature falls. In this study, the applicability and feasibility of ultrasound thermography for detecting defects in an engine block, which is a key component in the automobile industry, were verified. A nondestructive reliability test was conducted to study the defects, after which the results were analyzed.

• Composites Research
• /
• v.25 no.6
• /
• pp.236-240
• /
• 2012

The purpose of this study was to investigate the feasibility on the detection of dental composite delamination using a lock-in thermography method. Amplitude and phase images of detected thermal signals were analyzed according to the lock-in frequencies. At a lock-in frequency of 0.05 Hz, the ligament thickness of 0.5 mm in the specimen exhibited the highest amplitude contrast between defective area and sound area. For ligament thicknesses of 1 mm and 1.5 mm, delamination detection was possible at 0.025 Hz and 0.01 Hz through the amplitude differences. At lock-in frequencies of 0.006 Hz and 0.01 Hz, ligament thickness 0.5 mm exhibited the highest phase contrast. For ligament thicknesses of 1 mm and 1.5 mm, the phase contrast exhibited possible detection of delamination at 0.006-0.1 Hz.

• Fire Science and Engineering
• /
• v.30 no.6
• /
• pp.92-98
• /
• 2016

This study evaluated thermal image real-time estimation and fire alarm using by a CCD camera, which has been a seamless feature-point analysis method, according to the angle and position and image fusion by a vector coordinate point set-up of equal shape. The system has higher accuracy, fixing data value of temperature sensing and fire image of 0~255, and sensor output-value of 0~5,000. The operation time of a flame specimen within 500 m, 1000 m, and 1500 m from the test report specimen took 7 s, 26 s, and 62 s, respectively, and image creation was proven. A diagnosis of fire accident was designated to 3 steps: Caution/Alarm/Fire. Therefore, a series of process and the transmission of SNS were identified. A light bulb and fluorescent bulb were also tested for a false alarm test, but no false alarm occurred. The possibility that an unwanted alarm will be reduced was verified through a forecast of the fire progress or real-time estimation of a thermal image by the change in the image of a time-based flame and an analysis of the diffusion velocity.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.9
• /
• pp.2138-2144
• /
• 2015

Multimodal dual camera system has a stereo-like configuration equipped with an infrared thermal and optical camera. This paper presents stereo calibration methods on multimodal dual camera system using a target board that can be recognized by both thermal and optical camera. While a typical stereo calibration method usually performed with extracted intrinsic and extrinsic camera parameter, consecutive image processing steps were applied in this paper as follows. Firstly, the corner points were detected from the two images, and then the pixel error rate, the size difference, the rotation degree between the two images were calculated by using the pixel coordinates of detected corner points. Secondly, calibration was performed with the calculated values via affine transform. Lastly, result image was reconstructed with mapping regions on calibrated image.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.5
• /
• pp.136-143
• /
• 2010

There are three parts of tunnel which are influenced by outside temperature, entrance, exit and vent. These parts showed different tendency of deterioration(very rapid deterioration speed, wide range of defects, etc) compared with last parts of tunnel. Therefore, it needs to have different points of view when civil engineers analyze the defects on these parts and apply the retrofit or rehabilitation methods for them. However, when we conduct maintenance works, precise inspection and precise safety diagnosis, these defects had been neglected because those were considered as unimportant defects and caused from temporary weather and temperature change. In this study, two urban tunnels were analyzed to decide the range of tunnel which are influenced by outside temperature using a thermal camera, and to find out the causes of defects on these parts. From the results, the main points of maintenance were presented.