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Spatial Resolution Improvement of Digital and Thermographic Imaging Using an Automatic and Controllable Super-resolution Technique

WEIXIANG DU, YIFAN ZHAO, SRI ADDEPALLI

Abstract


Infrared thermography has become a widely applied Non-Destructive Testing (NDT) approach to detect near-surface and sub-surface defects of various materials. The detection accuracy and reliability is largely limited by a relatively low spatial resolution of thermal cameras in comparison to visible-light cameras. Using a high-end thermal camera to achieve high spatial resolution can be very costly. Furthermore, the maximal spatial resolution may be unachievable when a high sample rate has to be used for high heat-conductivity materials, such as metal. This paper reports an automatic and controllable spatial resolution improvement technology to improve the spatial resolution of passive thermal images without replacing the existing sensors. A high-resolution image is reconstructed by fusing a sequence of low-resolution images captured by precisely controlling the position between specimen and camera. The performance of the proposed system has been tested on both digital and IR cameras. Both visual and quantitative results demonstrate the considerable improvement of image quality.


DOI
10.12783/shm2019/32249

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