Contrast Enhancement of Power Plant Images Obtained from Industrial Borescope Devices

Abstract

The industrial Video scope (VS) device is designed for the endoscopic inspection of professional equipment, like motors, pumps, turbines, cavities in buildings and vehicle bodies, etc. The output of this device is images and videos, but some output images may suffer from low contrast and poor details. This paper presents three proposed approaches to enhance the quality of the VS images. The first proposed approach is based on Contrast Limited Adaptive Histogram Equalization (CLAHE) with adaptive gamma correction. By choosing the best clip limits in CLAHE and transfer function (adaptive gamma correction), the first proposal achieves optimum contrast enhancement for the VS images. The second proposed approach depends on the Homomorphic with emphasis high pass filter. The homomorphic filtering is utilized on the video scope image in logarithm domain, Applying this method gives more details in the VS images. The third proposed approach depends on Homomorphic with emphasis high pass filter with histogram equalization. Applying this method gives more accurate and best visual quality of the output VS images. Numerical results show the ability of the three proposals in improvement the VS image quality, and they can be recommended for industrial VS systems.