ENHANCEMENT OF PSR LUNAR CRATERS CAPTURED BY OHRC CHANDRAYAAN-2

Abstract

Permanently Shadowed Regions (PSRs) located near the lunar poles are among the most scientifically significant areas on the Moon due to their potential to contain water ice deposits and other volatile materials. However, these regions receive little or no direct sunlight, making image interpretation and analysis extremely challenging. This work presents an image enhancement framework for PSR lunar crater images captured by the Orbiter High Resolution Camera (OHRC) onboard Chandrayaan-2. The proposed methodology employs preprocessing techniques such as noise reduction, contrast enhancement, histogram equalization, Contrast Limited Adaptive Histogram Equalization (CLAHE), and gamma correction to improve the visibility of shadowed regions. The enhanced images reveal hidden surface features and geological structures that are difficult to observe in the original images. Performance evaluation is carried out using image quality metrics such as Peak Signalto-Noise Ratio (PSNR) and Structural Similarity Index Measure (SSIM). Experimental results demonstrate significant improvements in visual quality and feature visibility, supporting future lunar exploration and scientific investigations. KEYWORDS: Chandrayaan-2, OHRC, Lunar Craters, Permanently Shadowed Regions, PSR Enhancement, Image Processing, CLAHE, Histogram Equalization