Low Dynamic Brain Magnetic Resonance Image Enhancement Using Type-II Fuzzy Set

Magnetic resonance imaging (MRI) of the brain is a non-invasive medical imaging technique used to obtain detailed images of brain structures, and it is an indispensable tool in clinical practice. However, during the imaging process, low dynamic range MRI images may occur, with little variation between image brightness and contrast. This type of image may occur for various reasons and poses specific challenges. To address this issue, this paper proposes an improved algorithm based on Type-II fuzzy sets to enhance the contrast of grayscale images while preserving the brightness and details of the MRI images. The algorithm uses new upper and lower limits, a modified Hamacher t-conorm, and transformation-based gamma correction methods to provide enhanced images. Furthermore, the method offers good interpretability, which is crucial for improving diagnostic accuracy and transparency of the technique. The proposed method was compared with six recent contrast enhancement methods and showed good results on five evaluation metrics.