دانلود Improved partial differential equation-based enhancement for underwater images using local–global contrast operators and fuzzy homomorphic processes

Abstract

This study describes improved partial differential equation (PDE)-based formulations for combined global and local contrast  operators  for  underwater  image  enhancement.  The  algorithms  remove  the  limitations  of  conventional  closed-form approaches  and  the  problem  of  optimal  stopping  time  of  earlier  PDE-based  approaches.  Main  features  include  improved simultaneous combination, augmentation and control of various individual local and global processes, guided by optimisation of multiple image metrics. This ensures optimal operation of the algorithms in terms of visual and numerical results and proposed approaches ensure faster and fully automated processing of various images. Additional contributions include the incorporation of a colour space converter, fuzzy homomorphic and post-contrast enhancement processes for certain problematic images. Experimental comparisons indicate that the improved approaches yield better results than several of the proposed works from the literature for underwater image enhancement.