Open AccessSimple median‐based EP PP scheme for enhancement of reconstructed Bayer colour filter array images
Author(s) -
Yang YiHong,
Wang PengHua,
Chen PoNing
Publication year - 2016
Publication title -
iet image processing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 45
eISSN - 1751-9667
pISSN - 1751-9659
DOI - 10.1049/iet-ipr.2015.0815
Subject(s) - interpolation (computer graphics) , filter (signal processing) , demosaicing , mathematics , noise (video) , algorithm , artificial intelligence , signal to noise ratio (imaging) , enhanced data rates for gsm evolution , peak signal to noise ratio , phase (matter) , image processing , image (mathematics) , computer science , computer vision , statistics , color image , physics , quantum mechanics
In this study, the median‐based edge‐preserving (EP) modification is revisited and has been shown to improve effectively the quality of a reconstructed Bayer colour filter array image in terms of the composite peak signal‐to‐noise ratio (CPSNR) performance index. Along this research direction, the authors propose an EP‐modified signal‐correlation‐based (SCB) post‐processing (PP), called EP‐SCB, as an enhancement to any existing interpolation method. The Bayer image reconstruction system they consider thus consists of two operational phases. The first phase performs an initial estimation of the missing red, green and blue colours by using an existing interpolation method, whereas the second phase applies EP‐SCB PP. Since a certain class of images may not fulfil the premise of having small variations in local colour difference, which is assumed by SCB‐type interpolation, thereby resulting in a deterioration in CPSNR after EP‐SCB PP, a threshold test on local variance ratio is also devised to conditionally switch off the second phase. Experimental results show that the EP‐SCB PP with variance‐ratio test gives a worst average CPSNR than the original interpolation methods tested in none of the Kodak and IMAX image groups experimented.