The Removal of Blocking Effects Caused by Partially Overlapped Sub-Block Contrast Enhancement

Some medical images have significantly high levels of brightness contrast: parts of the image may be very bright while others may be very dark. Global contrast enhancement often fails to provide clinicians with an image that facilitates the easy visualisation of all the required information, while traditional local contrast enhancement is computationally intensive thus limiting its applications in practical diagnosis. POSHE, a technique proposed by Joung-Youn Kim et al., overcomes the computational barriers of other methods. However, with POSHE, two key factors accuracy and noise are not considered, making it largely unsuited for medical image processing. In this paper, a new algorithm is proposed for removing the blocking-effects that are generated in partially overlapped subblock contrast enhancement (POSCE). Experiments show that the new algorithm not only removes the more significant blocking-effects, while keeping image detail, but is suitable for many kinds of contrast enhancement. The algorithm thus expands the area of POSHE applications.