Image contrast enhancement using morphological decomposition by reconstruction
Ioan Jivet, Alin Brindusescu, Ivan Bogdanov · 2008
Abstract: - The paper presents a novel algorithm for the computation of the image decomposition using a morphological filter with reconstruction The target applications are image contrast enhancement especially those with high dynamic content. Both bright and dark regions contrast enhancement were considered. A new hardware efficient implementation of decomposition is presented. Following decomposition in 5 levels of detail a local contrast enhancement is performed. The new reconstruction algorithm and its hardware implementation as proposed is shown to be independent on structural element size and that it results in a predictable time frame operation. A mixed schematic and VHDL/Verilog description of the decomposition filters was synthesized and results show far higher speed performance compared with solutions found in recent literature. The FPGA implementation had as main objective real time operation. The performance of the architecture was found to exceed real time conditions of operation and fit into medium size FPGA. A test sample image was used for contrast enhancement schemes validation. The white areas local contrast was enhanced expanding the gray scale for the detail levels after a parabolic series. The scale warping in the white areas resulted in contrast enhancement while the dark areas did not. Key-Words:- image filtering, multi-dimensional kernel, FPGA implementation 1