Optics and Precision Engineering, Volume. 32, Issue 15, 2429(2024)
Digital diffraction method for single retinal image enhancement
Enhancing RGB retinal images is vital for retinopathy detection and monitoring, but issues like uneven intensity often degrade visual quality. This research introduces a digital diffraction-based method to improve uneven intensity and contrast while preserving color naturalness. Initially, the retinal image is converted to LCH color space, where intensity correction is applied to the L channel, treated as an optical field. A digital propagation with a specific kernel estimates the intensity pattern, which, when subtracted, yields a corrected L channel. Multi-image fusion with varied kernels then ensures uniform intensity. The same process corrects the C channel for color accuracy. Tested on 1 200 Messidor dataset images, this method surpasses Gamma correction and Retinex methods, enhancing contrast and uniformity by 3%-4% when combined with CLAHE. The improved contrast aids applications like retinopathy detection and blood vessel segmentation.
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Shuhe ZHANG, Liangcai CAO. Digital diffraction method for single retinal image enhancement[J]. Optics and Precision Engineering, 2024, 32(15): 2429
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Received: May. 23, 2024
Accepted: --
Published Online: Sep. 27, 2024
The Author Email: CAO Liangcai (clc@tsinghua.edu.cn)