Edge enhancement by unsharp masking using liquid-crystal displays

• Published in: Journal of modern optics Vol. 57; no. 10; pp. 866 - 871
• Main Authors: Ferrari, José A., Flores, Jorge L., Garcia-Torales, G.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 10.06.2010; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Derivatives; Display devices, liquid-crystal devices; Displays; edge enhancement; Exact sciences and technology; Experiments; Fundamental areas of phenomenology (including applications); Image forming and processing; Image processing; Image processing systems; Imaging and optical processing; Inspection; LCDs; Liquid crystal displays; Masking; Microscopy; Optical elements, devices, and systems; Optics; Physics; Real time; Replicas; Real time systems; Image processing; Liquid crystal displays
• ISSN: 0950-0340; 1362-3044
• DOI: 10.1080/09500340.2010.493244

A new method for real-time edge enhancement is presented. The method is based on the capacity of liquid-crystal displays to generate a contrast-reverted replica of the image displayed on it. When the negative replica is defocused and it is superposed to the original image (displayed in a second liquid-crystal display), one obtains an image with enhanced second derivatives. The proposed technique resembles the classical (photographic) unsharp masking method, but unlike the time-consuming photographic implementation, it can be applied in real-time. The proposed method is potentially interesting for image processing in areas such as microscopy, industrial edge inspection, etc. Validation experiments are presented.