A Real-Time Implementation of Nonlinear Unsharp Masking with FPLDs

Real-time performance of image enhancement algorithms is required in many applications. In this paper we present a real-time image contrast enhancement scheme using non-linear unsharp masking, implemented with FPLDs (Field Programmable Logic Devices). A quadratic filter has been chosen for the nonlinear unsharp masking. The implementation performs well on real images from medical and non-medical fields. Performance figures of the nonlinear filter on mammograms show substantial improvements over software-only and other filter implementations using linear schemes, thus achieving real-time image enhancement of large images. The implementation has been tested as an application-specific co-processor to a standard PC, but can also be used as a functional unit of an application-specific image enhancement processor.