Realization of a programmable rank-order filter architecture using capacitive threshold logic gates

We present a new architecture to realize a fully programmable rank order filter (ROF), based on capacitive threshold logic (CTL) gates. Variants of ROFs, especially median filters, are widely used in digital signal and image/video processing and image enhancement. The CTL realization of the majority gates used in the ROF architecture allows the filter rank and the window size to be user-programmable, using a much smaller silicon area, The overall filter architecture is also simplified significantly, compared to conventional realizations of digital median filters.