Gradient-based Edge Detection Using Nonlinear Edge-enhancing Prefilters

This correspondence examines the use of nonlinear edge enhancers as prefilters for edge detectors. The filters are able to convert smooth edges to step edges and suppress noise simultaneously. Thus, false alarms due to noise are minimized and edge gradient estimates tend to be large and localized. This leads to significantly improved edge maps

LUM Filters: A Class of Rank-order-based Filters for Smoothing and Sharpening

A new class of rank-order-based filters, called lower-upper-middle (LUM) filters, is introduced. The output of these filters is determined by comparing a lower- and an upper-order statistic to the middle sample in the filter window. These filters can be designed for smoothing and sharpening, or outlier rejection. The level of smoothing done by the filter can range from no smoothing to that of the medianfilter. This flexibility allows the LUM filter to be designed to best balance the tradeoffs between noisesmoothing and signal detail preservation. LUM filters for enhancing edge gradients can be designed to be insensitive to low levels of additive noise and to remove impulsive noise. Furthermore, LUM filters do not cause overshoot or undershoot. Some statistical and deterministic properties of the LUM filters are developed, and a number of experimental results are presented to illustrate the performance. These experiments include applications to 1D signals and to images

Witsenhausen’s counterexample and its links with multimedia security problems

Witsenhausen’s counterexample was proposed more than four decades ago in order to show that affine control strategies are not optimal for systems with non-classical information patterns. Finding the optimal solution to Witsenhausen’s problem however remains an open problem. Recently, the stochastic control community has re-discovered Costa’s Dirty Paper result as a potential solution to Witsenhausen’s problem. In this paper the similarities and differences between Witsenhausen’s scenario and multimedia security problems are reviewed, and the historical evolution of the solutions to Witsenhausen’s problem compared with those proposed for watermarking detection

Image and video noise: An industry perspective

© Springer International Publishing AG, part of Springer Nature 2018. Images and video are increasingly becoming a part of our everyday lives and with this growth, we find an increasing number of industrial and commercial applications of imagery. In this chapter, we will examine the problem of image noise from an industrial and commercial viewpoint. We will consider how noise enters the imaging chain in these settings and how noise is measured and quantified for later removal. We will also discuss standards and standardisation activities that relate to noise measurement in a commercial or industrial setting