Mitigation of Speckle Noise in Optical Coherence Tomograms

Optical Coherence Tomography (OCT) is a promising high-resolution imaging technique that works based on low coherent interferometry. However, like other low coherent imaging modalities, OCT suffers from an artifact called, speckle. Speckle reduces the detectability of diagnostically relevant features in the tissue. Retinal optical coherence tomograms are of a great importance in detecting and diagnosing eye diseases. Different hardware or software based techniques are devised in literatures to mitigate speckle noise. The ultimate aim of any software-based despeckling technique is to suppress the noise part of speckle while preserves the information carrying portion of that. In this chapter, we reviewed the most prominent speckle reduction methods for OCT images to date and then present a novel and intelligent speckle reduction algorithm to reduce speckle in OCT images of retina, based on an ensemble framework of Multi-Layer Perceptron (MLP) neural networks

An Introduction to Fingerprint Presentation Attack Detection

none3siThis chapter provides an introduction to Presentation Attack Detection (PAD), also coined anti-spoofing, in fingerprint biometrics, and summarizes key developments for that purpose in the last two decades. After a review of selected literature in the field, we also revisit the potential of quality assessment for presentation attack detection. We believe that, beyond the interest that the described techniques may intrinsically have by themselves, the case study presented may serve as an example of how to develop and validate fingerprint PAD techniques based on common and publicly available benchmarks and following a systematic and replicable protocol.noneGalbally, Javier; Fierrez, Julian; Cappelli, RaffaeleGalbally, Javier; Fierrez, Julian; Cappelli, Raffael