Face comparison in forensics:A deep dive into deep learning and likelihood rations

This thesis explores the transformative potential of deep learning techniques in the field of forensic face recognition. It aims to address the pivotal question of how deep learning can advance this traditionally manual field, focusing on three key areas: forensic face comparison, face image quality assessment, and likelihood ratio estimation. Using a comparative analysis of open-source automated systems and forensic experts, the study finds that automated systems excel in identifying non-matches in low-quality images, but lag behind experts in high-quality settings. The thesis also investigates the role of calibration methods in estimating likelihood ratios, revealing that quality score-based and feature-based calibrations are more effective than naive methods. To enhance face image quality assessment, a multi-task explainable quality network is proposed that not only gauges image quality, but also identifies contributing factors. Additionally, a novel images-to-video recognition method is introduced to improve the estimation of likelihood ratios in surveillance settings. The study employs multiple datasets and software systems for its evaluations, aiming for a comprehensive analysis that can serve as a cornerstone for future research in forensic face recognition

Face Liveness Detection Using a 2D Camera

Rozpoznávanie tváre je jednou z najviac spoločensky akceptovaných foriem biometrického rozpoznávania. Nedávna dostupnosť veľmi presných a efektívnych algoritmov rozpoznávania tváre ponecháva zraniteľnosť voči prezentačným útokom ako hlavnú výzvu pre riešenia rozpoznávania tváre. Táto práca sa zaoberá vysvetlením problematiky týkajúcej sa s detekciou živosti tváre, ktorá pomôže pochopiť rôzne možnosti útokov a ich vzťah k existujúcim riešeniam. A implementáciu algoritmu, ktorý na základe videa rozoznáva živosť tváre.Facial recognition is one of the most socially accepted forms of biometric recognition. The recent availability of highly accurate and efficient face recognition algorithms leaves vulnerability to presentation attacks as a major challenge for face recognition solutions. This work deals with the explanation of the issues related to the detection of facial liveliness, which will help to understand the various possibilities of attack and their relationship to existing solutions. And the implementation of an algorithm that recognizes the liveliness of the face based on videos.

Face Liveness Detection under Processed Image Attacks

Face recognition is a mature and reliable technology for identifying people. Due to high-definition cameras and supporting devices, it is considered the fastest and the least intrusive biometric recognition modality. Nevertheless, effective spoofing attempts on face recognition systems were found to be possible. As a result, various anti-spoofing algorithms were developed to counteract these attacks. They are commonly referred in the literature a liveness detection tests. In this research we highlight the effectiveness of some simple, direct spoofing attacks, and test one of the current robust liveness detection algorithms, i.e. the logistic regression based face liveness detection from a single image, proposed by the Tan et al. in 2010, against malicious attacks using processed imposter images. In particular, we study experimentally the effect of common image processing operations such as sharpening and smoothing, as well as corruption with salt and pepper noise, on the face liveness detection algorithm, and we find that it is especially vulnerable against spoofing attempts using processed imposter images. We design and present a new facial database, the Durham Face Database, which is the first, to the best of our knowledge, to have client, imposter as well as processed imposter images. Finally, we evaluate our claim on the effectiveness of proposed imposter image attacks using transfer learning on Convolutional Neural Networks. We verify that such attacks are more difficult to detect even when using high-end, expensive machine learning techniques