2022 |
Križaj, Janez; Dobrišek, Simon; Štruc, Vitomir In: Sensors, iss. 6, no. 2388, pp. 1-26, 2022. Abstract | Links | BibTeX | Tags: 3d face, biometrics, face, face analysis, face images, face recognition @article{KrizajSensors2022, Most commercially successful face recognition systems combine information from multiple sensors (2D and 3D, visible light and infrared, etc.) to achieve reliable recognition in various environments. When only a single sensor is available, the robustness as well as efficacy of the recognition process suffer. In this paper, we focus on face recognition using images captured by a single 3D sensor and propose a method based on the use of region covariance matrixes and Gaussian mixture models (GMMs). All steps of the proposed framework are automated, and no metadata, such as pre-annotated eye, nose, or mouth positions is required, while only a very simple clustering-based face detection is performed. The framework computes a set of region covariance descriptors from local regions of different face image representations and then uses the unscented transform to derive low-dimensional feature vectors, which are finally modeled by GMMs. In the last step, a support vector machine classification scheme is used to make a decision about the identity of the input 3D facial image. The proposed framework has several desirable characteristics, such as an inherent mechanism for data fusion/integration (through the region covariance matrixes), the ability to explore facial images at different levels of locality, and the ability to integrate a domain-specific prior knowledge into the modeling procedure. Several normalization techniques are incorporated into the proposed framework to further improve performance. Extensive experiments are performed on three prominent databases (FRGC v2, CASIA, and UMB-DB) yielding competitive results. |
2018 |
Križaj, Janez; Emeršič, Žiga; Dobrišek, Simon; Peer, Peter; Štruc, Vitomir Localization of Facial Landmarks in Depth Images Using Gated Multiple Ridge Descent Proceedings Article In: 2018 IEEE International Work Conference on Bioinspired Intelligence (IWOBI), pp. 1–8, IEEE 2018. Abstract | Links | BibTeX | Tags: 3d face, 3d landmarking, face alignment, face landmarking, gated ridge descent @inproceedings{krivzaj2018localization, A novel method for automatic facial landmark localization is presented. The method builds on the supervised descent framework, which was shown to successfully localize landmarks in the presence of large expression variations and mild occlusions, but struggles when localizing landmarks on faces with large pose variations. We propose an extension of the supervised descent framework that trains multiple descent maps and results in increased robustness to pose variations. The performance of the proposed method is demonstrated on the Bosphorus, the FRGC and the UND data sets for the problem of facial landmark localization from 3D data. Our experimental results show that the proposed method exhibits increased robustness to pose variations, while retaining high performance in the case of expression and occlusion variations. |