Abstract
Craniofacial Superimposition is a forensic technique for identifying skeletal remains by comparing a post-mortem skull with ante-mortem facial photographs. A critical step in this process is Skull-Face Overlay (SFO). This stage involves aligning a 3D skull model with a 2D facial image, typically guided by cranial and facial landmarks' correspondence. However, its accuracy is undermined by individual variability in soft-tissue thickness, introducing significant uncertainty into the overlay. This paper introduces Lilium, an automated evolutionary method to enhance the accuracy and robustness of SFO. Lilium explicitly models soft-tissue variability using a 3D cone-based representation whose parameters are optimized via a Differential Evolution algorithm. The method enforces anatomical, morphological, and photographic plausibility through a combination of constraints: landmark matching, camera parameter consistency, head pose alignment, skull containment within facial boundaries, and region parallelism. This emulation of the usual forensic practitioners' approach leads Lilium to outperform the state-of-the-art method in terms of both accuracy and robustness.
Abstract (translated)
颅面叠合技术是一种法医手段，通过比较死后的头骨与生前的面部照片来识别骨骼遗骸。在这个过程中最关键的步骤是颅面重叠（Skull-Face Overlay, SFO）。该阶段涉及将一个3D头骨模型与2D面部图像对齐，通常依据颅部和面部标志点的一致性来进行指导。然而，这种方法的准确性因个体软组织厚度的变化而受到影响，这引入了显著的不确定性。 本文介绍了Lilium这一自动化进化方法，旨在提高SFO的准确性和鲁棒性。Lilium通过使用基于3D锥体表示的模型来显式地建模软组织变化，并利用差分演化算法优化其参数。该方法通过一系列约束条件确保解剖学、形态学和摄影上的合理性：包括标志点匹配、相机参数一致性、头部姿态对齐、头骨位于面部边界内以及区域平行性。这种模仿传统法医从业者的方法使Lilium在准确性和鲁棒性方面都超越了当前最先进的方法。 简而言之，通过更精确地模拟软组织的变化，并优化模型的参数，Lilium能够提供比现有技术更加可靠和精准的结果。
URL
https://arxiv.org/abs/2603.00170
