Happy Feet - research into baby footprints as an infant biometric

The pressing infant biometric problem is to find a biometric means to identify infants cheaply, reliably, and automatically. Physical traits of infants are tiny, delicate, and grow rapidly. The authors focus on a novel area of friction-ridge skin as a potential answer: the ball under the big toe. The ballprint is readily accessible, with more features and larger ridges than a fingerprint. The authors followed 54 newborns for 2 years, capturing their ballprints with an adult fingerprint scanner within 3 days of birth, at 2 months, at 6 months, and at 2 years. The authors show the growth of the ballprint is isotropic rather than affine during infancy. The isotropic growth rate from birth can be measured by the change in inter-ridge spacing, which the authors show precisely mirrors change in physical length from birth, as recorded by World Health Organisation for large, diverse infant populations. From 2 months of age, by using isotropic scaling to compensate for growth, the authors successfully matched good quality images with 0% equal error rate using existing adult fingerprint technology, even for captures 22 months apart. These findings flag the value of ballprints as a practical means of infant identification, by themselves, or together or sequentially with other biometrics.Sample data attached, full data set available from author on request.

当下亟待解决的婴幼儿生物识别核心问题，是寻得一种低成本、可靠且可自动实现的婴幼儿生物识别手段。婴幼儿的身体特征尺寸微小、结构娇嫩且生长速度迅猛。本研究团队聚焦于摩擦脊皮肤（friction-ridge skin）这一潜在解决方案中的全新方向：拇趾球区域。该区域的球纹（ballprint）易于采集，且相较于指纹，具备更多特征点与更宽大的脊纹结构。研究团队对54名新生儿开展了为期2年的追踪研究，分别在出生后3日内、2月龄、6月龄及2周岁时，使用成人指纹扫描仪采集其球纹图像。研究证实，婴幼儿阶段的球纹生长呈现各向同性（isotropic）特征，而非仿射（affine）生长模式。通过脊间距的变化可测算出生后的各向同性生长速率，研究表明该速率与世界卫生组织针对大型多样化婴幼儿群体记录的出生后身体长度变化完全一致。自2月龄起，借助各向同性缩放补偿生长形变，研究团队利用现有成人指纹技术成功实现了高质量球纹图像的匹配，等错误率（equal error rate, EER）为0%，即便采集间隔长达22个月的图像也可完成精准匹配。上述研究结果凸显了球纹作为实用型婴幼儿生物识别方案的应用价值，可单独使用，亦可与其他生物识别技术结合或依次部署。本研究附带样本数据，完整数据集可应要求向作者申请获取。