Photo-Anthropometry
Definition
The measurement of anatomical facial landmark ratios (scale-invariant) from face images; sensitive to head pose differences and requires geometric correction for images taken at different angles.
- Field
- Facial recognition and comparison
- Measures
- Anatomical facial landmark ratios
- Property
- Scale-invariant
- Limitation
- Sensitive to head pose differences between images
Common questions
Why does head pose matter if the ratios are scale-invariant?+
Scale invariance corrects for how close or far the camera was, but it does not correct for the face being turned or tilted, which changes where landmarks project in the two-dimensional image and distorts the measured ratios.
How do examiners correct for pose before comparing ratios?+
Geometric correction techniques estimate the head's rotation and warp the image toward a common frontal reference before landmark ratios are measured, though residual error remains larger for extreme angle differences.
Is photo-anthropometry used alone in automated face recognition systems?+
Modern systems like those evaluated in NIST FRVT largely rely on machine-learned feature embeddings rather than manual landmark ratios, so photo-anthropometry today functions more as a supporting or explainable-comparison tool in forensic casework.
Related terms
- AFRS (India)
- Automated Facial Recognition System, the face recognition module within India's CCTNS, operated by the NCRB and used for searching against mug shots,...
- Deep Convolutional Neural Network (DCNN) Embedding
- The face descriptor produced by a neural network trained to map face images into a metric space where same-person images cluster together;...
- ENFSI BPM
- The ENFSI Best Practice Manual for Forensic Comparison of Speech (2015, rev. 2022); the operational standard for speaker comparison in European forensic...
- False Positive Identification Rate (FPIR)
- In 1:N identification, the rate at which a probe image of an individual not in the gallery generates a top-rank match. Critical...
- IPD Pixels
- Inter-pupillary distance measured in pixels, the primary resolution metric for face recognition; NIST FRVT finds reliable recognition requires approximately 50+ IPD pixels;...
- Morphological Analysis
- The systematic comparison of qualitative facial feature shapes from a standardised feature list; the primary method in ENFSI BPM facial image comparison,...
- NGI Face Component
- The face recognition module within the FBI's Next Generation Identification system, which searches a gallery of over 600 million images, including driver's...
- NIST FRVT
- The National Institute of Standards and Technology Face Recognition Vendor Testing programme, the primary independent benchmark for facial recognition algorithms, publishing ongoing...
- Verbal Likelihood Ratio (VLR)
- The scale used by ENFSI and the UK Forensic Science Regulator for forensic comparison conclusions, running from 'No support for the proposition...