3D Imaging Glossary for Aesthetic Medicine: 40 Terms Explained

Vendor brochures and research papers on 3D imaging use a lot of jargon. This glossary explains the terms you are most likely to meet, in plain language, grouped by topic. Bookmark it for your next vendor demo.

Capture

3D surface imaging: recording the outer shape of the face or body as a digital model. See what is 3D facial imaging.

Photogrammetry: building a 3D model from many overlapping 2D images by matching features and calculating depth. Explained in how smartphone 3D scanning works.

Stereophotogrammetry: photogrammetry using two or more cameras that fire at the same instant from known positions. The basis of most fixed clinical rigs.

Structured light: a scanner projects a known pattern onto the surface and measures how it bends to compute depth.

LiDAR: light detection and ranging; measures distance by timing reflected laser pulses. Present on some phones and tablets.

TrueDepth / infrared depth camera: a front-facing phone sensor that projects infrared dots to measure depth, originally built for face unlock.

Structure from motion (SfM): the step that works out where the camera was for each frame while also recovering rough 3D points.

Capture pass: the movement of the phone or scanner around the subject during a scan.

Frankfort horizontal plane: a clinical reference line from the top of the ear canal to the lowest point of the eye socket. Keeping it level helps standardise head position.

Model

Point cloud: a set of 3D points sampled from the surface. "Dense" point clouds have many thousands of points.

Mesh: a surface made of connected triangles built from the point cloud. This is the model you rotate and measure.

Vertex: a single corner point of a mesh triangle.

Texture map: the colour image wrapped onto the mesh so the model looks like the patient.

Resolution: how fine the detail of the model is; roughly, how close together the points are.

Scale: the link between model units and real millimetres. Without correct scale, measurements are meaningless.

Hole / gap: an area the capture missed, often under the chin or beside the nose. See capture tips.

STL / OBJ / PLY: common 3D file formats. OBJ and PLY can carry colour; STL usually does not.

Measurement

Landmark: a defined anatomical point, such as the tip of the nose (pronasale) or the corner of the mouth (cheilion).

Linear measurement: a straight-line distance between two landmarks, in millimetres.

Surface (geodesic) distance: the distance measured along the skin surface rather than through the air.

Volume difference: the volume between two aligned surfaces, used to measure filler, swelling or fat reduction. See dermal filler volume measurement.

Colour map / heat map: a visual of how far two surfaces are apart at each point, often with one colour for added volume and another for lost volume.

Symmetry analysis: mirroring one half of the face onto the other and measuring the differences. See facial symmetry analysis.

Projection: how far a feature stands out from a reference plane, such as chin or cheek projection.

Annotation: marks, lines and notes placed directly on the 3D model.

Comparison

Registration / alignment: positioning two scans so the same anatomy lines up, usually using stable regions like the forehead and nose bridge.

Superimposition / overlay: displaying two aligned scans together to show change.

Day 0 / baseline: the first scan before treatment, against which all follow-ups are compared.

Reference regions: areas assumed not to change between visits, used to align scans.

Accuracy and statistics

Trueness: how close a measurement is to the real value, often judged against a reference system.

Precision / repeatability: how close repeated measurements of the same thing are to each other.

Reference (gold standard) system: a well-validated system, such as a clinical rig, used to test a new one.

Mean deviation: the average distance between matching points on two models.

RMS (root mean square): an average of deviations that weights larger errors more heavily.

Bland-Altman analysis / limits of agreement: a method that shows how far two measurement methods can disagree for most measurements, often stated as 95% limits.

ICC (intraclass correlation coefficient): a score from 0 to 1 showing how consistently two methods agree; values above about 0.9 are usually called excellent.

Clinically acceptable threshold: the error below which a measurement is considered good enough for clinical use. In facial soft-tissue work, 2 mm is widely used. Read the evidence in how accurate is smartphone 3D face scanning.

Data and privacy

Biometric data: data about physical characteristics, including facial geometry. Treat 3D scans as sensitive.

Data fiduciary: under India's DPDP Act, the entity that decides why and how personal data is processed. For patient scans, that is usually the clinic.

Data processor: an entity that processes data on behalf of the fiduciary, such as an imaging software provider.

Pseudonymisation: storing scans separately from names and identifiers so that a breach of one does not expose the other.

Data localisation: keeping data stored and processed within India. For your obligations, see the DPDP Act and patient photos.

Frequently asked questions

What is a mesh in 3D imaging?

A mesh is the surface of a 3D model, made of many small connected triangles. It is built from a point cloud and is what you measure on.

What does RMS mean in 3D scan accuracy?

RMS, or root mean square, is an average of the deviations between two surfaces that gives more weight to larger errors. Lower RMS means the surfaces match more closely.

What is a superimposition in aesthetic imaging?

Superimposition, or overlay, aligns two 3D scans of the same patient, usually from different visits, so the difference between them can be seen and measured.

Edebo is a measurement and visualisation tool, not a diagnostic device. Clinical decisions remain with the treating practitioner.