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Get 478-Point Face Mesh Landmarks

Source: R/landmarks.R
get_face_landmarks.Rd

Extracts dense facial landmarks using MediaPipe Face Mesh, which provides 478 3D landmark points covering the entire face, including the irises.

Usage

get_face_landmarks(img_path, return_3d = TRUE)

Arguments

img_path

Path to the image file.

return_3d

Logical. If TRUE, returns 3D coordinates (x, y, z). If FALSE, returns only 2D coordinates (x, y). Default is TRUE.

Value

A list containing:

  • landmarks - Matrix of landmark coordinates (478 x 2 or 478 x 3)

  • face_detected - Logical indicating if a face was found

  • image_width - Width of the input image

  • image_height - Height of the input image

  • n_landmarks - Number of landmarks (when a face was found)

Details

MediaPipe Face Mesh provides detailed landmarks covering:

  • Face oval/contour

  • Left and right eyebrows

  • Left and right eyes, with 10 iris points (468 to 477)

  • Nose

  • Lips (inner and outer contours)

  • Face interior regions (cheeks, forehead)

The x and y coordinates are normalized to [0, 1] relative to image dimensions. The z coordinate represents depth relative to the face center.

Older MediaPipe releases expose the legacy mediapipe.solutions.face_mesh interface, which is used when present. Current releases have only the Tasks API (FaceLandmarker), which needs a model file. It is downloaded once, on first use, to tools::R_user_dir("r4lineups", "cache"). On macOS the Tasks API runs on the GPU delegate, because the CPU delegate in current macOS wheels aborts the process.

Note

Requires MediaPipe to be installed (installed by default with install_r4lineups_python()).

Examples

if (FALSE) { # \dontrun{
# Get face mesh landmarks
mesh <- get_face_landmarks("face.jpg")

# Plot the landmarks
plot(mesh$landmarks[, 1], mesh$landmarks[, 2], pch = ".")
} # }