Detect Objects in a Local Image

Run SAM3 object detection on a non-georeferenced image (PNG, JPG, etc.). For georeferenced satellite imagery, use sam_detect() instead.

Usage

sam_image(
  image,
  text = NULL,
  points = NULL,
  labels = NULL,
  boxes = NULL,
  exemplar = NULL,
  threshold = 0.5
)

Arguments

image

Path to image file (PNG, JPG, TIFF, etc.).

text

Text prompt describing objects to detect (e.g., "car", "person").

points

Matrix or data.frame of point coordinates in pixels (x, y). Column 1 is x (horizontal), column 2 is y (vertical, from top).

labels

Integer vector of labels for point prompts (1 = foreground, 0 = background). If NULL, all points are treated as foreground.

boxes

Matrix or data.frame of box coordinates in pixels. Each row: (xmin, ymin, xmax, ymax).

exemplar

Vector of box coordinates for an exemplar (xmin, ymin, xmax, ymax).

threshold

Detection confidence threshold (0-1).

Value

A geosam_image object containing detection masks and metadata. Use sam_as_sf() to extract polygons (in pixel coordinates). Returns NULL if no objects are detected.

Examples

if (FALSE) { # \dontrun{
# Text-based detection on a photo
result <- sam_image("photo.jpg", text = "dog")

# Point prompts (click locations in pixels)
result <- sam_image("photo.jpg", points = matrix(c(100, 200, 150, 250), ncol = 2, byrow = TRUE))

# Extract polygons
polys <- sam_as_sf(result)
} # }