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Extract transformation between two configurations

Source: R/get.R
get_transform.Rd

Calculate the scale, rotation, and translation needed to transform one configuration into another.

Usage

get_transform(source, target)

Arguments

source

Matrix (nx2). Source configuration.

target

Matrix (nx2). Target configuration.

Value

A list with three elements:

  • scale: Numeric. Scale factor.

  • rotation: Numeric. Rotation angle in radians.

  • translation: Numeric vector of length 2. Translation (dx, dy).

Details

Calculates transformation based on the furthest pair of points in the source configuration. Finds the corresponding pair in the target and extracts:

  • Scale: ratio of distances between furthest points

  • Rotation: angle difference between the two vectors

  • Translation: shift after scaling and rotation

Both configurations must have the same number of points.

See also

get_transformed()

Examples

source <- matrix(c(0,0, 1,0, 1,1, 0,1), ncol=2, byrow=TRUE)
target <- source * 2  # Scaled by 2
transform <- get_transform(source, target)
transform$scale  # Should be ~2
#> [1] 2