avg: Average Images

In webmorphR: Reproducible Stimuli

Average Images

Description

Create an average from a list of delineated stimuli.

Usage

avg(
  stimuli,
  texture = TRUE,
  norm = c("none", "twopoint", "rigid"),
  normpoint = 0:1
)

Arguments

stimuli	list of stimuli to average
texture	logical; whether textured should be averaged
norm	how to normalise; see Details
normpoint	points for twopoint normalisation

Details

Normalisation options

• none: averages will have all coordinates as the mathematical average of the coordinates in the component templates

• twopoint: all images are first aligned to the 2 alignment points designated in normpoint. Their position is set to their position in the first image in stimuli

• rigid: procrustes aligns all images to the position of the first image in stimuli

Texture

This applies a representative texture to the average, resulting in composite images with more realistic texture instead of the very smooth, bland texture most other averaging programs create. See the papers below for methodological details.

B. Tiddeman, M. Stirrat and D. Perrett (2005). Towards realism in facial prototyping: results of a wavelet MRF method. Theory and Practice of Computer Graphics.

B. Tiddeman, D.M. Burt and D. Perrett (2001). Computer Graphics in Facial Perception Research. IEEE Computer Graphics and Applications, 21(5), 42-50.

Value

list of stimuli with the average image and template

See Also

WebMorph.org functions continuum(), loop(), symmetrize(), trans(), webmorph_up()

Examples

if (webmorph_up()) {
  demo_stim() |> avg()
}

webmorphR documentation built on June 2, 2022, 5:07 p.m.