Frey Faces dataset

Converts Frey Faces Image dataset.

Usage

frey_faces()

Format

A data frame with 1965 rows and 561 variables.

Value

The Frey Faces dataset as a data frame.

Details

Returns the Frey Faces dataset in a data frame where each row is one image. This is a series of 1965 images (with dimension 20 x 28) of Brendan Frey's face taken from sequential frames of a video.

The variables are as follows:

• px1, px2, px3 ... px560 8-bit grayscale pixel values (0-255). The pixel index starts at the top right of the image (px1) and are then stored row-wise.

• color: A string representing a color in hex format. It can be used directly with e.g. the col parameter in the graphics::plot() function. The color goes from hsl(0, 50, 50) (red) at frame 1 to hsl(300, 50, 50) (purple) at frame 1965 and on a muted rainbow scale.

Note

Requires the RnavGraphImageData package to be installed.

See also

• Sam Roweis' dataset web page: http://www.cs.nyu.edu/~roweis/data.html.

• Each row can be visualized as an image using show_frey_face().

Examples

if (FALSE) { # \dontrun{
frey <- frey_faces()
# PCA Scores plot, with color indicating the frame index
frey_pca <- prcomp(frey[, -561], retx = TRUE, rank. = 2)
plot(frey_pca$x, col = frey$color, pch = 16, cex = 0.75)
} # }