Package 'image2data' reference manual

Title:	Turn Images into Data Sets
Description:	The goal of 'image2data' is to extract images and return them into a data set, especially for teaching data manipulation and data visualization. Basically, the eponymous function takes an image file ('png', 'tiff', 'jpeg', 'bmp') and turn it into a data set, pixels being rows (subjects) and columns (variables) being their coordinate positions (x- and y-axis) and their respective color (in hex codes). The function can return a complete image or a range of color (i.e., contour, silhouette). The data can then be manipulated as would any data set by either creating other related variables (to hide the image) or as a genuine toy data set.
Authors:	P.-O. Caron [aut, cre, cph] , Alexandre Dufresne [aut, cph]
Maintainer:	P.-O. Caron <[email protected]>
License:	MIT + file LICENSE
Version:	1.0.1
Built:	2025-02-03 02:37:42 UTC
Source:	https://github.com/quantmeth/image2data

Turn an image into data

Description

Extract an image file ("png", "tiff", "jpeg", "bmp") and turn it into an enjoyable data set, pixels being rows (subjects) and columns (variables) being their coordinate positions (x and y axis) and their respective color (in hex codes).

Usage

image2data(
  path,
  type = "fill",
  scaling = "standardized",
  showplot = TRUE,
  reduce = 1,
  A = 1,
  R = c(0, 0.05),
  G = c(0, 0.05),
  B = c(0, 0.05),
  Grey = NULL,
  precision = 1,
  seed = NULL
)
image2data(
  path,
  type = "fill",
  scaling = "standardized",
  showplot = TRUE,
  reduce = 1,
  A = 1,
  R = c(0, 0.05),
  G = c(0, 0.05),
  B = c(0, 0.05),
  Grey = NULL,
  precision = 1,
  seed = NULL
)

Arguments

`path`	Path to image file.
`type`	Type of extraction of data. `type = "fill"` (default) returns the complete image as data whereas `type = "line"` returns a specific range of color (default is black).
`scaling`	Tranform the data to a specified scale. Three options are available : `"standardized", "original", "normalized")`. `scaling = "standardized"` converts data in a standardized form, $\mu = 0, \sigma = 1$ (default); `scaling = "normalized"` converts data in a normalized form (to unit vectors); and `scaling = "original"` keeps the data untransformed.
`showplot`	Show a preliminary plot of the data (default is `TRUE`).
`reduce`	`reduce` can be a number `reduce > 0` or `reduce = "unique"`. By default `reduce = 1`, so all pixels are returned. Specified values between `0` to `1` will return the corrresponding proportion of the pixels. Values over `1` will return the number of pixels (e.g., `reduce = 3` returns 3 data). If the chosen number is over the number of pixels, then random duplicates are added. If `reduce = "unique"` only unique elements (given a certain `precision`) are returned.
`A`	Transparency, otherwise known as $\alpha$ . By default, only non transparent (`A = 1`) values are returned. Semi-transparent colors (`0 < A < 1`) are supported. Values between the `A` to `1` range will be return. If `A = 0`, all pixels are returned regardless of transparency.
`R`, `G`, `B`	Color to return with `type = "line"` (the default range is `c(0, .05)` for each, i.e., black). A single "range" of color can be used.
`Grey`	Grey range to be returned with `type = "line"`. `Grey` overwrites `R, G, B` and behaves similarly. Default is `NULL`
`precision`	Set precision of `reduce = "unique"`. Default is `1`. It can be any integer `>0`. Values closer to zero are less precised (less data), higher values are more precise (more data).
`seed`	Set seed value for random pixel returned with `reduce`.

Value

A data frame with pixels as rows and columns are x and y coordinates and g is their color in hex (factors).

Examples

path <- system.file(file.path("extdata", "success.png"), package = "image2data")
image2data(path = path, type = "line")
image2data(path = path, type = "line", Grey = c(0,.50))

## Not run: 
image2data(path = file.choose())

## End(Not run)
path <- system.file(file.path("extdata", "success.png"), package = "image2data")
image2data(path = path, type = "line")
image2data(path = path, type = "line", Grey = c(0,.50))

## Not run: 
image2data(path = file.choose())

## End(Not run)