sphericalRange: Find pixels within a target color range defined by a center...

In countcolors: Locates and Counts Pixels Within Color Range(s) in Images

Description

Searches for pixels within a radius of a single color. Draws a sphere around a region of color space in which to search for pixels.

Usage

sphericalRange(pixel.array, center, radius, target.color = "green",
  main = "", color.pixels = TRUE, plotting = TRUE)

Arguments

pixel.array	An image represented as a 3D array (as read in by readJPEG, readPNG, or loadImage) in which to change pixel colors.
center	A single color (RGB triplet) around which to search. RGB range 0-1 (not 0-255).
radius	A value between 0 and 1 specifying the size of the area around center to search.
target.color	Color with which to replace specified pixels. Can be either a an RGB triplet or one of the colors listed by colors.
main	Optional title to display for image.
color.pixels	Logical. Should a diagnostic image with pixels changed to target.color be returned?
plotting	Logical. Should output be plotted in the plot window?

Details

lower and upper should be vectors of length 3 in a 0-1 range, in the order R-G-B. For example, the upper bounds for white would be c(1, 1, 1), and the lower bounds might be c(0.8, 0.8, 0.8). This would search for all pixels where the red value, blue value, AND green value are all between 0.8 and 1.

Value

A list with the following elements:

• pixel.idx: Coordinates of pixels within color range.

• img.fraction: Proportion of the image within color range.

• original.img: The original RGB array.

• indicator.img: If color.pixels = TRUE, RGB array with color-swapped pixels.

Examples

# Target color: change all of the red flowers to turquoise
flowers <- jpeg::readJPEG(system.file("extdata", "flowers.jpg", package =
"countcolors"))

# Red:
center <- c(255, 75, 75) / 255

# Setting the radius too low:
red.flowers <- countcolors::sphericalRange(flowers, center = center, radius =
0.05, target.color = "turquoise")

# Setting the radius too high:
red.flowers <- countcolors::sphericalRange(flowers, center = center, radius =
0.4, target.color = "turquoise")

# Setting the radius just right:
red.flowers <- countcolors::sphericalRange(flowers, center = center, radius =
0.2, target.color = "turquoise")

countcolors documentation built on May 2, 2019, 6:08 a.m.