floodFill: Fills a Connected Component with a Given Color.

In swarm-lab/Rvision: Computer Vision Library for R

Fills a Connected Component with a Given Color.

Description

floodFill fills a connected component starting from a seed point with a specified color.

Usage

floodFill(
  image,
  seed = c(1, 1),
  color = "white",
  lo_diff = 0,
  up_diff = 0,
  connectivity = 4
)

Arguments

image	An Image object.
seed	A 2-element vector indicating the x and y coordinates of the seed point from where to start the filling.
color	A value or vector of any kind of R color specification compatible with col2bgr representing the color of the border (default: "white").
lo_diff	Maximal lower brightness/color difference between the currently observed pixel and one of its neighbors belonging to the component, or a seed pixel being added to the component (see Details). It can be a single value or a vector of the same length as the number n of channels in image. If it is shorter, its elements will be recycled. If it has more, only the first n elements will be used.
up_diff	Maximal upper brightness/color difference between the currently observed pixel and one of its neighbors belonging to the component, or a seed pixel being added to the component (see Details). It can be a single value or a vector of the same length as the number n of channels in image. If it is shorter, its elements will be recycled. If it has more, only the first n elements will be used.
connectivity	The connetivity neighborhood to decide whether 2 pixels are contiguous. This parameter can take two values: 4: the neighborhood of a pixel are the four pixels located above (north), below (south), to the left (west) and right (east) of the pixel. 8 (the default): the neighborhood of a pixel includes the four 4-neighbors and the four pixels along the diagonal directions (northeast, northwest, southeast, and southwest).

Details

The connectivity is determined by the color/brightness closeness of the neighbor pixels. The pixel at (x,y) is considered to belong to the repainted domain if:

• in case of a floating range:

  • image[x',y'] - lo_diff <= image[x,y] <= image[x',y'] + up_diff

• in case of a fixed range:

  • image[seed$x,seed$y] − lo_diff <= image[x,y] <= image(seed$x,seed$y) + up_diff

where image[x′,y′] is the value of one of pixel neighbors that is already known to belong to the component. That is, to be added to the connected component, a color/brightness of the pixel should be close enough to:

• Color/brightness of one of its neighbors that already belong to the connected component in case of a floating range.

• Color/brightness of the seed point in case of a fixed range.

Value

This function returns the number of pixels that were filled and modifies image in place.

Author(s)

Simon Garnier, [e-mail]

See Also

connectedComponents

Examples

dots <- image(system.file("sample_img/dots.jpg", package = "Rvision"))
floodFill(dots, color = "green")

swarm-lab/Rvision documentation built on Feb. 7, 2024, 4:59 a.m.