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Convert integer intensity image to RGB color string form.

Source: R/vis_volume.R
vol.intensity.to.color.Rd

Convert a gray-scale image defined by intensity values in range [0, 1] to an image with identical dimensions that contains an R color string (like #222222) at each position. The color strings are computed from the intensities, by taking the intensity value as the value for all three RGB channels. I.e., the output is still gray-scale, but defined in RGB space. To make it clear, this function does not apply a colormap. It only changes the representation of the data, not the resulting colors.

Usage

vol.intensity.to.color(volume, scale = NULL)

Arguments

volume

numeric array, typically a 3D image with intensities in range [0, 1]. This function now also supports numeric matrices (2D images, slices) and numeric vectors (1D).

scale

numeric or character string, a scaling to apply to the values. Defaults to NULL, which means no scaling and requires the values in volume to be in rage [0, 1]. You can pass a number like 255 or the string 'normalize' to scale based on the data. You can pass the string 'normalize_if_needed' to scale only if the data is outside the range [0, 1], so that data in range [0.3, 0.5] would not be rescaled to [0, 1].

Value

array (or matrix, or vector) of RGB color strings. All of them will represent gray values.

Examples

   vol.intensity.to.color(c(0.0, 0.5, 1.0));
#> [1] "#000000" "#808080" "#FFFFFF"
   # output: "#000000" "#808080" "#FFFFFF"
   vol.intensity.to.color(c(20, 186, 240), scale="normalize");
#> [1] "#000000" "#C0C0C0" "#FFFFFF"
   vol.intensity.to.color(c(20, 186, 240), scale=255);
#> [1] "#141414" "#BABABA" "#F0F0F0"
   vol.intensity.to.color(c(0.0, 0.5, 0.8), scale="normalize");
#> [1] "#000000" "#9F9F9F" "#FFFFFF"
   vol.intensity.to.color(c(0.0, 0.5, 0.8), scale="normalize_if_needed");
#> [1] "#000000" "#808080" "#CCCCCC"