scripts/builtin/img_posterize.dml

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#-------------------------------------------------------------

# Image Posterize
# Limit pixel values to 2^bits different values in the range [0, 255].
# Assumes the input image can attain values in the range [0, 255].
#
# INPUT PARAMETERS:
# ---------------------------------------------------------------------------------------------
# NAME       TYPE   DEFAULT MEANING
# ---------------------------------------------------------------------------------------------
# img_in     Matrix ---     Input image
# bits       Int    ---     The number of bits keep for the values.
#                           1 means black and white, 8 means every integer between 0 and 255.

# RETURN VALUES
# ---------------------------------------------------------------------------------------------
# img_out    Matrix ---     Output image
# ---------------------------------------------------------------------------------------------

m_img_posterize = function(Matrix[Double] img_in, Integer bits) return (Matrix[Double] img_out) {
  img_out = (img_in %/% 2^(8 - bits)) * (2^(8 - bits))
}