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Preprocessings

Read images

Use the load_gray2float function to read grayscale hologram images.

ParticleHolography.load_gray2float — Function
load_gray2float(path)

Load a grayscale image from a file and return it as a Array{Float32, 2} array.

Arguments

  • path::String: The path to the image file.

Returns

  • Array{Float32, 2}: The image as a Float32 array.
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Background removal

Given a list of hologram paths, a background image is generated by the mean or mode of the brightness values at each pixel of the hologram. Lists of holograms can be obtained using the Glob package. It is preferable if these are time series data that record few objects. It may takes a while to process a large number of holograms. A progress bar is displayed during processing.

using ParticleHolography
using Glob

pathlist = glob("path/to/hologram/*.png")
bkg = make_background(pathlist, mode=:mode)

# Remove the background
img = load_gray2float("path/to/hologram/holo1.png")
img .= img .- bkg .+ 64/255

The mode argument can be set to :mean or :mode. The default is :mode.

ParticleHolography.make_background — Function
make_background(pathlist; mode=:mode)

Make a background image from a list of image paths. The background image is calculated by taking the mean or mode of the images in the list. The default mode is :mode.

Arguments

  • pathlist::Vector{String}: A list of image paths. glob() can be used to generate this list.
  • mode::Symbol: The mode to use for calculating the background. Options are :mean or :mode. Default is :mode.

Returns

  • Array{Float64, 2}: The background image.
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