Adds PiecewiseLinearStretching

Project.toml

@@ -1,25 +1,32 @@
 name = "ImageContrastAdjustment"
 uuid = "f332f351-ec65-5f6a-b3d1-319c6670881a"
-authors = ["Dr. Zygmunt L. Szpak <zygmunt.szpak@gmail.com>"]
-version = "0.3.10"
+authors = ["Dr. Zygmunt L. Szpak <zygmunt.szpak@gmail.com> and contributors"]
+version = "0.4.0"
 
 [deps]
 ImageCore = "a09fc81d-aa75-5fe9-8630-4744c3626534"
 ImageTransformations = "02fcd773-0e25-5acc-982a-7f6622650795"
+IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 Parameters = "d96e819e-fc66-5662-9728-84c9c7592b0a"
+Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
+StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 
 [compat]
 ImageCore = "0.9.3"
 ImageTransformations = "0.8.1, 0.9"
+IntervalSets = "0.5.3"
 Parameters = "0.12"
+Reexport = "1.2.2"
+StatsBase = "0.33"
 julia = "1"
 
 [extras]
 ImageFiltering = "6a3955dd-da59-5b1f-98d4-e7296123deb5"
+ImageIO = "82e4d734-157c-48bb-816b-45c225c6df19"
 ImageMagick = "6218d12a-5da1-5696-b52f-db25d2ecc6d1"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 TestImages = "5e47fb64-e119-507b-a336-dd2b206d9990"
 
 [targets]
-test = ["Test", "ImageFiltering", "TestImages", "ImageMagick", "LinearAlgebra"]
+test = ["Test", "ImageFiltering", "TestImages", "ImageMagick", "ImageIO", "LinearAlgebra"]

docs/Project.toml

@@ -1,6 +1,7 @@
 [deps]
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
+ImageContrastAdjustment = "f332f351-ec65-5f6a-b3d1-319c6670881a"
 ImageCore = "a09fc81d-aa75-5fe9-8630-4744c3626534"
 ImageMagick = "6218d12a-5da1-5696-b52f-db25d2ecc6d1"
 ImageShow = "4e3cecfd-b093-5904-9786-8bbb286a6a31"

docs/src/reference.md

@@ -13,6 +13,12 @@ adjust_histogram!
 build_histogram
 ```
 
+## Adjunt Types
+```@docs
+Percentiles
+MinMax
+```
+
 ## Algorithms
 
 ```@docs
@@ -48,3 +54,8 @@ Matching
 ```@docs
 MidwayEqualization
 ```
+
+### PiecewiseLinearStretching
+```@docs
+PiecewiseLinearStretching
+```

src/ImageContrastAdjustment.jl

@@ -4,7 +4,11 @@ using ImageCore
 using ImageTransformations: imresize
 # Where possible we avoid a direct dependency to reduce the number of [compat] bounds
 using ImageCore.MappedArrays
+using IntervalSets
 using Parameters: @with_kw # Same as Base.@kwdef but works on Julia 1.0
+using Reexport
+using StatsBase: percentile
+@reexport using IntervalSets
 
 # TODO: port HistogramAdjustmentAPI to ImagesAPI
 include("HistogramAdjustmentAPI/HistogramAdjustmentAPI.jl")
@@ -14,6 +18,23 @@ import .HistogramAdjustmentAPI: AbstractHistogramAdjustmentAlgorithm,
 # TODO Relax this to all image color types
 const GenericGrayImage = AbstractArray{<:Union{Number, AbstractGray}}
 
+# Temporary definition which will be moved to ImageCore.
+"""
+    Percentiles(p₁, p₂, p₃, ..., pₙ)
+Specifies a length-n list of [percentiles](https://en.wikipedia.org/wiki/Percentile).
+"""
+struct Percentiles{T} <: Real
+    p::T
+end
+Percentiles(args...) = Percentiles(tuple(args...))
+"""
+    MinMax()
+A type that can be used to signal to [`PiecewiseLinearStretching`](@ref) that it should
+use the mininum and maximum value in an image as it source or destination interval. 
+"""
+struct MinMax end
+
+
 include("core.jl")
 include("build_histogram.jl")
 include("algorithms/common.jl")
@@ -24,6 +45,7 @@ include("algorithms/contrast_stretching.jl")
 include("algorithms/gamma_correction.jl")
 include("algorithms/matching.jl")
 include("algorithms/midway_equalization.jl")
+include("algorithms/piecewise_linear_stretching.jl")
 include("compat.jl")
 
 export
@@ -35,6 +57,9 @@ export
     GammaCorrection,
     LinearStretching,
     ContrastStretching,
+    PiecewiseLinearStretching,
+    Percentiles,
+    MinMax,
     build_histogram,
     adjust_histogram,
     adjust_histogram!