Added Median for background estimation

src/Background/Background.jl

@@ -1,7 +1,8 @@
 module Background
 
 export estimate_background,
-       Mean
+       Mean,
+       Median
 
 
 # Abstract types
@@ -33,9 +34,9 @@ estimate_background(T::Type{<:BackgroundEstimator}, d::AbstractArray; dims = :)
 
 Perform 2D background estimation using the given estimator using meshes and kernels.
 
-This function will estimate backgrounds in meshes of size `box_size`, using a filter kernel of size `kernel_size`. These correspond to the dimension, so for 2D data you could specify (20,) or (20,20) as the box/kernel size, matching with dims=1 for the scalar variant. 
+This function will estimate backgrounds in meshes of size `box_size`, using a filter kernel of size `kernel_size`. These correspond to the dimension, so for 2D data you could specify (20,) or (20,20) as the box/kernel size, matching with dims=1 for the scalar variant.
 
-If either size is an integer, the implicit shape will be square (eg. `box_size=4` is equivalent to `box_size=(4,4)`). Contrast this to a single dimension size, like `box_size=(4,)`. 
+If either size is an integer, the implicit shape will be square (eg. `box_size=4` is equivalent to `box_size=(4,4)`). Contrast this to a single dimension size, like `box_size=(4,)`.
 
 If the background estimator has no parameters (like [`Mean`](@ref)), you can just specify the type without construction.
 

src/Background/stat_estimators.jl

@@ -20,3 +20,24 @@ julia> estimate_background(Mean, data, dims=1)
 struct Mean <: BackgroundEstimator end
 
 estimate_background(::Mean, data; dims = :) = mean(data, dims = dims)
+
+"""
+    Median <: BackgroundEstimator
+
+This estimator returns the median of the input.
+
+#Example
+```jldoctest
+julia> data = ones(5 ,5)
+
+julia> estimate_background(Median, data)
+1.0
+
+julia> estimate_background(Median, data, dims=1)
+1×5 Array{Float64,2}:
+ 1.0  1.0  1.0  1.0  1.0
+```
+"""
+struct Median <: BackgroundEstimator end
+
+estimate_background(::Median, data; dims = :) = median(data, dims = dims)

test/background/simple.jl

@@ -14,7 +14,7 @@ function test_zeros(estimator)
     @test estimate_background(estimator, data, dims = 2) ≈ zeros(10)
 end
 
-@testset "$E"  for E in [Mean]
+@testset "$E"  for E in [Mean, Median]
     @test estimate_background(E, ones(10, 10)) == estimate_background(E(), ones(10, 10))
     test_ones(E)
     test_zeros(E)