Restore docstring deleted in #73

Author: timholy

src/fast_scanning.jl

@@ -20,6 +20,44 @@ getscalar(A::AbstractArray{T,N}, i::CartesianIndex{N}, block_length::CartesianIn
 
 getscalar(a::Real, i...) = a
 
+"""
+    seg_img = fast_scanning(img, threshold, [diff_fn])
+
+Segments the N-D image using a fast scanning algorithm and returns a
+[`SegmentedImage`](@ref) containing information about the segments.
+
+# Arguments:
+* `img`         : N-D image to be segmented (arbitrary axes are allowed)
+* `threshold`   : Upper bound of the difference measure (δ) for considering
+                  pixel into same segment; an `AbstractArray` can be passed
+                  having same number of dimensions as that of `img` for adaptive
+                  thresholding
+* `diff_fn`     : (Optional) Function that returns a difference measure (δ)
+                  between the mean color of a region and color of a point
+
+# Examples:
+
+```jldoctest; setup = :(using ImageCore, ImageMorphology, ImageSegmentation)
+julia> img = zeros(Float64, (3,3));
+
+julia> img[2,:] .= 0.5;
+
+julia> img[:,2] .= 0.6;
+
+julia> seg = fast_scanning(img, 0.2);
+
+julia> labels_map(seg)
+3×3 $(Matrix{Int}):
+ 1  4  5
+ 4  4  4
+ 3  4  6
+```
+
+# Citation:
+
+Jian-Jiun Ding, Cheng-Jin Kuo, Wen-Chih Hong,
+"An efficient image segmentation technique by fast scanning and adaptive merging"
+"""
 fast_scanning(img::AbstractArray{CT,N}, block::NTuple{N,Int} = ntuple(i->4,Val(N))) where {CT<:ImageCore.NumberLike,N} =
     fast_scanning(img, adaptive_thres(img, block))