Update README.md

Author: Cody-G

README.md

@@ -1,5 +1,30 @@
 # ImageInterpLast
 
-This package allows setting interpolation coefficients on a per-slice basis.  This allows one to compensate for non-simultaneous sampling of multiple image planes in a stack.
+This package uses interpolation to compensate for sampling time differences that occur when a sequence of 3D image "stacks" is assembled from a sequence of 2D snapshots.
 
-More thorough docs are on the way.
+```julia
+using ImageInterpLast
+
+#Lazy interpolation between "forward" stacks and "reverse" stacks in a bidirectional recording
+
+img = rand(10,10,10,10) #suppose this is a 4D image sequence (3D + time)
+
+coef = 0.5 #interpolation coefficient, 0.5 means simply average neighboring values
+
+#Construct an interpolated image.
+#This does not allocate memory, except for a cache holding data for the current image slice (reduces the number of reads from disk)
+img_itp = interp_last(img, coef; cache3d=false, out_type=Float32)
+
+#(cache3d=true would cache an entire 3D "stack" instead)
+
+@show size(img)
+@show size(img_itp) #one less in the time dimension due to interpolation
+
+#Index the object like an AbstractArray. Interpolated values are computed on-demand.
+#The statement below returns the pixel-wise average of stacks 3 and 4 (i.e. img[:,:,:,3] .* 0.5 + img[:,:,:,4] .* 0.5)
+stack3 = img_itp[:,:,:,3]
+
+#If needed you can also interpolate with a different coefficient for each 2D slice of a stack.
+#To do this simply pass a vector of coefficients to interp_last.
+#This would be useful for resampling an image timeseries acquired with conventional unidirectional scanning.
+```