conv2 for x-y separable kernels

JuliaLang · Dec 22, 2011 · 823cff9 · 823cff9
1 parent 7cd1f9e
commit 823cff9
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/j/abstractarray.j b/j/abstractarray.j
@@ -325,7 +325,7 @@ function hcat{T}(V::AbstractVector{T}...)
     for j = 2:length(V)
         if length(V[j]) != height; error("hcat: mismatched dimensions"); end
     end
-    [ V[j][i] | i=1:length(V[1]), j=1:length(V) ]
+    [ V[j][i]::T | i=1:length(V[1]), j=1:length(V) ]
 end
 
 function vcat{T}(V::AbstractVector{T}...)

diff --git a/j/signal.j b/j/signal.j
@@ -73,6 +73,22 @@ function conv{T}(u::Vector{T}, v::Vector{T})
     return y
 end
 
+function conv2{T}(y::Vector{T}, x::Vector{T}, A::Matrix{T})
+    m = length(y)+size(A,1)-1
+    n = length(x)+size(A,2)-1
+    B = zeros(T, m, n)
+    B[1:size(A,1),1:size(A,2)] = A
+    y = fft([y;zeros(T,m-length(y))])./m
+    Y = repmat(reshape(y,m,1), 1, n)
+    x = fft([x;zeros(T,n-length(x))])./n
+    X = repmat(reshape(x,1,n), m, 1)
+    C = ifft2(fft(fft(B,(),2).*X,(),1).*Y)
+    if T <: Real
+        return real(C)
+    end
+    return C
+end
+
 function xcorr(u, v)
     su = size(u,1); sv = size(v,1)
     if su < sv