matlab中的conv2卷积运算的三种形式

thinkfunny

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matlab中的conv2是用于对二维数据进行卷积运算，有三个参数可供选择，下面是help content of conv2

conv2 Two dimensional convolution.
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2 }' b6 M+ h/ K; e    C = conv2(A, B) peRForms the 2-D convolution of matrices A and B.
, p2 |# z- h8 S* w    If [ma,na] = size(A), [mb,nb] = size(B), and [mc,nc] = size(C), then
    mc = max([ma+mb-1,ma,mb]) and nc = max([na+nb-1,na,nb]).
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* z9 d* T( }# W: v2 `: h    C = conv2(H1, H2, A) first convolves each column of A with the vector
" T* m( [; x0 e7 ]. k, q  s7 Z* c    H1 and then convolves each row of the result with the vector H2.  If
+ G/ @9 r; y+ {, k; w. Z! Q( q    n1 = length(H1), n2 = length(H2), and [mc,nc] = size(C) then
+ M, |$ O& v$ u: O# Z0 A0 g# ?    mc = max([ma+n1-1,ma,n1]) and nc = max([na+n2-1,na,n2]).
& l: `* d# T4 l6 A& g8 K    conv2(H1, H2, A) is equivalent to conv2(H1(：)*H2(：).', A) up to
    round-off.

    C = conv2(..., SHAPE) returns a subsection of the 2-D
    convolution with size specified by SHAPE:
      'full'  - (default) returns the full 2-D convolution,
: v( I0 n" N# J8 R/ h& `      'same'  - returns the central part of the convolution
                that is the same size as A.
' o! c& J+ T. f+ `      'valid' - returns only those parts of the convolution
: j; ~* e1 x. g" X3 m! A: J$ _" q/ ?                that are computed without the zero-padded edges.
! X  L) ]7 E' `; ~4 @                size(C) = max([ma-max(0,mb-1),na-max(0,nb-1)],0).
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/ v+ ]& K, [  u# r7 u) ]关于full, same以及valid三种参数的区别，如下面的实例所示：

full

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6 o8 _7 B  e; |8 b* [3 ksame
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valid

yin123

三种形式的matlab中的conv2卷积运算