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
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5 S2 H8 d) e, j% E% K) v/ s# \conv2 Two dimensional convolution.

  Q2 P+ R$ a' A* A    C = conv2(A, B) peRForms the 2-D convolution of matrices A and B.
    If [ma,na] = size(A), [mb,nb] = size(B), and [mc,nc] = size(C), then
' N2 v( B6 E+ h' ~    mc = max([ma+mb-1,ma,mb]) and nc = max([na+nb-1,na,nb]).

    C = conv2(H1, H2, A) first convolves each column of A with the vector
0 w* C( f9 ~' O! K' W. d    H1 and then convolves each row of the result with the vector H2.  If
    n1 = length(H1), n2 = length(H2), and [mc,nc] = size(C) then
4 e. F  C' {. C+ d. S" W. F9 r( e    mc = max([ma+n1-1,ma,n1]) and nc = max([na+n2-1,na,n2]).
$ B" \% y- q# v% b0 M  `    conv2(H1, H2, A) is equivalent to conv2(H1(：)*H2(：).', A) up to
3 z5 \. c7 h0 m- q0 v+ o# W    round-off.
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) W! ], u# p5 P6 D" X9 S( ]    C = conv2(..., SHAPE) returns a subsection of the 2-D
    convolution with size specified by SHAPE:
7 N1 N4 L$ f: q, i- ]" w      'full'  - (default) returns the full 2-D convolution,
      'same'  - returns the central part of the convolution
                that is the same size as A.
      'valid' - returns only those parts of the convolution
                that are computed without the zero-padded edges.
                size(C) = max([ma-max(0,mb-1),na-max(0,nb-1)],0).

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关于full, same以及valid三种参数的区别，如下面的实例所示：
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full
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same
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valid



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yin123

三种形式的matlab中的conv2卷积运算