Matlab里面这个算法是什么意思：conv2(bw1,vertical,'same'),具体怎么

Question

Matlab里面这个算法是什么意思：conv2(bw1,vertical,'same'),具体怎么算出来的？

Answer 1

 help conv2

 conv2 Two dimensional convolution.

    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

    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

    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

    mc = max([ma+n1-1,ma,n1]) and nc = max([na+n2-1,na,n2]).

    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,

      '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).

功能：是二维卷积运算函数（与convmtx2相似）。如果a和b是两个离散变量n1和n2的函数，则关于a和b的二维卷积运算数学公式如下：

用法：C = conv2(A,B)
C = conv2(hcol,hrow,A)
C = conv2(...,'shape')
C = conv2(A,B)计算数组A和B的卷积。如果一个数组描述了一个二维FIR滤波器，则另一个数组被二维滤波。当A的大小为[ma,na],B的大小为[mb,nb]时，C的大小为[ma+mb-1,mb+nb-1]。‘shape’见下表

参数值
   含义
   

‘full’
   默认值，返回全部二维卷积值。
   

‘same’
   返回与A大小相同卷积值的中间部分
   

‘valid’
   当all(size(A)>=size(B)),C的大小为[ma+mb-1,mb+nb-1]；否则，C返回[]。在n维卷积运算中，C的大小为max(size(A)- size(B)+1,0)