Question

所以我有一堆代码需要大约一分钟才能运行，追溯到自适应阈值处理，特别是一行。有关如何加快这一点的任何建议或任何关于为什么这是不可避免的解释？...＆＃34; mIM = medfilt2（IM，[ws ws]）;＆＃34;是一切都放慢了。

function bw=adaptivethreshold(IM,ws,C,tm)
%ADAPTIVETHRESHOLD An adaptive thresholding algorithm that seperates the
%foreground from the background with nonuniform illumination.
%  bw=adaptivethreshold(IM,ws,C) outputs a binary image bw with the local 
%   threshold mean-C or median-C to the image IM.
%  ws is the local window size.
%  tm is 0 or 1, a switch between mean and median. tm=0 mean(default); tm=1 median.
%
%  Contributed by ...
%  at Tsinghua University, Beijing, China.
%
%  For more information, please see
%  http://homepages.inf.ed.ac.uk/rbf/HIPR2/adpthrsh.htm

if (nargin<3)
    error('You must provide the image IM, the window size ws, and C.');
elseif (nargin==3)
    tm=0;
elseif (tm~=0 && tm~=1)
    error('tm must be 0 or 1.');
end

IM=mat2gray(IM);
disp(strcat('100: ',datestr(now)))
if tm==0
    mIM=imfilter(IM,fspecial('average',ws),'replicate');
else
    mIM=medfilt2(IM,[ws ws]);
end
sIM=mIM-IM-C;
bw=im2bw(sIM,0);
bw=imcomplement(bw);

Answer 1

中值过滤是一种非线性操作，因此可能需要很长时间才能执行。对于较大的ws值，您应该更喜欢ordfilt2到medfilt2：它既快又灵活！

以下示例代码使用两个函数执行相同的中值过滤：

Img = imread('elephant.jpg');
ws = 100;

tic
Res = medfilt2(Img, [ws ws]);
toc

tic
Res = ordfilt2(Img, round(ws^2/2), true(ws));
toc

和我机器上的时间：

Elapsed time is 0.190697 seconds.
Elapsed time is 0.095528 seconds.

最佳，

MATLAB自适应阈值超慢

1 个答案: