Unrecognized function or variable 'adaptivethreshold'

Question

I am getting the following error message in Matlab "Unrecognized function or variable 'adaptivethreshold'" when every time I want to use Adaptive Threshold function

clear;close all;
im1=imread('page.png');
im2=imread('tshape.png');
bwim1=adaptivethreshold(im1,11,0.03,0);
bwim2=adaptivethreshold(im2,15,0.02,0);
subplot(2,2,1);
imshow(im1);
subplot(2,2,2);
imshow(bwim1);
subplot(2,2,3);
imshow(im2);
subplot(2,2,4);
imshow(bwim2);

those coding from https://www.mathworks.com/matlabcentral/fileexchange/8647-local-adaptive-thresholding

Is the folder where the png files and adaptivethreshold function in your path? If not you either need add that folder to your path of run your code from that folder — ThomasK, Jun 21 '22 at 07:53

AboAmmar · Answer 1 · 2022-06-18T13:18:36.790

You should open MATLAB editor inside a folder containing all files: adaptivethreshold.m, page.png, testadaptivethreshold.m, tshape.png and run your script testadaptivethreshold.

Or, you can copy-paste the function definition below the script as follows and make sure also that the images are in the same folder or MATLAB search path.

clear;close all;
im1=imread('page.png');
im2=imread('tshape.png');
bwim1=adaptivethreshold(im1,11,0.03,0);
bwim2=adaptivethreshold(im2,15,0.02,0);
subplot(2,2,1);
imshow(im1);
subplot(2,2,2);
imshow(bwim1);
subplot(2,2,3);
imshow(im2);
subplot(2,2,4);
imshow(bwim2);


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 Guanglei Xiong (xgl99@mails.tsinghua.edu.cn)
    %  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);

    if tm==0
        mIM=imfilter(IM,fspecial('average',ws),'replicate');
    else
        mIM=medfilt2(IM,[ws ws]);
    end
    sIM=mIM-IM-C;
    bw=imbinarize(sIM,0);
    bw=imcomplement(bw);
end

And here is how it shows the output:

Unrecognized function or variable 'adaptivethreshold'

1 Answers1