Index in position 1 is invalid. error after running multiple times

I am trying to extract features from a dataset. the problem that after a group of images features extracted it is stoped by itself for example features are extracted for 20 images then for image 21 it gives this error

Index in position 1 is invalid. Array indices must be positive integers or logical values.

my code

clc;
clear all;
close all;
warning off;
imds=imageDatastore('E:\dataset test','IncludeSubFolders',true,'LabelSource','foldernames');
trainingFeatures=[];
trainingLabels=imds.Labels;       
for i = 1:numel(imds.Files)         % Read images using a for loop
    img = readimage(imds,i);
    trainingFeatures(i,:) = example(img);
    end

the error

    Index in position 1 is invalid. Array indices must be positive integers or logical values.

Error in clipLine (line 85)
    inter1 = points(ind,:);

Error in A (line 55)
edge = clipLine(LINE, BOX);

Error in example (line 40)
[lensV, lensF] =A(img,N,pxMin,calLen);

Error in Untitled2 (line 30)
    trainingFeatures(i,:) = example(img);
 

[Ameer Hamza]

The error is caused by a function you defined, 'clipLine'. Add a breakpoint in this code to see what is causing the value of 'ind' to become invalid: https://www.mathworks.com/help/matlab/matlab_prog/set-breakpoints.html

Answer 1

[Hritika Suneja]

It's difficult to fix the error without seeing the complete code. However errors like ' Index in position 1 is invalid.' generlly occur because of some incorrect indexing in your code. It might happen that a wrong variable is being used to index an array. You can use the command mentioned below to debug these types of errors:

>>dbstop if error