how to solve otsu code problem

Hi i am new to matlab and modifing the Exiting code for the Project of my friend can anybudby solve this problem i am getting the error of

Undefined function or variable 'otsu'.

Error in run1 (line 35)

seg_f = otsu(dimg);

In Below Code

function main

%% input image
 
clc; 
close all; 
vid = videoinput('winvideo',2);

preview(vid); 
for i = 1:5 
	snapshot = getsnapshot(vid); 
	imagesc(snapshot); 
end

imwrite(snapshot,'E:\Gear_Fault_Detection.jpg'); 
inp = imread('E:\Gear_Fault_Detection.jpg');

if size(inp,3) > 1 
	inp = rgb2gray(inp); 
end 

figure, 
subplot(1,2,1); 
imshow(inp,[]); 
title('Input Image');


%% preprocessing 
dimg = medianfilter(inp); 
subplot(1,2,2); 
imshow(dimg,[]); 
title('denoised image');

%% segmentation 
seg_f = otsu(dimg); 
figure, 
subplot(1,2,1); 
imshow(seg_f); 
title('Otsu image'); 
[imgcnt] = bwlabel(double(seg_f)); 
stats = regionprops(img,'all'); 
for i = 1:cnt 
	ar = stats(i).Area; 
	if ar<= 500 
	img(img==i)=0; 
	cnt = cnt-1; 
end 
end 
subplot(1,2,2); 
imshow(img); 
title('segmented image'); 


%% cropping 
[img, cnt] = bwlabel(double(img)); 
for i = 1:cnt     
s = regionprops(img, 'BoundingBox'); 
rectangle('Position', s(1).BoundingBox,'EdgeColor','r'); 
 
end 
xmin = round(s(1).BoundingBox(1,1));
xmax = round(s(1).BoundingBox(1,1)+s(1).BoundingBox(1,3)); 


ymin = round(s(1).BoundingBox(1,2));
ymax = round(s(1).BoundingBox(1,2)+s(1).BoundingBox(1,4)); 
out = img(ymin:ymax,xmin:xmax); 
figure, 
imshow(out,[]); 
holdon 
stats = regionprops(out,'all'); 
cen = round(stats.Centroid); 
plot(cen(2),cen(1),'r*'); 
title('cropped image with centroid'); 
cnt = 0; 
for i = cen(2):size(out,1); 
if out(i,cen(1))==0 
    cnt = cnt+1; 
end 
end

A = out; 
% determine convex hull 
B = regionprops(double(A), 'ConvexImage', 'BoundingBox');

% generate mask image 
C = zeros(size(A)); 
C(floor(B.BoundingBox(2))+(1:size(B.ConvexImage,1)),floor(B .BoundingBox(1))+(1:size(B.ConvexImage,2)))=B.ConvexImage; 
C = bwmorph(C, 'erode', 2); 
% generate teeth image 

D = A; 
D(C) = 0; 
% count teeth 
D = bwfill(D,'holes'); 

[D, cnt] = bwlabel(D); 
 
stats = regionprops(D,'all'); 
for i = 1:cnt 
ar = stats(i).Area; 
if ar<= 7 
D(D==i)=0; 

cnt = cnt-1; 
end 
end 


[imgNumTeeth] = bwlabel(D); 
%disp(sprintf('Inner Diameter value: %d',cnt)); 
cnt1=5*cnt; 
%out11=2*(size(out,2)); 
%out11=50+out11; 
fprintf('InnerDiameter value:%d mm\n',(2*(2*cnt1)/10));

%disp(sprintf('Outer Diameter value: %d',out11)); 
fprintf('Outer Diameter value: %d mm\n',floor(round((3.2*size(out,2)/10))));

fprintf('No of Teeth: %d\n',NumTeeth);

fprintf('Tooth Height: %d mm\n',floor(round((3.2*size(out,2))-(2*cnt1))/100));

cnt2=((6*NumTeeth)/3.1415); 
fprintf('PCD: %d mm\n',cnt2);

cnt3=(cnt2/NumTeeth); 
fprintf('Module: %d mm\n',cnt3);


%if NumTeeth>= 12 &&floor(round(3.2*size(out,2)))>= 200  
if NumTeeth>= 12 && 2*(2*cnt1) >= 200 

s = serial('COM10');                              
s.baudrate=9600; 
fopen(s);  
fprintf(s,'K');  
fclose(s); 

else       

s = serial('COM10');                              
s.baudrate=9600; 
fopen(s);  
fprintf(s,'F');  
fclose(s); 
 
end 
end 

function dimg = medianfilter(inp)

% Padarray 
c=padarray(inp,[1,1],0,'both'); 
[R1, C1] = size(c); 

%Median filter 
for i=2:R1-1 
for j=2:C1-1         
	temp = [c(i-1,j-1) c(i-1,j) c(i-1,j+1);c(i,j-1) c(i,j) c(i,j+1);c(i+1,j-1) c(i+1,j) c(i+1,j+1)];         
	d = temp(:);         
	e = sort(d); 
	med = e(5,1); 
	dimg(i-1,j-1) = med; 
end 
end 
 
end 

[Saurav Desai]

Use function graythresh instead of otsu.Refer the link below for the same https://in.mathworks.com/help/images/ref/graythresh.html#d122e82100