error:Undefined function or variable 'values'.

clc;
clear all;

CAMERA = videoinput('pointgrey', '1');%camera initialization
start(CAMERA);
a = serial('COM3','BaudRate',9600);  %arduino initialization
fopen(a);
pause(1);

for a = 1:8
    automate(CAMERA)
    pause(8)
end

plot(values);                     %plotting values just for our visual understanding
[m,index] = max(values)
fprintf(a,'%d',index)            %"here is where we send the position of image to arduino"                                  
fclose(a)
hold on
plot(index,m,'*')
hold off
title("bodekke with spot images")
stop(CAMERA);                      %stop camera acquisition

function[addition] = bodekke(imagename)  %bodekke function mathematics behind the autofocus detection
im = double(imread(imagename))
bd = [-1 0 1]
cbd = conv2(im,bd)
squaredcbd = cbd.^2
addition = sum(squaredcbd(:))
end
       
function automate(CAMERA)
for i = 1:30    %to capture images
    
filename = sprintf('testtry%02d.jpg',i);
img = im2double(getsnapshot(CAMERA));  %captures images
img = rgb2gray(img);
imwrite(img,filename)

end

D = 'C:\Users\PRL\Desktop\just';  %location where image  is stored
S = dir(fullfile(D,'*.jpg'));      
for k = 1:numel(S)              %applies bodekke to all images
    F = fullfile(D,S(k).name);
    queen(k) = bodekke(F);        %bodekke function call                                                                                
end
end

[KSSV]

Which line number? How did you run/ call the function?

[barath V]

line 15,plot(values)

i get error

[Adam]

Like the error message says, the variable is undefined. What are you expecting to plot? You don't have any 'values'

[barath V]

but iam storing the return value from functions to variable values,u can see that i am assigning the function call to the variable "value".

[Alex Mcaulley]

Where are you doing this? I can't see this line...

[Adam]

You clearly aren't doing. Given that you have

clear all

at the top, then only these lines will have any impact before the plot instruction:

CAMERA = videoinput('pointgrey', '1');%camera initialization
start(CAMERA);
a = serial('COM3','BaudRate',9600);  %arduino initialization
fopen(a);
pause(1);
for a = 1:8
    automate(CAMERA)
    pause(8)
end

None of these lines assigns anything to 'values'

[barath V]

clc;
clear all;

CAMERA = videoinput('pointgrey', '1');%camera initialization
start(CAMERA);
ard = serial('COM3','BaudRate',9600);  %arduino initialization
fopen(ard);
pause(1);

for b = 1:8
    automate(CAMERA)
    pause(8)
end

fclose(ard)
stop(CAMERA);                      %stop camera acquisition

function[addition] = bodekke(imagename)  %bodekke function mathematics behind the autofocus detection
im = double(imread(imagename))
bd = [-1 0 1]
cbd = conv2(im,bd)
squaredcbd = cbd.^2
addition = sum(squaredcbd(:))
end
       
function automate(CAMERA)
for i = 1:30    %to capture images
    
filename = sprintf('testtry%02d.jpg',i);
img = im2double(getsnapshot(CAMERA));  %captures images
img = rgb2gray(img);
imwrite(img,filename)

end

D = 'C:\Users\PRL\Desktop\just';  %location where image  is stored
S = dir(fullfile(D,'*.jpg'));      
for k = 1:numel(S)              %applies bodekke to all images
    F = fullfile(D,S(k).name);
    addition(k) = bodekke(F);        %bodekke function call                                                                                
end
plot(addition);                     %plotting values just for our visual understanding
[m,index] = max(addition)
hold on
plot(index,m,'*')
hold off
title("bodekke with spot images")
fprintf(ard,'%d',index)            %"here is where we send the position of image to arduino"                                  



end

[barath V]

here i have changed variable name to addition and i have assigned the function call to the variable,here i get a error

Undefined function or variable 'ard'.

Error in bodekkealgo>automate (line 48)

fprintf(ard,'%d',index) %"here is where we send the position of image to arduino"

[Adam]

You need to get to understand how different workspaces work in Matlab (and many languages, for that matter)

https://uk.mathworks.com/help/matlab/matlab_prog/base-and-function-workspaces.html

A function has its own sealed workspace. The only variables it sees are those you pass in (unless it is a nested function), the only variables the outside world will see are the ones it returns as arguments. Once you understand the scope of workspaces and error like this is 100% self-explanatory from the message it gives.

You define ard in your code at the top, but you do not pass it to the automate function so this function does not know of a variable called ard, hence the error. Pass it in as an argument if you wish to use it in the function.

[barath V]

hi, i defined the object ard inside the function itself,but the close function for ard i have defined outside.

the motors are rotating,the actual execution of the code happens only once,and then i get this com port error and fopen() error.

clc;
clear all;

CAMERA = videoinput('pointgrey', '1');%camera initialization
start(CAMERA);


for b = 1:8
    automate(CAMERA)
    pause(8)
end

fclose(ard)
stop(CAMERA);                      %stop camera acquisition

function[addition] = bodekke(imagename)  %bodekke function mathematics behind the autofocus detection
im = double(imread(imagename))
bd = [-1 0 1]
cbd = conv2(im,bd)
squaredcbd = cbd.^2
addition = sum(squaredcbd(:))
end
       
function automate(CAMERA)
ard = serial('COM3','BaudRate',9600);  %arduino initialization
fopen(ard);
pause(1);
for i = 1:30    %to capture images
    
filename = sprintf('testtry%02d.jpg',i);
img = im2double(getsnapshot(CAMERA));  %captures images
img = rgb2gray(img);
imwrite(img,filename)

end

D = 'C:\Users\PRL\Desktop\just';  %location where image  is stored
S = dir(fullfile(D,'*.jpg'));      
for k = 1:numel(S)              %applies bodekke to all images
    F = fullfile(D,S(k).name);
    addition(k) = bodekke(F);        %bodekke function call                                                                                
end
plot(addition);                     %plotting values just for our visual understanding
[m,index] = max(addition)
hold on
plot(index,m,'*')
hold off
title("bodekke with spot images")
fprintf(ard,'%d',index)            %"here is where we send the position of image to arduino"                                  

end

i get this error:Error using serial/fopen (line 72)

Open failed: Port: COM3 is not available. Available ports: COM1.

Use INSTRFIND to determine if other instrument objects are connected to the requested device.

Error in bodekkealgo>automate (line 26)

fopen(ard);

[KALYAN ACHARJYA]

This error is completely different from previous one. May be: please look on the avalible port number in arduino interface.

[barath V]

i checked its COM3 only,this error occurs because i open the ardunio object ard,again while it is already open in the first itersation of function call.

i want to know how to use this line inside the function,without creating an object for ard inside the function.

fprintf(ard,'%d',index)   

[Walter Roberson]

Pass ard into the function?

[barath V]

yes it works, i tried that.but i cant see the plot and the fprintf() working during everey function call.

fprintf() works only during the first time and plot works only at the last.

[Walter Roberson]

You are not calling drawnow() or pause(), so you will only see the final graphics result. drawnow() or pause() tell the graphics system that the changes to the graphics objects can be sent to the display.

You are not sending a line terminator with your fprintf()

[barath V]

i used drawnow,but that doesnt solve the issue.

clc;
clear all;

CAMERA = videoinput('pointgrey', '1');%camera initialization
start(CAMERA);
ard = serial('COM3','BaudRate',9600);  %arduino initialization
fopen(ard);
pause(1)

for b = 1:8
    automate(CAMERA,ard)
    pause(8)
end
fclose(ard)
stop(CAMERA);             %stop camera acquisition

function[addition] = bodekke(imagename) %bodekke function mathematics behind the autofocus detection
im = double(imread(imagename))
bd = [-1 0 1]
cbd = conv2(im,bd)
squaredcbd = cbd.^2
addition = sum(squaredcbd(:))
end
       
function automate(CAMERA,ard)

for i = 1:30    %to capture images
    
filename = sprintf('testtry%02d.jpg',i);
img = im2double(getsnapshot(CAMERA));  %captures images
img = rgb2gray(img);
imwrite(img,filename)

end

D = 'C:\Users\PRL\Desktop\just';  %location where image  is stored
S = dir(fullfile(D,'*.jpg'));      
for k = 1:numel(S)              %applies bodekke to all images
    F = fullfile(D,S(k).name);
    addition(k) = bodekke(F);        %bodekke function call                                                                                
end
                    
[m,index] = max(addition)
fprintf(ard,'%d',index) %"here is where we send the position of image to arduino"        

plot(addition);    %plotting values just for our visual understanding                        
hold on
plot(index,m,'*')
hold off
title("bodekke with spot images")
drawnow
end

[Walter Roberson]

I am not clear as to what you are saying? Are you saying that plot(addition) is not producing a visual result, but the marking of the maximum is working?

You are still not sending a line termination to the arduino '%d\n'

[barath V]

Yes,the plot addition is not producing a visual result during each and every function call. I can see the plot only during last function call.

I changed the codes now,I added line termination to Arduino.

[Walter Roberson]

You imwrite using the filename pattern testtry%02d.jpg but it is not clear that your current directory is the same as the directory that you look inside, 'C:\Users\PRL\Desktop\just' . It would be better for you to move the assignment to D to before the for i loop, and that you use

imwrite(img, fullfile(D,filename))

[barath V]

i open the directory path in matlab and keep so the image gets copied there,anyway ill change it.

but how to solve the problem of plots i mentioned earlier?

[Walter Roberson]

After you do

S = dir(fullfile(D,'*.jpg'));      

what shows up for size(S) ?

[barath V]

IT IS 30

[barath V]

iam always getting the comport error also,i can only run the codes once,after it gets finished i again run the codes,but this time i get comport error,so i have to close and restart matlab again,then the code runs.

i ahve to do it each and everey time.

how to solve this error.

[Walter Roberson]

Use instrfind() to locate the com port object, and delete() the object. And change your code to delete(a) after you fclose(a)

[Walter Roberson]

For the purpose of debugging, after

title("bodekke with spot images")

add

fprintf('%d of %d elements in addition are finite', nnz(isfinite(addition)), numel(addition));

[barath V]

i want to thank mr.walter roberson and matlab people for continuously supporting my projects,thanks mr.walter

Answer 1

[barath V]

hi deleting the arduino object solved the pblm,thanlks.

how can i capture a video?

[Walter Roberson]

Your automate function is already capturing the video and writing it to file.

[barath V]

Yes,i capture imagea and analyse it using bodekke,later these images are overwritten. Iam trying to capture a video after i send a value to Arduino,that will be permanent and wont be overwritten or analysed.

[Walter Roberson]

Use different folders instead of always using

D = 'C:\Users\PRL\Desktop\just';

You could use uigetdir to have the user tell you the directory. Or you could look in the folder and see what subfolders already exist and use the next available one.