how can I use a threshold value?

Hello everybody,

I need some help! I have to answer to those questions:

9) Ask the user to enter a thresholding value for the binary mask

10) Given this value, transform the image to a binary image and display the result on the screen [useful tools: read(), im2bw()]

11) Ask the user whether he/she is happy of the result. Yes will be 1 and No will be 0. Put 1 as the default value.

12) Modify these previous lines of code with a loop that only stops when the user is happy of the result. Basically, you can be happy when the EHT is represented as a rectangle with its two ends surrounded by black pixels. If the user is not happy, ask him/her to enter a new thresholding value.

I have already found the following code:

*%question 1

    select=uigetfile('video.avi');

    %question 2

    video=mmreader('video.avi');

    %question3 

video.NumberOfFrames;

video.Height;

video.Width;

k=video.NumberOfFrames;

for k=100;

mov(1:k)=struct('cdata',[],'colormap',[]);

end;

%question4

%Display the first frame

vidFrame=read(video,k);

%Question 4

%to alert the user that he needs to draw a line on this frame

imshow(vidFrame);

uiwait(msgbox('draw a line on the frame and click on ok to continue', 'Alert')); 

%Question5

pos=wait(imline);

l=length(pos);

%question6

m=sqrt((pos(1,2)-pos(1,1)^2)-((pos(2,2)-pos(2,1)^2)));

question 7

prompt= {'enter the real length in micrometers'};

dlg_title='Enter';

num_lines=1;

def={'1'};

answer=inputdlg(prompt,dlg_title,num_lines,def);

%Question8

% Derive the ration pixel/micrometer

r=1/m;

%Question9

%Ask the user to enter a thresholding value for the binary mask

prompt={'enter a thresholding value - value between 0 and 1'};

dlg_title='Input';

num_lines=1;

def={'0.5'};

answer2=inputdlg(prompt,dlg_title,num_lines,def);

%Question 10

%BW = im2bw(vidFrame,answer2);

%imshow(BW);

%level=answer2;

A = str2num('answer2');%to tranform string answer2 in num answer2

level=input('answer2:');%Request user input

BW = im2bw(vidFrame,level);

imshow(BW);

%Question 11

prompt= {'Are you satisfied? 1 for yes or 0 for no'};

dlg_title='Input';

num_lines=1;

def={'1'};

answer3=inputdlg(prompt,dlg_title,num_lines,def);*

Thank you for your help. I'm very lost!!

YF.

[Walter Roberson]

It is not clear what you are asking for assistance with.

Answer 1

[Image Analyst]

This snippet may help

promptMessage = sprintf('Do you want to Continue processing,\nor Cancel to abort processing?');
titleBarCaption = 'Continue?';
button = questdlg(promptMessage, titleBarCaption, 'Continue', 'Cancel', 'Continue');
if strcmpi(button, 'Cancel')
  return; % or break, or continue - whatever you need.
end

[YF]

thanks so much for your help!

Season's Greetings!