Calculate Area % of either freehand or ellipse ROI

Hello - I'm trying to figure out the Area % of a thresholded ROI. Currently, I have my code set so that the image is thresholded, and then the user manual draws a freehand ROI (still debating if freehand or ellipse ROI is better). I want the code to give me the percent of area that is 'white' in the threshold over the total area in that ROI, but currently when I draw in the ROI, it is filled with 1's. How can I do this so that it is not filled and I can find the % Area? Below is my code. Thank you!

I=imread('Image.tif'); figure,imshow(I); BW = imbinarize(I,0.300); figure,imshow(BW); % Ask user to draw ROI. message = sprintf('Draw ROI on the wanted image.\nDouble click to finish drawing.'); uiwait(msgbox(message)); h=imfreehand;

[Victoria]

Update: I have found a way to find area percent with the following code:

percentageBlack=(1-nnz(BW)/numel(BW))*100;
AreaPercent=(100-percentageBlack)

Now I just need a way for this to ONLY calculate in a nonfilled manually selected ROI. Thanks!

Answer 1

[Image Analyst]

Use h to create a mask.

mask = h.createMask;

See attached demo for more details.

[Victoria]

Thank you - after playing around with the code it has given what I did. Last thing, how do I save what is given to me in the message box in an excel sheet. I know how to create the sheet, but I don't know how to make the message box be included. I tried coverting it to a table and then to a cell, but of course the message isn't an array so I can't do that.

This is what I have so far:

t = struct2table(message);
C = table2cell(t);
  %File Location
  path= 'C:\location';
  %File Name
  xlswrite(fullfile(path,'\Try.xlsx'), C, int2str(k));

This is a loop as well, but I have been able to make it work. Thanks for the help!

[Victoria]

I have managed to find a way to create a table, covert it to a cell, and then create an excel file from that. I will post the code later. Thanks for the help!

[Victoria]

   T1=table(meanGL, sdGL, percentageBlack, AreaPercent);
    head(T1,3)
    C = table2cell(T1);
    %File Location
    path= 'C:\Users\Vicki\Documents\Loyola\MATLAB';
    %File Name
    xlswrite(fullfile(path,'\try.xlsx'), C, int2str(k));

[Image Analyst]

You can use writetable() to write an Excel workbook without doing the convertion to a cell array.