how process sequence of the images in a loop without overwriting

here, i am solving around 20000 images at once but the output i'm getting is only the last iamge.

here is the code i got from the Matlab Answers, but also it didn't work can anyone help me.

[darova]

Please explain more. You have 20k images. What are you trying to do with them? And the result image is only one

[Akhir Shaik]

here, i need to find the breakup length, need to solve 20k images at once and need to save value in numerical or dat file.

the image processing code is ok. if i solve for 1 images i got the answer but solving for 20k images it is considering only the last image file in the folder.

[Stephen23]

Original Question: "how process sequence of the images in a loop without overwriting"

here, i am solving around 20000 images at once but the output i'm getting is only the last iamge.

here is the code i got from the Matlab Answers, but also it didn't work can anyone help me.

myFolder = 'E:\IMAGES\100k\flip';
if exist(myFolder, 'dir') ~= 7
  Message = sprintf('Error: The following folder does not exist:\n%s', myFolder);
  uiwait(warndlg(Message));
  return;
end
filePattern = fullfile(myFolder, '*.jpg');
jpegFiles   = dir(filePattern);
for i = 1:length(jpegFiles) 
    fileName = sprintf('%5.5d.jpg', i);
    piccell{i} = imread(fileName);
end
grayImage = imread(fileName);
[rows, columns, numberOfColorChannels] = size(grayImage);
if numberOfColorChannels > 1
	grayImage = rgb2gray(grayImage);
end
highThreshold = 150;
binaryImage = grayImage <= highThreshold;
binaryImage = bwareafilt(binaryImage, 1);
binaryImage = imfill(binaryImage, 'holes');
bottomLine = zeros(rows, 1);
for col = 1 : columns
	thisColumn = binaryImage(:, col);
	lastLine = find(thisColumn, 1, 'last');
	if ~isempty(lastLine)
	bottomLine(col) = lastLine;
	end
end
meanbottomLine = mean(bottomLine(bottomLine>0));
save bkl_.dat meanbottomLine -ascii

Answer 1

[Benjamin Großmann]

Have a look at your first for loop. Here you are generating a char called fileName which is overwritten in every loop count. furthermore, this loop is unnecessary since you already have your file names in the struct array jpegFiles.

Try to use

fileNameCell = {jpegFiles.name};

to get a cell array of file names. Then write a function which does your image manipulation for one file. Finally, call your function with cellfun and the fileNameCell to apply the image manipulation to every file in the cell.

You can also have a look at the imageSet class.

[Akhir Shaik]

thank you, how to use the cellfun and fileNamecell to apply every file in the cell?

[Benjamin Großmann]

First, write the function, save it as findmeanbottomline. This is basically your image manipulation code surrounded by function ... end.

function meanbottomLine =  findmeanbottomline(img_fullfile)

img = imread(img_fullfile);

[rows, columns, numberOfColorChannels] = size(img);
if numberOfColorChannels > 1
    grayImage = rgb2gray(img);
else
    grayImage = img;
end

highThreshold = 150;
binaryImage = grayImage <= highThreshold;
binaryImage = bwareafilt(binaryImage, 1);
binaryImage = imfill(binaryImage, 'holes');
bottomLine = zeros(rows, 1);
for col = 1 : columns
	thisColumn = binaryImage(:, col);
	lastLine = find(thisColumn, 1, 'last');
	if ~isempty(lastLine)
	bottomLine(col) = lastLine;
	end
end
meanbottomLine = mean(bottomLine(bottomLine>0));
end

Then call it with the script

clearvars, close all
clc

myFolder = 'C:\tmp\101_ObjectCategories';

filePattern = fullfile(myFolder, '*/*.jpg'); % my images are in subfolders, so i changed your filepattern
jpegFiles   = dir(filePattern);

% For simplicity of this example, lets use the full/absolute path to the images
fileNameCell = fullfile({jpegFiles.folder}, {jpegFiles.name}); 

% Call the function with cellfun; returns a cell with each entry corresponing to the fileNameCell
meanbottomlineCell = cellfun(@findmeanbottomline, fileNameCell);

Cellfun is archaic, but it's simple and I like it. You can also loop over the fileNameCell instead of using cellfun

for idx = 1:numel(fileNameCell)
    meanbottomline(idx) = findmeanbottomline(fileNameCell{idx});
end

If you have the Parallel Computing Toolbox (and a multi-core processor), you can speed this up by substituting "for" by "parfor" and starting a matlabpool.

[Akhir Shaik]

thank you, but it didn't work got an error

Error: File: findmeanbottomline.m Line: 16 Column: 28

Function 'findmeanbottomline' has already been declared within this scope.

[Benjamin Großmann]

Please consider the following:

• My first block of code has to be in one file ("the function") called "findmeanbottomline.m"; in general, the file name and the function name should match. My first line "function meanbottomline = findmeanbottomline(...) " has to be the first line of this file. Do not add lines before that line
• You need another file "the script" which you can name as you want, except for the function name "findmeanbottomline.m", then copy my second block of code inside that file.
• Run the script

The error indicates, that you may have done something wrong generating the function. Please also look thorugh https://de.mathworks.com/help/matlab/matlab_prog/create-functions-in-files.html

I also removed one line in my original code, it was a leftover from testing.

[Benjamin Großmann]

Additionaly, check the output of

which findmeanbottomline -all

[Akhir Shaik]

i followed in your suggestion. i got an errror.

Not enough input arguments.

Error in findmeanbottomline (line 3)

img = imread(img_fullfile);

[Benjamin Großmann]

Please put a breakpoint in line 3 of the function, then run the script and post the contents of img_fullfile after the breakpoint was reached

[Akhir Shaik]

i added the breakpoint and tried same error.

not enough input arguments.

i tried to solve this by using the loops and function file but not not working getting only the last image answer.

help pls,