I have 3 parameters, each parameter give one output image, now I put one loop for the parameters and I want to have 3 output images in each loop and save it, How can I do that using imwrite ?
Thanks a lot
I didn't understand your question as clearly as expected but are you looking for something like this:
for i=1:3
parameter=functionGivingParamater(input_argument);%%I guess paramter is the image format
imwrite(strcat('imageNo_'+num2str(i)),parameter);
end
Related
I have R,G,B image channels of an image and I want to concatenate them to get the colored image using a for loop. Is it possible?
I tried something like below but it gives me an error:
for i=1:3
image=cat(3,img(:,:,i)
end
I already know how to do it without a loop using the command cat : image=cat(3,imgR,imgG,imgB)
I don't see a point in using a loop here... it's very inefficient... especially if you know how many images you want to stack together. The call to cat as you have alluded to in your post at the very end is more than sufficient.
however, if you want to get this working, you have to specify at least two matrices that you want to use to concatenate together to create a new matrix when using cat in order to perform concatenation. You are only specifying one matrix and if you do this, the output will simply be just the channel itself and if you use this code, you will only extract out the blue channel (the last channel).
If you want to retain the concatenations made for each channel, do this instead:
for ii = 1 : 3
image = cat(3, image, img(:,:,ii));
end
This will take the pre-existing variable image and concatenate your matrix with each slice in img and update the variable image.
I am trying to cut off background from currency notes. I used a blobsDemo.m codes I found here, used on coins.jpeg. it worked we quite well for me, on one note.
But when I tried it on multiple images, it returns results on just one note:
For k=1:16
JpegFileName=sprintf('%d.jpeg',k);
Fullfilename=fullfile('Folder',jpegfilename);
Imagedata=imread(Fullfilename)
Originalimage=rgb2gray(imagedata);
Subplot(4,4,k)
Imshow(original image);%displays all my 16 distinct images.
%but when I run
ThresholdValue(k)=100
Binaryimage=originalimage>threshold. value(k);
%it returns for one image.
End
What am I doing wrong please? I need help. Thankyou
for example if your resultant image is stored in variable "IM_out" then use IM_out(:,:,k)
I have a folder which contains images (100) from the experiment that I did. I also have another folder which contains the background images (100 also) from the detector.
I have written a code that does something like this:
% Define images directory
% Define detector bg directory
% Loop over each frame and do some processing
for a=1:length(image directory)
%read files from directory
bg_corrected_image = frame#-bg_image# % # begins with 1
n=size(image directory)
new_images=zeros(n)
% Now sort through each pixel in bg_corrected image and assign value according to a criterion
for ii=1:size(bg_corrected_image,1)
jj=1:size(bg_corrected_image,2)
pixel=bg_corrected_image(ii,jj);
if pixel>500
pix_mod=0;
elseif pixel<30
pix_mod=0;
else
pix_mod=pixel;
end
new_image(ii,jj)=pix_mod;
end
******************* CODE TO SAVE IMAGE AND NOT OVERWRITE AFTER EACH
ITERATION OF LOOP?
end
What I want to do now is to save each image(frame) after it had gone through the pixel sorting regimen so that I can just sum them all after the loop has ended. I am not too sure what is the best way to do it? I think what I need to do is to create a cell array which saves a "new_image" after each iteration and the code for that should go where I put asteriks. Please note I don't want to save images earlier in my code. Any help much appreciated.
Maybe something like the below - load in all your images to a 3D matrix "imagestack", then process them all, then output them all. Note the vectorization on the pixel replacement here will be much faster than your for-loop iteration over the pixels.
IMAGECOUNT=100;
FILEPATH_IN='images/input/%d.jpg';
FILEPATH_OUT='images/output/%d.jpg';
I=imread(sprintf(FILEPATH,1));
[hei wid]=size(I);
imagestack=zeros(hei,wid,100);
for n=1:IMAGECOUNT
imagestack(:,:,n)=imread(sprintf(FILEPATH_IN,n));
end
imagestack(imagestack>500)=0;
imagestack(imagestack<30)=0;
for n=1:IMAGECOUNT
imwrite(imagestack(:,:,n),sprintf(FILEPATH_OUT,n));
end
i am new to matlab. While working through the Matlab GUI, i faced a problem which is as follows..i want to have 2 figure files, with one figure file calling the other. i know that just by calling the name of the 2nd fig file from the first fig file, we can call the 2nd figure. however, i also wish to send some parameters from one fig file to another.here i need to send the arguments and also obtain these parameters so as to do further processing.i havent been able to find a solution to this problem. i would be glad if someone helps me out with this problem. thanking you in advance
There are three ways I found to do this:
Method 1: Use setappdata and getappdata like so:
setappdata(0,'some_var',value)
some_other_var = getappdata(0,'some_var')
You would use setappdata() in the m-file for fig1 to store whatever data you wanted to pass around, and then call getappdata() in another m-file to retrieve it. The argument 0 to the two functions specifies the MATLAB root workspace, which is accessible by your program everywhere (i.e. it is global). As such, when you close your figures that data will still be available. You may want to use rmappdata to remove them.
Method 2: Use guidata:
Assuming you created your GUI with GUIDE, then you have access to a structure called handles which is passed around everywhere and which you can edit, and so you can do this in a GUI callback:
handles.some_var = some_value
guidata(hObject,handles)
Then you can access handles.some_var elsewhere in some other callback (because handles is automatically passed into it for you) in your other m-file:
some_other_var = get(handles.some_var)
Method 3: Use UserData:
Store the variable you want from your first figure:
set(name_of_fig, 'UserData', some_var)
Then to get it from your other one:
some_other_var = get(name_of_fig, 'UserData')
(Disclaimer: My actual knowledge of MATLAB is not all that great, but it helps to be able to find good resources like this and this, and even this from the official docs. What I've written here may be wrong, so you should definitely consult the docs for more help.)
I would do like this (assuming you're using the GUI builder GUIDE).
Let's say that your figures/m-files are named firstFigure.fig/m and secondFigure.fig/m. In the code of firstFigure, just call secondFigure and pass your parameters as arguments:
someNumber = 1;
someText = 'test';
aMatrix = rand(3);
secondFigure(someNumber, someText, aMatrix);
The arguments will be available to secondFigure as a variable varargin in the callback functions
function varargout = secondFigure(varargin)
and
function secondFigure_OpeningFcn(hObject, eventdata, handles, varargin)
varagin is a cell structure; use cell2mat and char to convert it back:
theNumber = cell2mat(varargin(1));
theText = char(varargin(2));
theTextAgain = cell2mat(varargin(2));
theMatrix = cell2mat(varargin(3));
This may help:
http://www.mathworks.ch/matlabcentral/newsreader/view_thread/171989
The easiest method is to wrap the parameters in a cell array and send them directly to the GUI constructor. A call with two parameters might look like:
figure2({param1, param2})
Then you can unpack the arguments in the opening function (figure2_OpeningFcn) with code like:
handles.par1 = varargin{1}{1};
handles.par2 = varargin{1}{2};
These lines must be placed somewhere before the line that says guidata(hObject, handles);. Then you can access handles.par1 and handles.par2 directly in all the other callbacks.
I assume you are using GUIDE to generate your GUI. You can find figure2_OpeningFcn in figure2.m which will be located in the same directory as figure2.fig.
Note: you can also return values from a figure, returnvalue = my_figure({my_input}). If you'd like instructions on that too, leave a comment and I'll extend my answer.
I created a GUI and used uiimport to import a dataset into matlab workspace, I would like to pass this imported data to another function in matlab...How do I pass this imported dataset into another function....I tried doing diz...but it couldnt pick diz....it doesnt pick the data on the matlab workspace....any ideas??
[file_input, pathname] = uigetfile( ...
{'*.txt', 'Text (*.txt)'; ...
'*.xls', 'Excel (*.xls)'; ...
'*.*', 'All Files (*.*)'}, ...
'Select files');
uiimport(file_input);
M = dlmread(file_input);
X = freed(M);
I think that you need to assign the result of this statement:
uiimport(file_input);
to a variable, like this
dataset = uiimport(file_input);
and then pass that to your next function:
M = dlmread(dataset);
This is a very basic feature of Matlab, which suggests to me that you would find it valuable to read some of the on-line help and some of the documentation for Matlab. When you've done that you'll probably find neater and quicker ways of doing this.
EDIT: Well, #Tim, if all else fails RTFM. So I did, and my previous answer is incorrect. What you need to pass to dlmread is the name of the file to read. So, you either use uiimport or dlmread to read the file, but not both. Which one you use depends on what you are trying to do and on the format of the input file. So, go RTFM and I'll do the same. If you are still having trouble, update your question and provide details of the contents of the file.
In your script you have three ways to read the file. Choose one on them depending on your file format. But first I would combine file name with the path:
file_input = fullfile(pathname,file_input);
I wouldn't use UIIMPORT in a script, since user can change way to read the data, and variable name depends on file name and user.
With DLMREAD you can only read numerical data from the file. You can also skip some number of rows or columns with
M = dlmread(file_input,'\t',1,1);
skipping the first row and one column on the left.
Or you can define a range in kind of Excel style. See the DLMREAD documentation for more details.
The filename you pass to DLMREAD must be a string. Don't pass a file handle or any data. You will get "Filename must be a string", if it's not a string. Easy.
FREAD reads data from a binary file. See the documentation if you really have to do it.
There are many other functions to read the data from file. If you still have problems, show us an example of your file format, so we can suggest the best way to read it.