I have an image. I would like to equalize histogram using histeq. But, I want only certain portion of the image be equalized and the rest part be displayed as it is. I could display the whole image and equalized image in two different plots but I want them to be in the same image such that certain portion of the image is different.
figure
imshow(a)
figure
b = a(1:100, 1:100);
b = histeq(b)
imshow(b)
Now how do I merge both these figures into one.
Is the region to be equalized a(1:100, 1:100)?
If so, just set a(1:100, 1:100) = b.
Related
I am following the Semantic Segmentation Examples tutorial by MathWorks.
I understand that I can load pixel labeled images
pxDir = fullfile(dataDir,'buildingPixelLabels');
Define the class names.
classNames = ["sky" "grass" "building" "sidewalk"];
Define the label ID for each class name.
pixelLabelID = [1 2 3 4];
and create a pixelLabelDatastore.
pxds = pixelLabelDatastore(pxDir,classNames,pixelLabelID);
But, how do I create a custom pixel labelled image where every pixel value represents the categorical label of that pixel?
I would then proceed by writing:
pxDir = fullfile(dataDir,'myCustomPixelLabels');
If I understood correctly, imageDatastore holds the actual image and not the pixel labels for that image.
EDIT:
On my system pxDir points to 'C:\Program Files\MATLAB\R2017a\toolbox\vision\visiondata\buildingPixelLabels'. Since I am on Matlab2017a so this example is not included by default, and I cannot compare or view the file to get a better understanding of what I need to do to reproduce this example.
The answer can be found here.
Matlab 2017a
Go to the APPS tab, and search for Image Labeler, or Training Image Labeler
Click on Add Images to add your training images.
Click on Add ROI Labels to add class names for the regions of interest.
Proceed to select the regions of interest manually from the uploaded images.
Once areas are selected, the data can be exported to workspace as a Ground Truth object.
I already made the image registration, and now I want to apply the registered image in rgb because I need to extract the countourr. As the imregister just work with grayscale images I converted my image to grayscale,but now I can´t find the intensity value of the contour to find the contour indexes. Wat kind of algorithm does imregister applies to the image, tochange the intensity value of the pixels? Or there is another way to go back to the rgb image to extract the inicial countour in the registered image? Does anyone have any sugestion?
There is my matlab code :
% Algorithm for image validation
% Open the two images which will be compared
name2=input('Image name ( automated segmentation) ','s');
img_automated=imread(name2,'png');
figure (1), imshow(img_automated), title('Image automated')
name=input('Image name ( manual segmentation) ','s');
img_manual=imread(name,'png');
img_manual_gray=rgb2gray(img_manual);
%img_manual_gray=img_manual(:,:,3);
figure (2), imshow (img_manual),title('Image manual')
img_automated_gray=rgb2gray(img_automated);
%img_automated_gray=img_automated(:,:,3);
%img_double=im2double(img_automated_gray);
figure (3), imshow (img_automated_gray), title (' Image converted to double ');
%img_automated_gray2=rgb2gray(img_automated);
% View images side by side
figure (6), imshowpair(img_manual,img_automated_eq,'diff')
title('Images overlap')
%% Configure parameters in imreconfig
[optimizer,metric]=imregconfig('Multimodal');
%% Default registration
registered=imregister(img_automated_gray,img_manual_gray,'rigid',optimizer,metric);
%tform = imregtform(img_automated,img_manual,imref2d,'affine',optimizer,metric)
figure(7), imshowpair(registered, img_manual_gray,'falsecolor'); title('Default registration');
figure(8), imshowpair(registered, img_manual_gray,'montage','Scaling','independent'); title('Default registration');
figure(9), imshow(registered);
C = imfuse(registered,img_automated);
figure(21);imshow(C);
%%%%%%%%%%%%%%% Here%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%I tried this process to recover the transformation applied in the registered image,and them aplly this in the initial automated rgb image,but B isn't the same as the registered image. Any suggestions??
tform = imregtform(img_automated_gray,img_manual_gray,'rigid',optimizer,metric);
B = imwarp(img_automated,tform);
figure(22);imshow(B);
Links to the images:
https://www.dropbox.com/s/xbanupnpjaaurj5/manual.png?dl=0 (manual- rgb)
https://www.dropbox.com/s/6fkwi3xbicwzonz/registered%20image.png?dl=0
You are on the right track with your use of imregtform. The missing piece is that imwarp, by default, chooses an output grid with the same resolution as the input grid with limits big enough to capture the entire output image.
In most registration cases, this is not what you want. What you want, is to specify the 'OutputView' Name/Value to specify the resolution and limits that you want in the output grid. In many registration use cases, this is the resolution/limits of the fixed image:
tform = imregtform(img_automated_gray,img_manual_gray,'rigid',optimizer,metric);
B = imwarp(img_automated,tform,'OutputView',imref2d(size(img_manual_gray)));
figure(22);imshow(B);
I am creating a GUI containing an image using the following code:
try
Imagenamehere = imread('Imagenamehere.jpg');
axes(handles.Logo)
image(Imagenamehere)
set(gca,'xtick',[],'ytick',[])
catch
msgbox('Please download all contents from the zipped file into working directory.')
end
The image shows up but for some reason is completely coloured blue as if put through a blue filter. I don't think it would be wise to upload the image but it is a simple logo coloured black and white.
Anyone know what could be causing this?
Check the size, type (probably uint8) and range of your image. It sounds like for some reason your images are being displayed with colormap as jet (the default), and possibly also that your range is not what MATLAB expects (e.g. 0 to 1 not 0 to 255), resulting in all your values being relatively low (blue on the jet colormap).
"black and white" is just one way of interpreting an image file which contains only two colors. MATLAB makes several assumptions when you pass data into a display function like image. If you don't specify colormap and image data range, it will make a guess based off things like data type.
One possibility is that your logo file is an indexed image. In these cases you need to do:
[Imagenamehere map] = imread('Imagenamehere.jpg');
colormap(map);
I am using R to plot trying to conditionally change parts of an array
based on the columns of the array.
I have worked out the following steps:
x<-array(1,dim=c(4,4,3))
r<-x[,,1]
g<-x[,,2]
b<-x[,,3]
r1<-apply(r[,2:3],1:2,function(f){return(0)})
g1<-apply(g[,2:3],1:2,function(f){return(0)})
b1<-apply(b[,2:3],1:2,function(f){return(0)})
r3<-cbind(r[,1],r1,r[,4])
g3<-cbind(g[,1],g1,g[,4])
b3<-cbind(b[,1],b1,b[,4])
# Pass to pixmapRGB
This works, but as I am new to R, I was wondering if
there was a more efficient way to manipulate parts
of an array.
For example, does apply know which element it is working on?
The bigger picture is that I want to graph a time-series scatter
plot over many pages.
I would like to have a thumbnail in the corner of the page that is
a graph of the whole series. I would like to color a portion of
that thumbnail a different color to indicate what range the
current page is examining.
There is alot of data, so it is not feasible to redraw a new plot
for the thumbnail on every page.
What I have done is to first write the thumbnail plot out to a tiff file.
Then I read the tiff file back in, used getChannels from pixmap
to break the picture into arrays, and used the above code to change
some of the pixels based on column.
Finally I then print the image to a viewport using
pixmapRGB/pixmapGrob/grid.draw
It seems like alot of steps. I would be grateful for any pointers
that would help me make this more efficient.
Maybe I don't understand your question, but if what you're trying to do is just "change some pixels based on column," why don't you just use the basic array indexing to do that?
This will do the same thing you have posted:
x<-array(1,dim=c(4,4,3))
r<-x[,,1]
g<-x[,,2]
b<-x[,,3]
r[,2:3]=0
g[,2:3]=0
b[,2:3]=0
Is that helpful?
Perhaps more of a comment than an answer, but when I try to plot over a number of pages I usually go left to right, breaking up the plots into quantiles and setting appropriate xlim (or ylim)
x <- rnorm(100000)
y <- rnorm(100000)
df <- data.frame(x,y)
seq1 <- quantile(df$x, probs = seq(0,1,0.1))
seq2 <- quantile(df$x, probs = seq(0,1,0.1))
for(x in 1:(length(seq1)-1)) {
plot(df, xlim=c(seq1[x],seq1[x+1]))
}
No idea how to overlay a thumbnail onto the graphs although I think you could do this with one of the rimage functions if you saved the thumbnail.
You could avoid having to read and paste a tiff thumbnail by actually replotting the whole chart at reduced scale. check out par(fig) , and then do something like
Rgames: plot(1:2,1:2)
Rgames: par(mar=c(.1,6,.1,.1),new=T,fig=c(0,.25,.5,.75))
Rgames: plot(1:2,1:2)
Rgames: polygon(c(1,2,2,1),c(1,1,2,2),col='red')
("Rgames:" is my prompt)
You'll have to play a bit with the margin values, but this will get your "mini-graph" set up.
I want to switch back and forth between two images, like blinking: 1 second for the first image and one second for second image.
I'm not totally sure of what you want to do (specifically what type of images you are trying to display), but here's some sample code that may do what you want:
image1 = imread('cameraman.tif'); % Load a test image
image2 = imread('circles.png'); % Load another test image
hAxes = gca; % Get a handle to the current axes
for iLoop = 1:5, % Loop five times
imshow(image1,'Parent',hAxes);
pause(1);
imshow(image2,'Parent',hAxes);
pause(1);
end
I used the general function IMSHOW, but this sometimes changes other properties of the figure/axes and that may not be to your liking (since you mention adding this to an existing GUI). You may want to use the IMAGE function instead. Also, instead of the for loop you could use a while loop that stops switching images when a condition is met (such as a button press).
How are your images stored in Matlab? As a matlab movie or a 3 or 4 dimensional matrix depending on if the images are color or grayscale. Also, if you have the image processing toolbox, implay and immovie. Another option assuming that your images are in a mxnx3xk (rgb color) or a mxnxk (gray scale) matrix. Then the following should work. Assuming the following
Img - matrix storing image data either with dimensions mxnx3xk
or mxnxk
handles.imageAxes -
handle for the axis you want to
display the image (set the tag of the
axis to imageAxes in GUIDE)
Now you can loop through Img
for i=1:k
% display the i^th image use `Img(:,:,i)` for a gray scale stack
image(Img(:,:,:,i),'parent',handles.imageAxes);
pause(1) % pause one second
end
that's it.