I found online that I can use matlab to capture the ellipse, but I want to change the background to white instead of png.
[FileName,PathName] = uigetfile({'*.jpg;*.tif;*.png;*.gif','All Image Files'},'Please Select an Image');
image = imread([PathName FileName]);
imshow(image) %needed to use imellipse
user_defined_ellipse = imellipse(gca, []); % creates user defined ellipse object.
wait(user_defined_ellipse);% You need to click twice to continue.
MASK = double(user_defined_ellipse.createMask());
new_image_name = [PathName 'Cropped_Image_' FileName];
new_image_name = new_image_name(1:strfind(new_image_name,'.')-1); %removing the .jpg, .tiff, etc
new_image_name = [new_image_name '.png']; % making the image .png so it can be transparent
imwrite(image, new_image_name,'png','Alpha',MASK);
msg = msgbox(['The image was written to ' new_image_name],'New Image Path');
waitfor(msg);`
enter image description here
Related
I want to segment a region from an image in MATLAB and display it in a different image file.
I have tried segmenting it but failed. I want to segment the region from 200:400(i.e. only the regions those are yellow and green)
I = imread('Intensity1.jpg');
imshow(I)
hold on
mask = false(size(I));
mask(200:400) = true;
visboundaries(mask,'Color','b');
I have detected the face from an image. Now I want to store that detected face as a jpg image in matlab. Plzz some one guide me.
code for face detection is:
img = imread('C:\Users\Anmol\Desktop\face_recognition\Pgm\image1');
facedetector = vision.CascadeObjectDetector()
BBOX = step(facedetector,img)
B = insertObjectAnnotation(img,'rectangle',BBOX,'Face');
title('detected faces');
n = size(BBOX,1);
string = num2str(n);
str = strcat('no of face=',string);
disp(str);
I would be very thankful is some could provide me the code for storing the detected face as a jpg image
You can crop the face using imcrop, and then save the cropped image using imwrite.
faceImage = imcrop(img, BBOX(1,:))
imwrite(img, 'face.jpg');
By default, MATLAB function imrotate rotate image with black color filled in rotated portion. See this, http://in.mathworks.com/help/examples/images_product/RotationFitgeotransExample_02.png
We can have rotated image with white background also.
Question is, Can we rotate an image (with or without using imrotate) filled with background of original image?
Specific to my problem: Colored image with very small angle of rotation (<=5 deg.)
Here's a naive approach, where we simply apply the same rotation to a mask and take only the parts of the rotated image, that correspond to the transformed mask. Then we just superimpose these pixels on the original image.
I ignore possible blending on the boundary.
A = imread('cameraman.tif');
angle = 10;
T = #(I) imrotate(I,angle,'bilinear','crop');
%// Apply transformation
TA = T(A);
mask = T(ones(size(A)))==1;
A(mask) = TA(mask);
%%// Show image
imshow(A);
You can use padarray() function with 'replicate' and 'both' option to interpolate your image. Then you can use imrotate() function.
In the code below, I've used ceil(size(im)/2) as pad size; but you may want bigger pad size to eliminate the black part. Also I've used s and S( writing imR(S(1)-s(1):S(1)+s(1), S(2)-s(2):S(2)+s(2), :)) to crop the image where you can extract bigger part of image just expanding boundary of index I used below for imR.
Try this:
im = imread('cameraman.tif'); %// You can also read a color image
s = ceil(size(im)/2);
imP = padarray(im, s(1:2), 'replicate', 'both');
imR = imrotate(imP, 45);
S = ceil(size(imR)/2);
imF = imR(S(1)-s(1):S(1)+s(1)-1, S(2)-s(2):S(2)+s(2)-1, :); %// Final form
figure,
subplot(1, 2, 1)
imshow(im);
title('Original Image')
subplot(1, 2, 2)
imshow(imF);
title('Rotated Image')
This gives the output below:
Not so good but better than black thing..
Say I have an image. How can I colour some specific pixels in that image using MATLAB?
Thanks.
RGB Pixels
I'd suggest working with an RGB image, so that you can easily represent color and gray pixels. Here's an example of making two red blocks on an image:
img = imread('moon.tif');
imgRGB = repmat(img,[1 1 3]);
% get a mask of the pixels you want and set an RGB vector to those pixels...
colorMask = false(size(imgRGB,1),size(imgRGB,2));
colorMask(251:300,151:200,:) = true; % two discontiguous blocks
colorMask(50:100,50:100,:) = true;
redPix = permute([255 0 0],[1 3 2]);
imgRGB(repmat(colorMask,[1 1 3])) = repmat(redPix, numel(find(colorMask)),1);
AlphaData image property
Another cool way of doing this is with an image's AlphaData property. See this example on a MathWorks blog. This essentially turns color on or off in certain parts of the image by making the gray image covering the color image transparent. To work with a gray image, do like the following:
img = imread('moon.tif');
influenceImg = abs(randn(size(img)));
influenceImg = influenceImg / (2*max(influenceImg(:)));
imshow(img, 'InitialMag', 'fit'); hold on
green = cat(3, zeros(size(img)), ones(size(img)), zeros(size(img)));
h = imshow(green); hold off
set(h, 'AlphaData', influenceImg)
See the second example at the MathWorks link.
I want to extract an elliptical region from an image (a portion of a face portion from an image) preferably in MATLAB:
For example, in this image, I want to extract the region within red boundary.
Can anyone help me with this ?
Cropping is easy, all you have to do is apply a proper mask. The trick is to create such a mask.
Assuming A is your image, try this:
%# Create an ellipse shaped mask
c = fix(size(A) / 2); %# Ellipse center point (y, x)
r_sq = [76, 100] .^ 2; %# Ellipse radii squared (y-axis, x-axis)
[X, Y] = meshgrid(1:size(A, 2), 1:size(A, 1));
ellipse_mask = (r_sq(2) * (X - c(2)) .^ 2 + ...
r_sq(1) * (Y - c(1)) .^ 2 <= prod(r_sq));
%# Apply the mask to the image
A_cropped = bsxfun(#times, A, uint8(ellipse_mask));
The cropped image will be stored in A_cropped.
Play with the coordinates of the center and the values of the radii until you get the desired result.
EDIT: I extended the solution for RGB images (if matrix A is 3-D).
This the method I use to crop faces into ellipse shape. It makes the background transparent.
[FileName,PathName] = uigetfile({'*.jpg;*.tif;*.png;*.gif','All Image Files'},'Please Select an Image');
image = imread([PathName FileName]);
imshow(image) %needed to use imellipse
user_defined_ellipse = imellipse(gca, []); % creates user defined ellipse object.
wait(user_defined_ellipse);% You need to click twice to continue.
MASK = double(user_defined_ellipse.createMask());
new_image_name = [PathName 'Cropped_Image_' FileName];
new_image_name = new_image_name(1:strfind(new_image_name,'.')-1); %removing the .jpg, .tiff, etc
new_image_name = [new_image_name '.png']; % making the image .png so it can be transparent
imwrite(image, new_image_name,'png','Alpha',MASK);
msg = msgbox(['The image was written to ' new_image_name],'New Image Path');
waitfor(msg);