提取椭圆区域并在 Matlab 中手动裁剪

Question

我有很多人脸图像，我想手动从图像中提取一个椭圆区域并裁剪并自动保存（如 imcrop 但不是矩形）。 你能帮我解决这个问题吗？

感谢您的帮助

Answer 1

您可以使用imellipse 函数。

Answer 2

%This is what you would do after creating the mask to get the coordinates.

structBoundaries = bwboundaries(binaryImage);
xy=structBoundaries{1}; % Get n by 2 array of x,y coordinates.
x = xy(:, 2); % Columns.
y = xy(:, 1); % Rows.

但是更好的方法是使用下面的代码。本质上，它要求用户选择图像，然后用户手动裁剪图像，然后将其保存到原始图像所在的位置。

[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);