如何将圆形蒙版的外部限制更改为不同的颜色

Question

我有以下函数可以成功地在图像输入上创建一个灰色圆形蒙版，这样新图像就是圆形图像周围的灰色边框。示例：Grey circular mask。

我想做的只是让面具变成一个非常特殊的绿色，但我没有成功。

代码如下：

function [newIm] = myCircularMask(im)

%Setting variables
rad = size(im,1)/2.1; %Radius of the circle window
im = double(im); 
[rows, cols, planes]= size(im);
newIm = zeros(rows, cols, planes);

%Generating hard-edged circular mask with 1 inside and 0 outside
M = rows;
[X,Y] = meshgrid(-M/2:1:(M-1)/2, -M/2:1:(M-1)/2);
mask = double(zeros(M,M));
mask(X.^2 + Y.^2 < rad^2) = 1;

% Soften edge of mask
gauss = fspecial('gaussian',[12 12],0.1);
mask = conv2(mask,gauss,'same'); 

% Multiply image by mask, i.e. x1 inside x0 outside
for k=1:planes
newIm(:,:,k) = im(:,:,k).*mask;
end

% Make mask either 0 inside or -127 outside
mask = (abs(mask-1)*127);

% now add mask to image
for k=1:planes
newIm(:,:,k) = newIm(:,:,k)+mask;
end
newIm = floor(newIm)/255;

我想使用的绿色类型是 RGB 值 [59 178 74]。 我是 MATLAB 的初学者，因此我们将不胜感激。

干杯！

史蒂夫

Answer 1

蒙版后，创建蒙版的彩色版本：

% test with simple mask
mask = ones(10,10);
mask(5:7,5:7)=0;
% invert mask, multiply with rgb-values, make rgb-matrix:
r_green=59/255; g_green=178/255; b_green=74/255;
invmask=(1-mask); % use mask with ones/zeroes
rgbmask=cat(3,invmask*r_green,invmask*g_green,invmask*b_green);

将此添加到您的蒙版图像中。

编辑：

function [newIm] = myCircularMask(im)

%Setting variables
rad = size(im,1)/2.1; %Radius of the circle window
im = double(im); 
[rows, cols, planes]= size(im);
newIm = zeros(rows, cols, planes);

%Generating hard-edged circular mask with 1 inside and 0 outside
M = rows;
[X,Y] = meshgrid(-M/2:1:(M-1)/2, -M/2:1:(M-1)/2);
mask = double(zeros(M,M));
mask(X.^2 + Y.^2 < rad^2) = 1;

% Soften edge of mask
gauss = fspecial('gaussian',[12 12],0.1);
mask = conv2(mask,gauss,'same'); 

% Multiply image by mask, i.e. x1 inside x0 outside
for k=1:planes
   newIm(:,:,k) = im(:,:,k).*mask;
end

% Here follows the new code:
% invert mask, multiply with rgb-values, make rgb-matrix:
r_green=59/255; g_green=178/255; b_green=74/255;
invmask=(1-mask); % use mask with ones/zeroes
rgbmask=cat(3,invmask*r_green,invmask*g_green,invmask*b_green);
newIm=newIm+rgbmask;

请注意，我无法测试我的建议，因此可能存在错误。