hwo can i do this image that shades from white at the image edges to black in the image centre

imageData=[]; % set up an empty array

imSize=100;

numRows=imSize;

numCols=imSize;

%populate using a nested loop

for row=[numRows:-1:1]

imageRow=[]; %empty vector for row

for col=[numCols:-1:1]

pixelVal=(col+row)/(imSize*2); % make a pixel val in 0..1

imageRow=[imageRow pixelVal]; %add value for pixel

end

imageData=[imageData; imageRow]; % add row of pixels

end

for row=[1:numRows]

imageRow=[]; %empty vector for row

for col=[numCols:-1:1]

pixelVal=(col+row)/(imSize*2); % make a pixel val in 0..1

imageRow=[imageRow pixelVal]; %add value for pixel

end

imageData=[imageData; imageRow]; % add row of pixels

end

for row=[numRows:-1:1]

imageRow=[]; %empty vector for row

for col=[1:numCols]

pixelVal=(col+row)/(imSize*2); % make a pixel val in 0..1

imageRow=[imageRow pixelVal]; %add value for pixel

end

imageData=[imageData; imageRow]; % add row of pixels

end

for row=[1:numRows]

imageRow=[]; %empty vector for row

for col=[1:numCols]

pixelVal=(col+row)/(imSize*2); % make a pixel val in 0..1

imageRow=[imageRow pixelVal ]; %add value for pixel

end

imageData=[imageData;imageRow]; % add row of pixels

end

% display as an image

imshow(imageData);

but i want this picture like

Answer 1

[Akira Agata]

I believe you can do this more efficiently. The following is an example:

% Set image size
imSize = 100;

% Make a left-top part of the image
[xGrid,yGrid] = meshgrid(1:imSize,1:imSize);
xGrid = fliplr(xGrid);
yGrid = flipud(yGrid);
imageData = (xGrid+yGrid)/(imSize*2);

% Concatenate with rotating the left-top image
imageData = [...
  imageData,        rot90(imageData,-1);...
  rot90(imageData), rot90(imageData,2)];

% Show the result
figure
imshow(imageData)

Answer 2

[Sahil]

% Set image size imSize = 100;

% Make a left-top part of the image [xGrid,yGrid] = meshgrid(1:imSize,1:imSize); xGrid = fliplr(xGrid); yGrid = flipud(yGrid); imageData = (xGrid+yGrid)/(imSize*2);

% Concatenate with rotating the left-top image imageData = [... imageData, rot90(imageData,-1);... rot90(imageData), rot90(imageData,2)];

% Show the result figure imshow(imageData)