How can i Blur the background of an image?

Hello, I have to be able to blur only object of a .jpg not subject. I have tried many times but the whole picture both subject and object is getting blurry.,any help would be greatly appreciated.

Answer 1

[DGM]

Create a mask which selects the foreground (or background). Compose the output using the mask, the original image, and a blurred copy.

% an image (RGB, uint8)
inpict = imread('peppers.png');

% an antialiased mask selecting the foreground (I, uint8)
mask = imread('chilipepmask.png');

% a blurred copy of the entire image
blurred = imgaussfilt(inpict,5);

% compose the output using MIMT tools
%outpict = replacepixels(inpict,blurred,mask);

% compose the output using base tools
mask = im2double(mask);
outpict = mask.*im2double(inpict) + (1-mask).*im2double(blurred);
outpict = im2uint8(outpict); % presuming the output should always be uint8

imshow(outpict,'border','tight')

See also:

https://www.mathworks.com/matlabcentral/answers/2058794-how-can-i-blur-an-image-background-only

https://www.mathworks.com/matlabcentral/answers/54320-how-to-blur-with-a-controlled-area

https://www.mathworks.com/matlabcentral/answers/46624-how-can-i-filter-region-of-interest-roi-selected-in-a-3-d-array-image-rgb-without-converting-to#answer_1097553