MATLAB: Perform operations on non-zero locations of the matrix

Question

pic1=rgb2gray(pic);

pic2 = imnoise(pic1,'salt & pepper',0.05);

%%%%%%%Hard Thresholding%%%%%%

Container=pic2>80;

Container=uint8(Container);

pic3=pic2.*Container;

Hi

this is my Hard Thresholding in pic3

now i want Soft Thresholding by subtracting the places have non-zero values in pic3 from 80 without using a loop

Thanks for your guidance

Answer 1

mask = pic3 > 0; % mask for non-zero values of pic3
pic3(mask) = pic3(mask) - 80;