Opencv codes convert Matlab

My opencv codes are:

I tried convert from opencv code blog to matlab code blog but i don't know how to do this. I have never been used opencv so, i can't do. Can you help me, please.

Algorithm is first of all, you generate random noise to image. secondly, if black noises is <10 and white noise >245 set 255 white and 0 black. You can look at opencv codes.

My tried codes:

% I generated random gaussian noise

I = imread('pears.png');

J = rgb2gray(I);

p3 = 0;

p4 = 0.05;

J = im2double(J);

b = J + sqrt(p4)*randn(size(J))+p3;

imshow(b)