increase image quality after decoder in matlab

main.m
% Load image
I = imread('image.png');

% Add noise
J = imnoise(I, 'gaussian', 0.01);

% Perform wavelet denoising
wname = 'sym8'; % wavelet name
level = 2; % decomposition level
[C,S] = wavedec2(J, level, wname);
sigma = mad(C(:)) / 0.6745; % estimate noise standard deviation
threshold = sigma * sqrt(2*log(prod(S(1,:)))));
soft = 'soft'; % thresholding mode
XC = wthresh(C, soft, threshold);
Jden = waverec2(XC, S, wname);

% Show original and denoised image
figure; imshow(J);
title('Original Image');
figure; imshow(Jden);
title('Denoised Image');
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