how to select threshold on haar wavelet

image compression using haar wavelet transform

Answer 1

[prabhat kumar sharma]

Hi Sholai,

MATLAB provides functions like wthresh for thresholding wavelet coefficients. You can use these functions to apply hard or soft thresholding.

You can refer this documentation for further information: https://www.mathworks.com/help/wavelet/ref/wthresh.html

You can refer below code piece:

% Perform Haar wavelet decomposition
[coeffs, sizes] = wavedec2(image, level, 'haar');

% Choose a global threshold value
threshold = 20; % Example value, adjust based on your needs

% Apply soft thresholding
coeffs_thresh = wthresh(coeffs, 's', threshold);

% Reconstruct the image from thresholded coefficients
compressed_image = waverec2(coeffs_thresh, sizes, 'haar');

% Display the compressed image
imshow(compressed_image, []);

I hope it helps!