M通道过采样图滤波器组的多尺度分解 matlab

代码：

function [pyr, filter] = m_channel_pyramid(img, levels, filter_size, filter_type)
% M_CHANNEL_PYRAMID: Construct a multi-channel pyramid for a given image.
%
%   [PYR, FILTER] = M_CHANNEL_PYRAMID(IMG, LEVELS, FILTER_SIZE, FILTER_TYPE)
%
%   - IMG: the input image, with size [h, w, c].
%   - LEVELS: the number of pyramid levels.
%   - FILTER_SIZE: the size of the filter, e.g., [3, 3].
%   - FILTER_TYPE: the type of the filter, e.g., 'gaussian'.

[h, w, c] = size(img);

% Define the filter
filter = cell(c, 1);
for i = 1:c
    filter{i} = get_filter(filter_size, filter_type);
end

pyr = cell(levels, c);
for i = 1:c
    % Pre-filtering
    img(:, :, i) = imfilter(img(:, :, i), filter{i}, 'replicate');

    % Multi-scale decomposition
    for j = 1:levels
        % Downsampling
        img = imresize(img, 1/2, 'bilinear');
        % Filtering
        img(:, :, i) = imfilter(img(:, :, i), filter{i}, 'replicate');
        % Save the result
        pyr{j, i} = img;
    end
end

function filter = get_filter(filter_size, filter_type)
% GET_FILTER: Get the filter for the given size and type.
%
%   FILTER = GET_FILTER(FILTER_SIZE, FILTER_TYPE)

if strcmp(filter_type, 'gaussian')
    sigma = 0.8;
    x = linspace(-filter_size(2)/2, filter_size(2)/2, filter_size(2));
    y = linspace(-filter_size(1)/2, filter_size(1)/2, filter_size(1));
    [X, Y] = meshgrid(x, y);
    filter = exp(-(X.^2 + Y.^2)/(2*sigma^2));
    filter = filter / sum(filter(:));
else
    error('Unsupported filter type.');
end

使用方法：

img = imread('lena.png');
img = im2double(img);

levels = 5;
filter_size = [3, 3];
filter_type = 'gaussian';

[pyr, filter] = m_channel_pyramid(img, levels, filter_size, filter_type);