laplacian_pyramid函数拉普拉斯差分matlab代码

以下是laplacian_pyramid函数的拉普拉斯差分Matlab代码：

function [lap_pyramid, filter] = laplacian_pyramid(im, levels)
% LAPLACIAN_PYRAMID Function to compute Laplacian pyramid.
%   Given an input image and number of levels, returns the Laplacian
%   pyramid and the filter used for the pyramid.
%
%   Arguments:
%       im      - Input image
%       levels  - Number of levels in the pyramid
%
%   Returns:
%       lap_pyramid - Laplacian pyramid
%       filter      - Filter used for the pyramid

% Set sigma value for Gaussian filter
sigma = 1.5;

% Generate filter for Gaussian pyramid
filter = fspecial('gaussian', [5 5], sigma);

% Create Gaussian pyramid
gauss_pyramid = cell(levels, 1);
gauss_pyramid{1} = im;

for i = 2:levels
    gauss_pyramid{i} = imresize(imfilter(gauss_pyramid{i-1}, filter), 0.5);
end

% Create Laplacian pyramid
lap_pyramid = cell(levels, 1);
lap_pyramid{levels} = gauss_pyramid{levels};

for i = levels-1:-1:1
    gauss_exp = imresize(gauss_pyramid{i+1}, size(gauss_pyramid{i}), 'bilinear');
    lap_pyramid{i} = gauss_pyramid{i} - gauss_exp;
end

end

此代码包含两个输出参数：lap_pyramid和filter。lap_pyramid包含拉普拉斯差分金字塔，filter是用于生成高斯金字塔和拉普拉斯差分金字塔的高斯滤波器。