matlab - What is the meaning of the parameter coif1 in wavelet decomposition?

Question

I have code for wavelet transform. Here they are using coif1 to decompose the signal. Can anybody explain what is the use of coif1? and what does it mean?

This is the code:

function wavelet = waveletTransform(image)
% input: image to process and extract wavelet coefficients from
% output: 1x20 feature vector containing the first 2 moments of wavelet
% coefficients

imgGray = double(rgb2gray(image))/255;
imgGray = imresize(imgGray, [256 256]);

coeff_1 = dwt2(imgGray', 'coif1');
coeff_2 = dwt2(coeff_1, 'coif1');
coeff_3 = dwt2(coeff_2, 'coif1');
coeff_4 = dwt2(coeff_3, 'coif1');

% construct the feaute vector
meanCoeff = mean(coeff_4);
stdCoeff = std(coeff_4);

wavelet = [meanCoeff stdCoeff];

end

Answer 1

在这里和那里查看Matlab 文档（参数文档wname），您会看到它意味着小波coif1是小波的类型，在这种情况下来自 coiflet 系列。

它是用作图像分解的滤波器的小波。