how to convert an image into low frequency and high frequency subbands using DWT

Question

ashok 2014-9-18

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https://ww2.mathworks.cn/matlabcentral/answers/155243-how-to-convert-an-image-into-low-frequency-and-high-frequency-subbands-using-dwt

评论： ashok 2014-9-18

while using dwt2 it gives 4 sub bands as LL LH HL HH but i need only as Low and High

if we take the LL and HH from dwt2 some of the details are missing how to do in matlab

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Answer 1

Michael scheinfeild 2014-9-18

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[cA,cH,cV,cD] = dwt2(X,'wname')

it gives you the sub bands you need of course it not gives all info if you take only two bands , you can try to filter or threshold http://www.mathworks.com/help/wavelet/ref/dwt2.html

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ashok 2014-9-18

i think after generate the low and high frequency filter coefficients then multiply with the input image and get the high or low frequency band and subtract with the original to get high freq sub band is there any reference code for that

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