Introduction - If you have any usage issues, please Google them yourself
Single layer wavelet transform to the two-dimensional image decomposition, [cA1, cH1, cV1, cD1]=dwt2 (X, db1 ): X single image specified calculation of two-dimensional discrete wavelet transform wavelet decomposition, where cA is the approximation of wavelet coefficient matrix, parameters of cH, cV and cD respectively the level of detail coefficients, wavelet decomposition and vertical detail coefficients the diagonal detail coefficients.