wrcoef与appcoef、detcoef的区别

liutian

请问，wrcoef与appcoef、detcoef有什么区别，自己在看书，怎么感觉它们的功能差不多啊。
请高手指教。

zhangnan3509

wrcoef reconstructs the coefficients of a one-dimensional signal, given a wavelet decomposition structure (C and L) and either a specified wavelet ('wname', see wfilters for more information) or specified reconstruction filters (Lo_R and Hi_R).

appcoef is a one-dimensional wavelet analysis function.

appcoef computes the approximation coefficients of a one-dimensional signal.




detcoef is a one-dimensional wavelet analysis function.

D = detcoef(C,L,N) extracts the detail coefficients at level N from the wavelet decomposition structure [C,L]. See wavedec for more information on C and L.

差别还是很明显的吧，

[ 本帖最后由 zhangnan3509 于 2007-8-17 11:23 编辑 ]

liutian

还是不是很明白，感觉wrcoef低频、高频都可以重构，appcoef只可以重构低频系数，detcoef只可以重构高频系数。但是它们重构的结果差别很大，虽然波形趋势一致，横坐标不一样。

破凰

appcoef和detcoef只是从小波分解框架中提取系数，没有进行单支重构。而wrcoef是要进行单支重构的。

liutian

明白了，谢谢！