This paper gives a view on the fusion of different modality images like PET and CT (Positron Emission Tomography & Computed Tomography) by two domain methods PCA and DWT methods. The spatial domain is PCA method. and another transformation domain method (DWT). In dwt decomposed coefficients of DWT (discrete wavelet transformation) are applied with the IDWT to get fused image information. https://threadheaders.shop/product-category/hat/