1. An image amplifying method, comprising steps of: obtaining, by an image amplifying device, high-frequency components and low-frequency components of a source image; performing, by the image amplifying device, pixel interpolation on the low-frequency components of the source image through a first interpolation algorithm, to obtain a low-frequency sub-image; performing, by the image amplifying device, pixel interpolation on the high-frequency components of the source image through a second interpolation algorithm, to obtain a high-frequency sub-image; and merging, by the image amplifying device, the low-frequency sub-image and the high-frequency sub-image, to obtain a merged image; wherein the first interpolation algorithm and the second interpolation algorithm adopt different algorithms.