Method and device for embedding and extracting invisible digital watermark in image

The embodiment of the invention provides a method for embedding and extracting an invisible digital watermark in an image, and the method comprises the steps: obtaining a target image, and converting the target image into a proper color space; processing a color channel in a color space by combining a DWT algorithm with a DCT algorithm to obtain frequency domain features corresponding to the target image; writing pre-processed transparent watermarking information into a high-frequency region of the frequency domain feature; and carrying out smoothing processing on the frequency domain features, converting the frequency domain features after smoothing processing back to spatial domain representation, and outputting an image with the invisible digital watermark. Through improvement in the aspects of embedding strategy selection, algorithm optimization, technology adjustment, security enhancement and the like, compared with a traditional method, the method has obvious differences in the aspects of visibility, ro