Image synthesis method and device based on chrominance image matting and video live broadcast system

The invention relates to an image synthesis method and device based on chromaticity image matting and a video live broadcast system, and the method comprises the steps: carrying out the extraction and enhancement of foreground details of a foreground image, and obtaining an enhanced detail image of the foreground image; obtaining a semitransparent channel image obtained by pre-matting the foreground image; synthesizing a background image to be synthesized with the enhanced detail image to obtain an enhanced background image; synthesizing the foreground image, the semitransparent channel image and the enhanced background image to obtain a target synthesized image; according to the technical scheme, in the synthesis process of the foreground image and the background image, the details in the foreground image are enhanced, so that detail objects which cannot be processed into effective foreground image parts by an image matting technology can be restored in the final synthesized image, the synthesized image is m