Paper laboratory sheet image preprocessing method and system

The invention discloses a paper laboratory sheet image preprocessing method and system. The method comprises the following steps: constructing a laboratory sheet image preprocessing model comprising a background estimation sub-network, a shadow removal sub-network and a crease removal sub-network; carrying out feature learning on the paper laboratory sheet image by adopting a background estimation sub-network to obtain a global background color and spatial distribution features of background and non-background pixels so as to construct a shadow attention map; training the shadow removal sub-network according to the original paper laboratory sheet image, the global background color and the shadow attention map to obtain a shadow-free image; and constructing a crease attention graph by adopting the background estimation sub-network according to the shadow-free image, and training the crease removal sub-network according to the shadow-free image and the crease attention graph to obtain a shadow-free crease-free