Method for flattening laser-based image of curved book page

A method for flattening a laser-based image of a curved book page, comprising:

• placing an opened book on a scanning platform that is horizontally arranged, and emitting a laser beam to a curved book page, wherein the laser beam forms a plurality of parallel laser lines on the curved book page;
• acquiring a horizontal image of the curved book page having the plurality of parallel laser lines, and acquiring a 2D planar coordinate (x, y) of each pixel on each of the plurality of parallel laser lines in the horizontal image;
• calculating an actual spatial height of a pixel on one of the plurality of parallel laser lines according to a tangent function using a y-coordinate of an intersection line of the laser beam and the scanning platform, and an intersection angle of the laser beam and the scanning platform;
• repeating the calculating step for all pixels on each of the plurality of parallel laser lines to obtain the actual spatial heights of all pixels on each laser line;
• constructing a 3D spatial curve for each of the plurality of parallel laser lines;
• constructing a 3D curved surface of the acquired book page using the 3D spatial curves for all of the plurality of parallel laser lines;
• associating pixels on the 3D curved surface with pixels in the horizontal image of the curved book page;
• replacing a pixel value of each of the pixels on the 3D curved surface with a pixel value of a corresponding pixel thereof in the horizontal image to transform a page content from a planar image of the curved book page to the 3D curved surface.