Normal Map Acquisition of Nearly Flat Objects Using a Flatbed Scanner

We propose a new efficient technique for acquiring normal maps of nearly flat objects using a flatbed scanner. The technique requires no hardware modification or dedicated calibration. Our setup consists of a conventional flatbed scanner and a clamp on which a planar checkerboard is glued. We take four scans of the object manually rotated by roughly 90 degrees. The scans are then registered by sub pixel checkerboard corners. Detailed normal map of the scanned surface is obtained by solving a linear least squares problem.