Exact integral images at generic angles for 2D barcode detection

Using integral images for fast computation of sums of rectangular areas is very popular in computer vision. However the method does not extend naturally to rotations at arbitrary angles. We propose a novel solution to elegantly compute integral images at generic angles. Our method is exact in the sense that no approximations are used to derive it and it is vulnerable only to the unavoidable aliasing effects of discretization. Detailed experiments show that our method is more accurate than previously proposed ideas. We also demonstrate its usefulness by detecting 2D barcodes embedded in images.