1. A method for differentiating between a textured, planar surface and a background region surrounding the surface comprising the steps of: illuminating both the textured, planar surface and the surrounding background region by directing light thereat so the light strikes the surface substantially normal to the plane thereof; capturing the image of the textured planar surface and the surrounding background region with an image-acquisition device which is positioned to sense the light reflected from the background region and the surface substantially normal to the plane of the surface thereof such that only the textured planar surface appears in focus within the captured image; determining the intensity of each of a plurality of small areas (pixels) within the captured image; determining the intensity gradient for each pixel; creating a gradient image by assigning to each pixel within the captured image an intensity value according to its intensity gradient; and binarizing the gradient image by causing each pixel therein to appear bright or dark, depending on whether the intensity gradient established for each pixel is above or below a predetermined threshold, respectively, thereby eliminating the background region from the captured image.