1. A method of forming a composite image of an object by combining a plurality of image frames formed by moving a handheld scanner over an object, the method comprising: with at least one processor: determining a position of each of the plurality of image frames relative to the composite image; and for each of a plurality of pixels in the composite image, each pixel representing an area of the object: identifying a set of the plurality of image frames comprising a portion representing the area of the object; and combining values based on the portion representing the area in each image frame of the set, the combining comprises forming a value for the pixel in the composite image.