1. A computer implemented method of estimating at least one dimension of a target object within a digital image which includes a reference object having a fiducial pattern printed thereon placed substantially in a plane of the target object, the method comprising: obtaining a digital image, on a computer, containing the target object and the reference object; locating, on a computer, the reference object in the digital image by searching for the fiducial pattern, said reference object having one or more known linear dimensions viewable in said digital image; determining, on a computer, pixel dimensions of said reference object using edge detection image processing to identify pixel locations bounding the reference object; calculating, on a computer, a pixel scale factor based on at least one reference object pixel dimension in the digital image and at least one known linear physical dimension of the reference object; locating, on a computer, the target object in the digital image; and calculating, on a computer, the at least one dimension of the target object based on the pixel scale factor.