1. A method of segmenting an object in a digital image having a plurality of pixels, wherein a foreground node located within the object and a background node located outside of the object are selected, comprising: determining a plurality of coefficients, each one of the plurality of coefficients being a function of the relative image data associated with two of the plurality of pixels; and solving a system of linear equations, the system of linear equations including the plurality of coefficients and being a function of the foreground node and the background node, to determine a boundary of the object, using a graphics processing unit.