1. A method of computing image gradients comprising the steps of: identifying a set of voxels; neglecting all voxels within the set of voxels having a gradient length below a predetermined threshold length; computing a series of local maxima points with sub-voxel precision along the gradient by comparing remaining voxels to neighboring voxels, the series of local maxima points representative of an interior surface of an object boundary that surrounds an interior of the object; and processing each point in the series to indirectly calculate a curve skeleton of the object by applying a topological analysis to a vector field that is computed based on the series of local maxima points such that the vectors of the vector field point towards the interior of the object; wherein said method is performed by a system comprising a processor and a storage medium operably connected to the processor, the storage medium capable of receiving and storing morphometric data.