High-resolution elastography employs a multiple-step process in which successively finer samplings of data and smaller areas of data are evaluated to provide increasingly accurate displacement measurements, wherein each displacement measurement guides the determination of corresponding regions of comparison used in the next displacement evaluation. Sample on the fly circuitry, set-reset circuitry and metastable rejection circuitry are used to provide a sufficient pulse width for sampling on the fly the one or more nodes when the one or more bus domain clocks require asynchronous operation. The positioning apparatus is connected to the chassis and configured to position the produce in the ground for harvesting and decoring. For QFT, multiple hypothesized frequency errors are applied to an input signal to obtain multiple rotated signals. Since the circuit board and the connector are mounted on the supporting member at positions protected by solid structures of the supporting member, they are prevented from being hit by vehicle parts falling apart when a collision occurs.