A magnetic field sensor comprising a plurality of magnetic sensing elements and a means for generating an image signal from the plurality of the signals generated thereby is used i) to sense a magnetic field proximate to a body portion of a vehicle for adjusting a magnetic circuit thereof, ii) to sense an occupant in a seat of a vehicle, or iii) to sense from within a body portion of a vehicle magnetic-field-influencing objects proximate thereto. In another aspect, the magnetic field sensor further comprises a plurality of magnetic focusing elements proximate to the magnetic sensing elements for improving the clarity of the magnetic image.