A magnetic sensor configured to reside in proximity to a recording medium during use having a high spin polarization reference layer stack above AFM layers. A residual limb model may include a residual limb portion and a bladder complementary in shape to the residual limb portion. In the signal processor DSP, the sum signal \u03a3 and the difference signal \u0394 are formed from the two sensor signals S1 and S2. The conveying section conveys the image sensor in a first direction and a second direction opposite to the first direction.