Figure 4.

(a) Pressure calibration system comprising a stepper motor and scale to apply a known force to the FBGs. (b) Photograph of the force measurement plate (RS Scan Footscan) with the combined sensor on top of it. The active area of the foot scan plate was 488 mm × 325 mm with 4096 sensors (arranged in a 64 × 64 matrix). The dimension of each foot scan plate sensor (pixel) was 7.62 mm × 5.08 mm. (c) Pressure map under the foot. The location of the combined optical fibre sensor underfoot is highlighted in the white frame.