Spatial Decoupling of Foot-Substrate Cross-Talk in Plantar Pressure Sensor Arrays

Measuring plantar pressure with smart insoles is widely used in gait analysis, medical rehabilitation, and clinical monitoring, but the continuous elastomeric layers of hybrid footwear transmit force between adjacent sensors and produce mechanical cross-talk that distorts local readings. The objective of this study was to develop a deterministic framework that identifies the spatial mechanical influence between sensors and compensates for it after signal acquisition. Controlled vertical loads were applied individually to each sensor, while the responses of all sensors were recorded each time as a vector and placed in a matrix; the resulting force data, complemented by a distance-dependent transfer function, formed the direct influence matrix of the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method. Normalization and inversion generated a static decoupling operator applied to the vector of raw measurements. Secondary signals, which initially ranged from 40 N to 970 N, were reduced to a residual band from 3 N to 75 N (97.8% attenuation). The system, once calibrated in this way, provides a clearer spatial representation of local plantar pressure without applying changes to the physical structure of the insole and can be executed through a single matrix-vector multiplication on microcontrollers used in wearable platforms with limited resources.