The 3D Plantar Pressure Viewer is an easy to use visualization tool that supports the podiatrist during the generation of an insole prescription, allowing the visualization of plantar pressure maps onto the foot 3D geometry, or the insole 3D geometry.

This Rhinoceros plug-in allows to overlap, automatically align and analyze pressure maps (from baropodometric or in-shoes systems) and foot scans (from 3D or 4D scanners), both in a static and in a dynamic analysis. In the dynamic analysis, the tool is also able to select and visualize foot shapes and plantar pressure maps regarding the main phases of the human gait: heel strike, foot flat, heel off and toe off

A specific module of this tool is the Pressure Predictor, a system developed to predict plantar pressures associated with a specific insole design (geometry and materials). It is internally implemented by means of sound mathematical models that are completely transparent for the final user, who needs no knowledge about them to understand and run the application. It makes use of the data acquired in the first visit of a patient undergoing diabetic foot to a podiatry clinic to assess the plantar pressures that the same patient will exert while walking with a specific insole.

 

3D Pressure Viewer

 

The 3D Plantar Pressure Viewer is useful for clinicians, to know exactly the plantar pressure values in the foot sole, both in a static condition and while the patient is walking: the tool is able to select and visualize foot shapes and plantar pressure maps regarding the main phases of the human gait, even if the input is made of different number of files for foot and pressure information. Moreover it offers a set of functions to analyze the foot condition, such as the possibility to align foot and pressure data, visualize the projection of pressure maps and calculate the relative isobar curves.

The Pressure Predictor module is also useful for clinicians in the framework of the project, since plantar pressures are a good indicator of how likely a diabetic patient is of undergoing ulcers in the foot, and this module is able to provide a pressure prediction given the characteristics of the prescribed insole. Therefore, if podiatrists know the relationship between a given insole and the corresponding plantar pressures, they will be able to prescribe the most adequate insole for each individual patient. Five key areas were selected as the most probable to have ulcers, hence models were focused on predicting pressures in each one of those areas.

The 3D Pressure Map Visualization Tool is Rhinoceros plug-in, compatible with Rhino 5.3 and with the OS Windows 7 and 8.

For the static analysis, as input it accepts one foot geometry (from a 3D or 4D scanner, STL format) or one insole model (IGS format), and one pressure map (real or predicted, TXT or ASC format). For the dynamic analysis, as input it accepts n foot scans (from a 4D scanners, list of STL files) and n pressure maps (real or predicted, TXT or ASC format), being n a variable number of scans and maps (from 1 to 100).

The system is able to export four different type of data: pressure map (PNG), projections (VRML), isobar curves (IGS), or a combination of previous data.

 

Pressure Predictor

Root Mean Square Error with the Median of pressures and material intertion condition,
after training the ANN with a learing rate equals to 0.001

 

The Pressure Predictor is an executable file, called directly from the 3D Pressure Viewer, which uses universal function approximators as mathematical models for pressure prediction. This module needs to be feed with data acquired in the first visit of the patients and provided by the Smart Prescription System (as an XML file): plantar pressures using a standard foot and insole (measured by means of sensors spread over the foot sole), as well as some patient characteristics (height, weight, age, shoe size, length of the first and fifth metatarsal, length of toe and arch height while standing). Given those data, the tool will be able to provide a pressure prediction given the characteristics of the insole (density, thickness, hardness, resilience, compression fatigue and Young’s module) and the position of the metatarsal bar.