The principle of measuring the arch of the foot using a plantar 3D scanner mainly relies on three-dimensional imaging technology and pressure distribution analysis to obtain the shape of the plantar surface, thereby measuring the height and shape of the arch.
There are usually several methods for three-dimensional structure reconstruction. Laser scanning emits a laser beam onto the plantar surface, and the sensor receives the reflected light. The three-dimensional coordinates of the plantar surface are calculated based on the time difference of the reflection or the change in the position of the light spot, generating a three-dimensional model of the plantar surface.
Optical stereo scanning projects striped or grid light onto the plantar surface, and a camera captures the deformation of the light stripes on the sole. The bending of the light stripes is used to calculate height information and generate a three-dimensional surface of the plantar area. Contact scanning records the plantar pressure distribution through a high-precision pressure sensing mat, where high-pressure areas correspond to low arches and low-pressure areas correspond to high arches. The software indirectly reconstructs the plantar shape based on this data.
For arch measurement, after the three-dimensional model is generated, the software identifies key points such as the center of the heel and the first and fifth metatarsal heads, draws the arch curve along the medial plantar contour, and calculates the arch height and arch index. Arch height is the vertical distance from the highest point of the medial arch to the ground, and the arch index is the ratio of the midfoot contact area to the total plantar area, used to determine high arches, normal arches, or flat feet. Some advanced scanners can also perform dynamic scanning, recording plantar pressure changes during standing or walking to analyze changes in the arch under load, thereby evaluating functional flatfoot or the risk of arch collapse.
The plantar 3D scanner accurately measures the height, curve, and area ratio of the arch and evaluates arch type through three-dimensional reconstruction of the plantar shape, key point identification, and pressure distribution data.
