1：Experimental Design and Method Selection:

The study used close-range photogrammetry with a self-calibration bundle adjustment technique to calibrate cameras. The methodology involved two phases: walking (three trials) and standing (one trial). Australis photogrammetric software was employed for bundle adjustment.

2：Sample Selection and Data Sources:

Retro-reflective targets on a human foot were used as object points. A 3D calibration plate (0.67x0.67 m) and scale bars (846 mm and 490.268 mm) were utilized for calibration and distance verification.

3：67x67 m) and scale bars (846 mm and 268 mm) were utilized for calibration and distance verification. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Cameras included JVC Everio GZ500s, Lumix DMC-FZ300, and Samsung Galaxy S6. A walking platform, gait boards (0.4x0.36 m and 0.8x0.6 m), and scale bars were used.

4：A walking platform, gait boards (4x36 m and 8x6 m), and scale bars were used. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Cameras were calibrated in a photogrammetric laboratory. For walking trials, three cameras captured video at 30 or 60 fps as a person walked on the platform. For standing trials, images were captured with the person stationary. Bundle adjustment was performed using Australis software to compute 3D coordinates and camera parameters.

5：Data Analysis Methods:

Root Mean Square (RMS) residuals were calculated to assess accuracy. Distances between points on the foot were measured and compared to real values using photogrammetric computations.