Abstract: A system comprises a camera for capturing an image, at least one processor and at least one memory, the at least one memory storing instructions configured to cause the processor to: obtain an image of a scene captured using the camera, the scene comprising a footprint of a user of the system; identify the footprint in the image; identify a first plurality of reference points each having a fixed position relative to the footprint in the image; identify a second plurality of reference points each having a fixed position relative to a three-dimensional model of the user's foot constructed based on at least one known dimension of the user's foot; determine a transformation matrix by mapping the second plurality of reference points of the three-dimensional model to the first plurality of reference points; and determine, based on the transformation matrix, a three-dimensional position of the camera relative to the footprint in the scene at the time of capturing the image.