FIG. 2.

In (a), the cone beam geometry is shown. The camera captures a two-dimensional (2D) projection image of the induced 3D light volume. In the context of conventional x-ray cone beam tomography geometry, this is equivalent to a detector plate placed at the focal plane of the image system, in which the detector pixel size is the resolution of the imaging pixels at the focal plane. In addition, in this configuration, the source to axis distance (SAD) is equivalent to the source to detector distance (SDD). In (b) and (c), reference images are shown, where the center of the imaging chip (1024 × 1024 pixels) is aligned with the isocenter of the Linac, and a reference resolution checkerboard object is imaged to determine the spatial resolution.