reprojectImageTo3D

reprojectImageTo3D is a function commonly found in image‑processing and visualization libraries that converts two‑dimensional image data into a three‑dimensional volume representation. It uses a camera or projection model to map pixel coordinates from the 2D source into 3D space, typically along a ray cast from a virtual camera origin. The function requires an input image, a projection matrix (or intrinsic/extrinsic camera parameters), and an optional sampling grid that defines the resolution and limits of the output volume. The algorithm samples values along each ray using interpolation methods such as nearest neighbour or trilinear interpolation, and writes the interpolated intensity into the corresponding voxel of the reconstructed 3D array. This reconstructed volume can be used for further analysis, rendering, or as a basis for registration and fusion with other 3D datasets.

Typical applications include reconstruction of volumetric data from single‑view images in medical imaging, where a CT or MRI slice is projected into a volumetric model for visualization, and in computer‑vision pipelines for depth estimation or shape reconstruction from monocular images. The function is often implemented in libraries such as ITK, SimpleITK, or custom visual‑processing suites, and is typically exposed as a method or standalone routine with a clear API for specifying output spacing, origin, and direction. Performance optimizations may involve GPU acceleration or multi‑threaded processing to handle large image sizes or high resolution output grids.