depthresolved

Depthresolved is a term used to describe data, measurements, or imaging that provide information as a function of depth within a material or medium. Depth-resolved information enables reconstruction of three-dimensional structure from measurements that are resolved along a depth axis rather than compressed to a single plane. The degree of depth resolution depends on the method and the physical properties of the medium.

Depth-resolving techniques exploit different physical principles. Time-of-flight measurement, coherence gating, interferometry, or phase-sensitive detection are common approaches to separate signals by their arrival time or optical path length, yielding axial or depth resolution. In practice, axial resolution is influenced by bandwidth, pulse length, coherence length, and refractive index variations.

Common depth-resolved modalities include optical coherence tomography, ultrasound imaging, photoacoustic tomography, depth-resolved confocal and multiphoton microscopy, and depth-scanned spectroscopy. In imaging, depth resolution manifests as cross-sectional or volumetric representations that distinguish structures at different depths. In spectroscopy, depth information can be inferred by scanning or by attenuated penetration depth of photons.

Applications span biomedical imaging (retina, skin, vasculature), material science and nondestructive testing, geophysics, and industrial inspection. Limitations include trade-offs between depth range and resolution, scattering that degrades depth discrimination in turbid media, motion artifacts, and refractive-index heterogeneities that confound depth estimates.