Abstract: The present invention provides a detection or imaging device and method that measures an effect upon the path traveled by a radiative wave through a medium where scattering of the radiative wave is strong, and uses this measured path effect to detect, localize, or characterize inhomogeneities in the medium, as well as of the medium itself, over time or space. In this embodiment, a radiative source (43), temporally modulated or intensity quantitated, is emitted into the medium (47). A detector (48) records radiative effects detected after travel through said medium, and the detected signal is measured for a path effect (45). Based upon one or more of these path effects, such as the distance the latest arriving photons have traveled, a quantifiable parameter of the medium is determined (49). This parameter can be the location, distance, speed, or other characteristic of the medium or inhomogeneity.