Early-time diffusion in imaging through obscuring random media: two-way propagation and deblurring

The radiative transport theory predicts that a short pulse propagating through a random medium consisting of discrete scatterers of sizes large compared to the wavelength develops to develop an "early-time diffusion" (ETD) component: a sharply rising structure in the time-resolved intensity, immediately following the coherent (ballistic) signal, but attenuated at a rate substantially lower than the coherent attenuation. This phenomenon offers a possibility of application in imaging through obscuring (e.g., atmospheric) media. We describe here an imaging scenario utilizing the ETD signal, evaluate the resulting point-spread function characterizing the image resolution, and show how that resolution can be significantly improved by means of regularized deconvolution techniques.