Imaging of absorbers in turbid media using visible light

We introduce a reconstruction algorithm suitable for relective imaging of absorbers in strongly scattering media without the need for prior knowledge of the optical parameters governing the experiment. Similar to medical ultrasonic devices our optical system, the scan-head, is scanning only one-sided along the surface of the specimen and is capable of localizing imbedded absorbers. For the reconstruction of the images from a series of measurements the propagation of the photons is modeled by a diffusion approximation to the Boltzmann transport equation, then linearized and inverted. The deduced ill-posed and very underdetermined system of equations is solved by a conjugate gradient method. Results of measurements and simulations are presented.