Image reconstruction techniques; (170.3880) Medical and biological imaging

Abstract: Diffuse optical tomography (DOT) reconstructs the images of internal optical parameter distribution using noninvasive boundary measurements. The image reconstruction procedure is known to be an ill-posed problem. In order to solve such a problem, a regularization technique is needed to constrain the solution space. In this study, a projection-error-based adaptive regularization (PAR) technique is proposed to improve the reconstructed image quality. Simulations are performed using a diffusion approximation model and the simulated results demonstrate that the PAR technique can improve reconstruction precision of object more effectively. The method is demonstrated to have low sensitivity to noise at various noise levels. Moreover, with the PAR method, the detectability of an object located both at the center and near the peripheral regions has been increased largely

Herstellung 3D-integrierter optischer Verbindungsmodule in Diffusionstechnik und LIGA Abschlussbericht

The goal of the project was the development of a technique which allows to integrate optical free space interconnections in a miniaturized form. By this three-dimensional integration optical systems can be realized in a more compact form. Thus integration densities could be achieved, which are comparable to micro-electronics. The basic elements of this integration technique are the use of a stacked-layer technique, lithography and refractive optics. For numerical simulation of the light propagation through refractive components a new method, the wave-propagation method (WPM) was developed. Compared to paraxial approximations this method allows the treatment of propagation angles up to 70 degrees. For this project three technologies have been employed: micro lenses were fabricated by ion exchange in glas. Beam splitting and beam deflecting elements were fabricated with LIGA-technique and beam forming elements have been realized by photo-polymerisation. By combining the individual component arrays a micro-optical system was demonstrated, which performs a perfect-shuffle permutation on an arry of 100 data channels within a volume of less than one mm"3. (orig.)SIGLEAvailable from TIB Hannover: D.Dt.F.QN1(14,2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman