US scorn for treaties hasn't improved nuclear security

2006

Observation of Interference Patterns in Reconstructed Digital Holograms of Atmospheric Ice Crystals

2009

Abstract The observation of interference patterns in reconstructed digital holograms of natural ice crystals is reported. It is suggested that an investigation of the interference fringes’ origin will yield a new application of holography in atmospheric sciences by revealing information on otherwise hardly accessible properties of the crystals.

Stereoscopic 3D visualization of particle fields reconstructed from digital inline holograms

2010

Abstract Holography is a powerful tool as it codes information, e.g. on 3D positions in a particle field in a single 2D hologram. In digital holography, the holograms are recorded on a digital image sensor. It is a particular challenge to visualize a digital hologram's depth information, such that it can be understood intuitively while retaining the advantages of a numerical reconstruction. In this contribution it is suggested and demonstrated how a numerically constructed volume can be used to calculate stereoscopic views, which even in the case of non-diffuse illumination allow for an intuitive visualization of particles’ positions in 3D space.

Cascaded adaptive-mask algorithm for twin-image removal and its application to digital holograms of ice crystals.

2009

An iterative Gerchberg-Saxton-type algorithm with a support constraint for twin-image removal from reconstructed Gabor inline holograms of single plane objects is described. It is applied to simulated holograms and to holograms of ice crystals recorded in the laboratory and in atmospheric clouds in situ. The algorithm is characterized by a distinction between object and background region and an iterative adaption of the object mask. Applying the algorithm to recorded inline holograms of atmospheric objects, the twin-image artifacts are removed successfully, for the first time allowing for a proper access to the in situ phase information on atmospheric ice crystals. It is also demonstrated t…