For the planning and documentation of maxillofacial surgery highly resolved tissue information is needed. In
our approach, the surface of an object is displayed and measured with pulsed holography. With a single laser
pulse (Nd:YAG) of 20 ns the object surface is recorded on a CCD sensor, movement artifacts are systematically
With the knowledge of the recording parameters, the original wave field is synthesized numerically from
the holographic interference pattern. The calculated slices are combined into an image stack, representing the
digitized real image. This wave field represents the object geometrically correct, but focussed and unfocussed
regions overlay. The focussed regions are identified numerically and combined into a height map, the texture
information is extracted from the real image simultaneously. Both, height and texture are combined, yielding
pixel-precise textured surface models.
With this novel method it is possible to capture the surface of moving objects, even 3d motion series are
possible. Skin can be detected in the real image, giving the potential application for facial measurements.
Compared to our analog holographic topometry, there are still limitations regarding the extent of the imageable
field and the axial resolution. The quick display of the reconstructed real image allows a direct appraisal of the
object topology. This method is a valuable tool for the surface visualization of living subjects, offering potential
for completely new fields of application.
For planning, simulation and documentation of interventions in maxillofacial surgery high resolving soft tissue information of the human face in upright position is needed. This information can be gained by holographic methods, which allow a recording of the whole face in an extremely short time period, so that no movement artefacts occur. The hologram is recorded with a single laser pulse of 25 ns duration and stored in photosensitive material. After automated wet-chemical processing, the hologram is optically reconstructed with a cw-laser. During the optical reconstruction, a light field, which is a one-to-one three-dimensional representation of the recorded face, emerges at its original position and is digitized into a set of two-dimensional projections. Digital image processing leads to merging of
these projections into a three-dimensional computer model. Besides the topometric information, a high resolving pixel precise texture is also extracted from the holographic reconstruction and used for the texturing of the computer models. The use of mirrors allows the simultaneous recording of three different views of the face with one laser pulse. The three different views of the face can be combined easily, because they are simultaneously recorded. Thus a recording range of approximately 270 degrees is achieved. In addition to the medical application, high resolving and textured computer models of faces are of tremendous importance for facial reconstruction in anthropology, forensic science and archaeology.
A novel 3d reconstruction method for medical application has been applied for the examination and documentation of a 2000-year-old bog body. An ultra-fast pulsed holographic camera has been modified to allow imaging of the bog body from different views. Full-scale daylight copies of the master holograms give a detailed impressive three-dimensional view of the mummy and can be exhibited instead of the object. In combination with a rapid prototyping model (built by the Rapid Prototyping group of the Stiftung caesar, Bonn, Germany) derived from computer tomography (CT) data our results are an ideal basis for a future facial reconstruction.