Biomedical subjects

R T Lipczynski

Publications and source records attributed to R T Lipczynski.

3 recordsLinked to original sources

PubMed1994

The three dimensional reconstruction and monitoring of facial surfaces.

The study and monitoring of facial appearance is particularly important in the field of orthodontics and reconstructive maxillo-facial surgery. The introduction of new medical imaging techniques, such as X-ray computerized tomography (CT), has enabled surgery to be planned in three dimensions, compared with conventional methods using lateral and antero-posterior cephalographic images. Whilst it is possible to visualize bone and soft tissue structure the repeated use of CT scanning is undesirable because of the high doses of radiation involved. The research involves the development of a simple, low cost and non-invasive three-dimensional scanning method for facial surfaces. This is achieved using a technique known as structured light, using a standard commercial slide projector, CCD cameras and a framestore linked to a PC. The eventual aim is to provide clinicians a software assisted surgical procedure, by merging X-ray and skin data, allowing the manipulation of bone and soft tissue. This will give the facility to predict and monitor post-surgical appearance, detailing the effects of surgery benefiting both the clinician and patient. The research focuses on how the images are obtained using the scanning system and the subsequent image processing of data to give a realistic 3D image using a standard PC.

Algorithms↗

PubMed1994

Automatic digitization and analysis of moiré topograms on a personal computer for clinical use.

Moiré topography is a non-invasive optical technique which may be used for the detection and follow up of spinal deformities such as scoliosis. The moiré technique produces interference patterns (moiré fringes) which are very good at showing up differences in symmetry on the patient's back. The moiré fringes follow lines of constant height and can therefore be considered analogous to contour lines on an ordinance survey map. The moiré technique is already being used as a tool for qualitative diagnosis but widespread use will wait until the task of interpreting the moiré patterns quantitatively has been automated. An automated process means extracting the third dimension from the moiré topogram to produce 3D representations from which various deformity indices may be calculated. Image processing of moiré topograms is not trivial due to the difficulty of producing distinct good contrast fringes. The contrast problem is addressed with an interactive contrast enhancing algorithm. The approach to extracting 3D information from the fringes is to tackle 'real world' problems head on; fringes are first detected using edge detection techniques and assigning heights to the fringes is accomplished with algorithms designed to cope with noisy and broken fringes.

Algorithms↗

PubMed1988

Practical low cost stand/sit system for mid-thoracic paraplegics.

The use of functional electrical stimulation (FES) to enable paraplegics to stand is not new or indeed difficult to undertake under laboratory conditions. However, there are substantial problems to overcome before such systems can be used routinely by patients without professional supervision. The overriding consideration has to be one of safety, i.e. the system must be 'fail safe'. Secondly, the system must be quick and easy to use in a wide variety of locations, otherwise it will not provide any increase in function. Finally, it must be inexpensive enough to be available to a large number of paraplegics. The primary aim of our work was to provide such a system to enable mid-thoracic lesion paraplegics to stand wherever they wish. This involved the development of a microprocessor-based stimulator to enable the stimulating envelope to be individually tailored to a given patient's requirements and the provision of closed loop control to minimize fatigue. A folding standing frame was also designed which replaces the arm rests on a standard wheelchair. Using this system, the user is able to stand within 30 s of stopping and can remain standing for up to 10 min. Cosmetic calipers (knee-ankle-foot orthoses) are also being used for paraplegics who require to stand for longer periods. It is hoped that such a system will provide stable standing for a large number of paraplegics at a unit cost of approximately 750 pound.

Electric Stimulation↗