Biomedical subjects

W Döler

Publications and source records attributed to W Döler.

5 recordsLinked to original sources

PubMed1991

Digital image processing techniques for cephalometric analysis.

This paper describes the application of digital image processing methods for better landmark identification in cephalometric analysis. Conventionally taken radiographs are captured by a video camera and processed by the IPS system (KONTRON). After a detailed analysis of the transfer characteristics of the image acquisition system, the algorithms for enhancing digitized cephalograms are described. The improvement of image quality is demonstrated by several examples. The limitations of video acquisition systems are discussed and possibilities for further development are indicated.

Cephalometry↗

PubMed1990

Semiautomatic method for histomorphometry.

A semiautomatic measurement system for histomorphometry is presented. The system is based on a steppermotor-driven scanning stage which the operator controls via a digitizer. Movement in the scanning stage is carried out with respect to stationary cross-wires in the ocular of the microscopy. The system is connected to a PC-AT computer which utilizes the x- and y-coordinates of these movements for the calculation of the morphometric measurements. In addition, the system is supplemented by software for storage and analysis of measurement data.

Diagnosis, Computer-Assisted↗

PubMed1990

Quantitative determination of alveolar bone density using digital image analysis of microradiographs.

Horizontal 100 microns ground sections of 20 alveolar bone specimens from adult human mandibles obtained from autopsies were prepared for microradiography. Quantitative analysis of bone density of the alveolar cortex was performed using a semiautomatic digital image analysis system (KONTRON). The results demonstrated that bone density was higher in the lingual than in the labial alveolar cortex (p less than 0.05). In addition, the coronal portion of alveolar cortical bone was significantly more porous than the medical and apical ones (p less than 0.05). These variances were primarily due to increased canal size rather than to an increased number of canals. No significant age dependent changes in bone density could be determined.

Adolescent↗

PubMed1989

Digital image processing in cephalometric analysis.

Digital image processing methods were applied to improve the practicability of cephalometric analysis. The individual X-ray film was digitized by the aid of a high resolution microscope-photometer. Digital processing was done using a VAX 8600 computer system. An improvement of the image quality was achieved by means of various digital enhancement and filtering techniques.

Cephalometry↗

PubMed1985

[Basic research on impediography].

Impediography, a method for ultrasonic tissue characterisation, is theoretically and exerpimentally investigated. After a short description of the mathematical formalism ("Inverse Scattering Problem"), digital processing of broadband ultrasonic signals and measuring problems are discussed. The obtained results are completed by measurements on tissue structures in vitro. The paper shows the limits of the application of impediography if inhomogenous tissue structures are present.

Biophysical Phenomena↗