Search PubMed⌕ Search

Biomedical subjects

B J Hosticka

Publications and source records attributed to B J Hosticka.

4 recordsLinked to original sources
PubMed2002

Image acquisition and image processing for the intraocular vision aid.

The contribution describes an "intraocular vision aid (IOVA)" system for patients suffering from corneal opacification. In order to gain patients' acceptance the system has to be miniaturized to a magnitude that image acquisition, image processing, and power supply can be integrated into a portable unit. A CMOS camera whose dynamic range covers more than 100 dB takes pictures of the scenery. Its image sensor has a resolution of 380 x 300 pixel. In order to reduce fixed pattern noise correlated double sampling is implemented on-chip. In addition, this sensor stands out for low power consumption, random pixel access, and local brightness adaptation. An analog-digital-converter allows direct coupling to an external signal processor or a monolithically integrated unit for image processing to compress data.

Computer Systems↗
PubMed2002

Wireless power and data transmission system for a micro implantable intraocular vision aid.

Wireless power and data transmission system developed for an intraocular vision aid for blind patients will be described. This system is applicable for patients suffering from bilateral corneal opacification but with intact posterior ocular. The system consists of an external unit as well as an implant. The external unit is required for image acquisition, channel coding, IR data transmission, and RF power transmission to the implant. The implantable unit contains a CMOS receiver, a receiver antenna coil, and the microdisplay based on a LED array. The CMOS receiver serves for reception and decoding of image data as well as driving circuits for the miniaturized LED array. In this case, mechanical wiring between the external unit and the implant is neither useful nor comfortable. An optimal technical solution needs a wireless data transfer. If the power is transferred to the implant wireless, too, the solution grows ideal. The system described in this communication employs wireless power and data transmission using an 13.56 MHz RF link for power transmission and an near IR (NIR) optical link for data transmission from an external CMOS camera and telemetry unit to the implantable micro display.

Corneal Opacity↗
PubMedDate not supplied

[Algorithm for automatic endocardium identification in digital echocardiography image sequences].

The present paper describes an automated procedure for the detection of left ventricular internal wall edges in digital echocardiographic image sequences. The proposed procedure is divided into three steps and programmed in C/UNIX. It includes the use of a specially designed, application-specific adaptive spatio-temporal filter for noise reduction in echocardiographic image sequences, local 3-D histogram equalization for augmented contrast, and segmentation of the left ventricle using a regional growth method. When designing the adaptive spatio-temporal filter, we took into account the fact that the background noise is correlated in tangential orientation due to beam deflection at interfaces characterized by a large impedance "jump". Using the specially designed filter, the background noise is successfully reduced without degrading the ventricular contours. The simulation results presented highlight the performance of the proposed method in an exemplary manner.

Algorithms↗