A new innovative Depth From Defocus method - identification of the impact of the marker size on the distance measurement result

The article presents results achieved during researching the distance measuring method belonging to Depth From Defocus techniques. The method has been developed to determining the shape of the flaccid membrane used in the Ventricular Assist Device (VAD). The shape is determined on the basis of distance measured between the CCD sensor plate of the camera and objects (markers) located on the flaccid membrane. The experiments were carried out using a stationary camera and circular markers with a diameter from 0,003m to 0,009 m. The goal of this paper is to present the influence of the size of the object (marker) on the distance range measured between the camera and diaphragm used in the pneumatic prosthetic heart.