Studying the influence of object size on the range of distance measurement in the new Depth From Defocus method

The article presents new results achieved during researching the distance measuring method that is a part of Depth From Defocus techniques. The method has been developed to determine the shape of the flaccid diaphragm 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 diaphragm. Experiments were carried out using a stationary camera and circular markers with a diameter from 3 mm to 9 mm. The goal of this paper is to present the influence of the object (marker) size on the distance range measured between the camera and diaphragm used in the external pneumatic prosthetic heart.