Study of the impact of the object's location on the image on the results of distance measurement by the DFD technique

The aim of the paper is to determine the impact of the object's location in relation to camera's optical axis on the distance measurement using the method belonging to the Depth From Defocus (DFD). The method has been developed to determining the shape of flaccid membrane used in Ventricular Assist Device (VAD). The tests were carried out in laboratory conditions. The research were carried out using a fixed miniature camera and a fixed focal length lens. The camera observed a marker with a diameter of 0.003 m, in various position relative to the optical axis perpendicular to the plane of the marker. The position of the marker was changed in three dimensions, with a 0.001 m step, in the range from 0 m to 0.010 m in directions according to X and Y. The Z direction was researched in the range from 0.100 m to 0.140 m with a step equal 0.001 m. The measurable effects of work are the recommendations regarding the correction of the distance measurement depending on the marker shift relative to the camera optical axis.