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.
The article presents the method of encoding a laser beam for control systems. The experiments were performed using a red laser emitting source with a wavelength of λ = 650 nm and a power of P ≈ 3 mW. The aim of the study was to develop methods of modulation and demodulation of the laser beam. Results of research, in which we determined the effect of selected camera parameters, such as image resolution, number of frames per second on the result of demodulation of optical signal, is also shown in the paper. The experiments showed that the adopted coding method provides sufficient information encoded in a single laser beam (36 codes with the effectiveness of decoding at 99.9%).
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.