An Infrared Sensor for Eye Tracking in a Harsh Car Environment

Arciuch

Pustelny

2016

Photon. Lett. Poland

Abstract-The article presents the results achieved while researching a distance measuring method belonging to Depth From Defocus techniques. The method has been developed to determine the shape of a 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 a camera and the markers located on the flaccid diaphragm. The goal of this paper is to present the influence of marker size on distance range measured between the camera and the diaphragm used in a pneumatic prosthetic heart.The article presents the impact of marker size on the result of a distance measurement method [1,2]. The method was developed for a video sensor to determine the instantaneous stroke volume of blood SV from a pneumatic pump heart assist device (VAD), Fig. 1a. When measuring SV, the flaccid diaphragm is equipped with markers which position and orientation in 3D space is subject to change in relation to the camera position. What is important in the method is that when measuring the position of the camera and all settings: the lens and the camera (focus, aperture, focal length) are invariable. Method [1, 2] also defines in 3D space the position of all the markers on the basis of analysis of only one image frame. In this respect, it has no equivalent in the literature. The vision systems mentioned in the literature typically create a stereoscopic system [3]. The distance in such a system is calculated knowing the optical parameters of the cameras and their mutual position. Measuring systems equipped with one camera are also used [4]. The distance to the object in these systems is determined using, for example, a perspective inverse transform [5]. A single camera configuration with an autofocus function is also possible. The distance to the object is then determined with a lens equation [6]. Other methods used to measure the distance are photogrammetry [7][8] and a fringe projection technique [9][10][11]. Their use, however, depends on: the scope of measured distances, required measurement speed, required image sensor resolution, light source type as well as target size and sensor weight.When determining the shape of a flaccid diaphragm, real time operation is particularly important (the shape of the diaphragm may change with a frequency of up to 3Hz) as * E-mail: Krzysztof.Murawski@wat.edu.pl well as simultaneous multipoint measurement of the position in 3D space in respect to all of the markers, Fig. 1b. The development of a soft-sensor for measuring the SV of a pulsating heart assist pump results from the needs and problems mentioned in [12]. In [12][13] it was demonstrated that SV can be determined by using the acoustic Helmholtz resonator theory. This method, however, has substantial limitations. For this reason the search for techniques of determining SV is still valid. The knowledge of changes dynamics in SV will enhance the safety of VAD usage, which currently depends on visual inspection: "One of the main advantages of the extracorporeal, po...

Section: Study Of Distance Range Visual Measurement In the Newmentioning

confidence: 99%

Study of distance range visual measurement in the new Depth From Defocus method

Arciuch

Pustelny

2016

Photon. Lett. Poland

“…The camera recorded the view of the marker registered in the near-infrared band (λ=850 nm) at 60 frame per second (fps). The IR heater construction was discussed in [17,18]. The developed measuring system has enabled powering the woofer coil with a DC voltage (Fig.…”

Section: Measurement System Configurationmentioning

confidence: 99%

Measurement of Membrane Displacement with a Motionless Camera Equipped with a Fixed Focus Lens

Metrology and Measurement Systems

2015

The paper presents a technique for measuring membrane displacements with one motionless camera. The method consists in measuring the distance to an object based on one image obtained from a motionless camera with a fixed-focus lens. The essence of the proposed measurement technique is to determine changes of the distance between a membrane and a video camera based on analysis of changes in the focus view of a marker placed on the membrane plane. It is proven that the used technique allows to monitor the frequency and amplitude of the membrane vibration. The tests were performed for the oscillation frequency in the range from 0.5 Hz to 6 Hz and deviations from the neutral position in the range of ±3 mm.

“…The active element in the made video-manometer was a white silicone at diaphragm with a thickness of 0.5 mm, LED diodes with a wavelength of λ = 850 nm, where the I F current was stabilized using the technique given in [18,19]. Fig.…”

Section: Construction Of the Video-manometermentioning

confidence: 99%

New Vision Sensor to Measure and Monitor Gas Pressure

2015

Acta Phys. Pol. A

Self Cite

The paper presents the construction and the use of a video sensor developed to measure air pressure. A characteristic feature of the device is pressure measurement based on digital image processing and self-diagnostics performed on the basis of an image. The paper presents the results of sensor calibration and measurements taken during the tests. It has been shown that the developed video-manometer model that is equipped with a at diaphragm allows measuring the air pressure in the range of 0100 mbar with an error less than 2%.