The eye tracker is used in many fields such as education, marketing, psychology, medicine, among others. However, commercial devices are costly, spanning from a few hundred to several thousand dollars. Therefore, an inexpensive-monocular-remote (IMR) eye tracker is developed for education and research, which implements the Pupil-Center-Corneal-Reflection technique. The IMR device consists of a low-cost camera with a near-IR pass filter that captures subject’s eye images, a moderate-cost computer that processes these images, as well as two near-IR light sources that create glints and illuminate the eye. The pupil detection algorithm is developed by combining the advantages of two recent algorithms, named BORE and PDIF, and gaze points are estimated from pupil-glints vectors via a fourth-order polynomial. An experimental evaluation is conducted concurrently on the research eye tracker IMR at the operating frequency of 30 Hz and the commercial-high-end-head-free device VT3 Mini at 60 Hz, in a challenge condition: subjects sit down near a window, and some of them wear glasses. Also, their heads are placed on a fixed chin rest, and the data is acquired when both devices successfully estimate gaze points. The experimental results in 11 sample data, obtained from 7 subjects, show that the overall ratio of the number of filtered/raw samples and raw/idea samples are 88.92% and 98.63% in order. Whereas the overall precision of the IMR eye tracker is nearly equal to that of the VT3 Mini device (0.57 degrees and 0.54 degrees, respectively), the overall accuracy of the proposed eye tracker is better than that of the commercial device (1.04 degrees and 1.34 degrees, respectively). Regarding eye safety, the radiant power and the burn-hazard-weighted radiance of the proposed device are much smaller than their limitations, according to IEC 62471. With these results, the IMR eye tracker is appropriate for education and needs to be improved in terms of data validation to satisfy the research purpose.
The difficulty of intravenous access in patients is an important clinical issue. Recently, many studies and several devices have been developed to assist physicians, nurses and surgeons in finding veins. Amongst them, near infrared imaging technology is one of the new technologies being widely used in the biomedical. NIR imaging allows visualizing veins underneath the skin of those having non-visibility of veins problem, mapping the normal and abnormal veins in treating disorders, or diagnosing related diseases. In this paper, we will introduce a portable device which can help doctors and nurses visualize blood vessel maps of their patients. On basic of combining a vein infrared imaging method and a projector system, this vein instrument can be optimally designed for viewing veins in the monitor or displaying vessel maps of patients directly on their skin.
Laser Doppler Velocimetry technique (LDV) isa measuring technique which has been developed since early 1980s. LDV has many advantages such as non-invasive measurement of one or all three components of velocity vector, measured dimensional vector of velocity, high accuracy, high resolution, wide measurement range ... Commercial Equipment based on LDV principle was applied to measure flow in industrial applications, in biomedical applications, etc. ... However, most of them are the specialized equipment which have high cost. In terms of technical training and education, LDV experiment is one of the basic experiments of application in high-tech optical measuring techniques, showing the skills of application of the principle of optical measurement applications in practical conditions. A model LDV system was designed and complete development within the lab for training purposes.
On the one hand, the adoption of managerial accounting in business is determined by corporate governance; on the other hand, it is also dependent on business environment and firm characteristic. Nonetheless, so far the causal relationships from corporate governance, business environment and firm characteristic to the adoption of managerial accounting in business have not been empirically explored in Vietnam. This research is conducted to investigate the simultaneous effects of corporate governance, business environment and firm characteristic on the adoption of managerial accounting in business. This study employs reliability analysis, exploratory factor analysis and regression analysis to deal with the data. The findings indicate that, corporate governance, business environment and firm characteristic concurrently affect the adoption of managerial accounting in business.
Cervical pathologies are frequently occuring diseases and may affect women’s quality of life in many ways. These pathologies are curable with early detection and with a following suitable treatment plans. Colposcopy is a standard examination among screening methods which are used to early detect the abnormal lesions on cervix’s surface. Recently, studies about processing polarized image show ability to support diagnosis of the cervix. In this research, we use cervix’s polarized images and image processing algorithms to segment the blood distribution of Nabothian cyst and Trichomonas vaginalis infection. These results have the potential to provide underlying information of the cervix to support the diagnosis.
The aim of the present study was to investigate the fluorescence properties of sound teeth and teeth with different types of lesions. Using light-emitting diodes operating in the near ultraviolet (UVA) spectral regions for excitation, the obtained fluorescence images and spectra of carious teeth were different from sound teeth spectra due to the presence of bacteria Streptococcus mutans producing metabolites called porphyrins. The sound teeth showed the blue fluorescence with broad emission spectra from 410 nm to 650 nm (maxima at 450 nm, 500 nm and 520 nm), while the carious regions illuminated the red light with three new peaks at 625 nm, 650 nm and 690 nm. The intensity of the red fluorescent signal depends on the density of the bacteria. Based on the red fluorescence emitted by porphyrins, not only the surface lesions but also the caries hiding under the enamel layer can be detected by UVA exciting. These results provide the ability to apply fluorescence technique in the development of an early dental diagnostic tool with a number of advantages such as safety, mobility, low cost and rapid test time.
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