RESUMEN
In this paper, we extend our previously proposed line detection method to line segmentation using a so-called unite-and-divide (UND) approach. The methodology includes two phases, namely the union of spectra in the frequency domain, and the division of the sinogram in Radon space. In the union phase, given an image, its sinogram is obtained by parallel 2D multilayer Fourier transforms, Cartesian-to-polar mapping and 1D inverse Fourier transform. In the division phase, the edges of butterfly wings in the neighborhood of every sinogram peak are firstly specified, with each neighborhood area corresponding to a window in image space. By applying the separated sinogram of each such windowed image, we can extract the line segments. The division Phase identifies the edges of butterfly wings in the neighborhood of every sinogram peak such that each neighborhood area corresponds to a window in image space. Line segments are extracted by applying the separated sinogram of each windowed image. Our experiments are conducted on benchmark images and the results reveal that the UND method yields higher accuracy, has lower computational cost and is more robust to noise, compared to existing state-of-the-art methods.
RESUMEN
The main objective of this study was to compare the performance of a portable impairment test device known as roadside impairment testing apparatus (RITA) with the field impairment tests (FIT) that are used at the roadside by UK police. One hundred and twenty two healthy volunteers aged 18-70 years took part in this two-period crossover evaluation. The volunteers received a dose of alcohol and placebo, in the form of a drink, on separate days. Doses were calculated to produce blood alcohol concentrations of 90 mg/100ml and RITA and FIT testing was carried out between 30 and 75 min post-drink. FIT was found to have a diagnostic accuracy of 62.7%. However, there was a substantial age effect for FIT scores, with volunteers aged over 40 showing failure rates on placebo similar to the failure rates on alcohol of younger volunteers. The accuracy of RITA was between 66 and 70%, not significantly higher than that of FIT. However, RITA did not show a marked age effect. Advantageously, this could result in fewer false positives being recorded if RITA were deployed at the roadside. Horizontal gaze nystagmus (HGN) was also investigated and posted an accuracy of 74%. The inclusion of HGN as one component of a UK roadside impairment test battery warrants further exploration with other drugs.