An Approach to a Comprehensive Test Framework for Analysis and Evaluation of Text Line Segmentation Algorithms

The paper introduces a testing framework for the evaluation and validation of text line segmentation algorithms. Text line segmentation represents the key action for correct optical character recognition. Many of the tests for the evaluation of text line segmentation algorithms deal with text databases as reference templates. Because of the mismatch, the reliable testing framework is required. Hence, a new approach to a comprehensive experimental framework for the evaluation of text line segmentation algorithms is proposed. It consists of synthetic multi-like text samples and real handwritten text as well. Although the tests are mutually independent, the results are cross-linked. The proposed method can be used for different types of scripts and languages. Furthermore, two different procedures for the evaluation of algorithm efficiency based on the obtained error type classification are proposed. The first is based on the segmentation line error description, while the second one incorporates well-known signal detection theory. Each of them has different capabilities and convenience, but they can be used as supplements to make the evaluation process efficient. Overall the proposed procedure based on the segmentation line error description has some advantages, characterized by five measures that describe measurement procedures

Survey of electronic properties and local structures around Fe in selected multinary chalcogenides

Paper presents detailed studies of local and electronic structure around Fe in Cd0.97Fe0.03Te, Cd0.98Fe0.02Te0.97Se0.03 and Cd0.99Fe0.01Te0.91S0.09 multinary chalcogenides by means of X ray absorption fine structure XAFS , X ray magnetic circular dichroism XMCD and electron paramagnetic resonance EPR measurements. In addition, electronic consequences of Fe incorporation into CdTe semiconductor host were studied by means of first principles calculations. In order to improve accuracy of the calculated total energies, the band gaps and the band edge positions, special attention is paid to the treatment of exchange correlation interaction and the description of highly localized Fe 3d states. Also, the Bader theory of the topological properties of the electron charge density is used to access details of the nature, strength and distribution of the next nearest neighbour bonds. Local and electronic structure around Fe in Cd0.97Fe0.03Te and Cd0.98Fe0.02Te0.97Se0.03 systems have been found to exhibit similar characteristics, since the first coordination sphere around Fe comprises four Te atoms located at approximately the same distance. In Cd0.99Fe0.01Te0.91S0.09 system, however, local bimodal distribution of distances has been revealed, with one Fe Te bond replaced with much shorter Fe S bond, resulting in much stronger crystal field. Along with the crystal field effect, the spin orbit interaction has proven to play decisive role in determining the nature of Fe doped CdTe systems. While the systems with higher Fe concentrations 25 at. are intrinsic insulators, in systems with only 3.125 at. Fe one spin channel contributes to the density of states at the Fermi level, which makes them suitable for spin selective electronic transport application

The role of configurality in the Thatcher illusion: an ERP study.

The Thatcher illusion (Thompson in Perception, 9, 483-484, 1980) is often explained as resulting from recognising a distortion of configural information when 'Thatcherised' faces are upright but not when inverted. However, recent behavioural studies suggest that there is an absence of perceptual configurality in upright Thatcherised faces (Donnelly et al. in Attention, Perception & Psychophysics, 74, 1475-1487, 2012) and both perceptual and decisional sources of configurality in behavioural tasks with Thatcherised stimuli (Mestry, Menneer et al. in Frontiers in Psychology, 3, 456, 2012). To examine sources linked to the behavioural experience of the illusion, we studied inversion and Thatcherisation of faces (comparing across conditions in which no features, the eyes, the mouth, or both features were Thatcherised) on a set of event-related potential (ERP) components. Effects of inversion were found at the N170, P2 and P3b. Effects of eye condition were restricted to the N170 generated in the right hemisphere. Critically, an interaction of orientation and eye Thatcherisation was found for the P3b amplitude. Results from an individual with acquired prosopagnosia who can discriminate Thatcherised from typical faces but cannot categorise them or perceive the illusion (Mestry, Donnelly et al. in Neuropsychologia, 50, 3410-3418, 2012) only differed from typical participants at the P3b component. Findings suggest the P3b links most directly to the experience of the illusion. Overall, the study showed evidence consistent with both perceptual and decisional sources and the need to consider both in relation to configurality

From upright to upside-down presentation: A spatio-temporal ERP study of the parametric effect of rotation on face and house processing

<p>Abstract</p> <p>Background</p> <p>While there is a general agreement that picture-plane inversion is more detrimental to face processing than to other seemingly complex visual objects, the origin of this effect is still largely debatable. Here, we address the question of whether face inversion reflects a quantitative or a qualitative change in processing mode by investigating the pattern of event-related potential (ERP) response changes with picture plane rotation of face and house pictures. Thorough analyses of topographical (Scalp Current Density maps, SCD) and dipole source modeling were also conducted.</p> <p>Results</p> <p>We find that whilst stimulus orientation affected in a similar fashion participants' response latencies to make face and house decisions, only the ERPs in the N170 latency range were modulated by picture plane rotation of faces. The pattern of N170 amplitude and latency enhancement to misrotated faces displayed a curvilinear shape with an almost linear increase for rotations from 0° to 90° and a dip at 112.5° up to 180° rotations. A similar discontinuity function was also described for SCD occipito-temporal and temporal current foci with no topographic distribution changes, suggesting that upright and misrotated faces activated similar brain sources. This was confirmed by dipole source analyses showing the involvement of bilateral sources in the fusiform and middle occipital gyri, the activity of which was differentially affected by face rotation.</p> <p>Conclusion</p> <p>Our N170 findings provide support for both the quantitative and qualitative accounts for face rotation effects. Although the qualitative explanation predicted the curvilinear shape of N170 modulations by face misrotations, topographical and source modeling findings suggest that the same brain regions, and thus the same mechanisms, are probably at work when processing upright and rotated faces. Taken collectively, our results indicate that the same processing mechanisms may be involved across the whole range of face orientations, but would operate in a non-linear fashion. Finally, the response tuning of the N170 to rotated faces extends previous reports and further demonstrates that face inversion affects perceptual analyses of faces, which is reflected within the time range of the N170 component.</p

The Effects of the Acute Hypoxia to the Fundamental Frequency of the Speech Signal

When people that live at the small altitudes (up to 400 m above the sea level) climb on the mountain, they are exposed to the effects of an acute hypoxia. As a consequence, theirs oxygen concentration decreases in the tissue. This paper presents the analysis of the acute hypoxia effects to the speech signal at the altitudes up to 2600 m above the sea level. For the experiment, the articulation of vowels (A, E, I, O, U) from the test group of persons was recorded at different altitudes, which creates the speech signal database. The speech signal from database is processed by the original algorithm. As the results, the fundamental frequency and the energy of dissonant intervals of speech signal are obtained. Furthermore, the acute hypoxia effect to the energy distribution in the dissonant intervals of the speech signal is analyzed. At the end, the comparative analysis of the acute hypoxia effects shows that the level of the hypoxia can be determined by the change of the fundamental frequency and the energy of the dissonant intervals of speech signal. Hence, it is possible to bring conclusions about the degree of hypoxia, which in many situations can be of importance for avoiding catastrophic consequences

The Effects of the Active Hypoxia to the Speech Signal Inharmonicity

When the people are climbing on the mountain, they are exposed to decreased oxygen concentration in the tissue, which is commonly called the active hypoxia. This paper addressed the problem of an acute hypoxia that affects the speech signal at the altitude up to 2500 m. For the experiment, the speech signal database that contains the articulation of vowels was recorded at different alti¬tudes. This speech signal was processed by the originally developed algorithm, which extracted the fundamental frequency and the inharmonicity coefficient. Then, they were subjected to the analysis in order to derive the effects of the acute hypoxia. The results showed that the hypoxia level can be determined by the change of the inharmonicity coefficient. Accordingly, the degree of hypoxia can be estimated