Rectilinear Features Research Articles

Vanishing point detection with direct and transposed fast Hough transform inside the neural network

In this paper, we suggest a new neural network architecture for vanishing point detection in images. The key element is the use of the direct and transposed fast Hough transforms separated by convolutional layer blocks with standard activation functions. It allows us to get the answer in the coordinates of the input image at the output of the network and thus to calculate the coordinates of the vanishing point by simply selecting the maximum. Besides, it was proved that calculation of the transposed fast Hough transform can be performed using the direct one. The use of integral operators enables the neural network to rely on global rectilinear features in the image, and so it is ideal for detecting vanishing points. To demonstrate the effectiveness of the proposed architecture, we use a set of images from a DVR and show its superiority over existing methods. Note, in addition, that the proposed neural network architecture essentially repeats the process of direct and back projection used, for example, in computed tomography.

Curvature processing in human visual cortical areas

Curvature is one of many visual features shown to be important for visual perception. We recently showed that curvilinear features provide sufficient information for categorizing animate vs. inanimate objects, while rectilinear features do not (Zachariou et al., 2018). Results from our fMRI study in rhesus monkeys (Yue et al., 2014) have shed light on some of the neural substrates underlying curvature processing by revealing a network of visual cortical patches with a curvature response preference. However, it is unknown whether a similar network exists in human visual cortex. Thus, the current study was designed to investigate cortical areas with a preference for curvature in the human brain using fMRI at 7T. Consistent with our monkey fMRI results, we found a network of curvature preferring cortical patches—some of which overlapped well-known face-selective areas. Moreover, principal component analysis (PCA) using all visually-responsive voxels indicated that curvilinear features of visual stimuli were associated with specific retinotopic regions in visual cortex. Regions associated with positive curvilinear PC values encompassed the central visual field representation of early visual areas and the lateral surface of temporal cortex, while those associated with negative curvilinear PC values encompassed the peripheral visual field representation of early visual areas and the medial surface of temporal cortex. Thus, we found that broad areas of curvature preference, which encompassed face-selective areas, were bound by central visual field representations. Our results support the hypothesis that curvilinearity preference interacts with central-peripheral processing biases as primary features underlying the organization of temporal cortex topography in the adult human brain.

MDI: integrity index of cytoskeletal fibers observed by AFM

The Modified Directional Index (MDI) is a form factor of the angular spectrum computed from the 2D Fourier transform of an image marking the prevalence of rectilinear features throughout the picture. We study some properties of the index and we apply it to AFM images of cell cytoskeleton regions featuring patterns of rectilinear nearly parallel actin filaments as in the case of microfilaments grouped in bundles. The analysis of AFM images through MDI calculation quantifies the fiber directionality changes which could be related to fiber damages. This parameter is applied to the images of Hs 578Bst cell line, non-tumoral and not immortalized human epithelial cell line, irradiated with X-rays at doses equivalent to typical radiotherapy treatment fractions. In the reported samples, we could conclude that the damages are mainly born to the membrane and not to the cytoskeleton. It could be interesting to test the parameter also using other kinds of chemical or physical agents.

Akanthou-Arkosykos, a ninth Millenium BC coastal settlement in Cyprus

The site of Akanthou-Arkosykos, also known as Tatlısu-Çiftlikdüzü, (henceforth Akanthou) located on the north coast of Cyprus, been dated to Early Aceramic Neolithic or Cypro-PPNB/MPPNB 8200–7700 BC. It has been revealed as one of the most important early Aceramic Neolithic sites on Cyprus. Rescue excavations since 2000 were undertaken to assess the site and protect it from agricultural damage and threats from construction. The site is now a scheduled monument protected under the Antiquities law. Despite plough and other agricultural damage there is excellent preservation. The excavations have revealed six buildings of stone and mud brick architecture with round and rectilinear features and painted plastered walls and plaster floors. These are enclosed by a wide ditch to the south of the settlement. This feature contains hundreds of individual deposits reflecting the life of a sedentary community and evidence for human exploitation of marine life, domesticated plants and a variety of domestic and semi-domesticated animals. Obsidian finds numbering in excess of 4000 pieces represents the highest number of such finds from Cyprus so far. They have been demonstrated to be of central Anatolian origin and appear to have come to the site as finished products. Akanthou is 40 miles across the sea from the Anatolian mainland and is possibly a key-site that can answer questions regarding the origin of early settlers as well as early domestication and trade in Cyprus.

Thinking outside the box: rectilinear shapes selectively activate scene-selective cortex.

Fifteen years ago, an intriguing area was found in human visual cortex. This area (the parahippocampal place area [PPA]) was initially interpreted as responding selectively to images of places. However, subsequent studies reported that PPA also responds strongly to a much wider range of image categories, including inanimate objects, tools, spatial context, landmarks, objectively large objects, indoor scenes, and/or isolated buildings. Here, we hypothesized that PPA responds selectively to a lower-level stimulus property (rectilinear features), which are common to many of the above higher-order categories. Using a novel wavelet image filter, we first demonstrated that rectangular features are common in these diverse stimulus categories. Then we tested whether PPA is selectively activated by rectangular features in six independent fMRI experiments using progressively simplified stimuli, from complex real-world images, through 3D/2D computer-generated shapes, through simple line stimuli. We found that PPA was consistently activated by rectilinear features, compared with curved and nonrectangular features. This rectilinear preference was (1) comparable in amplitude and selectivity, relative to the preference for category (scenes vs faces), (2) independent of known biases for specific orientations and spatial frequency, and (3) not predictable from V1 activity. Two additional scene-responsive areas were sensitive to a subset of rectilinear features. Thus, rectilinear selectivity may serve as a crucial building block for category-selective responses in PPA and functionally related areas.

Neotectonics and Quaternary landscape evolution of the Gödöllő Hills, Central Pannonian Basin, Hungary

Quaternary landscape evolution of the Gödöllő Hills was governed by both structural and climate-related erosional processes. Considerable neotectonic deformation has been documented in the form of inversion of deep-seated earlier normal faults and transpressive reactivation of a syn- to post-rift transtensional strike-slip zone, the Tápió–Tóalmás Zone (TaTZ) and related en echelon folds. The structural inversion is mainly expressed by the folding of the uppermost pre-Quaternary horizons and deformation of the surface, which suggests late Pliocene-Quaternary (∼4–0 Ma) compressional–transpressional deformation with NE–SW maximal horizontal stress axis. Drainage anomalies can be frequently connected to neotectonic structures. The uplift of the anticline hinges led to enhanced surface erosion, river piracy and development of radial drainage networks. Minor amplitude of surface undulations respective to the amplitude of folds in the upper Miocene layers reflects the syn-folding denudation of the surface during the early part of the neotectonic phase (late Pliocene to early Quaternary). On the other hand, the NW–SE-trending rectilinear features of the landscape show no tectonic control, they were shaped mostly by deflation. The combination of preliminary DEM analysis, field studies and the mapping of subsurface structural elements proved to be successful in separating landforms developed under or in absence of neotectonic control. The presence of landforms controlled by neotectonic structures suggests ongoing deformation of the Central Pannonian Basin.

Geophysical Surveys in the Jebel Hamrat Fidan, Jordan

The Jebel (Jebel is mountain in Arabic) Hamrat Fidan marks the “gateway” to the Feinan district of southern Jordan— one of the largest sources of copper during the prehistoric and Early Bronze Ages in the eastern Mediterranean. Preliminary excavations and surveys at sites along the Wadi Fidan have revealed a long history of settled occupation extending from the Pre-Pottery Neolithic (ca. 6,500 B.C.) to early medieval times. Because of this long history of occupation, and the fact that this area was a regional center for the production of copper, the study of this area is important for understanding early metallurgy, craft specialization, and social evolution. During the summer of 1997, geophysical investigations at a series of Neolithic and Bronze Age sites identified specific areas within Wadi Fidan for future intensive excavations. Three geophysical techniques (electromagnetic induction, ground-penetrating radar, and magnetometry) were used to help locate buried architectural and industrial features remaining from early mining and metallurgical operations, including copper ore bodies or voids. Geophysics was not used at the actual mining sites because of scheduling constraints; however, geophysics did delineate buried stone walls at three distinct Wadi Fidan sites. Magnetometry and ground penetrating radar provided little useful information. Buried stone walls were apparently “masked” by numerous magnetic stones on the ground surface making magnetometry useless. Reflections from known strata demonstrated that radar penetrated the ground adequately; however, known shallowly buried walls were not recognizable. Electromagnetic induction produced maps of linear and rectilinear features that suggested spatial distribution of widespread buried stone walls suitable for future excavation. A significant and unexpected finding was that electromagnetic induction proved capable of delineating buried stone walls. 2000 John Wiley & Sons, Inc.

Geophysical Surveys in the Jebel Hamrat Fidan, Jordan

The Jebel (Jebel is mountain in Arabic) Hamrat Fidan marks the “gateway” to the Feinan district of southern Jordan—one of the largest sources of copper during the prehistoric and Early Bronze Ages in the eastern Mediterranean. Preliminary excavations and surveys at sites along the Wadi Fidan have revealed a long history of settled occupation extending from the Pre-Pottery Neolithic (ca. 6,500 B.C.) to early medieval times. Because of this long history of occupation, and the fact that this area was a regional center for the production of copper, the study of this area is important for understanding early metallurgy, craft specialization, and social evolution. During the summer of 1997, geophysical investigations at a series of Neolithic and Bronze Age sites identified specific areas within Wadi Fidan for future intensive excavations. Three geophysical techniques (electromagnetic induction, ground-penetrating radar, and magnetometry) were used to help locate buried architectural and industrial features remaining from early mining and metallurgical operations, including copper ore bodies or voids. Geophysics was not used at the actual mining sites because of scheduling constraints; however, geophysics did delineate buried stone walls at three distinct Wadi Fidan sites. Magnetometry and ground penetrating radar provided little useful information. Buried stone walls were apparently “masked” by numerous magnetic stones on the ground surface making magnetometry useless. Reflections from known strata demonstrated that radar penetrated the ground adequately; however, known shallowly buried walls were not recognizable. Electromagnetic induction produced maps of linear and rectilinear features that suggested spatial distribution of widespread buried stone walls suitable for future excavation. A significant and unexpected finding was that electromagnetic induction proved capable of delineating buried stone walls. © 2000 John Wiley & Sons, Inc.

BASEMENT CONTROL ON THE DEVELOPMENT OF EXTENSIONAL SYSTEMS IN AUSTRALIA'S TIMOR SEA: AN EXAMPLE OF HYBRID HARD LINKED/SOFT LINKED FAULTING?

A series of rift models has been developed for basin systems in Australia's Timor Sea, via the interpretation of newly acquired deep crustal seismic and high resolution aeromagnetic data. These models, which incorporate observations on rift architecture, fault geometries, fault orientation, basement grain and composition, extensional transport direction and reactivation history, have then been iteratively tested by sophisticated analogue modelling experiments. This work has led to the development of a hybrid hard linked/soft linked (basement-involved/basement-detached) fault model. In this model, basement grain is the principal control on the rift architecture that develops, with pre-existing fracture systems acting to establish discrete offsets (hard linkages) between adjacent extensional faults. It is these basement features that produce the recti-linear features which are so common in aeromagnetic data around the Australian margin. With progressively greater extension, the basement-involved, hard linked system exerts no through-going (transfer fault-type) influence over the faulting within the overlying syn-rift phase, with the linkages between the syn-rift faults being 'soft' (via relay ramps, etc). However, as the hard links do act to relay the extensional faults or to flip their polarity (thereby typically producing cross-basinal highs), hard links strongly segment the extensional system into compartments of similar extensional style, and do control the relative positions of source rocks, fluid migration pathways and reservoirs within the rift. During basin reactivation (particularly inversion), the location and geometry of the underpinning, hard linked basement features closely control the locations of the traps that develop in the syn-and post-rift section, and the late-stage fluid flow history. When combined with aeromagnetic data, which define the location of the under-pinning, recti-linear, hard linked basement features, and some regional seismic data, these observations provide a first-pass predictive tool for determining where source depocentres, reservoirs and major structures are likely to be developed in a frontier basin, or where more subtle structural and/or stratigraphic traps might be found in a mature province.