Searching for the void: improving cave detection accuracy by multi-faceted geophysical survey reconciled with LiDAR DTM

2017 ◽  
Vol 61 (2) ◽  
pp. 45-59 ◽  
Author(s):  
Marek Kasprzak ◽  
Artur Sobczyk
Keyword(s):  
Geophysical Survey ◽  
Detection Accuracy ◽  
Cave Detection

Vivid Imagers Are Better at Detecting Salient Changes

2006 ◽  
Vol 27 (4) ◽  
pp. 218-228 ◽  
Author(s):  
Paul Rodway ◽  
Karen Gillies ◽  
Astrid Schepman
Keyword(s):  
Individual Differences ◽  
Change Detection ◽  
Visual Imagery ◽  
Detection Task ◽  
Level Of Detail ◽  
Detection Accuracy ◽  
Change Detection Task ◽  
Term Change ◽  
High Level

This study examined whether individual differences in the vividness of visual imagery influenced performance on a novel long-term change detection task. Participants were presented with a sequence of pictures, with each picture and its title displayed for 17  s, and then presented with changed or unchanged versions of those pictures and asked to detect whether the picture had been changed. Cuing the retrieval of the picture's image, by presenting the picture's title before the arrival of the changed picture, facilitated change detection accuracy. This suggests that the retrieval of the picture's representation immunizes it against overwriting by the arrival of the changed picture. The high and low vividness participants did not differ in overall levels of change detection accuracy. However, in replication of Gur and Hilgard (1975) , high vividness participants were significantly more accurate at detecting salient changes to pictures compared to low vividness participants. The results suggest that vivid images are not characterised by a high level of detail and that vivid imagery enhances memory for the salient aspects of a scene but not all of the details of a scene. Possible causes of this difference, and how they may lead to an understanding of individual differences in change detection, are considered.

Right-Hemisphere Specialization for Contour Grouping

2014 ◽  
Vol 61 (5) ◽  
pp. 331-339 ◽  
Author(s):  
Gregor Volberg
Keyword(s):  
Right Hemisphere ◽  
Contour Detection ◽  
Global Processing ◽  
Detection Accuracy ◽  
Frequency Spectra ◽  
Visual Hemifield ◽  
Spatial Frequencies ◽  
A Chain ◽  
The Right ◽  
Hemisphere Specialization

Previous studies often revealed a right-hemisphere specialization for processing the global level of compound visual stimuli. Here we explore whether a similar specialization exists for the detection of intersected contours defined by a chain of local elements. Subjects were presented with arrays of randomly oriented Gabor patches that could contain a global path of collinearly arranged elements in the left or in the right visual hemifield. As expected, the detection accuracy was higher for contours presented to the left visual field/right hemisphere. This difference was absent in two control conditions where the smoothness of the contour was decreased. The results demonstrate that the contour detection, often considered to be driven by lateral coactivation in primary visual cortex, relies on higher-level visual representations that differ between the hemispheres. Furthermore, because contour and non-contour stimuli had the same spatial frequency spectra, the results challenge the view that the right-hemisphere advantage in global processing depends on a specialization for processing low spatial frequencies.

Deception and dating: Knowledge of tactics may improve detection accuracy.

2009 ◽  
Vol 3 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Allyson Barnacz ◽  
Franco Amati ◽  
Christina Fenton ◽  
Amanda Johnson ◽  
Julian Paul Keenan
Keyword(s):  
Detection Accuracy

Detection of Malicious Spatial-Domain Steganography over Noisy Channels Using Convolutional Neural Networks

2020 ◽  
Vol 2020 (4) ◽  
pp. 76-1-76-7
Author(s):  
Swaroop Shankar Prasad ◽  
Ofer Hadar ◽  
Ilia Polian
Keyword(s):  
State Of The Art ◽  
Visual Quality ◽  
Channel Noise ◽  
Detection Accuracy ◽  
Noisy Channel ◽  
Noisy Channels ◽  
Reliable Transmission ◽  
Reliable Detection ◽  
Natural Noise ◽  
Will Force

Image steganography can have legitimate uses, for example, augmenting an image with a watermark for copyright reasons, but can also be utilized for malicious purposes. We investigate the detection of malicious steganography using neural networkbased classification when images are transmitted through a noisy channel. Noise makes detection harder because the classifier must not only detect perturbations in the image but also decide whether they are due to the malicious steganographic modifications or due to natural noise. Our results show that reliable detection is possible even for state-of-the-art steganographic algorithms that insert stego bits not affecting an image’s visual quality. The detection accuracy is high (above 85%) if the payload, or the amount of the steganographic content in an image, exceeds a certain threshold. At the same time, noise critically affects the steganographic information being transmitted, both through desynchronization (destruction of information which bits of the image contain steganographic information) and by flipping these bits themselves. This will force the adversary to use a redundant encoding with a substantial number of error-correction bits for reliable transmission, making detection feasible even for small payloads.

The Makrakomi Archaeological Landscapes Project. A preliminary report on investigations carried out in 2010–2012

2013 ◽  
Vol 6 ◽  
pp. 211-260 ◽  
Author(s):  
Maria-Foteini Papakonstantinou ◽  
Arto Penttinen ◽  
Gregory N. Tsokas ◽  
Panagiotis I. Tsourlos ◽  
Alexandros Stampolidis ◽  
...  
Keyword(s):  
Preliminary Report ◽  
Geophysical Survey ◽  
Small Scale ◽  
Hellenistic Period ◽  
Surface Survey ◽  
Multiple Structures ◽  
Recorded Data ◽  
Architectural Survey ◽  
The Hill ◽  
The Town

In this article we provide a preliminary report of the work carried out between 2010 and 2012 as part of the Makrakomi Archaeological Landscapes Project (MALP). The programme of research is carried out in co-operation between the Swedish Institute at Athens and the 14th Ephorate of Prehistoric and Classical Antiquities at Lamia. The interdisciplinary project started in the summer of 2010, when a pilot survey was conducted in and around the hill of Profitis Elias, in the modern municipality of Makrakomi, where extensive traces of ancient fortifications are still visible. Systematic investigations have been conducted since 2011 as part of a five-year plan of research involving surface survey, geophysical survey and small-scale archaeological excavation as well as geomorphological investigation. The primary aim of MALP is to examine the archaeology and geomorphology of the western Spercheios Valley, within the modern municipality of Makrakomi in order to achieve a better understanding of antiquity in the region, which has previously received scant scholarly attention. Through the archaeological surface survey and architectural survey in 2011 and 2012 we have been able to record traces of what can be termed as a nucleated and structured settlement in an area known locally as Asteria, which is formed by the projecting ridges to the east of Profitis Elias. The surface scatters recorded in this area suggest that the town was primarily occupied from the late 4th century BC and throughout the Hellenistic period. The geophysical survey conducted between 2011 and 2012 similarly recorded data which point to the presence of multiple structures according to a regular grid system. The excavation carried out in the central part of Asteria also uncovered remains of a single domestic structure (Building A) which seems to have been in use during the Late Classical and Hellenistic periods. The combined data acquired through the programme of research is thus highly encouraging, and has effectively demonstrated the importance of systematic archaeological research in this understudied area of Central Greece.

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