Search results for " Vision"

The cone of gaze

2011

Gaze direction is an important cue that regulates social interactions. Although humans are very accurate in determining gaze directions in general, they have a surprisingly liberal criterion for the presence of mutual gaze. We first established a psychophysical task to measure the cone of gaze, which required observers to adjust the eyes of a virtual head to the margins of the area of mutual gaze. Then we examined differences between 2D, 3D, and genuine real life gaze. Finally, the tolerance for image distortions when the virtual head is not viewed from the proper vantage point was investigated. Gaze direction was remarkably robust toward loss in detail and distortion. Important lessons for…

Semi-automated evaluation tool for retinal vasculopathy.

2009

The ocular fundus is the only area of human body where vascular system is visible using relatively simple instrumentation. Furthermore, there is medical suggestive evidence of a direct relationship between certain measures of vascular characteristics in the ocular fundus (arteriolar and venular calibers and focal arteriolar narrowing) and cardiovascular diseases. In order to establish such relationship on sound statistical basis a method must be provided to measure the needed values in an easy, yet precise and repeatable way. This paper presents a system to assist physicians in signaling and storing the data associated to signs of vascular deterioration and vascular calibers in non-mydriati…

Bias artifact suppression on MR volumes.

2007

RF-Inhomogeneity correction is a relevant research topic in the field of Magnetic Resonance Imaging (MRI). A volume corrupted by this artifact exhibits nonuni- form illumination both inside a single slice and between adjacent ones. In this work a bias correction technique is presented, which suppresses this artifact on MR vol- umes scanned from different body parts without any a-priori hypothesis on the artifact model. Theoretical foundations of the method are reported together with experimental results and a comparison is presented with both the 2D version of the algorithm and other techniques that are widely used in MRI literature.

Visually Perceived Distance Judgments: Tablet-Based Augmented Reality Versus the Real World

2016

Does visually perceived distance differ when objects are viewed in augmented reality (AR), as opposed to the real world? What are the differences? These questions are theoretically interesting, and the answers are important for the development of many tablet- and phone-based AR applications, including mobile AR navigation systems. This article presents a thorough literature review of distance judgment experimental protocols, and results from several areas of perceptual psychology. In addition to distance judgments of real and virtual objects, this section also discusses previous work in measuring the geometry of virtual picture space and considers how this work might be relevant to tablet A…

Unsupervised image processing scheme for transistor photon emission analysis in order to identify defect location

2015

International audience; The study of the light emitted by transistors in a highly scaled complementary metal oxide semiconductor (CMOS) integrated circuit (IC) has become a key method with which to analyze faulty devices, track the failure root cause, and have candidate locations for where to start the physical analysis. The localization of defective areas in IC corresponds to a reliability check and gives information to the designer to improve the IC design. The scaling of CMOS leads to an increase in the number of active nodes inside the acquisition area. There are also more differences between the spot’s intensities. In order to improve the identification of all of the photon emission sp…

AUTOMATIC QUALITY ENHANCEMENT AND NERVE FIBRE LAYER ARTEFACTS REMOVAL IN RETINA FUNDUS IMAGES BY OFF AXIS IMAGING

2011

International audience; Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Even with relative ease of use, the images produced sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or camera lens related reflections. We propose a technique that employs multiple fundus images to obtain a single higher quality image without these reflectance artefacts, which also compensates for a suboptimal illumination. The removal of bright artefacts, can have great benefits for the reduction of false positives in the detection of retinal lesions by automatic systems or manual inspectio…

A new Adaptive and Progressive Image Transmission Approach using Function Superpositions

2010

International audience; We present a novel approach to adaptive and progressive image transmission, based on the decomposition of an image into compositions and superpositions of monovariate functions. The monovariate functions are iteratively constructed and transmitted, one after the other, to progressively reconstruct the original image: the progressive transmission is performed directly in the 1D space of the monovariate functions and independently of any statistical properties of the image. Each monovariate function contains only a fraction of the pixels of the image. Each new transmitted monovariate function adds data to the previously transmitted monovariate functions. After each tra…

Verlustbehaftete Bilddatenreduktion von digitalen Koronarangiogrammen: Vergleich der Bildqualität durch einen objektiven Paramter

1997

Image quality metric based on multidimensional contrast perception models

1999

Abstract The procedure to compute the subjective difference between two input images should be equivalent to a straightforward difference between their perceived versions, hence reliable subjective difference metrics must be founded on a proper perception model. For image distortion evaluation purposes, perception can be considered as a set of signal transforms that successively map the original image in the spatial domain into a feature and a response space. The properties of the spatial pattern analyzers involved in these transforms determine the geometry of these different signal representation domains. In this work the general relations between the sensitivity of the human visual system…

WSN Design and Verification Using On-Board Executable Specifications

2019

The gap between informal functional specifications and the resulting implementation in the chosen programming language is notably a source of errors in embedded systems design. In this paper, we discuss a methodology and a software platform aimed at coping with this issue in programming resource-constrained wireless sensor network nodes (WSNs). Whereas the typical development model for the WSNs is based on cross compilation, the proposed approach supports high-level symbolic coding of abstract models and distributed applications, as well as their test and their execution, directly on the target hardware. As a working example, we discuss the application of our methodology to specify the func…