Search results for "VISION"
showing 10 items of 5066 documents
3D displacement field measurement with correlation based on the micro-geometrical surface texture
2011
Image correlation methods are widely used in experimental mechanics to obtain displacement field measurements. Currently, these methods are applied using digital images of the initial and deformed surfaces sprayed with black or white paint. Speckle patterns are then captured and the correlation is performed with a high degree of accuracy to an order of 0.01 pixels. In 3D, however, stereo-correlation leads to a lower degree of accuracy. Correlation techniques are based on the search for a sub-image (or pattern) displacement field. The work presented in this paper introduces a new correlation-based approach for 3D displacement field measurement that uses an additional 3D laser scanner and a C…
Object tracking in medical imaging using a 2D active mesh system
2003
International audience; Abstract: This article proposes a technique for tracking moving organs in medical imaging. It can be split into two stages. We first initialize a 2D-triangular mesh on the first image of the sequence. We distinguish different objects of interest by grouping together the triangles that make them up. Afterwards, we deform this mesh on the successive images in order to track each identified object. The tracking stage uses optical flow by adding a node relaxation step to avoid mesh deteriorations. The mesh deformations analysis provides access to motion information along the sequence. This technique is applied to a cine-MRI sequences of the heart and allows the analysis …
Depth Map Generation by Image Classification
2004
This paper presents a novel and fully automatic technique to estimate depth information from a single input image. The proposed method is based on a new image classification technique able to classify digital images (also in Bayer pattern format) as indoor, outdoor with geometric elements or outdoor without geometric elements. Using the information collected in the classification step a suitable depth map is estimated. The proposed technique is fully unsupervised and is able to generate depth map from a single view of the scene, requiring low computational resources.
An Enhanced Detector of Blurred and Noisy Edges
2007
Detecting edges in digital images is a tricky operation in image processing since images may contain areas with different degrees of noise, blurring and sharpness. Such operation represents an important step of the whole process of similarity shape analysis and retrieval.
Residents’corner June 2014. PhotogRaphic Clues: Best Settings for Dermatologic Photography
2014
Obtaining digital images either for documentation or research purposes is a daily need for the dermatologist. Photography, as the art of capturing light, relies mainly on three modifiable elements: lens aperture (defined as the opening through which light reaches the camera sensor; expressed as “F-stops”, the smaller the number, the broader the aperture), shutter speed (the total time during which light reaches the sensor; it is indicated as fractions of a second) and ISO sensitivity (the light [...]
Perceivability of Map Information for Disaster Situations for People with Low Vision
2019
Digital maps have become increasingly popular in disaster situation to provide overview of information. However, these maps have also created barriers for many people, particularly people with visual impairments. Existing research on accessible maps such as tactile and acoustic maps focuses on providing solutions for blind persons to be able to perceive the information digital maps present. For people with low vision, who often rely on magnifier, good contrast and good navigation support, current digital map solutions present many challenges. In this paper we have studied two types of digital maps and their related surrounding text in the home page of disaster applications. The study focuse…
Implementation of pattern recognition algorithm based on RBF neural network
2002
In this paper, we present implementations of a pattern recognition algorithm which uses a RBF (Radial Basis Function) neural network. Our aim is to elaborate a quite efficient system which realizes real time faces tracking and identity verification in natural video sequences. Hardware implementations have been realized on an embedded system developed by our laboratory. This system is based on a DSP (Digital Signal Processor) TMS320C6x. The optimization of implementations allow us to obtain a processing speed of 4.8 images (240x320 pixels) per second with a correct rate of 95% of faces tracking and identity verification.
Flow resistance law under equilibrium bed-load transport conditions
2018
Abstract The uniform flow resistance equation, in the form due to Manning or Darcy-Weisbach, is often applied to determine the stage-discharge relationship of a river cross-section. The application of this equation, namely the slope-area method, allows to indirectly measure by water level readings the corresponding river discharge. In this paper, a recently deduced flow resistance equation for open channel flow was tested during conditions of equilibrium bed-load transport. First the flow resistance equation was determined by dimensional analysis and applying the condition of incomplete self-similarity for the flow velocity profile. Then the analysis was developed by the following steps: (i…
Sparse Image Representation by Directionlets
2010
Despite the success of the standard wavelet transform (WT) in image processing in recent years, the efficiency and sparsity of its representation are limited by the spatial symmetry and separability of its basis functions built in the horizontal and vertical directions. One-dimensional discontinuities in images (edges or contours), which are important elements in visual perception, intersect too many wavelet basis functions and lead to a non-sparse representation. To capture efficiently these elongated structures characterized by geometrical regularity along different directions (not only the horizontal and vertical), a more complex multidirectional (M-DIR) and asymmetric transform is requi…
Divisible designs from semifield planes
2002
AbstractWe give a general method to construct divisible designs from semifield planes and we use this technique to construct some divisible designs. In particular, we give the case of twisted field plane as an example.