scholarly journals A Review on Image Denoising Techniques

2021 ◽  
Vol 9 (12) ◽  
pp. 761-764
Author(s):  
Smita Vasant Tempe
Keyword(s):  
Image Denoising ◽  
Visual Information ◽  
Filter Banks ◽  
Geometrical Structure ◽  
Two Dimensional ◽  
Sampled Data ◽  
Discrete Domain ◽  
Continuous Domain

Abstract: The goal of this study is to find a "genuine" two-dimensional transform that can capture the fundamental geometrical structure that is important in visual information. The discontinuous character of the data is the most difficult aspect of analysing geometry in photographs. Unlike previous approaches, such as curvelets, which generate a transform in the continuous domain and then discretize for sampled data, we begin with a discrete-domain construction and then investigate its convergence to a continuous-domain expansion. We use nonseparable filter banks to create a discrete-domain multiresolution and multidirection expansion, similar to how wavelets are produced from filter banks. As a result of this construction, a flexible multiresolution, local, and directed picture expansion employing contour segments is obtained, and it is therefore useful.

scholarly journals Imagens táteis tridimensionais: um modelo para a tradução tátil a partir de imagens estáticas bidimensionais | Three-dimensional tactile images: a model for tactile translation from two-dimensional static images

2017 ◽  
Vol 14 (2) ◽  
pp. 234-252
Author(s):  
Emilia Christie Picelli Sanches ◽  
Claudia Mara Scudelari Macedo ◽  
Juliana Bueno
Keyword(s):  
Visual Information ◽  
Three Dimensional ◽  
Information Design ◽  
Blind People ◽  
Two Dimensional ◽  
Test Results ◽  
Visual Content ◽  
Tactile Sense ◽  
Digital Modelling ◽  
Static Images

A acessibilidade na educação de pessoas cegas é um direito que deve ser cumprido. Levando-se em consideração que o design da informação almeja transmitir uma informação de forma efetiva ao receptor, e que uma imagem estática precisa ser adaptada para que um aluno cego tenha acesso a esse conteúdo visual, propõe-se uma maneira de traduzir a informação visual para o tátil. O propósito deste artigo, então, é apresentar um modelo para tradução de imagens estáticas bidimensionais em imagens táteis tridimensionais. Por isso, parte de uma breve revisão da literatura sobre cegueira, percepção tátil e imagens táteis. Na sequência, apresenta o modelo de tradução em três partes: (1) recomendações da literatura; (2) estrutura e (3) modelo preliminar para teste. Depois, descreve o teste do modelo realizado com dois designers com habilidades de modelagem digital (potenciais usuários). Como resultado dos testes, obtiveram-se duas modelagens distintas, uma utilizando da elevação e outra utilizando texturas, porém, os dois participantes realizaram com sucesso a tarefa pretendida. Ainda, a partir dos resultados dos obtidos, também, foi possível perceber falhas no modelo que necessitam ser ajustadas para as próximas etapas da pesquisa.+++++Accessibility in education of blind people is a right that must be fulfilled. Considering that information design aims to transmit an information in an effective way to the receiver, and that a static image needs to be adapted so that a blind student can have access to this visual content, it is proposed a way to translate the visual information to the tactile sense. The purpose of this paper is to present a translating model of static two-dimensional images into three-dimensional tactile images. First, it starts from a brief literature review aboutblindness, tactile perception and tactile images. Second, it presents the translating model in three sections: (1) literature recommendations; (2) structure and (3) finished model for testing. Then, it describes the tests with the model and two designers with digital modelling abilities (potential users). As a result from the tests, two distinct models were obtained, one using elevation and other using textures, although, both participants successfully made the intended task. Also from the test results, it was possible to perceive flaws on the model that need to be adjusted for the next steps of the research.

Anatomical segregation of two cortical visual pathways in the macaque monkey

1990 ◽  
Vol 4 (6) ◽  
pp. 555-578 ◽  
Author(s):  
Anne Morel ◽  
Jean Bullier
Keyword(s):  
Visual Information ◽  
Striate Cortex ◽  
Small Region ◽  
Macaque Monkey ◽  
Two Dimensional ◽  
Inferotemporal Cortex ◽  
Fast Blue ◽  
Prestriate Cortex ◽  
Inferior Parietal Cortex ◽  
Diamidino Yellow

AbstractA number of lines of evidence suggest that, in the macaque monkey, inferior parietal and inferotemporal cortices process different types of visual information. It has been suggested that visual information reaching these two subdivisions follows separate pathways from the striate cortex through the prestriate cortex. We examined directly this possibility by placing injections of the retrograde fluorescent tracers, fast blue and diamidino yellow, in inferior parietal and inferotemporal cortex and examining the spatial pattern of cortical areas containing labeled cells in two-dimensional reconstructions of the cortex.The results of injections in inferotemporal cortex show that TEO receives afferents from areas V2, ventral V3, V3A, central V4, V4t, and DPL in prestriate cortex and from areas IPa, PGa, and FST in the superior temporal sulcus (STS). Area TEp receives afferents only from V4 in prestriate cortex and from IPa, PGa, and FST in the anterior STS. Area TEa receives no prestriate input and is innervated by IPa, PGa, FST, and TPO in the anterior STS.The results of injections in inferior parietal cortex demonstrate that POa receives afferents from dorsal V3, V3A, peripheral V4, DPL, and PO in prestriate cortex, from MST and *VIP and from IPa, PGa, TPO, and FST in anterior STS. Area PGc (corresponding to 7a) is innervated by PO, MST, and by TPO in the anterior STS.Examination of the two-dimensional reconstructions of the pattern of labeling after combined injections of fast blue and diamidino yellow in areas POa and TEO revealed that these areas are principally innervated by different prestriate areas. Only a small region, centered on area V3A and extending into V4 and DPL, contained cells labeled by either injection as well as a small number of double-labeled cells. In contrast, areas POa and TEO receive afferents from extensive common regions in the anterior STS corresponding to areas IPa, PGa, and FST.These results directly demonstrate that visual information from the striate cortex reaches inferior parietal and inferotemporal cortices through largely separate prestriate cortical pathways. On the other hand, both parietal and inferotemporal cortices receive common inputs from extensive regions in the anterior STS which may play a role in linking the processing occurring in these two cortical subdivisions of the visual system.

Lateral geniculate neurons in behaving primates. I. Responses to two-dimensional stimuli

1991 ◽  
Vol 66 (3) ◽  
pp. 777-793 ◽  
Author(s):  
J. W. McClurkin ◽  
T. J. Gawne ◽  
B. J. Richmond ◽  
L. M. Optican ◽  
D. L. Robinson
Keyword(s):  
Receptive Field ◽  
Visual Information ◽  
Receptive Fields ◽  
Nonlinear Behavior ◽  
Temporal Patterns ◽  
Two Dimensional ◽  
Visual Responses ◽  
Linear Summation ◽  
Lateral Geniculate ◽  
Opposite Contrast

1. Using behaving monkeys, we studied the visual responses of single neurons in the parvocellular layers of the lateral geniculate nucleus (LGN) to a set of two-dimensional black and white patterns. We found that monkeys could be trained to make sufficiently reliable and stable fixations to enable us to plot and characterize the receptive fields of individual neurons. A qualitative examination of rasters and a statistical analysis of the data revealed that the responses of neurons were related to the stimuli. 2. The data from 5 of the 13 "X-like" neurons in our sample indicated the presence of antagonistic center and surround mechanisms and linear summation of luminance within center and surround mechanisms. We attribute the lack of evidence for surround antagonism in the eight neurons that failed to exhibit center-surround antagonism either to a mismatch between the size of the pixels in the stimuli and the size of the receptive field or to the lack of a surround mechanism (i.e., the type II neurons of Wiesel and Hubel). 3. The data from five other neurons confirm and extend previous reports indicating that the surround regions of X-like neurons can have nonlinearities. The responses of these neurons were not modulated when a contrast-reversing, bipartite stimulus was centered on the receptive field, which suggests a linear summation within the center and surround mechanisms. However, it was frequently the case for these neurons that stimuli of identical pattern but opposite contrast elicited responses of similar polarity, which indicates nonlinear behavior. 4. We found a wide variety of temporal patterns in the responses of individual LGN neurons, which included differences in the magnitude, width, and number of peaks of the initial on-transient and in the magnitude of the later sustained component. These different temporal patterns were repeatable and clearly different for different visual patterns. These results suggest that visual information may be carried in the shape as well as in the amplitude of the response waveform.

Sign in / Sign up

Export Citation Format

Share Document