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Physical Sciences and Mathematics Commons

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Selected Works

Professor Philip Ogunbona

Visual

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Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Perceived Similarity And Visual Descriptions In Content-Based Image Retrieval, Yuan Zhong, Lei Ye, Wanqing Li, Philip Ogunbona Sep 2012

Perceived Similarity And Visual Descriptions In Content-Based Image Retrieval, Yuan Zhong, Lei Ye, Wanqing Li, Philip Ogunbona

Professor Philip Ogunbona

The use of low-level feature descriptors is pervasive in content-based image retrieval tasks and the answer to the question of how well these features describe users’ intention is inconclusive. In this paper we devise experiments to gauge the degree of alignment between the description of target images by humans and that implicitly provided by low-level image feature descriptors. Data was collected on how humans perceive similarity in images. Using images judged by humans to be similar, as ground truth, the performance of some MPEG-7 visual feature descriptors were evaluated. It is found that various descriptors play different roles in different …


Application Of Visual Modelling In Image Restoration And Colour Image Processing, Aziz Qureshi, Philip Ogunbona Sep 2012

Application Of Visual Modelling In Image Restoration And Colour Image Processing, Aziz Qureshi, Philip Ogunbona

Professor Philip Ogunbona

This paper describes the application of human visual models in (i) defining a visually uniform colour representation space and (ii) the formulation of visually weighted Kalman filtering for image restoration. The former being useful in colour image quantisation and compression. For (i), the uniformity of chromaticity differences at the ouptut of Frei ’s colour vision model [3] is tested and compensated for by using MacAdam’s uniform chromaticity space. For (ii), the dynamical image model of the Kalman filter is visually weighted using the frequency response of Stockham’s model [l] of human vision.


Visual Information Processing And Content Management: An Overview, Philip Ogunbona Sep 2012

Visual Information Processing And Content Management: An Overview, Philip Ogunbona

Professor Philip Ogunbona

Visual information processing and the management of visual content has become a significant part of contemporary economy. The visual information processing pipeline is divided into several modules including, (i) capture and enhancement, (ii) efficient representation for storage and transmission, (iii) processing for efficient and secure distribution, and, (iv) representation for efficient archiving and retrieval. Advances in semiconductor technology and optimum signal processing models and algorithms, provide tools to improve each module of the processing pipeline. Insight from other areas of study including psychology augments and informs the models being developed to understand and design efficient visual content management systems. The …


Description Of Evolutional Changes In Image Time Sequences Using Mpeg-7 Visual Descriptors, Lei Ye, Lingzhi Cao, Philip Ogunbona, Wanqing Li Sep 2012

Description Of Evolutional Changes In Image Time Sequences Using Mpeg-7 Visual Descriptors, Lei Ye, Lingzhi Cao, Philip Ogunbona, Wanqing Li

Professor Philip Ogunbona

Colour and texture visual descriptors have been developed to represent structural features of images, mainly under the Query-by- Example (QBE) image retrieval paradigm. This paper explores applicability of MPEG-7 visual descriptors to describe and measure evolutional changes in image time sequences, using a fruit rotting process as an example. The research found that MPEG-7 visual descriptors can be applied to describe evolutional changes in image time sequences. The experimental results are provided using bananas captured in image time sequences. The results show the desirable monotonicity of description metrics of MPEG-7 similarity matching for image time sequences and their sensitivity to …