Perceptual image analysis

The problem considered in this paper is one of extracting perceptually relevant information from groups of objects based on their descriptions. Object descriptions are qualitatively represented by feature-value vectors containing probe function values computed in a manner similar to feature extraction in pattern classification theory. The work presented here is a generalisation of a solution to extracting perceptual information from images using near sets theory which provides a framework for measuring the perceptual nearness of objects. Further, near set theory is used to define a perception-based approach to image analysis that is inspired by traditional mathematical morphology and an application of this methodology is given by way of segmentation evaluation. The contribution of this article is the introduction of a new method of unsupervised segmentation evaluation that is base on human perception rather than on properties of ideal segmentations as is normally the case.https://www.inderscience.com/info/inarticle.php?artid=3309

Fractal Dimensions in Perceptual Color Space: A Comparison Study Using Jackson Pollock's Art

The fractal dimensions of color-specific paint patterns in various Jackson Pollock paintings are calculated using a filtering process which models perceptual response to color differences (\Lab color space). The advantage of the \Lab space filtering method over traditional RGB spaces is that the former is a perceptually-uniform (metric) space, leading to a more consistent definition of ``perceptually different'' colors. It is determined that the RGB filtering method underestimates the perceived fractal dimension of lighter colored patterns but not of darker ones, if the same selection criteria is applied to each. Implications of the findings to Fechner's 'Principle of the Aesthetic Middle' and Berlyne's work on perception of complexity are discussed.Comment: 21 pp LaTeX; two postscript figure

ASSESSING THE RELATIONS BETWEEN PERCEPTUAL AND AFFECTIVE COMPONENTS OF A DESTINATION IMAGE: A CASE OF CHINA AS A DESTINATION

Baloglu and McCleary’s (1999) destination image formation model suggests that a destination image has two hierarchically related components - perceptual and affective images, on which a holistic image is based. Although many studies adopt this image structure and agree on the hierarchical relationship between the two components, few of them have examined this relation and the way it is formed. The purpose of the study is twofold: first it is to identify the current perceptual and affective images of a destination, using China as a case; then to determine the inner relationship between the two image components. Survey data from an existing study on college students’ (N=421) destination image of China research are used to investigate the research questions. Results from the factor analysis reveal positively strong functional and moderate psychological factors within the perceptual image. Analysis of affective components shows a strong and positive reaction on activeness, and a slightly positive reaction on pleasantness. Results of multiple regression analyses indicate that functional factor are more effective in predicting activeness dimension while psychological factor are more significant in influencing pleasantness dimension. The findings provide useful implications for creating a positive destination image

Optimisation of paediatrics computed radiography for full spine curvature measurements using a phantom: a pilot study

Aim: Optimise a set of exposure factors, with the lowest effective dose, to delineate spinal curvature with the modified Cobb method in a full spine using computed radiography (CR) for a 5-year-old paediatric anthropomorphic phantom. Methods: Images were acquired by varying a set of parameters: positions (antero-posterior (AP), posteroanterior (PA) and lateral), kilo-voltage peak (kVp) (66-90), source-to-image distance (SID) (150 to 200cm), broad focus and the use of a grid (grid in/out) to analyse the impact on E and image quality (IQ). IQ was analysed applying two approaches: objective [contrast-to-noise-ratio/(CNR] and perceptual, using 5 observers. Monte-Carlo modelling was used for dose estimation. Cohen’s Kappa coefficient was used to calculate inter-observer-variability. The angle was measured using Cobb’s method on lateral projections under different imaging conditions. Results: PA promoted the lowest effective dose (0.013 mSv) compared to AP (0.048 mSv) and lateral (0.025 mSv). The exposure parameters that allowed lower dose were 200cm SID, 90 kVp, broad focus and grid out for paediatrics using an Agfa CR system. Thirty-seven images were assessed for IQ and thirty-two were classified adequate. Cobb angle measurements varied between 16°±2.9 and 19.9°±0.9. Conclusion: Cobb angle measurements can be performed using the lowest dose with a low contrast-tonoise ratio. The variation on measurements for this was ±2.9° and this is within the range of acceptable clinical error without impact on clinical diagnosis. Further work is recommended on improvement to the sample size and a more robust perceptual IQ assessment protocol for observers

Creating Color Image Features Using Local Contrast Method

Digital color images are now one of the most popular data types used in the digital processing environment. Color image recognition plays an important role in many vital applications, which makes the enhancement of image recognition or retrieval system an important issue. Using color image pixels to recognize or retrieve the image, but the issue of the huge color image size that requires accordingly more time and memory space to perform color image recognition and/or retrieval. In the current study, image local contrast was used to create local contrast victor, which was then used as a key to recognize or retrieve the image. The proposed local contrast method was properly implemented and tested. The obtained results proved its efficiency as compared with other methods

OPTIMAX 2014 - Radiation dose and image quality optimisation in medical imaging

Medical imaging is a powerful diagnostic tool. Consequently, the number of medical images taken has increased vastly over the past few decades. The most common medical imaging techniques use X-radiation as the primary investigative tool. The main limitation of using X-radiation is associated with the risk of developing cancers. Alongside this, technology has advanced and more centres now use CT scanners; these can incur significant radiation burdens compared with traditional X-ray imaging systems. The net effect is that the population radiation burden is rising steadily. Risk arising from X-radiation for diagnostic medical purposes needs minimising and one way to achieve this is through reducing radiation dose whilst optimising image quality. All ages are affected by risk from X-radiation however the increasing population age highlights the elderly as a new group that may require consideration. Of greatest concern are paediatric patients: firstly they are more sensitive to radiation; secondly their younger age means that the potential detriment to this group is greater. Containment of radiation exposure falls to a number of professionals within medical fields, from those who request imaging to those who produce the image. These staff are supported in their radiation protection role by engineers, physicists and technicians. It is important to realise that radiation protection is currently a major European focus of interest and minimum competence levels in radiation protection for radiographers have been defined through the integrated activities of the EU consortium called MEDRAPET. The outcomes of this project have been used by the European Federation of Radiographer Societies to describe the European Qualifications Framework levels for radiographers in radiation protection. Though variations exist between European countries radiographers and nuclear medicine technologists are normally the professional groups who are responsible for exposing screening populations and patients to X-radiation. As part of their training they learn fundamental principles of radiation protection and theoretical and practical approaches to dose minimisation. However dose minimisation is complex – it is not simply about reducing X-radiation without taking into account major contextual factors. These factors relate to the real world of clinical imaging and include the need to measure clinical image quality and lesion visibility when applying X-radiation dose reduction strategies. This requires the use of validated psychological and physics techniques to measure clinical image quality and lesion perceptibility

A Descriptive Tolerance Nearness Measure for Performing Graph Comparison

Accepted versionThis article proposes the tolerance nearness measure (TNM) as a computationally reduced alternative to the graph edit distance (GED) for performing graph comparisons. The TNM is defined within the context of near set theory, where the central idea is that determining similarity between sets of disjoint objects is at once intuitive and practically applicable. The TNM between two graphs is produced using the Bron-Kerbosh maximal clique enumeration algorithm. The result is that the TNM approach is less computationally complex than the bipartite-based GED algorithm. The contribution of this paper is the application of TNM to the problem of quantifying the similarity of disjoint graphs and that the maximal clique enumeration-based TNM produces comparable results to the GED when applied to the problem of content-based image processing, which becomes important as the number of nodes in a graph increases."This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant 418413."https://content.iospress.com/articles/fundamenta-informaticae/fi174

Radiation dose and image quality optimisation in medical imaging

Following the successful OPTIMAX summer school held in Salford, 2013, we organised another OPTIMAX summer school in Lisbon during August, 2014. Sixty six people participated,comprising PhD, MSc and BSc students as well as tutors from the 5 European partners. Professional mix was drawn from engineering, medical physics / physics, radiography and occupational therapy. The summer school was hosted by the Lisbon School of Health Technology, Polytechnic Institute of Lisbon, Portugal. It was funded by Erasmus,aside one additional student who was funded by Nuffield.The summer school comprised of lectures and group work in which experimental research projects were conducted in six teams. Team project focus varied, with two concentrating on iterative reconstruction (CT), one into interface pressure mapping (between human body and imaging couch) whilst the remaining three focused to determining ways to reduce dose whilst preserving image quality for different projection radiography procedures. The summer school culminated in a conference, in which each team presented two oral papers.One paper reviewed the literature on their area of interest,whilst the other considered their experimental findings. The oral papers were also presented in written format, in journal article style, and after editing they have been included within this book. At the time of editing this book, several of the experimental papers had been submitted to conferences and some lecturers have commenced development work in order to make them fit for submission to journals

OPTIMAX 2015 : multicultural team-based research in radiography, a holistic educational approach.

Following the successful OPTIMAX summer school held in Salford, 2013 and Lisbon, 2014 we organized OPTIMAX2015 summer school in Groningen. Fifty three people participated, comprising PhD, MSc and BSc students as well as tutors from the five European partners. Professional mix was drawn from engineering, medical physics/ physics and radiography. This summer school was hosted by the Hanze University of Applied Sciences Groningen in the Netherlands. It was funded by the partners. Two students from South Africa were invited by the Hanze University and one additional student from the United Kingdom who was funded by Nuffield. The summer school comprised of lectures and group work in which experimental research projects were conducted in five teams. Team project focus varied, two concentrating on CT reconstruction techniques and image quality, one on image quality high and low noise levels on DR systems, one on reliability and validity of detecting low dose radiation when using radiation detection applications and devices for smartphones. And one about ultrasound validity and reliability measuring rectus femoris muscle size. The summer school culminated in a poster market and conference, in which each team presented a poster and oral presentation on the conference. This book contains two parts, the first six chapters of this book shows the structure of organizing a summer school like OPTIMAX. The second part contains the oral papers in written format, in journal article style, and after editing they have been included within this book. At the time editing this book, several of the experimental papers has been commenced development work in order to make them fit for submission to conferences