Search results

1 – 10 of 13
To view the access options for this content please click here
Article
Publication date: 9 October 2017

Ali Sohaib, Laurence Broadbent, Abdul Rehman Farooq, Lyndon Neal Smith and Melvyn Lionel Smith

Significant research has been carried out in terms of development of new bidirectional reflectance distribution function (BRDF) instruments; however, there is still little…

Abstract

Purpose

Significant research has been carried out in terms of development of new bidirectional reflectance distribution function (BRDF) instruments; however, there is still little research available regarding spectral BRDF measurements of human skin. This study aims to investigate the variation in human skin reflectance using a new fibre optic-based spectral-BRDF measurement device.

Design/methodology/approach

Design of this system mainly involves use of multiple fibre optics to illuminate and detect light reflected from a sample, whereas a hemispherical dome was 3D printed to mount the fibres at various slant/tilt angles. To investigate the spectral differences in BRDF of human skin, 3 narrowband filters in the visible spectrum were used, whereas measurements were taken from the back of the hand for Caucasian and Asian skin types.

Findings

The experiments demonstrate that the BRDF of human skin varies with wavelengths in the visible spectrum and it is also different for Caucasian and Asian skin types. Both skin types exhibit off-specular reflection with increase in angle of incidence and show less variation with respect to viewing angles when the angle of incidence is normal to the surface.

Research implications

A database of spectral BRDF measurements of human skin will help not only in creating realistic skin renderings but also in development of novel skin reflectance models for biomedical and machine vision applications. The measurements would also provide means to validate the predictions from existing light transport/spectral simulation models for human skin and will ultimately help in the accurate diagnosis and simulation of various skin disorders.

Originality/value

The proposed system provides fast scatter measurements by utilising multiple fibres to detect light simultaneously at different angles while also allowing easy switching between incident light directions. Due to its flexible design and contact-based measurements, the device is independent of errors due to sample movements and does not require any image registration. Also, measurements taken from the device show that the BRDF of skin varies significantly in the visible spectrum and it is different for Caucasian and Asian skin types.

Details

Sensor Review, vol. 37 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

To view the access options for this content please click here
Article
Publication date: 28 October 2014

Ye Su, Ye Yutang, Xie Yu, Yi Maoli, Zhang Jing, Luo Ying and Du Chunlei

– This paper aims to solve the issue of target positioning in auto stiffener bonder (ASB) systems for flexible printed circuits.

Abstract

Purpose

This paper aims to solve the issue of target positioning in auto stiffener bonder (ASB) systems for flexible printed circuits.

Design/methodology/approach

The proposed approach uses Phong’s bidirectional reflectance distribution function (BRDF) model to simulate the reflection of light off a target in ASB systems to predict the current pose of the target based on image brightness, update the template, decrease the initial errors in the template and narrow down the search range.

Findings

The experimental results indicate that the proposed approach can predict the inclination angle of the target with precision, presenting angle prediction errors of less than three degrees. Furthermore, with larger inclined angles, the overall matching errors were less than 1.5 pixels. Comparisons with the unmodified matching algorithm revealed that the proposed approach resulted in 65 per cent less calculation time for the algorithm and 14 per cent higher overall work efficiency in the ASB system.

Originality/value

The edge-based perspective shape matching algorithm was modified using the Phong BRDF model and enhanced algorithm efficiency with the target pose prediction method while ensuring the precision and robustness of the system. The proposed approach has high potential value and can be expanded to recognition systems for objects with varying inclination angles and highly reflective surfaces.

To view the access options for this content please click here
Book part
Publication date: 27 May 2020

Angelique Pilon, John Madden, James Tansey and John Metras

Over the last 30 years, the University of British Columbia (UBC) in Vancouver, Canada has advanced sustainable development on campus and created a culture of…

Abstract

Over the last 30 years, the University of British Columbia (UBC) in Vancouver, Canada has advanced sustainable development on campus and created a culture of sustainability, with ambitious goals, and strong collaborative relationships. Launched in 2010, the Campus as a Living Laboratory (CLL) initiative utilizes the campus buildings and infrastructure as opportunities for research, teaching, and learning. Projects under the CLL bring together academic researchers, students, staff, and partners to demonstrate, test, research, and learn from new ideas for sustainable development. These projects range in scale from small and discrete educational or research projects, often led by students, to the design and construction of innovative buildings, with multiyear interdisciplinary research programs. CLL projects are opportunities for UBC students to engaged in applied research and learning that enhances their educational experience at the university, and may serve as models for other universities interested in expanding sustainable development on their campuses.

Details

Teaching and Learning Strategies for Sustainable Development
Type: Book
ISBN: 978-1-78973-639-7

Keywords

To view the access options for this content please click here
Article
Publication date: 1 November 2007

Yinlong Sun

This paper reports a study on reflection measurement of a textile surface. The measurement was made involving spatial directions and wavelength. To integrate a spectral…

Abstract

This paper reports a study on reflection measurement of a textile surface. The measurement was made involving spatial directions and wavelength. To integrate a spectral detector with a setup for different lighting and viewing directions, the method of fixed sample normal is proposed. In this method, the sample's surface normal is fixed and various lighting and viewing directions are obtained by relocating the source and detector. A visualization system was developed to help explore the measured data. The system allows the user to select a measured data point to display simultaneously the spectrum and its associated color and angle information. Finally, a new interpolation method based on space partition was proposed. Given an interpolation point P, the space is subdivided into subspaces and the data point closest to P in each subspace is selected. This generates a set of points and tetrahedrons, and if any tetrahedron contains P, it will be used for the interpolation based on the barycentric coordinates. This study is useful for multiple applications such as realistic image synthesis, verification of reflection models, and investigation of the relationships between textile appearances and the underlying physical parameters.

Details

Research Journal of Textile and Apparel, vol. 11 no. 4
Type: Research Article
ISSN: 1560-6074

Keywords

To view the access options for this content please click here
Article
Publication date: 14 September 2010

Jifeng Wang, Huigu Yang, Yaozhou Qian and Jianquan Zeng

The purpose of this paper is to analyze and show how to avoid the interference in infrared (IR) temperature field measurement during welding.

Abstract

Purpose

The purpose of this paper is to analyze and show how to avoid the interference in infrared (IR) temperature field measurement during welding.

Design/methodology/approach

First, the hardware used in this experiment is described. In this paper, these interferences are first classified into diffuse and specular reflection based on reflection model, and are restrained, respectively. Finally, IR temperature is calibrated by thermocouple.

Findings

The specular reflection is the primary interference which causes high light zone. And it can be transferred out of welding seam when the IR thermography is placed perpendicularly to welding seam.

Originality/value

The paper provides a new IR measure method and detailed analysis about the interferences in applying IR temperature sensing.

Details

Sensor Review, vol. 30 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

To view the access options for this content please click here
Article
Publication date: 1 February 2005

David K. McAllister and Anselmo Lastra

Most surfaces, including most fabrics, have different reflectance at different points on the surface. The reflectance also varies based on the incident and exitant light…

Downloads
16

Abstract

Most surfaces, including most fabrics, have different reflectance at different points on the surface. The reflectance also varies based on the incident and exitant light directions. This spatially and angularly varying surface appearance is a 6D function, sometimes called the Spatial Bi-directional Reflectance Distribution Function (SBRDF). We present a system for measuring the SBRDF of real fabrics in a lab setting. Our system is able to capture distinct anisotropic BRDFs at each point on the fabric.

The measurement device yields from 300 MB to 8 GB of reflectance data for complex fabrics. We compress the SBRDF using a sum of very few nonlinear bases suited to BRDFs, yielding a highly compact texture map of from 2 to 20 MB, suitable for accurately visualizing articles made of specific fabrics interactively using commodity graphics hardware. We provide an online database of sampled SBRDFs, both in raw form and as final texture maps.

Details

Research Journal of Textile and Apparel, vol. 9 no. 1
Type: Research Article
ISSN: 1560-6074

Keywords

To view the access options for this content please click here
Article
Publication date: 12 March 2018

Jiangping Yuan, Ming Zhu, Baohui Xu and Guangxue Chen

The purpose of this paper is provide a broad view for the standardization efforts of color quality evaluation of color 3D printing techniques. Further, this review paper…

Abstract

Purpose

The purpose of this paper is provide a broad view for the standardization efforts of color quality evaluation of color 3D printing techniques. Further, this review paper demonstrates the processes and color properties of most color 3D printing techniques with specific devices and applications to extend the range of possible memberships of standardization group.

Design/methodology/approach

Six color 3D printing techniques including plastic-based, paper-based, powder-based, organism-based, food-based and metal-based color 3D printing have been introduced and illustrated with colorization principles and forming features in detail. Moreover, for printed 3D color objects, literature about color measurement, color specification and color reproduction are described and analyzed, respectively.

Findings

Four color 3D printing techniques including plastic-based, paper-based, powder-based and food-based color 3D printing show great affinity toward standardization of color quality evaluation, while their colorization principles indicate that it is difficult with a single standard frame. It is possible to develop a completed color quality evaluation standard for color 3D printing based on approaches in color 2D printing when color measurement method and devices are standardized together.

Originality/value

The paper provides an important guide focusing on the efforts to standardize the colorization processes and color quality evaluation of the color 3D printing techniques.

To view the access options for this content please click here
Article
Publication date: 8 March 2018

Hui Wang, Zheng Zhang, Zhao Xiong, Tianye Liu, Kai Long, Xusong Quan and Xiaodong Yuan

It is a huge technical and engineering challenge to realize the precise assembly of thousands of large optics in high power solid-state laser system. Using the 400-mm…

Downloads
222

Abstract

Purpose

It is a huge technical and engineering challenge to realize the precise assembly of thousands of large optics in high power solid-state laser system. Using the 400-mm aperture-sized transport mirror as a case, this paper aims to present an intelligent numerical computation methodology for mounting performance analysis and modeling of large optics in a high-power laser system for inertial confinement fusion (ICF).

Design/methodology/approach

Fundamental principles of modeling and analysis of the transport mirror surface distortion are proposed, and a genetic algorithm-based computation framework is proposed to evaluate and optimize the assembly and mounting performance of large laser optics.

Findings

The stringent specifications of large ICF optics place very tight constraints upon the transport mirror’s assembly and mounts. The operational requirements on surface distortion [peak-to-valley and root mean square (RMS)] can be met as it is appropriately assembled by the close loop of assembly-inspection-optimization-fastening. In the end, the experimental study validates the reliability and effectiveness of the transport mirror mounting method.

Originality/value

In the assembly design and mounting performance evaluation of large laser optics, the whole study has the advantages of accurate evaluation and intelligent optimization on nano-level optical surface distortion, which provides a fundamental methodology for precise assembly and mounting of large ICF optics.

Details

Assembly Automation, vol. 38 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

Content available
Article
Publication date: 1 October 1998

Downloads
107

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 70 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

To view the access options for this content please click here
Book part
Publication date: 27 May 2020

Abstract

Details

Teaching and Learning Strategies for Sustainable Development
Type: Book
ISBN: 978-1-78973-639-7

1 – 10 of 13