Peter Bryanston-cross

University of Warwick · School of Engineering

This poster presents an overview of several current super-resolution diagnostic techniques, describing the different optical limitations and resolutions as well as a discussion. Optical super-resolution diagnostics have revolutionised the field of imaging by visualising structures beyond the previously established diffraction and information resolu...

Digital holographic microscopy (DHM) is a 3D method for imaging cells without using labels. It gives detailed information about cell shape and behavior. This study has explored two applications of 3D phase imaging. Firstly, an image was made of an out-of-focus monochromatically illuminated cheek cell with a conventional light field microscope. The...

Optical super-resolution diagnostics have revolu-tionised the field of imaging by visualising structures beyond the previously established diffraction and information resolution limits established by [1]-[3]. They have enabled the visualisation of structures at the nanoscale, changing the field of microscopic imaging for a variety of fields, includ...

The work described in this paper represents a premiere in the application of Particle Image Velocimetry (PIV) to turbomachinery flows. This technique allowed the visualisation of the instantaneous transonic flow in the inter-blade passage of a rotating annular cascade at engine conditions. By means of photographic recording of flow tracers and spec...

The polarization perception sensitivity of the human eyes affects the perceived polarized image quality. In this paper, we used polarized spatiotemporal structured images to develop a spatiotemporal age mapping of the polarization perception of human eyes. We built an optical modulation transfer function mathematical model of the aging human eyes w...

A compact in-line digital holographic microscope (DHM) has been constructed to make a series of holographic images of cancer cells. The system has a lateral resolution of 250nm. A phase reconstruction process has been used to make quantitative biological measurements of A549, MCF-7 and 7721 cells growth changes and drug responses with a depth reso...

The sensitivity of the human eye affects the quality of images perceived by it. This paper presents an approach to optimize the polarized image stimulus. We investigated the macular perception of polarized images with the help of a theoretically derived spatiotemporal function which maximizes the observer’s polarized image visibility. The spatiotem...

This paper endeavours, from an engineering viewpoint, to investigate the main sources of Carbon Dioxide emission globally and to suggest how a lower emission can be achieved within the application of current technology. Firstly, it presents the personal efforts by the author to improve aerodynamic and combustion efficiency. It then charts the growt...

This paper endeavours, from an engineering viewpoint, to investigate the main sources of Carbon Dioxide emission globally and to suggest how a lower emission can be achieved within the application of current technology. Firstly, it presents the personal efforts by the author to improve aerodynamic and combustion efficiency. It then charts the growt...

A compact and high resolution in-line digital holographic microscope (DHM) consisting of a 532nm laser, mirrors, microscope objectives (10×, NA=0.25 and 40×, NA=0.65) and CCD camera is described. It provides a resolution of 0.25µm calibrated by reconstructed amplitude image of a line grating with 0.5µm periodicity. Using the system, a series of hol...

This paper presents a matrix approach, developed using a 3D Stokes vector analysis, to simulate polarized light as perceived by the macular of the human eye, and views the human perception of polarized light as a multivariable applied optics problem then approached it in an analytical manner as a complex optical system. The objective is to give pur...

Summary In high pressure turbines the flow in the stator-rotor interaction region is highly complex with periodic and random unsteady effects generated as the stator wakes impinge on the rotor blades. Measuring the flow in this region is difficult with conventional instrumentation, further complicated in a short duration facility. This paper d...

Super Resolution is an important tool for imaging in a number of scientific disciplines including in particular the study of living cells and organisms. Optics has previously been confined in spatial resolution of the Abbe diffraction limit. Recently the area of Super-Resolution has opened up the possibility of going beyond this limit. The presen...

The geometric approach presented in this paper concerns the degree of polarization (DoP) of a random 3D statistical electromagnetic field. We use that a 3*3 coherency matrix can always be decomposed into an incoherent superposition of three specific coherency matrices, to construct the first orthant of a spherical shell(0<x,y,z<1,sqrt(3)/3<r<1) . F...

Using three-dimensional (3D) coherency vector (9 × 1), we develop a new 3D polarization algebra to calculate the polarization properties of all polarization sensitive optical systems, especially when the incident optical field is partially polarized or un-polarized. The polarization properties of a high numerical aperture (NA) microscope objective...

We studied the fuel atomization process of two fuel injectors to be fitted in a new small rotary engine design. The aim was to improve the efficiency of the engine by optimizing the fuel injection system. Fuel sprays were visualised by an optical diagnostic system. Images of fuel sprays were produced under various testing conditions, by changing th...

Carbon capture and storage could significantly reduce carbon dioxide (CO2) emissions. One of the major limitations of this technology is the energy penalty for the compression of CO2 to supercritical conditions. To reduce the power requirements, supercritical carbon dioxide compressors must operate near saturation where phase change effects are imp...

On a ten-year timescale, Carbon Capture and Storage could significantly reduce carbon dioxide (CO2) emissions. One of the major limitations of this technology is the energy penalty for the compression of CO2 to supercritical conditions, which can require up to 15% of the plant’s gross power output. To reduce the power requirements supercritical car...

There are many research areas where the birefringent properties of materials can be used to provide relevant measurements. In this paper 2 examples are presented which describe how a high resolution phase-encoded intensity distribution of birefringence may be used to non-intrusively derive the stress experienced by use of an anodised aluminium rive...

There are many research areas where the birefringent properties of materials can be used to provide relevant measurements. In this paper 2 examples are presented which describe how a high resolution phase-encoded intensity distribution of birefringence may be used to non-intrusively derive the stress experienced by use of an anodised aluminium rive...

Abstract— The paper describes an automated Particle Image Velocimetry (PIV) system designed for synchronised combined 2- and 3-component velocity measurements. The system has been designed to make measurements of velocity in the exhaust region of a scaled version of a gas turbine engine operating at high sub-sonic velocities and high temperatures (...

Advanced compressors for supercritical CO2 (S-CO2) are a key enabling technology for carbon capture and sequestration (CCS), enhanced oil recovery (EOR), and power cycles. For example in CO2 compressor applications, the thermodynamic state of the working fluid is close to the two-phase region where phase change effects are important. The expansion...

The paper describes an automated Particle Image Velocimetry (PIV) system designed for synchronised combined 2- and 3-component velocity measurements. The system has been designed to make measurements of velocity in the exhaust region of a scaled version of a gas turbine engine operating at high subsonic velocities and high temperatures (typically 8...

This is a Guardian article from 1997.

This study explores both theoretically and experimentally the human perception of polarized light beyond that currently established. The radial analyser theory of Haidinger's phenomenon (HP) is used to predict the effect of observing visual stimuli comprising patterned zones characterized by orthogonal planes of linear polarization (linear polariza...

A laser sheet digital imaging system was developed to visualize and characterize aviation fuel sprays through the use of a high-resolution camera and a pulsed laser. Image processing and particle image velocimetry (PIV) were employed to investigate the spray development process during an individual injection pulse. The experimental setup of the vis...

Photoeleasticity has a long history of application to material testing. However, it often requires a complex coating of a suitable material to reveal the stresses experienced. The alternative is to create a transparent birefringent model. The disadvantages being that the measurements can be masked by the effect of the coating applied or in the case...

The paper presents the development of techniques to study flows in human conducting airways aimed at improving understanding of underlying mechanisms in asthma and Chronic Obstructive Pulmonary Disease (COPD). The models developed are made through additive layer manufacturing (ALM) of segmented lung Computed Tomography (CT) scans. The flow dynamics...

Number: 1984 Publication Number: P2274 Abstract Group: 1.3. Imaging Keyword 1: Asthma-mechanism Keyword 2: COPD-mechanism Keyword 3: Imaging

Particle Image Velocimetry (PIV) technique produces the velocity vector fields of various aerodynamic flows by the correlation between a set of successive images. The flow is usually seeded by lightweight microscopic particles, which scatter the optical energy towards camera sensors. A monochromatic light sheet illuminates the seeding particles. In...

The space-bandwidth product (SBP) is a measure for the information capacity an optical system possesses. The two information processing steps in digital holography, recording, and reconstruction are analyzed with respect to the SBP. The recording setups for a Fresnel hologram, Fourier hologram, and image-plane hologram, which represent the most com...

This paper reports on an exploratory study to assess the capability of a novel, form-finding methodology for generating optimal shapes of shell-type structures subjected to complex load regimes, using an axial-flow, compressor blade as a case study. The methodology exploits the natural principle of ‘form follows force’, in which the structural form...

A novel (to our knowledge) approach for resolution improvement in digital holography is presented in this paper. The proposed method is based on recording the incoming interference field on a complementary metal-oxide semiconductor (CMOS) camera with subpixel resolution. The method takes advantage of the small pixel size of the CMOS sensor, while o...

In the last two decades digital holography emerged as one of the most promising techniques for obtaining the complex object-wave (amplitude and phase). However, due to the coherent nature of the light source used in digital holography, the reconstructed hologram is subjected to speckle noise. Moreover, the resolution and size of the sensor employed...

This paper presents a digital imaging and optical characterization system in a high-speed spray jet. Different fuel injection arrangements have been evaluated as part of fuel delivery system prior to application in a rotary “Wankel” engine; the objective being to improve combustion efficiency and engine performance. High-power lasers, high-resoluti...

Currently under investigation is a technique for exposing and measuring coherent structures in turbulent flows. The technique is summarised in the following steps: 1. Proper orthogonal Decomposition of the Vector Map Ensemble. 2. Partial Reconstruction of the Ensemble using a limited number of modes. 3. Coherent Structure centre detection. 4....

In digital holography the sinusoidal interference pattern resulting from the interference between reference and object-wave is stored on a digital receiver, such as CCD or CMOS cameras. The maximum resolution of such receivers (typically 500 lp/mm) is small compared to the typical resolution of photographic plates (3000 lp/mm) originally used in op...

The development of a highly configurable triple digital particle image velocimetry (DPIV) system is described, which is capable of acquiring both continuous, statistically independent measurements at up to 14 Hz and time-resolved PIV data at MHz rates. The system was used at QinetiQ's Noise Test Facility (NTF) as part of the EU-funded CoJeN program...

A low-cost, robust, versatile digital shadowgraph visualization system is presented that provides a fast nonintrusive diagnostic for unsteady high-speed flows. The technique is particularly designed for real-time automated tracking of shock positions, enabling high-speed active shock control. The visualization system is based on a high-intensity wh...

A novel qualitative method is presented for determining the macroscopic distribution of collagen lamellae within the central human cornea in vivo. A modified digital photo slit-lamp camera adapted for use with circular polarised light is used. 19 eyes of 10 pseudophakic subjects (with prosthetic intraocular lens implants) are involved in the experi...

Two novel optical techniques are presented for non-intrusive, spatially resolved study of combustion, both based on passive Optical Emission Tomography (OET). Firstly, OET is used for non-intrusive study of heat release through the detection of chemiluminescence by the hydroxyl radical that is generated in the burning process. The OET technique pre...

A suitable setup for deformation measurement based on polarization optics, ensuring high phase step accuracy, is demonstrated. Digital Double Exposure Holography has been applied for the investigation of the camera captured intensity images.

This paper reviews the potential benefits that can be obtained by the implementation of data fusion in a multi-sensor environment. A thorough review of the commonly used data fusion frameworks is presented together with important factors that need to be considered during the development of an effective data fusion problem-solving strategy. A system...

The mechanisms involved in infrared laser tissue ablation are studied using a free electron laser (FELIX) in order to clarify whether the increased ablation efficiency reported in literature for certain infrared wavelengths is due to a wavelength effect or to the specific pulse structure of the lasers that are generally used in these studies. Inves...

This paper investigates the application of fringe analysis to the measurement of geometric lens aberration and the creation of a Fresnel zone plate based diffractive corrective for the removal of chromatic aberration. The objective of the work has been firstly to create a Fourier fringe analysis approach to analyse the minor geometric distortions f...

SUMMARY The work presented in this paper is concerned with the first successful application of particle image velocimetry to accurately map the intra-passage transonic flow within a rotating annular cascade at engine conditions. The image processing of the sparse PlV images was based on the interrogation of the optical profile of individual partic...

A unique new type of Nd:YAG laser has been constructed to produce a maximum of 10 ultra high-repetition pulses of 10mJ energy and 3 ns duration each with separation times adjustable from 1µs between consecutive pulses up to a total of 300 µs between the first and last pulse. This enables the development of time-resolved Particle Image Velocimetry f...

Mechanical devices are normally used under conditions of dynamic motion. Due to resonance effects, this condition produces undesired modes of vibration, which are necessary to be measured for satisfactory design. This paper describes a method to measure the temporal development of the vibrational modes in mechanical objects subjected to external vi...

A low-cost and low-maintenance digital focused shadowgraph flow visualization system has been developed to provide fast diagnostics of rapidly changing phenomena in supersonic flows. The system is particularly designed for tracking shock positions in a supersonic inlet, enabling high-speed active shock control. It is based on a low-cost, high-inten...

This report describes the work done during the period between July 1, 2000 and June 30, 2003 on two topics: active control of separation and distortion in high subsonic supersonic inlets, and active control of inlet unstart in supersonic inlets. The report is divided into a summary, which highlights the major accomplishments of the program, and a s...

Heat transfer between the working fluid and the combustion chamber in an internal combustion engine is one of the most important parameters for cycle simulation and analysis. The heat transfer influences the in-cylinder pressure and temperature levels, engine efficiency, and exhaust emissions. Most of the current research carried out on combustion...

Mechanical devices are normally used under conditions of dynamic motion. Due to resonance effects, this condition produces undesired modes of vibration, which are necessary to be measured for satisfactory design. This paper describes a method to measure the temporal development of the vibrational modes in mechanical objects subjected to external vi...

Optical engineering is currently evolving more rapidly than at any previous time. A series of optical and medical engineering innovations, promising to create new types of intelligent optical diagnostic technology, have been developed at Warwick University through interaction between Engineering, Computer Science and Medical Science. Some combustio...

Optical engineering is currently evolving more rapidly than at any previous time. A series of optical and medical engineering innovations, promising to create new types of intelligent optical diagnostic technology, have been developed at Warwick University through interaction between Engineering, Computer Science and Medical Science. Some combustio...

Glaucoma is an increasingly common cause of visual impairment, and in some cases causes blindness. The approach to develop a low cost and non-contact tonometer for the detection of glaucoma, to replace the Goldmann tonometer used worldwide, is presented in this paper. The new tonometer exploits the vibration property of the cornea - the resonance f...

This article introduces an experiment designed to investigate which wavelength of light is best reflected by the cornea. Results indicate that the human cornea reflects near-infrared or violet light more efficiently than it does bright visible light. Further, results indicate that at a wavelength of 580nm, the reflectivity of the cornea decreases t...

Polyacrylamide gel electrophoresis is a technique that allows the constituents of complex biological mixtures to be resolved with respect to their molecular weight. This is a technique that has been used to identify protein or nucleic acid fragments, and it is now being applied to allow molecular analysis of laser-tissue ablation products. The hope...

Three independent measurements have been used to investigate combustion within a single cylinder four- stroke research engine operating at low load. THIN FILM GAUGES - Heat transfer between the working fluid and the combustion chamber in an internal combustion engine is one of the most important parameters for cycle simulation and analysis. Heat tr...

Three independent measurements have been used to investigate combustion within a single cylinder four-stroke research engine operating at low load. 1) thin film gauges. Heat transfer is determined using platinum thin film resistance thermometers exposed to the combustion gases. These give a frequency response of greater than 100 kHz; hence can trac...

This paper presents a method for determining the slope and period of oblique and equi-spaced fringes by fringe pattern matching. In the method, two pairs of image patches in two different regions of a fringe pattern are selected for fringe pattern matching, and the phase shift between the fringes in the two selected regions of the fringe pattern is...

The Free Electron Laser for Infrared EXperiments (FELIX) Free Electron Laser Facility provides a continuously tunable source ranging continuously through the 4.5 to 200 micron region. The infrared beam consists of short micropulses, which have a nominal duration of 5 ps and are separated by intervals of either 1 ns or 40 ns of zero intensity. The m...

A review of several current optical diagnostics used for flow visualization is presented and the limitations and strengths of each technique are described. A new type of intelligent diagnostic optic designed for making three-dimensional measurement of velocity in a gas turbine combustor is proposed. The diagnostic uses an in-line tomographic approa...

Background: Profuse bleeding due to retinal tearing represents a common problem when working in the posterior chamber of the diabetic eye. If the traction and vibration associated with traditional vitrectomy tools could be eliminated, then many of their associated problems could also be removed. By investigating the tuning of laser energy in order...

Qualitative comparisons are made between Particle Image Velocimetry data and Computational Fluid Dynamics predictions for the flow around two adjacent rotating cylinders. For this novel flow configuration, the cylinders rotate in opposite directions with their outer surfaces in contact. Steady state sets are carried out of the following rotational...

A rugged optical method has been designed for making measurements in a hostile industrial environments such as the combustion exit now of a gas turbine engine. Typically the gas temperature in such a combustor is 1000 K and the speed of the flow 700m/s. A transient shock tube has been constructed at MIT (Massachusetts Institute of Technology). The...

Application of LCD in Phase Stepping An LCD has been used as a phase stepping device. An example is presented of the reconstruction of a contoured 3D surface. The value of the contours has been determined by applying a phase shift to the LCD.

The concept of the intelligent engine is a generically derived solution which can be applied to any type of engine. The engine performs complex functions, from the operation of a vehicle to that of a complete factory. By making measurements which relate the specific to the global, it is possible to use the concept of data fusion to give an understa...

Using holographic interferometry the three-dimensional structure of unsteady and large-scale motions within subsonic and transonic turbulent jet flows has been studied. The instantaneous 3D flow structure is obtained by tomographic reconstruction techniques from quantitative phase maps recorded using a rapid-switching, double reference beam, double...

A monolithic x-ray interferometer has been developed which provides a means of producing high-quality x-ray Moiré fringes with readily controlled pitch (spacing). It was designed as a calibrator of sub-microradian angular displacements and it has successfully demonstrated the feasibility of the approach. The quality of its output, when combined wit...

Presents a new method of fringe-pattern analysis by spatial phase stepping (SPS). The SPS method combines the computational simplicity of phase stepping with the single-image analysis capability of the Fourier transform method. The technique works by subdividing a linearized fringe pattern into three component images, from which the phase is calcul...

This paper describes a double-exposure holographic contouring technique by the movement of the object beam through fibre optics. Single-mode optic fibres are used to transfer both object and reference beams. Between two exposures the object illumination beam is displaced. The contouring fringes can be visualised on the object surfaces. The fringe p...