Search results for: Andrew J. Lambert

Items from 1 to 20 out of 28 results

article

Subjective measurement of the Stiles‐Crawford effect of the first kind with variation in accommodation

Vinay Kumar Nilagiri, Marwan Suheimat, Andrew J Lambert, David A Atchison

Ophthalmic and Physiological Optics > 41 > 5 > 1110 - 1118

Purpose To measure the Stiles‐Crawford effect of the first kind (SCE‐I), corresponding to central vision, with innovative technology to evaluate changes in the directionality and photoreceptor alignment with accommodation. Methods A uniaxial Maxwellian system (spot size in pupil 0.5 mm diameter) was employed, incorporating a spatial light modulator to flicker at 2 Hz between two 2.3° fields corresponding...

chapter

Improved robustness of 3D CT to 2D fluoroscopy image registration using log polar transforms

Masuma Akter, Andrew J. Lambert, Mark R. Pickering, Jenne M. Scarvell, more

2016 2nd International Conference on Electrical, Computer & Telecommunication Engineering (ICECTE) > 1 - 5

2016 2nd International Conference on Electrical, Computer & Telecommunication Engineering (ICECTE)

Automatic image registration algorithms that rely on a gradient descent based approach may fail when the initial misalignment between objects is large. The registration task is even more difficult for multi-modal images because of the non-linear relationship between the pixel intensities in the images to be aligned. In this paper we will present a multi-modal image registration algorithm which successfully...

article

Robust DT CWT-Based DIBR 3D Video Watermarking Using Chrominance Embedding

Md. Asikuzzaman, Md. Jahangir Alam, Andrew J. Lambert, Mark R. Pickering

IEEE Transactions on Multimedia > 2016 > 18 > 9 > 1733 - 1748

The popularity of 3D video is increasing daily due to the availability of low-cost 3D televisions and high-speed Internet access. However, currently the contents of 3D video can be distributed illegally without any protection. For views generated using a depth-image-based rendering technique, not only the left and right views can be distributed as 3D content, but also the center, left, or right views...

article

High-Precision OFDM-Based Multiple Ultrasonic Transducer Positioning Using a Robust Optimization Approach

Md. Omar Khyam, Md. Jahangir Alam, Andrew J. Lambert, Matthew A. Garratt, more

IEEE Sensors Journal > 2016 > 16 > 13 > 5325 - 5336

Ultrasonic positioning systems (UPSs) are used for various types of applications across a wide variety of fields, including robot navigation, device location, and pose estimation. In this paper, the focus is on investigating two major problems in the signaling and positioning the phases of existing UPSs and providing corresponding solutions. First, most of the existing UPSs use a single tone or a...

article

Monocular vision-based real-time target recognition and tracking for autonomously landing an UAV in a cluttered shipboard environment

Shanggang Lin, Matthew A. Garratt, Andrew J. Lambert

Autonomous Robots > 2017 > 41 > 4 > 881-901

We present a vision system design for landing an unmanned aerial vehicle on a ship’s flight deck autonomously. The edge information from the international landing target is used to perform line segment detection, feature point mapping and clustering. Then a cascade filtering scheme is applied for target recognition. Meanwhile, the 4 DoF pose of the vehicle with respect to the target is estimated....

chapter

Real-time 6DoF deck pose estimation and target tracking for landing an UAV in a cluttered shipboard environment using on-board vision

Shanggang Lin, Matthew A. Garratt, Andrew J. Lambert

2015 IEEE International Conference on Mechatronics and Automation (ICMA) > 474 - 481

2015 IEEE International Conference on Mechatronics and Automation (ICMA)

We present a novel vision system for estimating the 6DoF relative pose of an UAV from a shipdeck. The vision system aims to detect the international landing target using the edge information of the target to perform line segment mapping, feature point clustering and filtering. A novel target-shape evaluation scheme is developed to fuse the measurements. Real-time onboard flight tests demonstrate that...

chapter

Speckle reduction and deblurring of ultrasound images using artificial neural network

Muhammad Shahin Uddin, Kalyan Kumar Halder, Murat Tahtali, Andrew J. Lambert, more

2015 Picture Coding Symposium (PCS) > 105 - 108

2015 Picture Coding Symposium (PCS)

Ultrasound (US) imaging is widely used in clinical diagnostics as it is an economical, portable, painless, comparatively safe, and non-invasive real-time tool. However, the image quality of US imaging is severely affected by the presence of speckle noise during the acquisition process. It is essential to achieve speckle-free high resolution US imaging for better clinical diagnosis. In this paper,...

article

A note on CSMA performance in underwater acoustic networks

Qichao Zhao, Andrew J. Lambert, Craig R. Benson

Computer Communications > 2015 > 55 > Complete > 62-68

Carrier sensing MAC protocols have limited utility in underwater acoustic networks because the propagation delay is not small relative to the packet duration. A recent publication shows simulated results that would appear superior to those predicted by accepted theoretical analysis. We compare the simulated performance against theoretical predictions, then provide an independent simulation of the...

chapter

A Blind and Robust Video Watermarking Scheme Using Chrominance Embedding

Md. Asikuzzaman, Md. Jahangir Alam, Andrew J. Lambert, Mark R. Pickering

2014 International Conference on Digital Image Computing: Techniques and Applications (DICTA) > 1 - 6

2014 International Conference on Digital Image Computing: Techniques and Applications (DICTA)

Piracy of a digital movie is a significant threat for movie studios and producers. Digital video watermarking is an important technique that can be used to protect the content. In existing watermarking algorithms, robustness to several attacks of the watermark has been improved. However, none of the existing techniques are robust to a combination of the common geometric distortions of scaling, rotation,...

chapter

A blind watermarking scheme for depth-image-based rendered 3D video using the dual-tree complex wavelet transform

Md. Asikuzzaman, Md. Jahangir Alam, Andrew J. Lambert, Mark R. Pickering

2014 IEEE International Conference on Image Processing (ICIP) > 5497 - 5501

2014 IEEE International Conference on Image Processing (ICIP)

The amount of unauthorized distribution of 3D video is increasing day by day due to the availability of high speed Internet and low cost 3D TV. Note that, not only both left and right views generated using depth-image-based rendering can be distributed as 3D content but also the centre, left or right view individually as 2D content. Video watermarking is a possible way to protect this type of illegal...

chapter

3D CT to 2D low dose single-plane fluoroscopy registration algorithm for in-vivo knee motion analysis

Masuma Akter, Andrew J. Lambert, Mark R. Pickering, Jennie M. Scarvell, more

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society > 5121 - 5124

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

A limitation to accurate automatic tracking of knee motion is the noise and blurring present in low dose X-ray fluoroscopy images. For more accurate tracking, this noise should be reduced while preserving anatomical structures such as bone. Noise in low dose X-ray images is generated from different sources, however quantum noise is by far the most dominant. In this paper we present an accurate multi-modal...

article

Imperceptible and Robust Blind Video Watermarking Using Chrominance Embedding: A Set of Approaches in the DT CWT Domain

Md. Asikuzzaman, Md. Jahangir Alam, Andrew J. Lambert, Mark Richard Pickering

IEEE Transactions on Information Forensics and Security > 2014 > 9 > 9 > 1502 - 1517

Illegal distribution of a digital movie is a significant threat to the film industries. With the advent of high-speed broadband Internet access, a pirated copy of a digital video can be easily distributed to a global audience. Digital video watermarking is a possible means of limiting this type of digital distribution. In existing watermarking methods, the watermark is usually embedded into the luminance...

chapter

A non-invasive method for kinematic analysis of knee joints

Masuma Akter, Andrew J. Lambert, Mark R. Pickering, Jennie M. Scarvell, more

IEEE International Symposium on Signal Processing and Information Technology > 386 - 391

2013 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT)

The most popular and accurate kinematic analysis methods for musculoskeletal injuries or diseases, prosthesis planning and design are invasive in nature. The invasive methods are harmful and painful for the patient and not practically feasible to use for pre-operation planning on healthy knees. This paper presents a novel non-invasive, accurate kinematic analysis approach for measuring the relative...

chapter

High precision multiple ultrasonic transducer positioning using a robust optimization approach

Md. Omar Khyam, Md. Jahangir Alam, Andrew J. Lambert, Craig R. Benson, more

IEEE International Symposium on Signal Processing and Information Technology > 192 - 197

2013 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT)

Ultrasonic positioning systems are used for various types of applications across a wide variety of fields, including robot navigation, device location and pose estimation. Current ultrasonic positioning systems have limitations when simultaneously locating multiple transmitters in three-dimensional (3D) space using narrowband ultrasonic transducers. They are also unable to calculate a transmitter's...

chapter

Robust 3D Multi-Modal Registration of MRI Volumes Using the Sum of Conditional Variance

Nargis Aktar, Md. Jahangir Alam, Andrew J. Lambert, Mark R. Pickering

2013 International Conference on Digital Image Computing: Techniques and Applications (DICTA) > 1 - 5

2013 International Conference on Digital Image Computing: Techniques and Applications (DICTA)

Multi-modal registration is a fundamental step for many medical imaging procedures. In this paper, the sum of conditional variance (SCV) similarity measure is proposed for 3D multi-modal medical image registration. The SCV similarity measure is based on minimizing the sum of conditional variances that are calculated using the joint histogram of the two images to be registered. Standard Gauss-Newton...

chapter

A blind high definition videowatermarking scheme robust to geometric and temporal synchronization attacks

Md. Asikuzzaman, Md. Jahangir Alam, Andrew J. Lambert, Mark R. Pickering

2013 Visual Communications and Image Processing (VCIP) > 1 - 6

2013 Visual Communications and Image Processing (VCIP)

Due to the availability of high speed online streaming sites, a pirated copy of a digital video can be easily distributed to a global audience. This paper proposes a digital video watermarking technique based on the dual-tree complex wavelet transform that can protect this pirated digital video content. In this scheme, the watermark is embedded into the chrominance channel of the video frames to provide...

chapter

Speckle reduction for ultrasound images using nonlinear multi-scale complex wavelet diffusion

Muhammad Shahin Uddin, Murat Tahtali, Andrew J. Lambert, Mark R. Pickering

2013 IEEE International Conference on Signal and Image Processing Applications > 31 - 36

2013 IEEE International Conference on Signal and Image Processing Applications (ICSIPA)

Speckle noise is a major shortcoming of any type of ultrasound imaging. Hence, speckle reduction is vital in providing a better clinical diagnosis. The key objective of any speckle reduction algorithm is to attain a speckle free image, whilst preserving the important anatomical features. In this paper, we introduce a nonlinear multi-scale complex wavelet diffusion based algorithm for speckle reduction...

chapter

High precision ultrasonic positioning using a robust optimization approach

Md. Omar Khyam, Md. Jahangir Alam, Andrew J. Lambert, Craig R. Benson, more

2013 18th International Conference on Digital Signal Processing (DSP) > 1 - 6

2013 18th International Conference on Digital Signal Processing (DSP)

Typically, indoor positioning systems require higher precision than outdoor positioning systems. Outdoor positioning technologies such as GPS provide poor accuracy in indoor environments due to signal attenuation by the building fabric. In indoor environments, commercial motion-capture systems are proficient at measuring the 3D position of an object precisely. The main disadvantages of this method...

article

Improved fixation quality provided by a Bessel beacon in an adaptive optics system

Andrew J Lambert, Elizabeth M Daly, Christopher J Dainty

Ophthalmic and Physiological Optics > 33 > 4 > 403 - 411

PurposeWe investigate whether a structured probe beam that creates the beacon for use in a retinal imaging adaptive optics system can provide useful side effects. In particular we investigate whether a Bessel beam that is seen by the subject as a set of concentric rings has a dampening effect on fixation variations of the subject under observation. This calming effect would allow longer periods of...

article

Design of a 3D snapshot based visual flight control system using a single camera in hover

Matthew A. Garratt, Andrew J. Lambert, Hamid Teimoori

Autonomous Robots > 2013 > 34 > 1-2 > 19-34

The problem of developing a reliable system for sensing and controlling the hover of a Micro Air Vehicle (MAV) using visual snapshots is considered. The current problem is part of a larger project, which is developing an autonomous MAV, controlled by vision only information. A new algorithm is proposed that uses a stored image of the ground, a snapshot taken of the ground directly under the MAV, as...

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Search results for: Andrew J. Lambert

Subjective measurement of the Stiles‐Crawford effect of the first kind with variation in accommodation

Improved robustness of 3D CT to 2D fluoroscopy image registration using log polar transforms

Robust DT CWT-Based DIBR 3D Video Watermarking Using Chrominance Embedding

High-Precision OFDM-Based Multiple Ultrasonic Transducer Positioning Using a Robust Optimization Approach

Monocular vision-based real-time target recognition and tracking for autonomously landing an UAV in a cluttered shipboard environment

Real-time 6DoF deck pose estimation and target tracking for landing an UAV in a cluttered shipboard environment using on-board vision

Speckle reduction and deblurring of ultrasound images using artificial neural network

A note on CSMA performance in underwater acoustic networks

A Blind and Robust Video Watermarking Scheme Using Chrominance Embedding

A blind watermarking scheme for depth-image-based rendered 3D video using the dual-tree complex wavelet transform

3D CT to 2D low dose single-plane fluoroscopy registration algorithm for in-vivo knee motion analysis

Imperceptible and Robust Blind Video Watermarking Using Chrominance Embedding: A Set of Approaches in the DT CWT Domain

A non-invasive method for kinematic analysis of knee joints

High precision multiple ultrasonic transducer positioning using a robust optimization approach

Robust 3D Multi-Modal Registration of MRI Volumes Using the Sum of Conditional Variance

A blind high definition videowatermarking scheme robust to geometric and temporal synchronization attacks

Speckle reduction for ultrasound images using nonlinear multi-scale complex wavelet diffusion

High precision ultrasonic positioning using a robust optimization approach

Improved fixation quality provided by a Bessel beacon in an adaptive optics system

Design of a 3D snapshot based visual flight control system using a single camera in hover

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