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    Analysis of the pancreato-biliary system from MRCP

    Robinson, K. ; Whelan, P.F.
    Computer-Based Medical Systems, 2005. Proceedings. 18th IEEE Symposium on

    Digital Object Identifier: 10.1109/CBMS.2005.31
    Publication Year: 2005 , Page(s): 253 - 258

    IEEE Conference Publications

    We present a preprocessing and segmentation scheme designed to address the particular difficulties encountered in the analysis of magnetic resonance cholangiopancreatography (MRCP) data, as a precursor to the application of computer assisted diagnosis (CAD) techniques. MRCP generates noisy, low resolution, non-isometric data which often exhibits significant greylevel inhomogeneities. This combination of characteristics results in data volumes in which reliable segmentation and analysis are difficult to achieve. In this paper we describe a data processing approach developed to overcome these difficulties and allow for the effective application of automated CAD procedures in the analysis of the biliary tree and pancreatic duct in MRCP examinations. View full abstract»

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    Colour saliency-based parameter optimisation for adaptive colour segmentation

    Ilea, D.E. ; Whelan, P.F.
    Image Processing (ICIP), 2009 16th IEEE International Conference on

    Digital Object Identifier: 10.1109/ICIP.2009.5414039
    Publication Year: 2009 , Page(s): 973 - 976

    IEEE Conference Publications

    In this paper we present a parameter optimisation procedure that is designed to automatically initialise the number of clusters and the initial colour prototypes required by data space partitioning techniques. The proposed optimisation approach involves a colour saliency measure used in conjunction with a SOM classification procedure. For evaluation purposes, we have integrated the proposed initialisation technique in an unsupervised colour segmentation scheme based on K-Means clustering and the evaluation has been carried out in the context of the unsupervised segmentation of natural images. View full abstract»

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    Tracking using self-initialising active meshes

    Molloy, D. ; Whelan, P.F.
    Image Processing and Its Applications, 1999. Seventh International Conference on (Conf. Publ. No. 465)

    Volume: 2
    Digital Object Identifier: 10.1049/cp:19990414
    Publication Year: 1999 , Page(s): 701 - 705 vol.2
    Cited by:  Papers (2)

    IET Conference Publications

    This paper describes a method of visual tracking using an `active-mesh' that is automatically created and configured directly from a single frame of an image sequence. The aim of this approach is to perform visual tracking in unconstrained motion environments, allowing movement of the camera, the scene and even the inclusion of background-independent moving objects View full abstract»

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    Fibre optic in-fibre Bragg grating sensors for use in composite material structural element characterisation and structural monitoring

    Kenny, R.P. ; Gutierrez, E. ; Lucia, A.C. ; Whelan, M.P. ; Gaiazzi, F. ; Sheridan, J.T.
    Optical Techniques for Smart Structures and Structural Mmonitoring (Digest No. 1997/033), IEE Colloquium on

    Digital Object Identifier: 10.1049/ic:19970209
    Publication Year: 1997 , Page(s): 11/1 - 11/6

    IET Conference Publications

    An overview of our recent work on fibre optic sensor systems for structural element characterisation and monitoring is presented. The initial aim has been to explore the feasibility and utility of such fibre optic sensors, and to use them to improve measurements and to obtain results unobtainable by other means in application areas of interest. Two particular applications areas currently under study are the characterisation and testing of pultruded composite beams, and the shape reconstruction of composite panels. The motivation for these projects and their theoretical and experimental status are described. Fibre optic sensor systems to suit these applications have been developed; the main aspects of the development of an all-fibre passive demodulation scheme for in-fibre Bragg grating sensors are presented View full abstract»

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    CTex—An Adaptive Unsupervised Segmentation Algorithm Based on Color-Texture Coherence

    Ilea, D.E. ; Whelan, P.F.
    Image Processing, IEEE Transactions on

    Volume: 17 , Issue: 10
    Digital Object Identifier: 10.1109/TIP.2008.2001047
    Publication Year: 2008 , Page(s): 1926 - 1939
    Cited by:  Papers (31)

    IEEE Journals & Magazines

    This paper presents the development of an unsupervised image segmentation framework (referred to as CTex) that is based on the adaptive inclusion of color and texture in the process of data partition. An important contribution of this work consists of a new formulation for the extraction of color features that evaluates the input image in a multispace color representation. To achieve this, we have used the opponent characteristics of the RGB and YIQ color spaces where the key component was the inclusion of the self organizing map (SOM) network in the computation of the dominant colors and estimation of the optimal number of clusters in the image. The texture features are computed using a multichannel texture decomposition scheme based on Gabor filtering. The major contribution of this work resides in the adaptive integration of the color and texture features in a compound mathematical descriptor with the aim of identifying the homogenous regions in the image. This integration is performed by a novel adaptive clustering algorithm that enforces the spatial continuity during the data assignment process. A comprehensive qualitative and quantitative performance evaluation has been carried out and the experimental results indicate that the proposed technique is accurate in capturing the color and texture characteristics when applied to complex natural images. View full abstract»

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    An automatic 2D CAD algorithm for the segmentation of the IMT in ultrasound carotid artery images

    Ilea, D.E. ; Whelan, P.F. ; Brown, C. ; Stanton, A.
    Engineering in Medicine and Biology Society, 2009. EMBC 2009. Annual International Conference of the IEEE

    Digital Object Identifier: 10.1109/IEMBS.2009.5333773
    Publication Year: 2009 , Page(s): 515 - 519

    IEEE Conference Publications

    Common carotid intima-media thickness (IMT) is a reliable measure of early atherosclerosis - its accurate measurement can be used in the process of evaluating the presence and tracking the progression of disease. The aim of this study is to introduce a novel unsupervised Computer Aided Detection (CAD) algorithm that is able to identify and measure the IMT in 2D ultrasound carotid images. The developed technique relies on a suite of image processing algorithms that embeds a statistical model to identify the two interfaces that form the IMT without any user intervention. The proposed image segmentation scheme is based on a spatially continuous vascular model and consists of several steps including data preprocessing, edge filtering, model selection, edge reconstruction and data refinement. To conduct a quantitative evaluation each image was manually segmented by clinical experts and performance metrics between the segmentation results obtained by the proposed method and the ground truth data were calculated. The experimental results show that the proposed CAD system is robust in accurately estimating the IMT in ultrasound carotid data. View full abstract»

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    Texture Enhanced Histogram Equalization Using TV- {\rm L}^{1} Image Decomposition

    Ghita, O. ; Ilea, D.E. ; Whelan, P.F.
    Image Processing, IEEE Transactions on

    Volume: 22 , Issue: 8
    Digital Object Identifier: 10.1109/TIP.2013.2259839
    Publication Year: 2013 , Page(s): 3133 - 3144

    IEEE Journals & Magazines

    Histogram transformation defines a class of image processing operations that are widely applied in the implementation of data normalization algorithms. In this paper, we present a new variational approach for image enhancement that is constructed to alleviate the intensity saturation effects that are introduced by standard contrast enhancement (CE) methods based on histogram equalization. In this paper, we initially apply total variation (TV) minimization with a L1 fidelity term to decompose the input image with respect to cartoon and texture components. Contrary to previous papers that rely solely on the information encompassed in the distribution of the intensity information, in this paper, the texture information is also employed to emphasize the contribution of the local textural features in the CE process. This is achieved by implementing a nonlinear histogram warping CE strategy that is able to maximize the information content in the transformed image. Our experimental study addresses the CE of a wide variety of image data and comparative evaluations are provided to illustrate that our method produces better results than conventional CE strategies. View full abstract»

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    Application of a Logarithmic Complementary Metal–Oxide–Semiconductor Camera in White-Light Interferometry

    Egan, P. ; Lakestani, Fereydoun ; Whelan, M.P. ; Connelly, M.J.
    Instrumentation and Measurement, IEEE Transactions on

    Volume: 57 , Issue: 1
    Digital Object Identifier: 10.1109/TIM.2007.907962
    Publication Year: 2008 , Page(s): 134 - 139

    IEEE Journals & Magazines

    This paper describes the characterization, modeling, and application of a direct-readout complementary metal-oxide-semiconductor (CMOS) camera in white-light interferometry (WLI). The camera that was used consisted of a direct-readout 1024times1024 pixel logarithmic CMOS sensor. A continuous analog voltage from each pixel was converted to an 8-bit value by an internal analog-to-digital converter and processed with a digital signal processor. A mathematical model relating the input light intensity to the 8-bit digitized output is developed, which is critical in applications where knowledge of the scene intensity is essential to estimating the maximum allowable frame rates. The camera was utilized in WLI, and its application is analyzed in terms of maximum output signal amplitude, imaging speed, and light intensity. The mathematical modeling is implemented with SPICE simulations and verified with experimental data. View full abstract»

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    Laser Doppler Vibrometry system using the synthetic-heterodyne interferometric demodulation scheme implemented on a CMOS DSP camera

    Connelly, M.J. ; Szecowka, P.M. ; Jallapuram, R. ; Martin, S. ; Toal, V. ; Whelan, M.P.
    Communication Systems, Networks and Digital Signal Processing, 2008. CNSDSP 2008. 6th International Symposium on

    Digital Object Identifier: 10.1109/CSNDSP.2008.4610788
    Publication Year: 2008 , Page(s): 133 - 136

    IEEE Conference Publications

    A laser Doppler vibrometer (LDV) is described which uses a CMOS digital camera, incorporating a digital signal processor, to carry out real-time signal processing of the interferometer output to allow multipoint LDV to be implemented. The synthetic-heterodyne technique is used to overcome the interferometric fading effect due to slow environmental changes. Vibration frequencies up to 100 Hz were detected successfully. View full abstract»

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    A novel method for power line interference suppression

    Keratiotis, G. ; Lind, L. ; Cook, J.W. ; Patel, M. ; Croft, D. ; Whelan, P. ; Hughes, P.
    Acoustics, Speech, and Signal Processing, 1999. Proceedings., 1999 IEEE International Conference on

    Volume: 3
    Digital Object Identifier: 10.1109/ICASSP.1999.756275
    Publication Year: 1999 , Page(s): 1529 - 1532 vol.3

    IEEE Conference Publications

    A novel method to suppress the power line interference induced into telephone lines that are in proximity to power conductors is proposed. A phase-locked loop is used to synchronize the interference signal with an anti-phase waveform, which is stored in a buffer. The anti-phase signal is injected on the line and the samples of the residual signal are used to update the anti-phase waveform. Computer simulations are used to compare the novel adaptive phase-locked buffer (APLB) approach with the traditional least mean squares (LMS) algorithm in an adaptive noise cancellation configuration. The new technique achieves 15 dB further suppression compared to LMS and since it can be implemented on a single digital signal processor (DSP) chip it proves to be a very efficient solution to the power line interference problem View full abstract»

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    An information model for a CAM database to support flexible manufacture of printed circuit boards

    Whelan, P.T.
    Electronics Manufacturing Technology Symposium, 1991., Eleventh IEEE/CHMT International

    Digital Object Identifier: 10.1109/IEMT.1991.279783
    Publication Year: 1991 , Page(s): 226 - 230

    IEEE Conference Publications

    The author presents key features from an information model for a CAM (computer-aided manufacturing) database that supports flexible manufacture of printed circuit boards and other selected components and products. This model incorporates information from several sources: shop orders, CAD (computer-aided design), bill of materials, and process setup. The essential activities of manufacturing can be subdivided into several information categories. These categories include products, processes, factory structure, factory operations, and factory inventory. The information model identifies the entities and data elements that are associated with each of these categories, as well as the relationships among the entities. Appropriate levels of abstraction enable this model to support a wide variety of products and processes. The resulting relational database implementation is integrated with multiple manufacturing software applications to assist with the operation of a manufacturing facility View full abstract»

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    A novel method for periodic interference suppression on local telephone loops

    Keratiotis, G. ; Lind, L. ; Cook, J.W. ; Patel, M. ; Whelan, P. ; Croft, D. ; Hughes, P.
    Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on

    Volume: 47 , Issue: 7
    Digital Object Identifier: 10.1109/81.855467
    Publication Year: 2000 , Page(s): 1096 - 1100
    Cited by:  Papers (3)

    IEEE Journals & Magazines

    An efficient method for real-time periodic interference suppression on telephone lines is proposed. The periodicity of the interference Is exploited by an adaptive phase-locked buffer (APLB), which is used to create the antiphase noise replica. Computer simulations are used to compare the APLB approach with the traditional least mean squares (LMS) algorithm in an adaptive noise cancellation configuration. The new technique outperforms the LMS noise canceller and proves to be a very efficient solution to the power line interference problem View full abstract»

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    Computer Aided Detection of Polyps: A Medical Application of Image Processing & Analysis

    Whelan, P.F.
    Irish Signals and Systems Conference, 2006. IET

    Publication Year: 2006 , Page(s): 5 - 8

    IET Conference Publications

    This talk will outline how image processing and analysis (IPA) can be applied in the automated analysis of computed tomography (CT) colonography data sets for the detection of colorectal cancer using standard and low-dose radiation CT acquisition [CAD-CTC]. By focusing on this specific task we will illustrate a range of issues facing the application of digital IPA in the medical domain. The talk will place the work in context, outlining the key issues that must be addressed as well as discussing the systems engineering model adopted. We will also introduce some of the IPA techniques developed by our team in tackling this application. Finally we will present results indicating the success of our approach View full abstract»

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    Extraction of epi-cardium contours from unseen images using a shape database

    Lynch, M. ; Ghita, O. ; Whelan, P.F.
    Nuclear Science Symposium Conference Record, 2004 IEEE

    Volume: 6
    Digital Object Identifier: 10.1109/NSSMIC.2004.1466681
    Publication Year: 2004 , Page(s): 3685 - 3688 Vol. 6
    Cited by:  Papers (1)  |  Patents (2)

    IEEE Conference Publications

    Accurate segmentation of the myocardium in cardiac magnetic resonance images can be restricted by image noise and low discrimination between the epi-cardium boundary and other organs. Segmentation of the epi-cardium is important for the calculation of left ventricle mass. In this paper we propose a novel method of epi-cardium segmentation, which firstly segments the left ventricle cavity. The epi-cardium boundary is found using the edge information in the image, and where such information is lacking it enhances the shape with the best fitting scaled segment, taken from a database of expertly assisted hand segmented images. In the final stage the segments are connected using a natural closed spline. The method was evaluated using a leave-one-out strategy on 24 volumes and calculates the coefficient of determination as 0.93 and a root mean square of the point to curve error of 1.54 mm when compared to manually segmented images. View full abstract»

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    A knowledge base network for connector assembly specifications

    McClay, W.J. ; MacVicar-Whelan, P.J.
    Robotics and Automation, 1988. Proceedings., 1988 IEEE International Conference on

    Digital Object Identifier: 10.1109/ROBOT.1988.12295
    Publication Year: 1988 , Page(s): 1601 - 1605 vol.3

    IEEE Conference Publications

    A 10000-rule knowledge-based system composed of a network of knowledge bases (a clip-board system) that aids shop floor personnel doing electrical connector assembly to select the correct tools and materials for each connector is described. The system requirements, design and implementation are examined. The current production version of the system, which was tested and released for shop use in October 1986, has reduced process specification search time by a factor of 10 View full abstract»

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    Colon centreline calculation for CT colonography using optimised 3D opological thinning

    Sadleir, R.J.T. ; Whelan, P.F.
    3D Data Processing Visualization and Transmission, 2002. Proceedings. First International Symposium on

    Digital Object Identifier: 10.1109/TDPVT.2002.1024163
    Publication Year: 2002 , Page(s): 800 - 803
    Cited by:  Papers (1)  |  Patents (1)

    IEEE Conference Publications

    First Page of the Article
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    Note on Feature Selection for Polyp Detection in CT Colonography

    Chowdhury, T.A. ; Ghita, O. ; Whelan, P.F. ; Miranda, A.
    Pattern Recognition, 2006. ICPR 2006. 18th International Conference on

    Volume: 1
    Digital Object Identifier: 10.1109/ICPR.2006.870
    Publication Year: 2006 , Page(s): 1017 - 1021

    IEEE Conference Publications

    In this paper we describe a computer aided detection (CAD) algorithm for robust detection of polyps in computed tomography (CT) colonography. The devised algorithm identifies suspicious polyp candidate surfaces using the surface normal intersection, Hough transform, 3D histogram analysis, region growing and a convexity test. From these detected surfaces we extract statistical and morphological features in order to evaluate if the surface in question is a polyp or fold. In order to devise the optimal classification scheme the performance of two different classifiers are evaluated when the algorithm is applied to synthetic and real patient data. The experimental results indicate that the overall polyp detection performance shows sensitivity higher than 92% for polyps larger than 5mm with an average of 4.7 to 6.0 false positives per dataset View full abstract»

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    An active particle-based tracking framework for 2D and 3D time-lapse microscopy images

    Hossain, M.J. ; Whelan, P.F. ; Czirok, A. ; Ghita, O.
    Engineering in Medicine and Biology Society,EMBC, 2011 Annual International Conference of the IEEE

    Digital Object Identifier: 10.1109/IEMBS.2011.6091631
    Publication Year: 2011 , Page(s): 6613 - 6618

    IEEE Conference Publications

    The process required to track cellular structures is a key task in the study of cell migration. This allows the accurate estimation of motility indicators that help in the understanding of mechanisms behind various biological processes. This paper reports a particle-based fully automatic tracking framework that is able to quantify the motility of living cells in time-lapse images. Contrary to the standard tracking methods based on predefined motion models, in this paper we reformulate the tracking mechanism as a data driven optimization process to remove its reliance on a priory motion models. The proposed method has been evaluated using 2D and 3D deconvolved epifluorescent in-vivo image sequences that describe the development of the quail embryo. View full abstract»

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    A robust algorithm for detection and classification of traffic signs in video data

    Bui-Minh, T. ; Ghita, O. ; Whelan, P.F. ; Hoang, T.
    Control, Automation and Information Sciences (ICCAIS), 2012 International Conference on

    Digital Object Identifier: 10.1109/ICCAIS.2012.6466568
    Publication Year: 2012 , Page(s): 108 - 113

    IEEE Conference Publications

    The accurate identification and recognition of the traffic signs is a challenging problem as the developed systems have to address a large number of imaging problems such as motion artifacts, various weather conditions, shadows and partial occlusion, issues that are often encountered in video traffic sequences that are captured from a moving vehicle. These factors substantially degrade the performance of the existing traffic sign recognition (TSR) systems and in this paper we detail the implementation of a new strategy that entails three distinct computational stages. The first component addresses the robust identification of the candidate traffic signs in each frame of the video sequence. The second component discards the traffic sign candidates that do not comply with stringent shape constraints, and the last component implements the classification of the traffic signs using Support Vector Machines (SVMs). The main novel elements of our TSR algorithm are given by the approach that has been developed for traffic sign classification and by the experimental evaluation that was employed to identify the optimal image attributes that are able to maximize the traffic sign classification performance. The TSR algorithm has been validated using video sequences that include the most important categories of signs that are used to regulate the traffic on the Irish and UK roads, and it achieved 87.6% sign detection, 99.2% traffic sign classification accuracy and 86.7% overall traffic sign recognition. View full abstract»

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    System engineering issues in industrial inspection

    Whelan, P.F.
    Industrial Inspection (Digest No: 1997/041), IEE Colloquium on

    Digital Object Identifier: 10.1049/ic:19970258
    Publication Year: 1997 , Page(s): 1/1 - 1/6
    Cited by:  Papers (1)

    IET Conference Publications

    The design of industrial inspection systems, requires a broad spectrum of techniques and disciplines. These include electronic engineering (hardware and software design), engineering mathematics, physics (optics and lighting) and mechanical engineering (since industrial vision systems deal with a mainly mechanical world). However, many industrial vision systems continue to be designed from a purely software engineering perspective, without consideration for any of the other system disciplines. While it is acknowledged that the software engineering task in industrial inspection is a critical one, the other system elements are neglected at our peril. No single discipline should be emphasised at the expense of the others. Lately, a number of researchers have argued for the design of vision systems to be firmly placed back into a systems engineering framework. This arises from the belief that an inadequate amount of vision research deals with the genuine design and systems problems involved in the implementation of industrial vision systems. The aim of this paper is to discuss the current state of industrial inspection, as seen from a systems engineering perspective View full abstract»

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    A Fully Automatic CAD-CTC System Based on Curvature Analysis for Standard and Low-Dose CT Data

    Chowdhury, T.A. ; Whelan, P.F. ; Ghita, O.
    Biomedical Engineering, IEEE Transactions on

    Volume: 55 , Issue: 3
    Digital Object Identifier: 10.1109/TBME.2007.909506
    Publication Year: 2008 , Page(s): 888 - 901
    Cited by:  Papers (4)

    IEEE Journals & Magazines

    Computed tomography colonography (CTC) is a rapidly evolving noninvasive medical investigation that is viewed by radiologists as a potential screening technique for the detection of colorectal polyps. Due to the technical advances in CT system design, the volume of data required to be processed by radiologists has increased significantly, and as a consequence the manual analysis of this information has become an increasingly time consuming process whose results can be affected by inter- and intrauser variability. The aim of this paper is to detail the implementation of a fully integrated CAD-CTC system that is able to robustly identify the clinically significant polyps in the CT data. The CAD-CTC system described in this paper is a multistage implementation whose main system components are: 1) automatic colon segmentation; 2) candidate surface extraction; 3) feature extraction; and 4) classification. Our CAD-CTC system performs at 100% sensitivity for polyps larger than 10 mm, 92% sensitivity for polyps in the range 5 to 10 mm, and 57.14% sensitivity for polyps smaller than 5 mm with an average of 3.38 false positives per dataset. The developed system has been evaluated on synthetic and real patient CT data acquired with standard and low-dose radiation levels. View full abstract»

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    Integration of feature distributions for colour texture segmentation

    Nammalwar, P. ; Ghita, O. ; Whelan, P.F.
    Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on

    Volume: 1
    Digital Object Identifier: 10.1109/ICPR.2004.1334283
    Publication Year: 2004 , Page(s): 716 - 719 Vol.1
    Cited by:  Papers (2)

    IEEE Conference Publications

    This paper proposes a new framework for colour texture segmentation and determines the contribution of colour and texture. The distributions of colour and texture features provides the discrimination between different colour textured regions in an image. The proposed method was tested using different mosaic and natural images. From the results, it is evident that the incorporation of colour information enhanced the colour texture segmentation and the developed framework is effective. View full abstract»

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    Adaptive noise removal approach for restoration of digital images corrupted by multimodal noise

    Ghita, O. ; Ilea, D.E. ; Whelan, P.F.
    Image Processing, IET

    Volume: 6 , Issue: 8
    Digital Object Identifier: 10.1049/iet-ipr.2010.0587
    Publication Year: 2012 , Page(s): 1148 - 1160

    IET Journals & Magazines

    Data smoothing algorithms are commonly applied to reduce the level of noise and eliminate the weak textures contained in digital images. Anisotropic diffusion algorithms form a distinct category of noise removal approaches that implement the smoothing process locally in agreement with image features such as edges that are typically determined by applying diverse partial differential equation (PDE) models. While this approach is opportune since it allows the implementation of feature-preserving data smoothing strategies, the inclusion of the PDE models in the formulation of the data smoothing process compromises the performance of the anisotropic diffusion schemes when applied to data corrupted by non-Gaussian and multimodal image noise. In this study the authors first evaluate the positive aspects related to the inclusion of a multi-scale edge detector based on the generalisation of the Di Zenzo operator into the formulation of the anisotropic diffusion process. Then, a new approach that embeds vector median filtering into discrete implementation of the anisotropic diffusion is introduced to improve the performance of the noise removal algorithm when applied to multimodal noise suppression. To evaluate the performance of the proposed data smoothing strategy, a large number of experiments on various types of digital images corrupted by multimodal noise were conducted. View full abstract»

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    Adaptive Pre-Filtering Techniques for Colour Image Analysis

    Ilea, D.E. ; Whelan, P.F.
    Machine Vision and Image Processing Conference, 2007. IMVIP 2007. International

    Digital Object Identifier: 10.1109/IMVIP.2007.17
    Publication Year: 2007 , Page(s): 150 - 157
    Cited by:  Papers (2)

    IEEE Conference Publications

    One important step in the process of colour image segmentation is to reduce the errors caused by image noise and local colour inhomogeneities. This can be achieved by filtering the data with a smoothing operator that eliminates the noise and the weak textures. In this regard, the aim of this paper is to evaluate the performance of two image smoothing techniques designed for colour images, namely bilateral filtering for edge preserving smoothing and coupled forward and backward anisotropic diffusion scheme (FAB). Both techniques are non-linear and have the purpose of eliminating the image noise, reduce weak textures and artefacts and improve the coherence of colour information. A quantitative comparison between them will be evaluated and also the ability of such techniques to preserve the edge information will be investigated. View full abstract»

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    Efficient Generic Calibration Method for General Cameras with Single Centre of Projection

    Dunne, A.K. ; Mallon, J. ; Whelan, P.F.
    Computer Vision, 2007. ICCV 2007. IEEE 11th International Conference on

    Digital Object Identifier: 10.1109/ICCV.2007.4408990
    Publication Year: 2007 , Page(s): 1 - 8

    IEEE Conference Publications

    Generic camera calibration is a non-parametric calibration technique that is applicable to any type of vision sensor. However, the standard generic calibration method was developed with the goal of generality and it is therefore sub-optimal for the common case of cameras with a single centre of projection (e.g. pinhole, fisheye, hyperboloidal catadioptric). This paper proposes novel improvements to the standard generic calibration method for central cameras that reduce its complexity, and improve its accuracy and robustness. Improvements are achieved by taking advantage of the geometric constraints resulting from a single centre of projection. Input data for the algorithm is acquired using active grids, the performance of which is characterised. A new linear estimation stage to the generic algorithm is proposed incorporating classical pinhole calibration techniques, and it is shown to be significantly more accurate than the linear estimation stage of the standard method. A linear method for pose estimation is also proposed and evaluated against the existing polynomial method. Distortion correction and motion reconstruction experiments are conducted with real data for a hyperboloidal catadioptric sensor for both the standard and proposed methods. Results show the accuracy and robustness of the proposed method to be superior to those of the standard method. View full abstract»

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