Future development in areas such as digital television transmission using data compression techniques, television standards conversion or video noise reduction depends highly on the inclusion of accurate motion vector...
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Future development in areas such as digital television transmission using data compression techniques, television standards conversion or video noise reduction depends highly on the inclusion of accurate motion vector information in the process. The motion vector field resulting from estimation with a translation model are horizontal and vertical displacement vectors which describe how each pixel has moved between the current and the previous picture. techniques to generate the motion vector field include pel recursive gradient methods, phase correlation in the transform domain and block correlation techniques. The paper describes an implementation of an extended block correlation method which is robust, gives accurate motion vector estimates and also is suitable for compact implementation for high bandwidth signals.< >
Although remote sensing is generally associated with satellite imagery, it can also be applied to sea-floor imagery collected by acoustic surveying techniques. Sea-floor surveying is important in environmental and oce...
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Although remote sensing is generally associated with satellite imagery, it can also be applied to sea-floor imagery collected by acoustic surveying techniques. Sea-floor surveying is important in environmental and oceanographic research, and for mineral prospecting and marine civil engineering projects. The main instrument for sea-floor mapping is the side-scan sonar. This generates an image of the sea-floor by recording the backscattered energy at shallow grazing angles from a short acoustic pulse, which is transmitted along a fan shaped beam, narrow in azimuth but wide in elevation. Typical carrier frequencies are in the region of 100 kHz and chirp sources are becoming available. Seismic profiling is used to obtain information of the sub-bottom by transmitting an acoustic pulse into the seabed and recording the reflected signals. The seismic sensor looks directly downwards at the sea-floor and operates at much lower frequencies, typically 1-3 kHz. This paper is confined to the classical remote sensing problems of delineating boundaries between different regions of the images and classifying the domains within these boundaries.< >
The York Probabilistic Automata Machine is a video rate 256 cube Automata Array. The system has been developed primarily in ASIC based components, with the bulk of processing performed through a set of overlapped pipe...
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The York Probabilistic Automata Machine is a video rate 256 cube Automata Array. The system has been developed primarily in ASIC based components, with the bulk of processing performed through a set of overlapped pipelines. Physical connectivity is limited to 128 nodes (in three dimensions), although higher 'virtual connectivities' are possible. Individual operations permitted at cellular level include binary and 'fuzzy' logic, plus simple weighted arithmetic. To complement the processor configuration, high bandwidth I/O and display units are currently under development, allowing arbitrary mappings of data I/O onto three dimensional surfaces within the unit. This paper introduces the York PAM and develops the application of virtual connectivity in automata like systems for massively parallel computation. The design and implementation of the individual processing element are presented, and the design of the three dimensional video re-sequencer discussed. Finally the use of probabilistic automata for the presentation of high level image data and facial recognition through neural techniques are presented.< >
In the weaving industry a variety of meshes are manufactured, using both metallic and nonmetallic materials, for a wide variety of filtration applications. At present the quality of the mesh is monitored at several st...
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In the weaving industry a variety of meshes are manufactured, using both metallic and nonmetallic materials, for a wide variety of filtration applications. At present the quality of the mesh is monitored at several stages of the manufacturing process to keep selected parameters within specified limits. This involves stopping the process approximately every half hour, manually assessing the mesh quality, and taking remedial action as necessary. There is a need to replace these manual checks with an automatic system that can continually monitor the mesh as it is being manufactured and, with appropriate actuators, control the loom on-line. The authors present initial results of research being conducted at Sheffield University to develop such a system for wire mesh. Early experiments proved that a contact measurement technique is inappropriate due to the severe vibrations and backlash nonlinearities present in most looms. The approach adopted here therefore, is to use imageprocessingtechniques. The instrument is transputer based so that the imageprocessing can be performed on several processors to achieve the real-time performance necessary for on-line monitoring and control purposes.< >
The past twenty years have seen a number of rapid advances in medical imaging technology. Many of the imaging systems produce volume data either as serial slices or as data points gathered from within a global 3D spac...
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The past twenty years have seen a number of rapid advances in medical imaging technology. Many of the imaging systems produce volume data either as serial slices or as data points gathered from within a global 3D space. Whilst the imaging technology may have evolved rapidly, the ability to extract objective and quantitative information from the data has advanced much less. One clearly defined need is an effective way of representing 3D volumes and efficiently interacting with the images thereby generated. A general approach to the display of 3D data involves the identification of external of internal surfaces and structures, followed by a visualisation model. One can either segment the data to provide a surface for display or use some parameter of the data itself, such as opacity, to visualise structure. The two common techniques are surface modelling and voxel methods. The authors review the techniques in use and identify some of the current clinical applications.< >
Border following techniques have a wide variety of applications. Existing methods can satisfactorily find and trace outermost borders. However, it will be shown that interior holes are often incorrectly traced or foll...
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Border following techniques have a wide variety of applications. Existing methods can satisfactorily find and trace outermost borders. However, it will be shown that interior holes are often incorrectly traced or follow sub-optimal paths. This paper will examine the reasons for this, and put forward a new method that overcomes these deficiencies. The paper will examine only the case of binary 2D raster images.
Describes the parallel implementation of an interactive imageprocessing system based on a ternary tree configuration of transputers. The tree can be extended to utilise available processors. Approximately 100 image p...
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Describes the parallel implementation of an interactive imageprocessing system based on a ternary tree configuration of transputers. The tree can be extended to utilise available processors. Approximately 100 imageprocessing algorithms have been implemented, involving low level transformations, feature extraction, and preliminary scene interpretation. Dynamic load balancing techniques have been utilised extensively in order to distribute the workload and data around the processors for these operations.< >
Describes the development of a system to analyse X-ray images of artificial heart valves and to detect whether the valve is malfunctioning. The imageprocessingtechniques used in the system are straight forward but t...
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Describes the development of a system to analyse X-ray images of artificial heart valves and to detect whether the valve is malfunctioning. The imageprocessingtechniques used in the system are straight forward but the potential benefits are great. The method currently employed to detect functional abnormalities of the valve is to x-ray it in operation and record the results on cine film. This can be replayed frame by frame to show the point when the valve is fully open or fully closed. A visual assessment is made to determine whether the valve is being obstructed from fully opening or closing by a clot; or indeed if the angle of opening is too great in the case of mechanical fatigue. The aim of the new system is to calculate accurately the angle of the disk to the valve ring when fully open and hence to ascertain if there is a problem.< >
The authors discuss the design of prototype imaging systems based on both linear and phased array concepts. Further work will lead to a new real time skin imaging system using digital signal processingtechniques.
The authors discuss the design of prototype imaging systems based on both linear and phased array concepts. Further work will lead to a new real time skin imaging system using digital signal processingtechniques.< >
Describes a pyramidal architecture for Knowledge-Based sonar image interpretation. The architecture will finally use the Inmos T800 Transputer as its basic processing agent. A Knowledge-Based System (KBS), is one appr...
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Describes a pyramidal architecture for Knowledge-Based sonar image interpretation. The architecture will finally use the Inmos T800 Transputer as its basic processing agent. A Knowledge-Based System (KBS), is one approach which attempts to encode the knowledge and expertise required to reason in a specific problem domain. This knowledge is coded as a series of rules and facts and forms the Knowledge-Base of the system. However, KBS systems are often computationally intensive and to date, real-time response characteristics have not been apparent. By utilising a pyramidal architecture which pulls on techniques developed in the parallel processing community, a system is being designed and implemented which will provide this real-time performance.< >
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