The largest single feature on a mammogram is the skin-air interface, or breast contour. Extraction of the breast contour is useful for a number of reasons. Foremost it allows the search for abnormalities to be limited...
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ISBN:
(纸本)0769521274
The largest single feature on a mammogram is the skin-air interface, or breast contour. Extraction of the breast contour is useful for a number of reasons. Foremost it allows the search for abnormalities to be limited to the region of the breast without undue influence from the background of the mammogram. Segmentation of the breast-region from the background is made difficult by the tapering nature of the breast, such that the breast contour lies in between the soft-tissue and the non-breast region. This paper explores the application of snakes to the problem of automatically extracting the breast region in mammograms.
In this paper, we propose an iterative method of 3D location of 2D parallelogram or 3D parallelepiped shapes by monocular vision from a single image. The method we propose assumes that the camera is calibrated and tha...
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ISBN:
(纸本)0769521274
In this paper, we propose an iterative method of 3D location of 2D parallelogram or 3D parallelepiped shapes by monocular vision from a single image. The method we propose assumes that the camera is calibrated and that the size of the polygonal object is known. The 3D location is obtained in the following way. First we try to find the orientation of a geometric model of the object imaged such that they share the same vanishing points. This property known as "involution" in the 17(th) century insures that the model and the object have the same orientation. Moreover this property in invariant to translation. This greatly simplifies the location problem by allowing to decouple rotation and translation assessments. The method is illustrated and tested with real scene images.
Simulated based network design is a powerful technique in vision metrology systems (VMS) to automate camera placement process. Relatively expensive and time-consuming process of building 3D simulated CAD model is the ...
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ISBN:
(纸本)0769521274
Simulated based network design is a powerful technique in vision metrology systems (VMS) to automate camera placement process. Relatively expensive and time-consuming process of building 3D simulated CAD model is the main drawback of this technique which causes to do not be practically attended by users. In this paper, a new visibility prediction analysis using artificial neural network (ANN) is proposed. This flexible and reliable method can be installed in intelligent cameras to predict the visibility of weak points during imaging in order to suggest the best position and situation of next camera station. Our primary tests on a complex network demonstrated high capability of the proposed method.
The output signals of inertial sensors and a camera are used to realise a pen-like human-computer interface with six degrees of freedom. The pen-like interface works over planar structured surfaces. The pose estimatio...
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ISBN:
(纸本)0769521274
The output signals of inertial sensors and a camera are used to realise a pen-like human-computer interface with six degrees of freedom. The pen-like interface works over planar structured surfaces. The pose estimation with a monocular camera has a high uncertainty on the rotation if the surface is unknown and no pre-known markers are used. A hybrid pose estimation method is used to improve accuracy. From output signals of three orthogonally placed accelerometers the absolute 2D tilt of the pen-like interface with respect to the gravitational field is calculated. This 2D rotation information is used to improve the robustness of the pose estimation using a modified homography calculation. Utilising three-dimensional detection of the pen's pose several applications are possible, e.g. ergonomic human-computer interfaces in 6D, image mosaicing applications or devices for handwriting input.
Content-aware watermarks represent a new generation of digital watermarks where the contents of the image are taken into account at both embedding and detection times. In this paper, we present a performance analysis ...
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ISBN:
(纸本)0769521274
Content-aware watermarks represent a new generation of digital watermarks where the contents of the image are taken into account at both embedding and detection times. In this paper, we present a performance analysis of a content-aware watermarking algorithm in terms of its impact on the perceptual quality of watermarked images using three different metrics. We also discuss the additional complexity involved in content-aware processing. Finally, based on our simulation results, we propose methods for achieving a better trade-off between watermark robustness and perceptual quality.
The Selective Tuning Model is a proposal for modelling visual attention in primates and humans. This paper describes ongoing research to include attention to motion stimuli within the model. The effort is unique becau...
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ISBN:
(纸本)0769521274
The Selective Tuning Model is a proposal for modelling visual attention in primates and humans. This paper describes ongoing research to include attention to motion stimuli within the model. The effort is unique because it seems that no past model presents a motion hierarchy plus attention to motion. We propose a biologically realistic model of the primate visual motion system attempting to explain how a hierarchical feed-forward network consisting of layers representing cortical areas V 1, MT, Mst, and 7a detects and classifies different kinds of motion patterns. The stM model is then integrated into this hierarchy demonstrating that successfully attending to motion patterns results in localization (segmentation) and labeling of those patterns.
A stereo vision Linear Triangulation (LT) algorithm can be utilized in space robotics assembly operations. The LT algorithm recovers the relative orientation and translation (pose) of objects marked with high contrast...
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ISBN:
(纸本)0769521274
A stereo vision Linear Triangulation (LT) algorithm can be utilized in space robotics assembly operations. The LT algorithm recovers the relative orientation and translation (pose) of objects marked with high contrast targets using two or more pinhole charge-coupled device (CCD) cameras. The cameras view a set (including a disjoint set) of targets measured with respect to the same point in space. This study evaluates the theoretical accuracy of the LT algorithm, its benefits and performance. The introduction of a third camera into the vision system envelope is also examined and discussed. Experiments indicated that most accuracy in pose estimation is gained by the first 15-25 degrees of camera separation, and then the decrease in values of the covariance matrix elements stabilizes. We compare the numerical data for singe, two-camera and three-camera cases using extensive experiments on simulated images.
A vision based navigation system is presented for determining a mobile robot's position and orientation using panoramic imagery. An omni-directional image sensor mounted on the robot is useful in obtaining a 360de...
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ISBN:
(纸本)0769521274
A vision based navigation system is presented for determining a mobile robot's position and orientation using panoramic imagery. An omni-directional image sensor mounted on the robot is useful in obtaining a 360degrees field of view, permitting navigational markers from all sides to be viewed simultaneously. A robust marker-based system is presented using vertically positioned linear markers as landmarks. The markers consist of linearly encoded digital patterns, similar to a barcode but distinguishable with less pixels. A set of patterns are orthogonal from one another and are readily recognized with any continous section visible. With a vertically posed panoramic image sensor these vertically mounted linear markers appear along radial lines. The panoramic image is pre-processed according to edge directions to find candidate regions which are spatially sampled into digital symbols. This extracted binary sequence is examined to determine if it belongs in the marker pattern set. This system is shown to be robust even with the low resolution of a panoramic sensor with 800x800 active pixels. Experiments are shown with synthetic imagery and with three real prototype systems.
We propose a method of expression learning by imitating the process of a baby's learning process. A baby cannot know what an expression means but he/she can be affected by the action that people do to him or her, ...
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ISBN:
(纸本)0769521274
We propose a method of expression learning by imitating the process of a baby's learning process. A baby cannot know what an expression means but he/she can be affected by the action that people do to him or her, and then he/she remembers this facial expression. In our system, a robotstarts learning facial expression by recognizing human actions. Our system detects the face regions and extracts the facial features using four direction features: horizontal, vertical and diagonally in both directions. Previously we used skin-color information for face detection, but this is weak in some environments. So we detect facial regions using template matching this time. We experimented facial expressions recognition compared both methods of face detection. Consequently, the rate of recognition of expression rose in proportion to the amount of data used for learning in both methods.
In robot teleoperation, contacting mechanical devices and sensors have been commonly used to track operator hand and arm motion. While camera-based tracking has the benefit of being non-contacting, markerless camera-b...
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ISBN:
(纸本)0769521274
In robot teleoperation, contacting mechanical devices and sensors have been commonly used to track operator hand and arm motion. While camera-based tracking has the benefit of being non-contacting, markerless camera-based human tracking offers a further advantage of not requiring markers and thus avoiding marker occlusion. This paper presents an application of markerless image-based arm tracking to real-time teleoperation of a robot manipulator. The markerless tracking is carried out by processing images from two calibrated cameras in real-time, to estimate the Positions of the joint centres of the wrist and elbow in three dimensions (3D), and to compute the 3D positions of the index finger and thumb in order to estimate the hand orientation. These are used to determine the position and orientation of the end-effector of a robot-manipulator in real-time teleoperation. Markerless tracking for teleoperation was demonstrated for pick-and-place tasks.
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