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...
详细信息
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, ...
详细信息
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...
详细信息
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.
In this paper a multiscale wavelet-based algorithm for matching stand-alone shapes is developed. The algorithm uses the Dyadic Wavelet Transform (DWT) to decompose a shape's boundary into multi-scale levels. Featu...
详细信息
ISBN:
(纸本)0769521274
In this paper a multiscale wavelet-based algorithm for matching stand-alone shapes is developed. The algorithm uses the Dyadic Wavelet Transform (DWT) to decompose a shape's boundary into multi-scale levels. Features are extracted by calculating the curve moment invariants of the approximation coefficients. If the measured dissimilarity is small, then the shapes are globally similar Local similarily is investigated by calculating the normalized cross correlation of the 1-D triangle area representation of the detail coefficients. The presented algorithm not only finds similar shapes, but it also can easily distinguish between seemingly similar shapes. The algorithm is invariant to the affine transformation and to the starting point variation of the shape contour.
One of the problems in image processing is finding an appropriate threshold in order to convert an image to a binary one. In this paper we introduce a new method for image thresholding. We use reinforcement learning a...
详细信息
ISBN:
(纸本)0769521274
One of the problems in image processing is finding an appropriate threshold in order to convert an image to a binary one. In this paper we introduce a new method for image thresholding. We use reinforcement learning as an effective way to find the optimal threshold. Q (A) is implemented as a learning algorithm to achieve more accurate results. The reinforcement agent uses objective rewards to explore/exploit the solution space. It means that there is not any experienced operator involved and the reward and punishment function must be defined for the agent. The results show that this method works successfully and can be trained for any particular application.
Many image watermarking schemes against geometric attacks have been proposed. Rotation, scaling, translation (Rst) invariant image watermarking based on log-polar mapping (LPM) and Radon transform is one of them. In t...
详细信息
ISBN:
(纸本)0769521274
Many image watermarking schemes against geometric attacks have been proposed. Rotation, scaling, translation (Rst) invariant image watermarking based on log-polar mapping (LPM) and Radon transform is one of them. In this paper, we analyze the embedding and detection process of the above-mentioned method. We focus on how to select the watermark data, how to embed the watermark into the original image, and how to implement approximative inverse log-polar mapping (ILPM) during the embedding process. We analyze watermark detection when a watermarked image is scaled or rotated, and propose to use the rotation rectification to battle rotation. Three detection methods are compared.
One of the most important steps in digital mammography is an adequate segmentation of possible abnormalities. This obviously minimizes errors in further stages such as in classification. However, several factors affec...
详细信息
ISBN:
(纸本)0769521274
One of the most important steps in digital mammography is an adequate segmentation of possible abnormalities. This obviously minimizes errors in further stages such as in classification. However, several factors affect the proper segmentation of mammograms. Mammograms contain low signal to noise ratio (low contrast) and a complicated structured background. In this article we are describing a generic approach for detecting patterns of architectural distortions in mammograms that is both complete and uncommitted to any type of training. Our detection algorithm dynamically updates the pixels intensities by following their neighboring transition zone. Such approach proved to be effective for detecting the edges of all types of breast abnormalities including the stellate.
We present a system that detects people in indoor scenes by modeling the motion history of foreground blobs, rather than their shape or appearance. The system tracks all foreground blobs over time with a multi-hypothe...
详细信息
ISBN:
(纸本)0769521274
We present a system that detects people in indoor scenes by modeling the motion history of foreground blobs, rather than their shape or appearance. The system tracks all foreground blobs over time with a multi-hypothesis tracker, and considers a blob to be a person if it exhibited sufficient autonomous movement in the course of its tracking history. This way, people can be correctly classified even if they are seen in a wide range of body poses, if they remain still for a long time, or if they change appearance by taking off a coat. Evaluation on over 1h of video demonstrated good performance for both heuristic and decision tree based classification.
Range image segmentation has many applications in computervision areas such as computer graphics and robotic vision. A generic methodology for 3D point set analysis in which planar structures play an important role i...
详细信息
ISBN:
(纸本)0769521274
Range image segmentation has many applications in computervision areas such as computer graphics and robotic vision. A generic methodology for 3D point set analysis in which planar structures play an important role is defined. It consists mainly of a specific K-means algorithm which is able to process different shapes in cluster. At the same time, within geometric and topologic considerations, a set of application-driven heuristics is designed. This helps to find out the right number of structures in point sets in order to give a good visualization and representation of a large scale environment without a priori models. Our aim is to propose a simple and generic frame for 3D scene understanding. Tests were realised on different types of environment data: natural and man-made. This research project has been realized with EADS (French Air Space Society). Keywords: Fuzzy clustering, 3D reconstruction and scene analysis, range image segmentation, environment modeling, stereovision.
We report on the computation of 3D volumetric optical flow on gated MRI datasets. We extend the 2D least squares and regularization approaches of Lucas and Kanade and Horn and Schunck and show flow fields (as XY and X...
详细信息
ISBN:
(纸本)0769521274
We report on the computation of 3D volumetric optical flow on gated MRI datasets. We extend the 2D least squares and regularization approaches of Lucas and Kanade and Horn and Schunck and show flow fields (as XY and XZ 2D flows) for a beating heart. The flow not only can capture the expansion and contraction of various parts of the heart motion but also can capture the twisting motion of the heart.
暂无评论