26 research outputs found
Methods and Apparatus for Autonomous Robotic Control
Sensory processing of visual, auditory, and other sensor information (e.g., visual imagery, LIDAR, RADAR) is conventionally based on "stovepiped," or isolated processing, with little interactions between modules. Biological systems, on the other hand, fuse multi-sensory information to identify nearby objects of interest more quickly, more efficiently, and with higher signal-to-noise ratios. Similarly, examples of the OpenSense technology disclosed herein use neurally inspired processing to identify and locate objects in a robot's environment. This enables the robot to navigate its environment more quickly and with lower computational and power requirements
Proceedings of the Third International Workshop on Neural Networks and Fuzzy Logic, volume 2
Papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by the National Aeronautics and Space Administration and cosponsored by the University of Houston, Clear Lake, held 1-3 Jun. 1992 at the Lyndon B. Johnson Space Center in Houston, Texas are included. During the three days approximately 50 papers were presented. Technical topics addressed included adaptive systems; learning algorithms; network architectures; vision; robotics; neurobiological connections; speech recognition and synthesis; fuzzy set theory and application, control and dynamics processing; space applications; fuzzy logic and neural network computers; approximate reasoning; and multiobject decision making
Automatic human face detection in color images
Automatic human face detection in digital image has been an active area of research over the past decade. Among its numerous applications, face detection plays a key role in face recognition system for biometric personal identification, face tracking for intelligent human computer interface (HCI), and face segmentation for object-based video coding. Despite significant progress in the field in recent years, detecting human faces in unconstrained and complex images remains a challenging problem in computer vision. An automatic system that possesses a similar capability as the human vision system in detecting faces is still a far-reaching goal. This thesis focuses on the problem of detecting human laces in color images. Although many early face detection algorithms were designed to work on gray-scale Images, strong evidence exists to suggest face detection can be done more efficiently by taking into account color characteristics of the human face. In this thesis, we present a complete and systematic face detection algorithm that combines the strengths of both analytic and holistic approaches to face detection. The algorithm is developed to detect quasi-frontal faces in complex color Images. This face class, which represents typical detection scenarios in most practical applications of face detection, covers a wide range of face poses Including all in-plane rotations and some out-of-plane rotations. The algorithm is organized into a number of cascading stages including skin region segmentation, face candidate selection, and face verification. In each of these stages, various visual cues are utilized to narrow the search space for faces. In this thesis, we present a comprehensive analysis of skin detection using color pixel classification, and the effects of factors such as the color space, color classification algorithm on segmentation performance. We also propose a novel and efficient face candidate selection technique that is based on color-based eye region detection and a geometric face model. This candidate selection technique eliminates the computation-intensive step of window scanning often employed In holistic face detection, and simplifies the task of detecting rotated faces. Besides various heuristic techniques for face candidate verification, we developface/nonface classifiers based on the naive Bayesian model, and investigate three feature extraction schemes, namely intensity, projection on face subspace and edge-based. Techniques for improving face/nonface classification are also proposed, including bootstrapping, classifier combination and using contextual information. On a test set of face and nonface patterns, the combination of three Bayesian classifiers has a correct detection rate of 98.6% at a false positive rate of 10%. Extensive testing results have shown that the proposed face detector achieves good performance in terms of both detection rate and alignment between the detected faces and the true faces. On a test set of 200 images containing 231 faces taken from the ECU face detection database, the proposed face detector has a correct detection rate of 90.04% and makes 10 false detections. We have found that the proposed face detector is more robust In detecting in-plane rotated laces, compared to existing face detectors. +D2
Automatic caption generation for content-based image information retrieval.
Ma, Ka Ho.Thesis (M.Phil.)--Chinese University of Hong Kong, 1999.Includes bibliographical references (leaves 82-87).Abstract and appendix in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Objective of This Research --- p.4Chapter 1.2 --- Organization of This Thesis --- p.5Chapter 2 --- Background --- p.6Chapter 2.1 --- Textual - Image Query Approach --- p.7Chapter 2.1.1 --- Yahoo! Image Surfer --- p.7Chapter 2.1.2 --- QBIC (Query By Image Content) --- p.8Chapter 2.2 --- Feature-based Approach --- p.9Chapter 2.2.1 --- Texture Thesaurus for Aerial Photos --- p.9Chapter 2.3 --- Caption-aided Approach --- p.10Chapter 2.3.1 --- PICTION (Picture and capTION) --- p.10Chapter 2.3.2 --- MARIE --- p.11Chapter 2.4 --- Summary --- p.11Chapter 3 --- Caption Generation --- p.13Chapter 3.1 --- System Architecture --- p.13Chapter 3.2 --- Domain Pool --- p.15Chapter 3.3 --- Image Feature Extraction --- p.16Chapter 3.3.1 --- Preprocessing --- p.16Chapter 3.3.2 --- Image Segmentation --- p.17Chapter 3.4 --- Classification --- p.24Chapter 3.4.1 --- Self-Organizing Map (SOM) --- p.26Chapter 3.4.2 --- Learning Vector Quantization (LVQ) --- p.28Chapter 3.4.3 --- Output of the Classification --- p.30Chapter 3.5 --- Caption Generation --- p.30Chapter 3.5.1 --- Phase One: Logical Form Generation --- p.31Chapter 3.5.2 --- Phase Two: Simplification --- p.32Chapter 3.5.3 --- Phase Three: Captioning --- p.33Chapter 3.6 --- Summary --- p.35Chapter 4 --- Query Examples --- p.37Chapter 4.1 --- Query Types --- p.37Chapter 4.1.1 --- Non-content-based Retrieval --- p.38Chapter 4.1.2 --- Content-based Retrieval --- p.38Chapter 4.2 --- Hierarchy Graph --- p.41Chapter 4.3 --- Matching --- p.42Chapter 4.4 --- Summary --- p.48Chapter 5 --- Evaluation --- p.49Chapter 5.1 --- Experimental Set-up --- p.50Chapter 5.2 --- Experimental Results --- p.51Chapter 5.2.1 --- Segmentation --- p.51Chapter 5.2.2 --- Classification --- p.53Chapter 5.2.3 --- Captioning --- p.55Chapter 5.2.4 --- Overall Performance --- p.56Chapter 5.3 --- Observations --- p.57Chapter 5.4 --- Summary --- p.58Chapter 6 --- Another Application --- p.59Chapter 6.1 --- Police Force Crimes Investigation --- p.59Chapter 6.1.1 --- Image Feature Extraction --- p.61Chapter 6.1.2 --- Caption Generation --- p.64Chapter 6.1.3 --- Query --- p.66Chapter 6.2 --- An Illustrative Example --- p.68Chapter 6.3 --- Summary --- p.72Chapter 7 --- Conclusions --- p.74Chapter 7.1 --- Contribution --- p.77Chapter 7.2 --- Future Work --- p.78Bibliography --- p.81Appendices --- p.88Chapter A --- Segmentation Result Under Different Parametes --- p.89Chapter B --- Segmentation Time of 10 Randomly Selected Images --- p.90Chapter C --- Sample Captions --- p.9
Intelligent sensing for robot mapping and simultaneous human localization and activity recognition
Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Science of Bilkent University, 2011.Thesis (Ph. D.) -- Bilkent University, 2011.Includes bibliographical references leaves 147-163.We consider three different problems in two different sensing domains, namely
ultrasonic sensing and inertial sensing. Since the applications considered in each
domain are inherently different, this thesis is composed of two main parts. The
approach common to the two parts is that raw data acquired from simple sensors
is processed intelligently to extract useful information about the environment.
In the first part, we employ active snake contours and Kohonen’s selforganizing
feature maps (SOMs) for representing and evaluating discrete point
maps of indoor environments efficiently and compactly. We develop a generic
error criterion for comparing two different sets of points based on the Euclidean
distance measure. The point sets can be chosen as (i) two different sets of map
points acquired with different mapping techniques or different sensing modalities,
(ii) two sets of fitted curve points to maps extracted by different mapping techniques
or sensing modalities, or (iii) a set of extracted map points and a set of
fitted curve points. The error criterion makes it possible to compare the accuracy
of maps obtained with different techniques among themselves, as well as with an
absolute reference. We optimize the parameters of active snake contours and
SOMs using uniform sampling of the parameter space and particle swarm optimization.
A demonstrative example from ultrasonic mapping is given based on
experimental data and compared with a very accurate laser map, considered an
absolute reference. Both techniques can fill the erroneous gaps in discrete point
maps. Snake curve fitting results in more accurate maps than SOMs because it is
more robust to outliers. The two methods and the error criterion are sufficiently
general that they can also be applied to discrete point maps acquired with other
mapping techniques and other sensing modalities.
In the second part, we use body-worn inertial/magnetic sensor units for recognition
of daily and sports activities, as well as for human localization in GPSdenied
environments. Each sensor unit comprises a tri-axial gyroscope, a tri-axial
accelerometer, and a tri-axial magnetometer. The error characteristics of the sensors
are modeled using the Allan variance technique, and the parameters of lowand
high-frequency error components are estimated.
Then, we provide a comparative study on the different techniques of classifying
human activities that are performed using body-worn miniature inertial and
magnetic sensors. Human activities are classified using five sensor units worn
on the chest, the arms, and the legs. We compute a large number of features
extracted from the sensor data, and reduce these features using both Principal
Components Analysis (PCA) and sequential forward feature selection (SFFS).
We consider eight different pattern recognition techniques and provide a comparison
in terms of the correct classification rates, computational costs, and their
training and storage requirements. Results with sensors mounted on various locations
on the body are also provided. The results indicate that if the system
is trained by the data of an individual person, it is possible to obtain over 99%
correct classification rates with a simple quadratic classifier such as the Bayesian
decision method. However, if the training data of that person are not available
beforehand, one has to resort to more complex classifiers with an expected correct
classification rate of about 85%.
We also consider the human localization problem using body-worn inertial/
magnetic sensors. Inertial sensors are characterized by drift error caused
by the integration of their rate output to get position information. Because of
this drift, the position and orientation data obtained from inertial sensor signals
are reliable over only short periods of time. Therefore, position updates from externally
referenced sensors are essential. However, if the map of the environment
is known, the activity context of the user provides information about position. In
particular, the switches in the activity context correspond to discrete locations
on the map. By performing activity recognition simultaneously with localization,
one can detect the activity context switches and use the corresponding position
information as position updates in the localization filter. The localization filter
also involves a smoother, which combines the two estimates obtained by running
the zero-velocity update (ZUPT) algorithm both forward and backward in time.
We performed experiments with eight subjects in an indoor and an outdoor environment
involving “walking,” “turning,” and “standing” activities. Using the
error criterion in the first part of the thesis, we show that the position errors can
be decreased by about 85% on the average. We also present the results of a 3-D
experiment performed in a realistic indoor environment and demonstrate that it
is possible to achieve over 90% error reduction in position by performing activity
recognition simultaneously with localization.Altun, KeremPh.D
Recommended from our members
The application of artificial neural networks to interpret acoustic emissions from submerged arc welding
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Automated fusion welding processes play a fundamental role in modern manufacturing industries. The proliferation of joint geometries together with the large permutation of associated process variable configurations has given rise to research into complex system modelling and control strategies. Many of these techniques have involved monitoring of not only the electrical characteristics of the process but visual and acoustic information. Acoustic information derived from certain welding processes is well documented as it is an established fact that skilled manual welders utilise such information as an aid to creating an optimum weld. The experimental investigation presented in this thesis is dedicated to the feasibility of monitoring airborne acoustic emissions of Submerged Arc Welding (SAW) for diagnostic and real time control purposes. The experimental method adopted for this research takes a cybernetic approach to data processing and interpretation in an attempt to replicate the robustness of human biological functions. A custom designed audio hardware system was used to analyse signals obtained from bead on mild steel plate fusion welds. Time and frequency domains were used in an attempt to establish salient characteristics or identify the signatures associated with changes of the process variables. The featured parameters were voltage / current and weld travel speed, due to their ease of validation. However, consideration has also been given to weld defect prediction due to process instabilities. As the data proved to be highly correlated and erratic when subjected to off line statistical analysis, extensive investigation was given to the application of artificial neural networks to signal processing and real time control scenarios. As a consequence, a dedicated neural based software system was developed, utilising supervised and unsupervised neural techniques to monitor the process. The research was aimed at proving the feasibility of monitoring the electrical process parameters and stability of the welding process in real time. It was shown to be possible, by the exploitation of artificial neural networks, to generate a number of monitoring parameters indicative of the welding process state. The limitations of the present neural method and proposed developments are discussed, together with an overview of applied neural network technology and its impact on artificial intelligence and robotic control. Further developments are considered together with recommendations for future areas of research
IMAGE UNDERSTANDING OF MOLAR PREGNANCY BASED ON ANOMALIES DETECTION
Cancer occurs when normal cells grow and multiply without normal control. As the cells multiply, they form an area of abnormal cells, known as a tumour. Many tumours exhibit abnormal chromosomal segregation at cell division. These anomalies play an important role in detecting molar pregnancy cancer.
Molar pregnancy, also known as hydatidiform mole, can be categorised into partial (PHM) and complete (CHM) mole, persistent gestational trophoblastic and choriocarcinoma. Hydatidiform moles are most commonly found in women under the age of 17 or over the age of 35. Hydatidiform moles can be detected by morphological and histopathological examination. Even experienced pathologists cannot easily classify between complete and partial hydatidiform moles. However, the distinction between complete and partial hydatidiform moles is important in order to recommend the appropriate treatment method. Therefore, research into molar pregnancy image analysis and understanding is critical.
The hypothesis of this research project is that an anomaly detection approach to analyse molar pregnancy images can improve image analysis and classification of normal PHM and CHM villi. The primary aim of this research project is to develop a novel method, based on anomaly detection, to identify and classify anomalous villi in molar pregnancy stained images.
The novel method is developed to simulate expert pathologists’ approach in diagnosis of anomalous villi. The knowledge and heuristics elicited from two expert pathologists are combined with the morphological domain knowledge of molar pregnancy, to develop a heuristic multi-neural network architecture designed to classify the villi into their appropriated anomalous types.
This study confirmed that a single feature cannot give enough discriminative power for villi classification. Whereas expert pathologists consider the size and shape before textural features, this thesis demonstrated that the textural feature has a higher discriminative power than size and shape.
The first heuristic-based multi-neural network, which was based on 15 elicited features, achieved an improved average accuracy of 81.2%, compared to the traditional multi-layer perceptron (80.5%); however, the recall of CHM villi class was still low (64.3%). Two further textural features, which were elicited and added to the second heuristic-based multi-neural network, have improved the average accuracy from 81.2% to 86.1% and the recall of CHM villi class from 64.3% to 73.5%. The precision of the multi-neural network
II
has also increased from 82.7% to 89.5% for normal villi class, from 81.3% to 84.7% for PHM villi class and from 80.8% to 86% for CHM villi class.
To support pathologists to visualise the results of the segmentation, a software tool, Hydatidiform Mole Analysis Tool (HYMAT), was developed compiling the morphological and pathological data for each villus analysis