An automatic assessment scheme for steel quality inspection

This paper presents an automatic system for steel quality assessment, by measuring textural properties of carbide distributions. In current steel inspection, specially etched and polished steel specimen surfaces are classified manually under a light microscope, by comparisons with a standard chart. This procedure is basically two-dimensional, reflecting the size of the carbide agglomerations and their directional distribution. To capture these textural properties in terms of image fea tures, we first apply a rich set of image-processing operations, including mathematical morphology, multi-channel Gabor filtering, and the computation of texture measures with automatic scale selection in linear scale-space. Then, a feature selector is applied to a 40-dimensional feature space, and a classification scheme is defined, which on a sample set of more than 400 images has classification performance values comparable to those of human metallographers. Finally, a fully automatic inspection system is designed, which actively selects the most salient carbide structure on the specimen surface for subsequent classification. The feasibility of the overall approach for future use in the production process is demonstrated by a prototype system. It is also shown how the presented classification scheme allows for the definition of a new reference chart in terms of quantitative measures. Received: 16 February 1999 / Accepted: 29 March 2000     

Pipelined parallelisation of automatic face inspection

A parallel pipeline is shown to be a natural method of speeding up a typical computer vision application, face inspection using `eigenfaces'. Faces within a stream of video images are continuously surveyed in a manner akin to a `conveyor belt' inspection process. The parallelisation is a new exemplar of a scheme for the rapid prototyping of large-scale, multi-algorithm applications suitable for transfer to a message-passing multicomputer. A general solution, pipelined processor farms, is preferred to a customised solution. This paper gives details of the software tools and software engineering methods employed to tackle this class of problem.     

Machine vision system for curved surface inspection

This application-oriented paper discusses a non-contact 3D range data measurement system to improve the performance of the existing 2D herring roe grading system. The existing system uses a single CCD camera with unstructured halogen lighting to acquire and analyze the shape of the 2D shape of the herring roe for size and deformity grading. Our system will act as an additional system module, which can be integrated into the existing 2D grading system, providing the additional third dimension to detect deformities in the herring roe, which were not detected in the 2D analysis. Furthermore, the additional surface depth data will increase the accuracy of the weight information used in the existing grading system. In the proposed system, multiple laser light stripes are projected into the herring roe and the single B/W CCD camera records the image of the scene. The distortion in the projected line pattern is due to the surface curvature and orientation. Utilizing the linear relation between the projected line distortion and surface depth, the range data was recovered from a single camera image. The measurement technique is described and the depth information is obtained through four steps: (1) image capture, (2) stripe extraction, (3) stripe coding, (4) triangulation, and system calibration. Then, this depth information can be converted into the curvature and orientation of the shape for deformity inspection, and also used for the weight estimation. Preliminary results are included to show the feasibility and performance of our measurement technique. The accuracy and reliability of the computerized herring roe grading system can be greatly improved by integrating this system into existing system in the future.     

Active shape from stereo for highway inspection

Abstract. This paper describes an unsupervised algorithm for estimating the 3D profile of potholes in the highway surface, using structured illumination. Structured light is used to accelerate computation and to simplify the estimation of range. A low-resolution edge map is generated so that further processing may be focused on relevant regions of interest. Edge points in each region of interest are used to initialise open, active contour models, which are propagated and refined, via a pyramid, to a higher resolution. At each resolution, internal and external constraints are applied to a snake; the internal constraint is a smoothness function and the external one is a maximum-likelihood estimate of the grey-level response at the edge of each light stripe. Results of a provisional evaluation study indicate that this automated procedure provides estimates of pothole dimension suitable for use in a first, screening, assessment of highway condition. Received: 9 October 1998 / Accepted: 22 February 2000     

A golden-template self-generating method for patterned wafer inspection

This paper presents a novel golden-template self-generating technique for detecting possible defects in periodic two-dimensional wafer images. A golden template of the patterned wafer image under inspection can be obtained from the wafer image itself and no other prior knowledge is needed. It is a bridge between the existing self-reference methods and image-to-image reference methods. Spectral estimation is used in the first step to derive the periods of repeating patterns in both di r ections. Then a building block representing the structure of the patterns is extracted using interpolation to obtain sub-pixel resolution. After that, a new defect-free golden template is built based on the extracted building block. Finally, a pixel-to-pixel comparison is all we need to find possible defects. A comparison between the results of the proposed method and those of the previously published methods is presented. Received: 19 May 1999 / Accepted: 20 May 2000     

A case study towards validation of global illumination algorithms: progressive hierarchical radiosity with clustering

In this paper, we present an efficient global illumination technique, and then we discuss the results of its extensive experimental validation. The technique is a hybrid of cluster-based hierarchical and progressive radiosity techniques, which does not require storing links between interacting surfaces and clusters. We tested our technique by applying a multistage validation procedure, which we designed specifically for global illumination solutions. First, we experimentally validate the algorithm against analytically derived and measured real-world data to check how calculation speed is traded for lighting simulation accuracy for various clustering and meshing scenarios. Then we test the algorithm performance and rendering quality by directly comparing the virtual and real-world images of a complex environment.     

The end of zero-hit queries: query previews for NASA’s Global Change Master Directory

The Human-Computer Interaction Laboratory (HCIL) of the University of Maryland and NASA have collaborated over three years to refine and apply user interface research concepts developed at HCIL in order to improve the usability of NASA data services. The research focused on dynamic query user interfaces, visualization, and overview + preview designs. An operational prototype, using query previews, was implemented with NASA’s Global Change Master Directory (GCMD), a directory service for earth science datasets. Users can see the histogram of the data distribution over several attributes and choose among attribute values. A result bar shows the cardinality of the result set, thereby preventing users from submitting queries that would have zero hits. Our experience confirmed the importance of metadata accuracy and completeness. The query preview interfaces make visible the problems or gaps in the metadata that are undetectable with classic form fill-in interfaces. This could be seen as a problem, but we think that it will have a long-term beneficial effect on the quality of the metadata as data providers will be compelled to produce more complete and accurate metadata. The adaptation of the research prototype to the NASA data required revised data structures and algorithms. Received: 12 December 1997 / Revised: June 1999     

Genetic algorithms for clustering in machine vision

The paper presents a genetic algorithm for clustering objects in images based on their visual features. In particular, a novel solution code (named Boolean Matching Code) and a correspondent reproduction operator (the Single Gene Crossover) are defined specifically for clustering and are compared with other standard genetic approaches. The paper describes the clustering algorithm in detail, in order to show the suitability of the genetic paradigm and underline the importance of effective tuning of algorithm parameters to the application. The algorithm is evaluated on some test sets and an example of its application in automated visual inspection is presented. Received: 6 August 1996 / Accepted: 11 November 1997     

User interaction in digital libraries: coping with diversity through adaptation

User interface adaptations can be used to address several user interaction challenges in the development of digital library systems. This paper: (a) examines some of the intrinsic characteristics of digital library systems; (b) identifies some of the key Human–Computer Interaction (HCI) challenges in relation to design and architectural abstraction for user interfaces to digital library systems; and (c) develops an argumentation for adaptations in digital library systems. By drawing parallels to recent HCI research into adaptable and adaptive user interaction, the paper illustrates potential areas in which user interface adaptation can provide a useful technique for advancing the quality of human interaction with a digital library system. Received: 18 December 1998 / Revised: 31 May 1999     

The ALIVE system: wireless, full-body interaction with autonomous agents

The cumbersome nature of wired interfaces often limits the range of application of virtual environments. In this paper, we discuss the design and implementation of a novel system, called ALIVE, which allows unencumbered full-body interaction between a human participant and a rich graphical world inhabited by autonomous agents. Based on results obtained with thousands of users, the paper argues that this kind of system can provide more complex and very different experiences than traditional virtual reality systems. The ALIVE system significantly broadens the range of potential applications of virtual reality systems; in particular, the paper discusses novel applications in the area of training and teaching, entertainment, and digital assistants or interface agents. We give an overview of the methods used in the implementation of the existing ALIVE systems.     

An interactive tool for recognizing structured figures with variable shapes

In electric power supply, railway, and other companies with many facilities, facility management is a laborious task. To realize a computerized facility management system, numerous paper-based facility maps should be stored in a database. In this paper, we present a system that constructs a facility management database by interpretation of paper-based facility maps. This system can automatically recognize structured figures with variable shapes on maps, while conventional methods cannot recognize these figures. And this system can easily generate relational data between facilities and character strings on maps. We compare our recognition method of structured figures with variable shapes with a conventional recognition method, and show the effectiveness of our system. Received: 18 November 1996 / Accepted: 16 February 1998     

Experiments with adaptation strategies for a prototype-based recognition system for isolated handwritten characters

This paper describes an adaptive recognition system for isolated handwritten characters and the experiments carried out with it. The characters used in our experiments are alphanumeric characters, including both the upper- and lower-case versions of the Latin alphabets and three Scandinavian diacriticals. The writers are allowed to use their own natural style of writing. The recognition system is based on the k-nearest neighbor rule. The six character similarity measures applied by the system are all based on dynamic time warping. The aim of the first experiments is to choose the best combination of the simple preprocessing and normalization operations and the dissimilarity measure for a multi-writer system. However, the main focus of the work is on online adaptation. The purpose of the adaptations is to turn a writer-independent system into writer-dependent and increase recognition performance. The adaptation is carried out by modifying the prototype set of the classifier according to its recognition performance and the user's writing style. The ways of adaptation include: (1) adding new prototypes; (2) inactivating confusing prototypes; and (3) reshaping existing prototypes. The reshaping algorithm is based on the Learning Vector Quantization. Four different adaptation strategies, according to which the modifications of the prototype set are performed, have been studied both offline and online. Adaptation is carried out in a self-supervised fashion during normal use and thus remains unnoticed by the user. Received June 30, 1999 / Revised September 29, 2000     

Strategy-based interactive cluster visualization for information retrieval

In this paper we investigate a general purpose interactive information organization system. The system organizes documents by placing them into 1-, 2-, or 3-dimensional space based on their similarity and a spring-embedding algorithm. We begin by developing a method for estimating the quality of the organization when it is applied to a set of documents returned in response to a query. We show how the relevant documents tend to clump together in space. We proceed by presenting a method for measuring the amount of structure in the organization and explain how this knowledge can be used to refine the system. We also show that increasing the dimensionality of the organization generally improves its quality, albeit only a small amount. We introduce two methods for modifying the organization based on information obtained from the user and show how such feedback improves the organization. All the analysis is done offline without direct user intervention. Received: 21 December 1998 / Revised: 30 May 1999     

Building a color classification system for textured and hue homogeneous surfaces: system calibration and algorithm

We present a system for classifying the color aspect of textured surfaces having a nearly constant hue (such as wooden boards, textiles, wallpaper, etc.). The system is designed to compensate for small fluctuations (over time) of the light source and for inhomogeneous illumination conditions (shading correction). This is an important feature because even in industrial environments where the lighting conditions are controlled, a constant and homogeneous illumination cannot be guaranteed. Together with an appropriate camera calibration (which includes a periodic update), our approach offers a robust system which is able to “distinguish” (i.e., classify correctly) between surface classes which exhibit visually barely perceptible color variations. In particular, our approach is based on relative (not absolute) color measurements. In this paper, we outline the classification algorithm while focusing in detail on the camera calibration and a method for compensating for fluctuations of the light source. Received: 1 September 1998 / Accepted: 16 March 2000     

Drag-and-drop multimedia: ¶an interface framework for digital libraries

In this paper, we describe a new interface for querying multimedia digital libraries and an interface building framework. The interface employs a drag-and-drop style of interaction and combines a structured natural-language style query specification with reusable multimedia objects. We call this interface DanDMM, short for “drag-and-drop multimedia”. DanDMM interfaces capture the syntax of the underlying query language, and dynamically reconfigure to reflect the contents of the data repository. A distinguishing feature of DanDMM is its ability to synthesize integrated interfaces that incorporate both example-based specification using multimedia objects, and traditional techniques including keyword, attribute, and free text-based search. We describe the DanDMM-builder, a framework for synthesizing DanDMM interfaces, and give several examples of interfaces that have been constructed using DanDMM-builder, including a remote-sensing library application and a video digital library. Received: 15 December 1997 / Revised: June 1999     

A graphical user interface for Boolean query specification

Online information repositories commonly provide keyword search facilities through textual query languages based on Boolean logic. However, there is evidence to suggest that the syntactic demands of such languages can lead to user errors and adversely affect the time that it takes users to form queries. Users also face difficulties because of the conflict in semantics between AND and OR when used in Boolean logic and English language. Analysis of usage logs for the New Zealand Digital Library (NZDL) show that few Boolean queries contain more than three terms, use of the intersection operator dominates and that query refinement is common. We suggest that graphical query languages, in particular Venn-like diagrams, can alleviate the problems that users experience when forming Boolean expressions with textual languages. A study of the utility of Venn diagrams for query specification indicates that with little or no training users can interpret and form Venn-like diagrams in a consistent manner which accurately correspond to Boolean expressions. We describe VQuery, a Venn-diagram based user interface to the New Zealand Digital Library (NZDL). In a study which compared VQuery with a standard textual Boolean interface, users took significantly longer to form queries and produced more erroneous queries when using VQuery. We discuss the implications of these results and suggest directions for future work. Received: 15 December 1997 / Revised: June 1999     

Designing Leisure Applications for the Mundane Car-Commute

Commuting by car from home to work can be very time consuming. We have conducted a study to explore what people are doing, and want to do, while commuting. People use their time in the car on a wide variety of activities with great innovation. There was no unanimous activity that everyone wanted, rather a wide variety of activities were requested. Three different categories of activity were identified which we refer to as mundane, vocational and traffic related. To demonstrate a possible IT service supporting commuters, a prototype based on speech output and a simple input mechanism from a wheel was developed. This service moves sampling of music from the conventional shop into the car. The prototype was informally tested with users, which resulted in a number of improvements. Preliminary user results indicate good functionality, a comprehensive interaction interface.     

Making Space for Voice: Technologies to Support Children’s Fantasy and Storytelling

Fantasy play and storytelling serve an important role in young children’s development. While computers are increasingly present in the world of young children, there is a lack of computational tools to support children’s voices in everyday storytelling, particularly in the context of fantasy play. We believe that there is a need for computational systems that engage in story-listening rather than story-telling. This paper introduces StoryMat, a system that supports and listens to children’s voices in their own storytelling play. StoryMat offers a child-driven, story-listening space by recording and recalling children’s narrating voices, and the movements they make with their stuffed animals on a colourful story-evoking quilt. Empirical research with children shows that StoryMat fosters developmentally advanced forms of storytelling of the kind that has been shown to provide a bridge to written literacy, and provides a space where children engage in fantasy storytelling collaboratively with or without a playmate. The paper addresses the importance of supporting young children’s fantasy play and suggests a new way for technology to play an integral part in that activity.