共查询到20条相似文献,搜索用时 31 毫秒
1.
CATALOG: a system for detection and rendering of internal log defects using computer tomography 总被引:1,自引:0,他引:1
Suchendra M. Bhandarkar Timothy D. Faust Mengjin Tang 《Machine Vision and Applications》1999,11(4):171-190
This paper describes the design and implementation of a machine vision system CATALOG for detection and classification of
some important internal defects in hardwood logs via analysis of computer axial tomography (CT or CAT) images. The defect
identification and classification in CATALOG consists of two phases. The first phase comprises of the segmentation of a single
CT image slice, which results in the extraction of 2D defect-like regions from the CT image slice. The second phase comprises
of the correlation of the 2D defect-like regions across CT image slices in order to establish 3D support. The segmentation
algorithm for a single CT image is a complex form of multiple-value thresholding that exploits both, the prior knowledge of
the wood structure within the log and the gray-level characteristics of the image. The algorithm for extraction of 2D defect-like
regions in a single CT image first locates the pith of the log cross section, groups the pixels in the segmented image on
the basis of their connectivity and classifies each 2D region as either a defect-like region or a defect-free region using
shape, orientation and morphological features. Each 2D defect-like region is classified as a defect or non-defect via correlation
across corresponding 2D defect-like regions in neighboring CT image slices. The 2D defect-like regions with adequate 3D support
are labeled as true defects. The current version of CATALOG is capable of 3D reconstruction and rendering of the log and its
internal defects from the individual CT image slices. CATALOG is also capable of simulation and rendering of key machining
operations such as sawing and veneering on the 3D reconstructions of the logs. The current version of CATALOG is intended
as a decision aid for sawyers and machinists in lumber mills and also as an interactive training tool for novice sawyers and
machinists.
Received: 1 August 1997 / Accepted: 25 August 1999 相似文献
2.
E. Appiani F. Cesarini A.M. Colla M. Diligenti M. Gori S. Marinai G. Soda 《International Journal on Document Analysis and Recognition》2001,4(2):69-83
In this paper a system for analysis and automatic indexing of imaged documents for high-volume applications is described.
This system, named STRETCH (STorage and RETrieval by Content of imaged documents), is based on an Archiving and Retrieval Engine, which overcomes the bottleneck of document profiling bypassing some limitations of existing pre-defined indexing schemes.
The engine exploits a structured document representation and can activate appropriate methods to characterise and automatically
index heterogeneous documents with variable layout. The originality of STRETCH lies principally in the possibility for unskilled
users to define the indexes relevant to the document domains of their interest by simply presenting visual examples and applying
reliable automatic information extraction methods (document classification, flexible reading strategies) to index the documents
automatically, thus creating archives as desired. STRETCH offers ease of use and application programming and the ability to
dynamically adapt to new types of documents. The system has been tested in two applications in particular, one concerning
passive invoices and the other bank documents. In these applications, several classes of documents are involved. The indexing
strategy first automatically classifies the document, thus avoiding pre-sorting, then locates and reads the information pertaining
to the specific document class. Experimental results are encouraging overall; in particular, document classification results
fulfill the requirements of high-volume application. Integration into production lines is under execution.
Received March 30, 2000 / Revised June 26, 2001 相似文献
3.
Scene change detection techniques for video database systems 总被引:1,自引:0,他引:1
Haitao Jiang Abdelsalam Helal Ahmed K. Elmagarmid Anupam Joshi 《Multimedia Systems》1998,6(3):186-195
Scene change detection (SCD) is one of several fundamental problems in the design of a video database management system (VDBMS).
It is the first step towards the automatic segmentation, annotation, and indexing of video data. SCD is also used in other
aspects of VDBMS, e.g., hierarchical representation and efficient browsing of the video data. In this paper, we provide a
taxonomy that classifies existing SCD algorithms into three categories: full-video-image-based, compressed-video-based, and
model-based algorithms. The capabilities and limitations of the SCD algorithms are discussed in detail. The paper also proposes
a set of criteria for measuring and comparing the performance of various SCD algorithms. We conclude by discussing some important
research directions. 相似文献
4.
New demands on modern manufacturing systems, such as increased flexibility, higher quality standards, customer responsiveness,
and higher innovative capacities, have emphasised the need for higher levels of overall system reliability. Within this context
disturbances play a critical role, because of the effects they may have on production or on safety, which are both strong
determinants of overall system performance. The main focus of this paper is the reliability of manufacturing personnel and
the way in which this interrelates with overall system performance. A framework – Human Error and Disturbance Occurrence in
Manufacturing Systems (HEDOMS) – integrates human reliability with overall system performance, relating human error with disturbance
occurrence and handling. HEDOMS has been extended into a toolkit to enable the identification of potential for human error
and disturbance occurrence in manufacturing systems, as well as the definition of suitable error reduction measures. 相似文献
5.
H. Courteney 《Cognition, Technology & Work》2000,2(3):142-153
Cognitive engineering has developed enormously over the last fifteen years. Yet, despite many excellent research projects
and publications, its full potential has not been embraced into mainstream system design. This paper will examine the reasons
for this failure and argue that the problem is not simply inertia or lack of education. There are strong organisational influences
that cause resistance to this particular approach. The discipline itself has characteristics that make it fragile in the modern
corporate structure. In addition, the cognitive engineers themselves are not blameless in the equation. They appear to have
done exactly what they criticise the engineering community for doing: they have packaged their product in a manner that is
not ‘user friendly’ to its target population, not structured to suit its application, and not output in the format required.
Suggestions will be made to rectify the situation: a list of actions is proposed for practising cognitive engineers to make
their product more likely to enjoy widespread uptake. 相似文献
6.
7.
Norifumi Katafuchi Mutsuo Sano Shuichi Ohara Masashi Okudaira 《Machine Vision and Applications》2000,12(4):170-176
A new method based on an optics model for highly reliable surface inspection of industrial parts has been developed. This
method uses multiple images taken under different camera conditions. Phong's model is employed for surface reflection, and
then the albedo and the reflection model parameters are estimated by the least squares method. The developed method has advantages
over conventional binarization in that it can easily determine the threshold of product acceptability and cope with changes
in light intensity when detecting defects. 相似文献
8.
From Non-Functional Requirements to Design through Patterns 总被引:8,自引:2,他引:6
9.
Automatic high-resolution optoelectronic photogrammetric 3D surface geometry acquisition system 总被引:1,自引:0,他引:1
A fast, high-resolution, automatic, non-contact 3D surface geometry measuring system using a photogrammetric optoelectronic
technique based on lateral-photoeffect diode detectors has been developed. Designed for the acquisition of surface geometries
such as machined surfaces, biological surfaces, and deformed parts, the system can be used in design, manufacturing, inspection,
and range finding. A laser beam is focused and scanned onto the surface of the object to be measured. Two cameras in stereo
positions capture the reflected light from the surface at 10 kHz. Photogrammetric triangulation quickly transforms the pair
of 2D signals created by the camera detectors into 3D coordinates of the light spot. Because only one small spot on the object
is illuminated at a time, the stereo correspondence problem is solved in real time. The resolution is determined by a 12-bit
A/D converter and can be improved up to 25 60025 600 by oversampling. The irregular 3D data can be regularized for use with image-based algorithms.
Received: 8 October 1996 / Accepted: 3 February 1997 相似文献
10.
Carl L. Sable Vasileios Hatzivassiloglou 《International Journal on Digital Libraries》2000,3(3):261-275
The rapid expansion of multimedia digital collections brings to the fore the need for classifying not only text documents
but their embedded non-textual parts as well. We propose a model for basing classification of multimedia on broad, non-topical
features, and show how information on targeted nearby pieces of text can be used to effectively classify photographs on a
first such feature, distinguishing between indoor and outdoor images. We examine several variations to a TF*IDF-based approach
for this task, empirically analyze their effects, and evaluate our system on a large collection of images from current news
newsgroups. In addition, we investigate alternative classification and evaluation methods, and the effects that secondary
features have on indoor/outdoor classification. Using density estimation over the raw TF*IDF values, we obtain a classification
accuracy of 82%, a number that outperforms baseline estimates and earlier, image-based approaches, at least in the domain
of news articles, and that nears the accuracy of humans who perform the same task with access to comparable information.
Published online: 22 September 2000 相似文献
11.
As feedback from Three Mile Island No. 2, a large amount of human–machine interface (HMI) design has been proposed to support
operators during accidents by presenting information on plant status, some of which is implemented in commercial nuclear power
plants (NPPs). However, it has not yet been discussed what role HMI should play under conditions where operators must take
action as instructed under emergency operating procedure. Regarding this principal issue, an HMI design is proposed together
with specific screen images. The advantage of this design is based on the involvement of an ex-operator in NPP in this paper.
The participation of users in the design of HMI has been rare. Accordingly the proposed HMI is comprehensive for average operators
and is expected to be acceptable for future implementation in commercial NPPs. The effectiveness of the proposed HMI has been
examined in a small experiment. 相似文献
12.
Wood inspection with non-supervised clustering 总被引:9,自引:0,他引:9
Abstract. The appearance of sawn timber has huge natural variations that the human inspector easily compensates for mentally when determining
the types of defects and the grade of each board. However, for automatic wood inspection systems these variations are a major
source for complication. This makes it difficult to use textbook methodologies for visual inspection. These methodologies
generally aim at systems that are trained in a supervised manner with samples of defects and good material, but selecting
and labeling the samples is an error-prone process that limits the accuracy that can be achieved. We present a non-supervised
clustering-based approach for detecting and recognizing defects in lumber boards. A key idea is to employ a self-organizing
map (SOM) for discriminating between sound wood and defects. Human involvement needed for training is minimal. The approach
has been tested with color images of lumber boards, and the achieved false detection and error escape rates are low. The approach
also provides a self-intuitive visual user interface.
Received: 16 December 2000 / Accepted: 8 December 2001
Correspondence to: O. Silvén 相似文献
13.
An intelligent computer aided defect analysis (ICADA) system, based on artificial intelligence techniques, has been developed to identify design, process or material parameters which could be responsible for the occurrence of defective castings in a manufacturing campaign. The data on defective castings for a particular time frame, which is an input to the ICADA system, has been analysed. It was observed that a large proportion, i.e. 50–80% of all the defective castings produced in a foundry, have two, three or four types of defects occurring above a threshold proportion, say 10%. Also, a large number of defect types are either not found at all or found in a very small proportion, with a threshold value below 2%. An important feature of the ICADA system is the recognition of this pattern in the analysis. Thirty casting defect types and a large number of causes numbering between 50 and 70 for each, as identified in the AFS analysis of casting defects—the standard reference source for a casting process—constituted the foundation for building the knowledge base. Scientific rationale underlying the formation of a defect during the casting process was identified and 38 metacauses were coded. Process, material and design parameters which contribute to the metacauses were systematically examined and 112 were identified as rootcauses. The interconnections between defects, metacauses and rootcauses were represented as a three tier structured graph and the handling of uncertainty in the occurrence of events such as defects, metacauses and rootcauses was achieved by Bayesian analysis. The hill climbing search technique, associated with forward reasoning, was employed to recognize one or several root causes. 相似文献
14.
Concurrency control in hierarchical multidatabase systems 总被引:1,自引:0,他引:1
Sharad Mehrotra Henry F. Korth Avi Silberschatz 《The VLDB Journal The International Journal on Very Large Data Bases》1997,6(2):152-172
Over the past decade, significant research has been done towards developing transaction management algorithms for multidatabase
systems. Most of this work assumes a monolithic architecture of the multidatabase system with a single software module that
follows a single transaction management algorithm to ensure the consistency of data stored in the local databases. This monolithic
architecture is not appropriate in a multidatabase environment where the system spans multiple different organizations that
are distributed over various geographically distant locations. In this paper, we propose an alternative multidatabase transaction
management architecture, where the system is hierarchical in nature. Hierarchical architecture has consequences on the design
of transaction management algorithms. An implication of the architecture is that the transaction management algorithms followed
by a multidatabase system must be composable– that is, it must be possible to incorporate individual multidatabase systems as elements in a larger multidatabase system.
We present a hierarchical architecture for a multidatabase environment and develop techniques for concurrency control in such
systems.
Edited by R. Sacks-Davis. Received June 27, 1994 / Accepted September 26, 1995 相似文献
15.
An automatic assessment scheme for steel quality inspection 总被引:1,自引:0,他引:1
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 相似文献
16.
In control systems, the interfaces between software and its embedding environment are a major source of costly errors. For
example, Lutz reported that 20–35% of the safety-related errors discovered during integration and system testing of two spacecraft
were related to the interfaces between the software and the embedding hardware. Also, the software’s operating environment
is likely to change over time, further complicating the issues related to system-level inter-component communication. In this
paper we discuss a formal approach to the specification and analysis of inter-component communication using a revised version
of RSML (Requirements State Machine Language). The formalism allows rigorous specification of the physical aspects of the
inter-component communication and forces encapsulation of communication-related properties in well-defined and easy-to-read
interface specifications. This enables us both to analyse a system design to detect incompatibilities between connected components
and to use the interface specifications as safety kernels to enforce safety constraints. 相似文献
17.
Detection, segmentation, and classification of specific objects are the key building blocks of a computer vision system for
image analysis. This paper presents a unified model-based approach to these three tasks. It is based on using unsupervised
learning to find a set of templates specific to the objects being outlined by the user. The templates are formed by averaging
the shapes that belong to a particular cluster, and are used to guide a probabilistic search through the space of possible
objects. The main difference from previously reported methods is the use of on-line learning, ideal for highly repetitive
tasks. This results in faster and more accurate object detection, as system performance improves with continued use. Further,
the information gained through clustering and user feedback is used to classify the objects for problems in which shape is
relevant to the classification. The effectiveness of the resulting system is demonstrated in two applications: a medical diagnosis
task using cytological images, and a vehicle recognition task.
Received: 5 November 2000 / Accepted: 29 June 2001
Correspondence to: K.-M. Lee 相似文献
18.
The study of planning and scheduling from a human factors perspective has re-emerged as an important area for research in
contemporary manufacturing enterprises. Improved decision support systems are needed that optimally integrate people with
computer-based systems in order to increase productivity and responsiveness. However, there is a dearth of knowledge on the
reality of the human factors of planning and scheduling practice across manufacturing industry. This paper reviews previous
studies of scheduling practice and demonstrates the lack of clearly reported and justified methods to study scheduling behaviour
and to interpret and represent the findings. Field study is proposed as the most appropriate approach for carrying out studies
of scheduling in practice and various methods used in scheduling field studies are specified. Particular emphasis is given
to the investigation of the nature of planning and scheduling practice in the context of a functionally, spatially and temporally
complex environment. 相似文献
19.
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 相似文献