Roger W. Ehrich

Virginia Tech

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Co-Authors

Faith McCreary

Intel (United States)

Melissa Lisanti

Radford University

John L. Sibert

George Washington University

Ray A. Reaux

Computer Technology Associates (United States)

Jörgen P. Foith

University of Kaiserslautern

Xiangdong Liu

Beijing Institute of Technology

Keith Rowland

Montgomery County Public Schools

Robert M. Haralick

City University of New York

Jiang Qian

University of Electronic Science and Technology of China

David J. Kasik

Boeing (United States)

Cooperative Institutions

Virginia Tech

University of Virginia

IBM (United States)

University of Massachusetts Amherst

Montgomery County Public Schools

Tsinghua University

Carnegie Mellon University

Southeast University

Chinese Academy of Sciences

Virginia Tech - Wake Forest University School of Biomedical Engineering & Sciences

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Primary detection of hardwood log defects using laser surface scanning

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2003)

E. G. Thomas Liya Thomas Lamine Mili Roger W. Ehrich A. Lynn Abbott

The use of laser technology to scan hardwood log surfaces for defects holds great promise for improving processing efficiency and the value and volume of lumber produced. External and internal defect detection to optimize hardwood log and lumber processing is one of the top four technological needs in the nation's hardwood industry. The location, type, and severity of defects on hardwood logs are the key indicators of log quality and value. These visual cues provide information about internal log characteristics and products for which the log is suitable. We scanned 162 logs with a high-resolution industrial four-head laser surface scanner. The resulting data sets contain hundreds of thousands of three-dimensional coordinate points. The size of the data and noise presented special problems during processing. Robust regression models were used to fit geometric shapes to the data. The estimated orthogonal distances between the fitted model and the log surface are converted to a two-dimensional image to facilitate defect detection. Using robust regression methods and standard image processing tools we have demonstrated that severe surface defects on hardwood logs can be detected using height and contour analyses of three-dimensional laser scan data.

Laser Scanning

Wood processing

Data Processing

10.1117/12.474036

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Citations (3)

Computer graphics and applications

Computer Vision Graphics and Image Processing (1985)

Roger W. Ehrich

10.1016/0734-189x(85)90098-2

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Citations (23)

DMS—A system for defining and managing human-computer dialogues

Automatica (1983)

Roger W. Ehrich

Programmer

10.1016/0005-1098(83)90029-8

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Citations (6)

Home-School Networking To Support Constructivist Learning in a Rural Elementary School: Lessons from Families, Schools, and Researchers.

Roger W. Ehrich Faith McCreary Ray A. Reaux Keith Rowland Amy Ramsey

Constructivist teaching methods

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Citations (3)

Spatial reasoning in remotely sensed data

James B. Campbell Roger W. Ehrich David B. Elliott Robert M. Haralick S. Wang

Photointerpreters employ a variety of implicit spatial models to provide interpretations from remotely sensed aerial or satellite imagery. In this paper one application is illustrated: how ridges and valleys can be automatically interpreted from Landsat imagery of a mountainous area, and how a relative elevation terrain model can be constructed from this interpretation. How to examine valleys for the possible presence of streams or rivers is shown, and how a spatial relational model can be set up to make a final interpretation of the river drainage network is explored.

Elevation (ballistics)

Drainage network

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Citations (3)

Computer Analysis of User Interfaces Based on Repetition inTranscripts of User Sessions

Antonio C. Siochi Roger W. Ehrich

It is generally acknowledged that the production of quality user interfaces requires a thorough understanding of the user and that this involves evaluating the interface by observing the user working with the system, or by performing human factors experiments. Such methods traditionally involve the use of video tape, protocol analysis, critical incident analysis, etc. These methods require time consuming analyses and may be invasive. In addition, the data obtained through such methods represent a relatively small portion of the use of a system. An alternative approach is to record all user input and systems output, i.e., log the user session. Such transcripts can be collected automatically and non-invasively over a long period of time. Unfortunately, this produces voluminous amounts of data. There is, therefore, a need for tools and techniques that allow an evaluator to identify potential performance and usability problems from such data. It is hypothesized that repetition of user actions is an important indicator of potential user interface problems.

Interface (matter)

Repetition (rhetorical device)

User requirements document

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Determining Object Orientations from Run Length Encodings

Visvanathan Ramesh Roger W. Ehrich

Run length codes are widely used for image compression, and efficient algorithms have been devised for identifying objects and calculating geometric features directly from these codes. However, if the image objects are rotated it can be difficult to determine their orientation and position so that they can be grasped by manipulators. This paper describes a method for structural determination of object orientation directly from the run length codes of successive image scan lines. An algorithm is described that makes use of the equations of object boundary segments to form hypotheses about object orientations that are refined as scanning progresses. 2-dimensional polygonal objects are discussed, and it is assumed that objects do not touch or overlap, although the algorithm could be extended to include those situations.

Position (finance)

Chain code

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DMS

John Roach H. Rex Hartson Roger W. Ehrich Tamer Yunten Deborah H. Johnson

As the complexity of human-computer interfaces increases, those who use these interfaces as well as those reponsible for their design have recognized an urgent need for substantive research in the human factors of software development [2], [5]. Because of the magnitude of the task of producing software for individual human-computer interfaces, appropriate tools are needed for defining and improving such interfaces, both in research and production environments. This paper describes the research being carried out to construct DMS (Dialogue Management System), which is a complete system for defining, modifying, executing, and metering human-computer dialogues.

10.1145/800049.801763

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Citations (14)

Extraction of lines and regions from grey tone line drawing images

Pattern Recognition (1984)

Layne T. Watson K Arvind Roger W. Ehrich Robert M. Haralick

Line drawings

Line (geometry)

Tone (literature)

Grey level

10.1016/0031-3203(84)90047-5

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Citations (39)

A Social Network Study of Online Communication among Elementary Students and Teachers with Home Internet Access

Proceedings of the Human Factors and Ergonomics Society Annual Meeting (2001)

Faith McCreary Roger W. Ehrich Melissa Lisanti

This paper presents preliminary results from a social network study of an after-school, online community among 24 fifth grade students and two teachers from the PCs for Families Project. The project provided students and teachers with free home network technology and Internet access. A proxy server recorded home Internet usage so that student communication patterns could be determined. All recorded instances of after-school communication took place via email or project chat rooms. Teachers and students made greater use of email than chat to communicate outside the classroom. Students were more likely to communicate with students of the same gender using the Internet, with female students more likely than male students to email the female teaching staff. Further, once the physical classroom community ceased to exist, the Internet-enabled community virtually disappeared. Study results have implications for both research (e.g., how student characteristics relate to a student's role in Internet communication networks) and design (e.g., what means of Internet communication are must successful at promoting after-school interaction).

Chat room

Online Community

Social network (sociolinguistics)

Computer-Mediated Communication

10.1177/154193120104500507

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Citations (3)