Knowledge-based recognition of crosshatched areas in engineering drawings

Ablameyko, Sergey; Bereishik, V.; Frantskevich, O.; Homenko, M.; Paramonova, N.

doi:10.1007/bfb0033267

Cited by 3 publications

(2 citation statements)

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“…The problem of arc detection was recently studied in [77] proposing a method that combines two of the most reliable techniques in the literature. Hatched pattern detection is an important concern in the field of document analysis [78,69,73] and is usually solved by clustering parallel lines having the same slope angle and sorting them along a normal direction. Dimensions usually follow strict standards.…”

Section: Engineering Drawingsmentioning

confidence: 99%

Symbol Recognition: Current Advances and Perspectives

Lladós¹,

Valveny²,

Sánchez³

et al. 2002

Lecture Notes in Computer Science

102

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Abstract. The recognition of symbols in graphic documents is an intensive research activity in the community of pattern recognition and document analysis. A key issue in the interpretation of maps, engineering drawings, diagrams, etc. is the recognition of domain dependent symbols according to a symbol database. In this work we first review the most outstanding symbol recognition methods from two different points of view: application domains and pattern recognition methods. In the second part of the paper, open and unaddressed problems involved in symbol recognition are described, analyzing their current state of art and discussing future research challenges. Thus, issues such as symbol representation, matching, segmentation, learning, scalability of recognition methods and performance evaluation are addressed in this work. Finally, we discuss the perspectives of symbol recognition concerning to new paradigms such as user interfaces in handheld computers or document database and WWW indexing by graphical content.

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Section: Engineering Drawingsmentioning

confidence: 99%

Symbol Recognition: Current Advances and Perspectives

Lladós¹,

Valveny²,

Sánchez³

et al. 2002

Lecture Notes in Computer Science

102

View full text Add to dashboard Cite

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“…A vector-based algorithm to recognize crosshatched areas in EDs has been proposed by Ablameyko et al 3,7 The area is assembled on a vector image where all lines and area boundaries are detected concurrently. Thus the dependence on line width is reduced to a minimum.…”

Section: Recognition Of Crosshatched Areasmentioning

confidence: 99%

Recognition of Engineering Drawing Entities: Review of Approaches

Ablameyko

Uchida

2007

Int. J. Image Grap.

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Recognition of engineering drawing entities is one of the most difficult stages in engineering drawing interpretation and many attempts to recognize various types of ED entities have been made. In this paper, we review algorithms for the recognition of ED entities, especially dimensions and crosshatching areas. For the recognition of dimensions, we analyze how dimension texts can be separated from graphics and how arrowheads of dimension lines are recognized. We also analyze the recent systems of ED interpretation. Finally, future tasks are discussed. Int. J. Image Grap. 2007.07:709-733. Downloaded from www.worldscientific.com by UNIVERSITY OF CALGARY on 02/05/15. For personal use only. Recognition of Engineering Drawing Entities 711arrowheads are recognized. We review complete or near-complete ED interpretation systems. During the past 20 years, many ED interpretation systems have been developed for automatic or semi-automatic conversion of paper-based EDs to 3D CAD model. Some review material can be found in Refs. 55, 66, 70 and 75. We shall not touch in this paper a character (and other specific symbol) recognition task. There are many papers published for recognition of characters and symbols and we can refer to only several review papers published recently. 12,20,25,49 For editing and 3D reconstruction approaches, which are also omitted here, we can refer to Refs. 9, 10, 13 and 32. ED Entities What are the ED entities?Vectorized ED can be represented in two ways: by graphic primitives or by ED entities. The first representation is rather simple and not always useful. Straight lines, arcs, curves are the most commonly used graphic primitives. They can be grouped for forming more complex primitives, such as chained lines, text blocks, and arrows. Those complex primitives may be further combined into higher-level elements, that is, ED entities such as • contour lines (often represented by solid lines), • symmetry axes (dash-dotted lines), • hidden contour lines (dashed lines), • matter areas (represented by crosshatching), • dimensions (thin lines with arrows, witness lines and so on),• annotation text, and • circles including concentric circles.Examples of some ED entities are shown in Fig. 2.ED entities can be roughly separated into simple and complex ones. Simple ED entities are used for the description for simple ED structures, e.g. a symmetry axis, a crosshatching line, the border of matter area, etc. and can be represented as rather simple combinations of graphic primitives (or their pieces). In Fig. 2. Examples of ED entities; (a) dimension, (b) symmetry axis, (c) crosshatching area, (d) border of crosshatching area, and (e) a set of concentric circles. Among them, (a), (c), and (e) are complex entities and (b) and (d) are simple entities. Int. J. Image Grap. 2007.07:709-733. Downloaded from www.worldscientific.com by UNIVERSITY OF CALGARY on 02/05/15. For personal use only.

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