Philip J. Farrugia

Scribbles to vectors: preparation of scribble drawings for CAD interpretation

This paper describes the work carried out on off-line paper based scribbles such that they can be incorporated into a sketch-based interface without forcing designers to change their natural drawing habits. In this work, the scribbled drawings are converted into a vectorial format which can be recognized by a CAD system. This is achieved by using pattern analysis techniques, namely the Gabor filter to simplify the scribbled drawing. Vector line are then extracted from the resulting drawing by means of Kalman filtering.

Extracting 3D shape models and related life knowledge from paper-based sketches

The main problem addressed in this paper concerns the lack of computational tools that allow designers to automatically extract three-dimensional (3D) shape models from paper-based form sketches during early design. To address this problem, various Computer-Aided Sketching (CAS) tools have been developed. However, their digital sketching medium replaces the natural, portable and readily available paper. To address these issues, this paper reports the development of a framework, which allows designers to obtain 3D virtual models and related life-cycle knowledge directly from early form paper-based sketches. The evaluation results of the implemented prototype tool, X-SKetch, provide a degree of evidence that this framework is a step towards making 3D geometric modelling software and computer technology available not only to designers but also to other users.

Adaptation of Brensen's thresholding algorithm for sketched line drawings

Image binarisation is one of the first image processing techniques within a sketched line drawing interpretation system. In order to achieve an automated system, it is necessary to have a single algorithmwhich may be used for all image types. This is difficult to obtain if the parameters required by an algorithm are set manually, however, the adaptive evaluation of parameters form image properties is a step towards this goal. This paper discusses the methods by which the parameters required for Brensens Algorithm may be evaluated adaptively form the image properties.

A language for representing and extracting 3D geometry semantics from paper-based sketches

Every product that exists, ranging from a toothbrush to a car, has first been conceived as a mental concept. Due to its efficacy in rapidly externalizing concepts, paper-based sketching is still extensively used by practising designers to gradually develop the three-dimensional (3D) geometric form of a concept. It is a common practice that form concepts are sketched on paper prior to generating 3D virtual models in commercial Computer-Aided Design (CAD) systems. However, the user-interface of such systems does not support automatic generation of 3D models from sketches. Furthermore, the inherent characteristics of form sketching (e.g. idiosyncrasy) pose a challenge to computer-based understanding of the form concept semantics expressed on paper. To address these issues, this paper is therefore concerned with the development of a visual language that is prescribed and to be used by product designers to annotate paper-based sketches such that the form geometry semantics can be formally represented; parsing the annotated sketch allows for the automatic generation of 3D virtual models in CAD. Inspired by re-usable 3D CAD modelling functions and the related environmental constraints and requirements, a prescribed sketching language, PSL, has been developed to annotate paper-based form sketches. The framework architecture which parses the annotated sketch and subsequently extracts the form concept semantics is described. Based on this framework, a prototype computer tool has been implemented and evaluated. Evaluation results provide a degree of evidence, first on the suitability of PSL in representing the semantics of a range of forms, and secondly on the designers? acceptance of taking up this annotated sketching approach in practice. The key contribution is a visual language to formally represent form geometry semantics on paper.Parsing the language allows for the automatic generation of 3D virtual models.A proof-of-concept prototype tool was implemented.The language is capable to roughly model forms with linear topological ordering.Evaluation results show that practising designers would use the language.

A sketching alphabet for paper-based collaborative design

Despite the importance of the early design phase, designers still lack computer support in rapidly modelling their form concepts in Computer-Aided Design (CAD) systems due to the rigid User-Interface. Owing to its efficacy in instantly capturing ideas, traditional pen-and-paper sketching is still very popular amongst designers to record their concepts not only inside but also outside their office. This paper reports the ongoing research aimed at developing a portable, sketch-based tool allowing designers to obtain and share 3D CAD models on cameraphones directly from paper sketches. More specifically, the focus is on a prescribed sketching alphabet required to create a seamless link between sketching and CAD. Results of semi-structured interviews carried out with various design practitioners contribute important insights into the alphabet suitability. Further, the results and an implemented tool indicate that a sketching language based on this alphabet will be beneficial for designers, especially in a collaborative design environment.

Influence of sketch types on distributed design team work

Product development is a collaborative activity more often than ever carried out by distributed design teams. It is critical to determine how sketches are used in such environments in order to improve the design process. Sketches produced by students participating in a collaborative design project of three European Universities are classified according to the intention of the designer when producing a sketch, the level of detail shown in the sketch and the phase when the sketch was produced. The adapted classification system used in this paper helps to analyse type of sketches with most variety of ideas. Furthermore, this paper reviews which type of sketches offers the most potential to be further developed. Results show that persuasive sketches offer the broadest range of ideas since they are produced as a combination of ideas from brainstorming sessions. Shared sketches help to achieve consensus in decision-making since the sketches are most likely to be produced by the entire group rather than individually.

A new sketch based interface using the gray-level co-occurrence matrix for perceptual simplification of paper based scribbles

The sketching activity has an important role in conceptual design and a variety of tools exist which help designers to facilitate the generation of 3D models form sketched drawings. This paper describes a new sketch-to-3D tool, which uses annotations to aid the interpretation of the drawing. Over-traced lines present in the designers scribbles provide an interpretation challenge, which must be resolved in order to obtain 3D models from these sketches. Perceptual grouping techniques used to interpret such images require that the drawing is represented as vectors. These are generally obtained through thinning or edge detection. However, we show that processing scribbles using these techniques result in a large number of vectors which do not provide a faithful representation of the drawing. This paper investigates the use of the co-occurrence matrix to perceptually simplify these drawings, thus obtaining a smaller number of vectors which describe the drawing more faithfully.

Design for Micro Insert Moulding: A Review

Nowadays micro technologies are constantly increasing in importance due to the rapid growth of their respective applications. Recent works have investigated the potential of multi material micro fabrication technologies. One of the most cost efficient polymer micro fabrication technologies is injection moulding. Such cost effectiveness arises due to the reusability of a micro mould cavity. A process variant of multi material micro injection moulding is insert moulding. This paper characterizes the process of micro injection moulding in general and contributes a review of the state-of-the-art research studies together with technologies relevant specifically to micro insert injection moulding. From the literature review a research gap has been identified, namely that designers and process engineers lack support in the form of guidelines to develop micro multi-material components by insert moulding. Research directions are recommended to address this gap. These include methods to generate and formalize design and manufacturing guidelines for micro insert moulding.Copyright

Knowledge Intensive Design Technology

This chapter presents an approach to product modelling, which aims to provide interoperability when a common data model is not available. It uses computational agents that represent product components. They autonomously organise themselves in a situated manner to form a society that represents the

A concurrent engineering approach to develop BioMEMS employed in a deep brain stimulator integrated with a drug delivery system

This paper presents an Integrated Product Development (IPD) based model to specifically develop bio-medical micro-electro-mechanical-systems (BioMEMS). The concurrent engineering model is based on the IPD model phases, which are presented and formulated by the Integration DEFinition (IDEF) modelling language. To evaluate the IPD model, a case study concerning the development of a BioMEMS device for a deep brain stimulation (DBS) system was investigated. By following the relevant mechanisms and controls in the model, a design concept of a wireless headmounted DBS implant integrated with a drug delivery system (DDS) was conceived. The contribution of this paper is the IDEF model, which provides a road map to the product development team members in order to take a concurrent engineering approach to develop BioMEMS. The qualitative feedback received from the identified stakeholders, together with the quality of the case study employed, namely, an integrated DBS and DDS solution, indicate a degree of evidence that the model provides a sound basis in this direction.