Guy Adams

Augmented paper: developing relationships between digital content and paper

Some of the most interesting developments within computer system design in recent years have emerged from an exploration of the ways everyday objects and artefacts can be augmented with computational resources. Often under the rubric of “ubiquitous computing”, research programmes in Europe, North America and Japan have directed substantial funding towards these initiatives, and leading industrial and academic research laboratories have developed a diverse range of ubiquitous computing “solutions”. These developments mark an important shift in system design, a shift that is having a corresponding impact on social science research. Surprisingly though, given the growing commitment to the ubiquitous and the tangible, there is a mundane, even humble artefact that pervades our ordinary lives that has received less attention than one might imagine. This artefact is paper.

Using paper to support collaboration in educational activities

This paper describes findings from a pilot study that compared the collaborative use by children of three different media formats: a paper book, a CD-ROM in a standard PC set-up, and a paper booklet augmented with digital content. These findings show how the book’s ergonomics provide a flexible and easily accessible interface which engenders fluid collaboration between pairs of children. These qualities are also observed when children work with the augmented paper booklet. The value of digital content is demonstrated in a participatory design activity, where we find how digital media can ‘bring to life’ the information presented on paper. In contrast to developments focused narrowly on new technologies, this study presents evidence for the use and value of paper, and paper augmented with digital media, in educational settings.

High-resolution glyph-inspection based security system

This paper describes the use of a 1∶1 magnification 3.5 micron true resolution Dyson Relay lens-based 3 MPixel USB CMOS imaging device (DR CID) and software forensic image analysis system. The device enables the simultaneous capture of both intentional printing shapes and unintentional printing artifacts caused by the printing process and the interaction of the ink with the substrate on which printing occurs. The custom image analysis system written for the DR CID device allows even a single printed character to simultaneously provide fiducial marking, inspection information, authentication and forensics. We report herein on the sensitivity of the system and initial results for the reliable authentication of a printed character using DR CID hardware devices.

Model based print signature profile extraction for forensic analysis of individual text glyphs

Forensic analysis of individual printed items, including single characters, enables the addition of some level of security to any printed item (label, document, package, etc.). In this paper, we present a model-based approach for extracting a signature profile around the outer edge of virtually any text glyph. We show that for two high-resolution imaging devices (the Dyson Relay CMOS Imaging Device, called DrCID, and a high speed line-scan camera) this signature encodes that part of the glyph boundary that is due to the random fluctuation of the print process, enabling significantly higher levels of forensic discrimination than previously shown. The model-based approach enables a security workflow where the line-scan device is integrated into production line inspection with later forensic investigation in the field using the DrCID device. We also develop a simple shape descriptor to encode the signature profile, making it easier to manipulate, test and store. We argue that the shape descriptor provides forensic-level authentication of a single printed character.

Hand held Dyson Relay Lens for anti-counterfeiting

In this paper we describe the application, design and performance of a novel, small form factor Dyson Relay lens with inbuilt illumination configured for imaging printed marks. The high resolving power of the design clearly reveals the microscopic stochastic nature of printing processes and ink/substrate interactions. These imperfections provide a hard to copy “printed mark signature” that can be used for checking authenticity.

An imaging system for simultaneous inspection, authentication and forensics

A high-resolution, handheld, USB-powered imaging device can be used to simultaneously provide authentication, inspection and forensic imaging capabilities. In this paper, we describe the capture of 6.55 × 4.84 mm, 7600 lines/inch resolution images that afford the reading of intentional (authentication) and stochastic (forensic) information using the same image. Because of the high-resolution, high-contrast nature of the images, they can also be used for inspection of print quality. The security payload density obtained (per unit area) exceeds that of fixed bed scanners, and our data shows that the density is limited by the capabilities of the printing process, not the imaging. Taking advantage of the structured nature of security deterrents, we readily incorporate a simple shape warp descriptor feature to distinguish between sets of authentic (same deterrent imaged multiple times) and counterfeit (same image data, different prints) deterrents. This capability affords the simultaneous achievement of payload reading (mass serialization, track & trace) and high-quality proof of authenticity. We discuss the implications for providing an overall imaging ecosystem for product identification, track & trace, authentication and forensic validation.

Resolving distortion between linear and area sensors for forensic print inspection

Forensic analysis of individual printed items, including single characters, provides a readily-integrated means to extend security to any printed item (label, document, package, etc.). In this paper we demonstrate, for the first time, forensic levels of image inspection for workflows involving two very different high-resolution imaging devices, the Dyson Relay CMOS Imaging Device (DrCID) and a high speed line-scan camera. In particular, we show how a similarity metric can be used to identify specific characters with less than 1 in 109 chance of false matching, while closing the loop between in-line (production) using the line-scan camera and end-user (investigative) inspection with DrCID.

Document imaging security and forensics ecosystem considerations

Much of the focus in document security tends to be on the deterrent -- the physical (printed, manufactured) item placed on a document, often used for routing in addition to security purposes. Hybrid (multiple) deterrents are not always reliably read by a single imaging device, and so a single device generally cannot simultaneously provide overall document security. We herein show how a relatively simple deterrent can be used in combination with multiple imaging devices to provide document security. In this paper, we show how these devices can be used to classify the printing technology used, a subject of importance for counterfeiter identification as well as printer quality control. Forensic-level imaging is also useful in preventing repudiation and forging, while mobile and/or simple scanning can be used to prevent tampering -- propitiously in addition to providing useful, non-security related, capabilities such as document routing (track and trace) and workflow association.

A kinematic calibration technique for robotic manipulators with multiple Degrees of Freedom

Robotic manipulators are sold with reference to repeatability, but the manufacturers rarely quote figures for accuracy. The repeatability figures for many small/medium sized industrial 5 degree or 6 degree of freedom (5/6DoF) arms are on the scale of 20µm, which is certainly impressive. But, this is not a measure of accuracy it is a measure of whether the arm will return to the same requested position again. As the paper will reveal, we encountered accuracy nearly two orders of magnitude worse than the repeatability metric. Our work on integrating 2D and 3D imaging systems with robotic manipulators for high precision interaction with 3D objects identified the requirement to determine the level of intrinsic/out of the box errors. This is in order to prevent potential collisions when automatically interacting at close proximity with any object in an unknown orientation where typical teach pendent or other prior correction is not applicable. In addition, understanding how to derive accurate calibration data allowed us to develop an approach for precise kinematic re-calibration of the manipulator.

Testing the Validity of Lamberts Law for Micro-scale Photometric Stereo Applied to Paper Substrates

This paper presents an empirical study to investigate the use of photometric stereo (PS) for micro-scale 3D measurement of paper samples. PS estimates per-pixel surface orientation from images of a surface captured from the same viewpoint but under different illumination directions. Specifically, we investigate the surface properties of paper to test whether they are sufficiently well approximated by a Lambertian reflectance model to allow veridical surface reconstruction under PS and explore the range of conditions for which this model is valid. We present an empirical setup that is used to conduct a series of experiments in order to analyse the applicability of PS at the micro-scale. In addition, we determine the best 4, 6, and 8 light source tilt (illumination) angles with respect to multi-source micro-scale PS. Furthermore, an intensity based image registration method is used to test the accuracy of the recovery of surface normals. The results demonstrate that at the micro-scale: (a) Lambert model represents well the data sets with low root mean square (RMS) error between the original and reconstructed image, (b) increasing the light sources from 4 to 8 reduces RMS error, and (c) PS can be used to extract veridical surface normals.