Authentication of Fingerprint Scanners

To counter certain security threats in biometric authentication systems, particularly in portable devices (e.g., phones and laptops), we have developed a technology for automated authentication of fingerprint scanners of exactly the same type, manufacturer, and model. The technology uses unique, persistent, and unalterable characteristics of the fingerprint scanners to detect attacks on the scanners, such as detecting an image containing the fingerprint pattern of the legitimate user and acquired with the authentic fingerprint scanner replaced by another image that still contains the fingerprint pattern of the legitimate user but has been acquired with another, unauthentic fingerprint scanner. The technology uses the conventional authentication steps of enrolment and verification, each of which can be implemented in a portable device, a desktop, or a remote server. The technology is extremely accurate, computationally efficient, robust in a wide range of conditions, does not require any hardware modifications, and can be added (as a software add-on) to systems already manufactured and placed into service. We have also implemented the technology in a demonstration prototype for both area and swipe scanners

Digital imaging technology assessment: Digital document storage project

An ongoing technical assessment and requirements definition project is examining the potential role of digital imaging technology at NASA's STI facility. The focus is on the basic components of imaging technology in today's marketplace as well as the components anticipated in the near future. Presented is a requirement specification for a prototype project, an initial examination of current image processing at the STI facility, and an initial summary of image processing projects at other sites. Operational imaging systems incorporate scanners, optical storage, high resolution monitors, processing nodes, magnetic storage, jukeboxes, specialized boards, optical character recognition gear, pixel addressable printers, communications, and complex software processes

Flatbed scanner identification based on dust and scratches over scanner platen

In this paper, a novel individual source scanner identification scheme is proposed. The scheme uses traces of dust, dirt, and scratches over scanner platen on scanned images to character-ize a source scanner. The efficacy of the proposed scheme is substantiated with experimental analysis. The robustness of the scheme to the JPEG compression is also investigated. Ex-perimental results show that proposed scheme could be used to match a scanned image to its source. Index Terms — Image analysis, Object detection. 1

Narratives of Shape and Colour

My practice-led research investigates how narrative concepts can be employed to generate abstract compositions in painting, drawing and print. The project challenges the view that narrative and abstract art are mutually exclusive forms by creating abstract artworks that employ narrative concepts and strategies. My research negotiates this by identifying the essential components of narrative and proposing that they can also function as formal elements in an abstract work. This is supported by theories of narrative that present it as a set of structural conventions that mediate and summarise real or imagined events, and make them conform to the material limits of an artwork. The research question is tested exhaustively in the studio using a variety of forms and methods: including digital sketches, pen and ink drawings, scanography, and densely layered paintings. My abstract compositions begin by conforming to the material limits of the flat picture plane, yet by applying narrative concepts they expand to project speculative histories and alternative versions of themselves

The Effect Of Scanning Resolution In Digital Photogrammetric Work

Photogrammetry is one branch in surveying that has largely been affected by the development in computer technology in data acquisition, image development and processing, adjustment and further in mapping of data. Digital photogrammetric workstation is one of the yields of these developments in photogrammetry, which is gradually replacing analogue and analytical plotters. Pixel resolution is one of the main factors that affect the final results in digital photogrammetry in general and in digital photogrammetric work station in particular. In this research work, various subjects relevant to the process of digital mapping using digital photogrammetric work station were discussed. Theses subjects include: • Digital camera: The present alternative of the conventional camera and by which direct digital photogrammetric data can be acquired. • Scanners: Special precise photogrammetric scanners are used to transform hard copy images into a digital form. • Digital image processing: Image reduction and enlargement, image enhancement, edge sharpening, and so on, are now at the dispose of user’s fingertips using special softwares, rather than spending a long time in traditional manual manipulation. Two experiments were carried out in this research work, one in a mountainous area, and the other in a flat one. In the first test an aerial wide-angle hard copy stereopair at scale 1:40,000 of mountainous terrain in Switzerland was transformed to a soft copy using a different scanning resolutions by a special photogrammetric scanner. A digital photogrammetric workstation was used to measure a number of control points of known ground coordinates. The root mean square error of the measured ground coordinates of these points and their actual coordinates were computed for each scanning resolution. ERDAS software package was used to digitally rectify the scanned images using the same pixel resolution used above. The coordinates of points were measured and the root mean square errors were computed again. The result of digital rectification is required to be supported by another test in a flat terrain. In this test an aerial wide-angle hard copy stereopair at 1:20,000 scale of a flat terrain, in the center of Khartoum, was transformed to a soft copy and rectified. The results of these investigations proved that the accuracy of the measurements in digital photogrammetry is nonlinearly proportional to the scanning pixel resolution in both horizontal and vertical measurements. Mathematical models were developed to estimate the accuracy against scanning resolution and suitable plotting scales in both horizontal and vertical mapping. Production of maps using digital image rectification using software packages such as ERDAS is suitable only in a flat terrain. On the other hand, a digital photogrammetric workstation is a productive way for mapping in both flat and mountainous terrain

Towards a Unified Theory of Sensor Pattern Noise: An analysis of dark current, lens effects, and temperature bias in CMOS image sensors

Matching images to a discrete camera is of significance in forensic investigation. In the case of digital images, forensic matching is possible through the use of sensor noise present within every image. There exist misconceptions, however, around how this noise reacts under variables such as temperature and the use of different lens systems. This study aims to formulate a revised model of the additive noise for an image sensor to determine if a new method for matching images to sensors could be created which uses fewer resources than the existing methods, and takes into account a wider range of environmental conditions. Specifically, a revised noise model was needed to determine the effects of different lens systems and the impact of temperature on sensor noise. To determine the revised model, an updated literature search was conducted on the background theory relating to CMOS sensors, as the existing work focuses on CCD imaging sensors. This theory was then applied using six off the shelf CMOS imaging sensors with integrated lens systems. An image sensor was examined under scanning electron microscopy and through the use of Energydispersive x-ray spectroscopy the non-uniform structure of individual pixels was visually observed within the sensor. The lens systems were removed and made interchangeable through the use of a 3D printed camera housing. Lens effects were assessed by swapping lens systems between the cameras and using a pinhole lens to remove all optical effects. The temperature was controlled using an Arduino controlled Peltier plate device, and dark current images were obtained at different temperatures using a blackout lens. It was observed that dark current could be used to identify the temperature of the image sensor at the time of acquisition, contrary to the statements in existing literature that sensor pattern noise is temperature invariant. It was shown that the lens system contributes approximately a quarter of the signal power xii used for pattern matching between the image and sensor. Moreover, through the use of targeted signal processing methods and simple ”Goldilocks” filters processing times could be reduced by more than half by sacrificing precision without losing accuracy. This work indicates that sensor pattern noise, while already viable for forensic identification of images to a specific camera, can also be used for identification of an image to a specific lens system and an image sensors temperature. It has also shown that a tool using sensor pattern noise may have a viable future as a forensic method of triage when confronted with large image data sets. Such additional information could prove effective for forensic investigators, intelligence agencies and police when faced with any form of crime involving imaging technology such as fraud, child exploitation or terrorism.Thesis (Ph.D.) -- University of Adelaide, School of Electrical & Electronic Engineering, 201

An assessment of archive stereo-aerial photographs for 3-dimensional reconstruction of damaged and destroyed archaeological earthworks

Archaeological earthworks are being damaged and destroyed at a rate and scale never before seen, which has resulted from increased mechanisation of human activity in the landscape since World War II. Along with natural degradation processes, recording earthwork metrics prior to their loss is increasingly difficult, which can subsequently hinder the interpretation of a site or landscape because of this missing evidence. A tool for regaining such data is vital to alleviate this problem and to fulfil the stipulation for metric information as required by national and international conservation charters. This research investigates whether it is possible to regain earthwork metrics from archive stereo-aerial photographs (SAPs) using digital photogrammetry to create digital surface models (DSMs) of archaeological sites within the UK dating from the 1940s to 2010. A literature search confirmed the utility of SAPs for reconstructing geomorphological events, such as landslides, whilst also verifying that such an approach had not been thoroughly investigated for archaeological adaptation. Via experimentation, a photogrammetric workflow has been designed and a number of variables identified that affect the quality of DSMs obtained from SAPs. The magnitude of these variables has been verified by quantitative assessment using independent survey data, namely Airborne Laser Scanning (ALS) gathered by the Environment Agency, and ground-based collection using Global Navigation Satellite Systems (GNSS) and Terrestrial Laser Scanning (TLS). Empirical differences between these independent data and the SAP DSMs were identified using global statistical measures such as Mean Error (ME), Standard Deviation (SD) and root mean square error (RMSE), and spatial autocorrelation techniques, namely Local Moran’s I. Two study sites were selected on which to ascertain whether variations occur in the empirical quality of SAP DSMs and archaeological content at different locations. Over six decades of photography were collected for Flowers Barrow Hillfort, situated near Lulworth in Dorset, UK, which has remained in good condition throughout this period, due to the protection afforded it by inclusion within Ministry of Defence land. Eggardon Hillfort and earthworks, near Bridport in Dorset, UK, were also selected due to the exceptional preservation state of some earthworks, versus the plough-damaged remains of others. These sites thus offered an opportunity to rigorously test the reconstruction capabilities of the SAPs. The results from both study sites confirmed that the metric quality of SAP DSMs improves as the age of the imagery decreases, although this is dependent on image quality, scanner properties (i.e. whether the scanner is photogrammetric or desktop) and the result of the block bundle adjustment in the photogrammetric software. This thesis concludes that SAPs can recreate earthwork metrics and provides a list of considerations for archaeologists to consult when planning the use of SAPs for creating DSMs. Recommendations for future work are provided that encourage the investigation of SAPs from other countries and the rigorous assessment of DSMs derived from structure-from-motion (SfM) software that is rapidly gaining popularity

The use of stereolithography and related technologies to produce short run tooling

ThesisWhere material properties are critical to a polymer part, rapid prototype (RP) models are inappropriate for evaluation purposes and actual parts moulded in a range of materials are required for evaluation. Conventional tool making processes have extremely long lead times considering that numerous iterations may be required. The aim of this project was to generate polymer parts, utilising various approaches to Rapid Tooling (RT) , including Stereolithography or related technologies, as part of the process. The objective was to establish decision-making criteria for deciding on the appropriateness of various processes and the risks involved to assist prospective users of these technologies. The first phase of the project focused on the process validation of utilising Stereolithography as a direct means to generate injection mould tooling inserts, which were fitted into an injection mould designed for the trial purposes. The objective was to obtain process information with regard to insert generation for Stereolithography. A three dimensional model of the part was generated with CAD and the associated mould was generated around the part. The insert halves were processed and solid epoxy inserts were generated with the 3D Systems SLA500 Stereolithography machine. These inserts were post-finished and fitted to the injection mould . Additional features were added to the inserts to test cooling and gating and wear resistance of the cavity material. The author attended the basic injection tool setting course of the Plastics Federation to enable him to contribute more directly to this process. This also highlighted some of the design issues to facilitate ease of production . Initial difficulties were experienced in finding optimal process parameters. A total of 70 parts were produced, with measurable insert degradation. During the author's training at 3D Systems in the USA, he obtained additional insight in current methods of insert modelling and insert generation. If these process problems could be overcome, it would be possible to produce in excess of a 100 parts with one set of inserts, assuming a tolerance specification of 0.2mm. The cost of producing the inserts was approximately 50% that of conventional tooling fabrication . The time lapse between growing of the inserts and production of parts was one week compared to 6 to 8 weeks tool manufacture time with conventional methods. The second phase of the project focused on methods to enhance the cavity surface. Electroplating of inserts and inserts generated from Aluminium filled epoxy were tested , to investigate the effects that plating has on tool life, dimensional accuracy, temperature distribution, and the cost implications for these subsequent process steps. Stereolithography inserts were generated, taking into account the design considerations. Aluminium filled epoxy inserts were subsequently cast from silicone moulds drawn off the Stereolithography master patterns. Two sets of Stereolithography inserts were plated with 20 ~m of electrolytic nickel plating. One set of aluminium filled epoxy inserts were plated with electrolytic copper followed by electroless nickel. The mould sets were subjected to the same injection moulding trials using Polypropylene. The third phase of the project evaluated the use of Stereolithography investment casting masters to produce tool steel inserts, through the QuickCast process. Porosity was evident, with substantial machining required to fit the inserts. Not all the detail was retained during the casting process. Thin rib features on the part were thus lost. Due to the porosity the cooling was changed to copper tubes fitted into the rear of the tool and back-filled with aluminium epoxy. As the Stereolithography patterns were not polished the metal inserts had to be hand finished. This was a time consuming process and skill is required to obtain a good finish. A cost comparison indicated that machining aluminium inserts would be more cost effective. The tool manufacture time and eventual cost is not significantly less than conventional machining . In fact, trials with aluminium High speed CNC machining proved to be more time, finish and cost effective. This is discussed as part of the trial examples. Wax injection into AIM tooling was investigated on behalf of a client, with good results . As ceramic and polymer injection are very similar, apart from the ceramic being far more abrasive, it is the author's opinion that AIM tooling would be applicable, taking into account that fewer parts may be achieved. The KelTool process was also investigated during the author's USA visit. The licensing fees and additional equipment are extremely costly due to the Rand IDollar exchange rate. Issues related to this process are documented in this report. Clearly the deciding factors remain the quantity of parts required and the complexity of form. Each manufacturing process has a certain level of risk involved. Accumulative risk not only sets manufactured parts at risk but could jeopardise project time scales and iterations of a process have significant impact on a project budget