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Editor-in-Chief Harry Levinson introduces a new set of guidelines for papers related to computational lithography.

Photoacoustic (PA) imaging for the examination of altered documents in forensic science has been investigated by an innovative system with a nanosecond pulsed laser, a microphone, and a handmade sample holder. The PA signals from lines written by black pens on paper were successfully detected without coupling media such as gels, and the signal amplitude was found to depend on the type of writing pen. The original contents of the document changed by the addition of a line and of the obliterated document were clearly observed by the PA imaging. The nondestructive PA measurement and imaging have been demonstrated to be a high-potential technique to discriminate writing inks and to examine altered documents.

Electronic readers, with their attractive functionality, are a rapidly growing market despite shortcomings of the most commonly used e-paper technology, electrophoretic displays (EPDs).1 The limitations include a slow response time not suitable for video operation, relatively low contrast, and an absence of color. However, since EPD e-readers operate using ambient light (in reflective mode), they have very low power consumption, resulting in long battery operation. The current main competition comes from liquid crystal display-based tablets, which use backlit transmissive displays with full color and video. Tablets have many additional capabilities beyond being e-readers. However, they consume more power and are generally bulkier and heavier than EPDs. Another approach (see Figure 1) being pursued uses electrowetting2 (EW) to form a light valve by moving two immiscible liquids (one clear and one colored) in and out of the light path by applying an electric field. Figure 2(a) shows a schematic illustration of the EW effect in a pixel containing oil and water for zero and applied bias along with photographs of a portion of an array under corresponding conditions. EW technology has many applications, including flat-panel displays, electronic-focus lenses, and microfluidic devices. The EW light-valve display approach is quite versatile, allowing for reflective,3 transmissive,4, 5 and even emissive6 operation. Most important, its switching speed is in the millisecond time range,3, 6 which enables video operation. An important consideration in all display technologies is power consumption. In EW displays, several approaches for minimizing power use have been reported, including bistable,7 multi-value stable,8 and complementary operation.9 Figure 2(b) shows complementary operation of EW devices under applied voltage. We have achieved a reversal of the normal twofluid competitive (water vs. oil) EW on a dielectric by plasma Figure 1. Flexible electronic-paper technology.

Paper-based microfluidic devices offer great potential as a low-cost platform to perform chemical and biochemical tests. Commercially available formats such as dipsticks and lateral-flow test devices are widely popular as they are easy to handle and produce fast and unambiguous results. Although these simple devices lack precise control over the flow to enable integration of complex functionality for multistep processes or the ability to multiplex several tests, intense research in this area is rapidly expanding the possibilities. Modeling and simulation is increasingly more instrumental in gaining insight into the underlying physics driving the processes inside the channels; however, simulation of flow in paper-based microfluidic devices has barely been explored to aid in the optimum design and prototyping of these devices for precise control of the flow. We implement a multiphase fluid flow model through porous media for the simulation of paper imbibition of an incompressible, Newtonian fluid such as when water, urine, or serum is employed. The formulation incorporates mass and momentum conservation equations under Stokes flow conditions and results in two coupled Darcy’s law equations for the pressures and saturations of the wetting and nonwetting phases, further simplified to the Richard’s equation for the saturation of the wetting fluid, which is then solved using a finite element solver. The model tracks the wetting fluid front as it displaces the nonwetting fluid by computing the time-dependent saturation of the wetting fluid. We apply this to the study of liquid transport in two-dimensional paper networks and validate against experimental data concerning the wetting dynamics of paper layouts of varying geometries.

We present a method of measure of the roughness of the paper based on the analysis of a speckle pattern on the surface. Images of speckle over the surface of paper are captured by means of a simple configuration using a laser, beam expander, and a camera charge-coupled device (CCD). Then we use the normalized covariance function of the fields, leaving the surface to find the roughness. We compare the results obtained with the results obtained with a confocal microscope and the Bendtsen method that is a standard of the paper industry. This method can be considered as a noncontact surface profiling method that can be used online. We present a method of measure of the roughness of the paper based on the analysis of a speckle pattern on the surface. Images of speckle over the surface of paper are captured by means of a simple configuration using a laser, beam expander, and a camera charge-coupled device (CCD). Then we use the normalized covariance function of the fields, leaving the surface to find the roughness. We compare the results obtained with the results obtained with a confocal microscope and the Bendtsen method that is a standard of the paper industry. This method can be considered as a noncontact surface profiling method that can be used online.

A copy-protection system was developed in order to pre- vent the unauthorized reproduction of photographic prints at a digital print station. The copy-protection system consists of two parts: (1) copy-protected photographic paper manufactured with a latent im- age of an array of yellow microdots; and (2) digital print stations equipped with software that detects the presence of the microdots in the digital image of a photographic print made on copy-protected photographic paper. The system has a detection rate of 78% and a negligible rate of false detection. © 2000 SPIE and IS&T.

Editor-in-Chief Chris Mack explains what motivates scientists to write and publish research.

This PDF file contains the editorial “How to Write a Good Scientific Paper: Review Articles” for JM3 Vol. 15 Issue 02

We address the restoration of noisy and blurred images that are scanned from photographic paper. In this case, we need to consider the nonilnearities introduced by both the photographic film and the paper. To this effect, we first transform the measured refiection density of the photographic paper into the scene exposure domain in which a linear convolutional relationship between the orig- Thai scene and the degraded image can be established. As a result of this transformation, any additive noise Th the reflection density domaTh becomes multiplicative Th the scene exposure domaTh. We then propose a linear filter for deconvolution Th the exposure domaTh in the presence of multiplicative observation noise. Experiments with actual noisy and blurred images scanned from photographic paper Thdicate that the noniThear sensor characteristics must be Thcorporated Thto image restoration to obtaTh satisfactory results. We also compare the quality of the restoration results when the same blurred image is scanned from the photographic negative (film) and the prTht (paper) obtaThed from this negative.

This PDF file contains the editorial “JATIS papers among SPIE’s most downloaded” for JATIS Vol. 1 Issue 04

This PDF file contains the editorial “How to Write a Good Scientific Paper: Picking the Right Journal” for JM3 Vol. 14 Issue 04

Writing is inherently a creative process. That would seem agood fit for the science researcher, where creativity coupledwith critical thinking is the key to success. Alas, many scien-tists donot thinkofthemselves asqualified writers,some find-ingthetaskofwritingbothintimidatingandarduous.Forthosereaders who are not already experienced at writing articles forsciencejournals,Ihaveasecrettoshare:youdon’thavetobea good writer to write a good science paper. The reason isthis: there is a formula for how to structure and organize a sci-entific paper, so that the scientist/writer can focus on whatthey know best – the science – and worry less about thewriting.A formula for writing? That may sound like a recipe formediocrity, and in some contexts this would surely be true.But for the science paper, the emphasis must always stayon the science, with the words mere tools for effectively con-veying information. Over the last 350 years scientific journalshave evolved a distinctive style, structure, and organizationthat makes it easy for both the writer and the reader to getwhat they need from the paper: effective communication ofscientific ideas.A major difference between journal-based science writingand the many diverse forms of writing found elsewhere is thevery limited scope of our medium. A science paper does nothave to be all things to all people. It is a narrow genre with anarrow (though very important) purpose. A specific scientificcommunity (say, the readership of JM

Optical Engineering has had some outstanding special sections over the past few years and some that were not so great. To me, the key is the guest editors who provide the energy behind the special section. A good solid special section has around 10 to 20 papers all within the scope of a single subject. The subject must be interesting, timely, and important. We have had special sections with upwards of 30 thoroughly reviewed papers, and these specials have provided a great reference to scientist and engineers working in a particular field.