T his paper describes a real-time prototype computer vision system for monitoring driver vigilance. The main components of the system consists of a remotely located video CCD camera, a specially designed hardware system for real-time image acquisition and for controlling the illuminator and the alarm system, and various computer vision algorithms for simultaneously, real-time and non-intrusively monitoring various visual bio-behaviors that typically characterize a driver's level of vigilance. The visual behaviors include eyelid movement, face orientation, and gaze movement (pupil movement). The system was tested in a simulating environment with subjects of different ethnic backgrounds, different genders, ages, with/without glasses, and under different illumination conditions, and it was found very robust, reliable and accurate. IntroductionThe ever-increasing number of traffic accidents in the US due to a diminished driver's vigilance level has become a problem of serious concern to society. Drivers with a diminished vigilance level suffer from a marked decline in their abilities of perception, recognition, and vehicle control, and therefore pose serious danger to their own life and the lives of other people. Statistics show that a leading cause for fatal or injury-causing traffic accidents is due to drivers with a diminished vigilance level. In the trucking industry, 57% fatal truck accidents are due to driver fatigue. It is the number 1 cause for heavy truck crashes. Seventy percent of American drivers report driving fatigued. With the ever-growing traffic conditions, this problem will further deteriorate. For this reason, developing systems actively monitoring a driver's level of vigilance and alerting the driver of any insecure driving conditions is essential to prevent accidents.Many efforts [1][2][3][4][5][6][7][8][9] have been reported in the literature for developing active safety systems intended for reducing the number of automobile accidents due to Real-Time Imaging 8, 357-377 (2002Imaging 8, 357-377 ( ) doi:10.1006Imaging 8, 357-377 ( /rtim.2002, available online at http://www.idealibrary.com on reduced vigilance. Among different techniques, the best detection accuracy is achieved with techniques that measure physiological conditions like brain waves, heart rate, and pulse rate [8,10] People in fatigue exhibit certain visual behaviors easily observable from changes in their facial features like the eyes, head, and face. Typical visual characteristics observable from the image of a person with reduced alertness level include slow eyelid movement [12,13], smaller degree of eye openness (or even closed), frequent nodding [14], yawning, gaze (narrowness in the line of sight), sluggish in facial expression, and sagging posture. To make use of these visual cues, another increasingly popular and non-invasive approach for monitoring fatigue is to assess a driver's vigilance level through visual observation of his/her physical conditions using a camera and state-of-the-art technologies in computer vision. ...

We present the smallest reported side-viewing needle probe for optical coherence tomography (OCT). Design, fabrication, optical characterization, and initial application of a 30-gauge (outer diameter 0.31 mm) needle probe are demonstrated. Extreme miniaturization is achieved by using a simple all-fiber probe design incorporating an angle-polished and reflection-coated fiber-tip beam deflector. When inserted into biological tissue, aqueous interstitial fluids reduce the probe's inherent astigmatism ratio to 1.8, resulting in a working distance of 300 μm and a depth-of-field of 550 μm with beam diameters below 30 μm. The needle probe was interfaced with an 840 nm spectral-domain OCT system and the measured sensitivity was shown to be only 7 dB lower than that of a comparable galvo-scanning sample arm configuration. 3D OCT images of lamb lungs were acquired over a depth range of ~600 μm, showing individual alveoli and bronchioles.

Artificial muscles triggered by light are of great importance, especially for the development of non-contact and remotely controlled materials. Common materials for synthesis of photoinduced artificial muscles typically rely on polymer-based photomechanical materials. Herein, we are able to prepare artificial muscles using a mixed-matrix membrane strategy to incorporate photomechanical molecular crystals with connective polymers (e.g. PVDF). The formed hybrid materials inherit not only the advantages of the photomechanical crystals, including faster light response, higher Young's modulus and ordered structure, but also the elastomer properties from polymers. This new type of artificial muscles demonstrates various muscle movements, including lifting objects, grasping objects, crawling and swimming, triggered by light irradiation. These results open a new direction to prepare light-driven artificial muscles based on molecular crystals.

The introduction of twist during the spinning of carbon nanotubes from their arrays (forests) has been widely applied in making ultrastrong, stiff, and lightweight nanotube fibers. Here, for the first time, an important observation of a double-peak behavior of the tensile properties, as a function of the twist angle, that is different from the single peak of traditional fibers is reported. Raman spectra show that the new peak arises from the collapse of nanotubes, showing a strong "nano" element in applying the ancient draw-and-twist technique, besides the downsizing. A qualitative continuum model is also presented to describe the collapse-induced enhancement as well as traditional fibers. Our combined experimental and theoretical studies indicate the direction of full utilization of the nano element in improving the mechanical properties of nanotube fibers.

McLaughlin RA, Yang X, Quirk BC, Lorenser D, Kirk RW, Noble PB, Sampson DD. Static and dynamic imaging of alveoli using optical coherence tomography needle probes.

In the past decade, the use of visible light to promote organic transformations has gained intense attention. In this study, we developed a template-directed synthesis method to use homogeneous Ru and Ir photocatalysts as structure-directing templates and succeeded to prepare a series of photocatalyst-encapsulating metal−organic frameworks (photocatalyst@MOFs) with zeolite-like structures. The open channels and polyhedral cages of MOFs effectively dispersed the encapsulated photocatalysts and facilitated the transport of reactants and products, leading to boosted catalytic activity and good reusability toward important organic reactions such as aerobic oxidation reaction of benzyl halides and the cyclization of tertiary anilines and maleimides under visible light. Moreover, we also demonstrate the versatility and universality of our templating strategy. It not only can form MOFs which cannot be accessed by other synthesis methods, but also can encapsulate various commercially available homogeneous photocatalysts into MOFs. This work explores an avenue to prepare heterogeneous photocatalysts to catalyze value-added reactions.

We report on a novel scheme for extending the depth of focus (DOF) of ultrathin (125 μm diameter) fiber probes for optical coherence tomography (OCT) using a simple phase mask consisting of graded-index (GRIN) fiber. The technique is compatible with existing all-in-fiber probe fabrication techniques, and our simulations show that it can provide a DOF gain of ~2 at a modest ~5 dB reduction of peak sensitivity. In a prototype device using commercially available GRIN fiber, a DOF gain of 1.55 is obtained, validated by beam profiling and OCT imaging.

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