This PDF file contains the front matter associated with SPIE Proceedings Volume 7596, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Surgical technology advances slowly and only when there is overwhelming need for change. Change is resisted by surgeons and is made hard by FDA rules that inhibit innovation. There is a pressing need to improve surgeon's visualization of the operative field during laparoscopic surgery to minimize the risk for significant injury that can occur when surgeons are operating around delicate, hidden structures. We propose to use a Digital Light Processor-based hyperspectral imaging system to assist an operating surgeon's ability to see through tissues and identify otherwise hidden structures such as bile ducts during laparoscopic cholecystectomy.

Information is presented as to the design of a versatile pattern light projection device that has been essential in the development of the Artemis Broad Spectrum Vision System for imaging of spatial tissue oxygen-saturation measurement as well as of near infrared fluorescent-labeled tumors to facilitate their surgical removal. The combined technology for molecular imaging (Artemis Camera) and image-guided projection of light (Artemis DMD-Projection System) is of significant benefit for various clinical applications. In case of tissue oxygen measurements, the application of illumination patterns of specific near-infrared light and concomitant read out of reflected light from non-illuminated areas theoretically will reveal information from deeper structures. As regards tumor surgery, photodynamic therapy for elimination of tumor tissue is the most exciting and even more demanding, in that the areas to be illuminated perfectly have to match the areas where cancerous tissue is detected. Several performance criteria had to be met for the projection system: mixing wavelengths from different light sources via a 3-channel prism; apochromatic from 430 to 1,000 nm; the projector's zoom-function to follow the Artemis camera zoom settings; the angle of projection to adapt to the full working distance range; and the integration of O₂view´s custom camera controls with the DLP-chip.

Utilizing seed funding from Texas Instruments, a DLP (R)Hyperspectral Imaging system was developed by integrating a focal-plane array, FPA, detector with a DLP based spectrally tunable illumination source. Software is used to synchronize FPA with DLP hardware for collecting spectroscopic images as well as running novel illumination schemes and chemometric deconvolution methods for producing gray scale or color encoded images visualizing molecular constituents at video rate. Optical spectra and spectroscopic image data of a variety of live human organs and diseased tissue collected from patients during surgical procedures and clinical visits being cataloged for a database will be presented.

Novel hyperspectral imaging (HSI) methods may play several important roles in Combat Casualty Care: (1) HSI of the skin may provide spatial data on hemoglobin saturation of oxygen, as a "window" into perfusion during shock. (2) HSI or similar technology could be incorporated into closed-loop, feedback-controlled resuscitation systems. (3) HSI may provide information about tissue viability and/or wound infection. (4) HSI in the near-infrared range may provide information on the tissue water content--greatly affected, e.g., by fluid resuscitation. Thus, further refinements in the speed and size of HSI systems are sought to make these capabilities available on the battlefield.

Mapping of absolute oxygen levels in the brain is critical during stroke and other disorders. One of the standard methods for measuring oxygen tension is through oxygen dependent quenching of phosphorescence. Typically these measurements are limited to a single spatial location due to the need to measure phosphorescence lifetimes. We have developed an instrument to obtain spatial maps oxygen tension in the brain by combining a DMD with phosphorescence lifetime measurements. Blood flow is measured simultaneously with laser speckle contrast imaging. In this paper we describe this instrument and demonstrate its use in studying stroke progression in animal models.

Human vision by a clinical practitioner is often the first disease detection tool. Illumination for such procedures as endoscopy use broadband white light, with luminance level being the only control available. The use of staining dyes for contrast improvement have shown limited adoption due to the additional steps needed and small number of approved dyes for in vivo use. Here we explore the control of the illuminant spectral distribution to improve chromatic contrast without the use of dyes. The computational steps used in converting spectral data to RGB and use of the CIELAB chromatic and luminance contrast metric as criteria in determining the appropriate lighting spectral distribution will be discussed. The skin on the back of the hand and the skin section over a vein are used as examples of tissue features to be contrasted. A 3-wavelelength LED lamp and an incandescent lamp with the yellow spectral region filtered out are shown as examples that spectrally-shaped illumination can enhance visual contrast.

We report the development of a confocal fluorescence imaging system based on a digital micro-mirror device (DMD). A DMD has an advantage of offering lateral sample scanning with programmable light modulation at an ultrahigh speed, while providing pinhole arrays on the source and/or detector side to enhance depth and lateral resolution for confocal detection. In this paper, we present a DMD-based fluorescence detection system for studying dynamics of multiple cells in vitro that are cultured in a microfluidic cell culture device. For feasibility, we tested the optical system using USAF target and studied imaging with fluorescence microbeads (φ = 10 μm) as an equivalent to a cell.

Optoelectronic tweezers (OET) have emerged in recent years as a powerful form of optically-induced dielectrophoresis for addressing single cells and trapping individual nanostructures with DMD-based virtual-electrodes. In this technique an alternating electric field is used to induce a dipole within structures of interest while very low-intensity optical images are used to produce local electric field gradients that create dynamic trapping potentials. Addressing living cells, particularly for heat-sensitive cell lines, with OET's optical virtual-electrodes requires an in-depth understanding of heating profiles within OET devices. In this work we present quantitative measurements of the thermal characteristics of single-crystalline-silicon phototransistor based optoelectronic tweezers (PhOET). Midwave infrared (3 - 5 micron) thermographic imaging is used to determine relative heating in PhOET devices both with and without DMD-based optical actuation. Temperature increases of approximately 2°C from electrolyte Joule-heating are observable in the absence of DMD-illumination when glass is used as a support for PhOET devices. An additional temperature increase of no more than 0.2°C is observed when DMD-illumination is used. Furthermore, significantly reduced heating can be achieved when devices are fabricated in direct contact with a metallic heat-sink.

Laser beams with precisely controlled intensity profiles are essential for many areas of optics and optical physics. We create such beams from real-world lasers: quasi-Gaussian beams obtained directly from a laser and beam-expanding telescope without spatial filtering. Our application is to form optical standing-wave lattices for Bose-Einstein condensates in quantum emulators. This requires controlled amplitude and flat phase, and that the beam be free of temporal modulation from either pixel dithering or refresh cycles. We describe the development of the pattern design algorithms and demonstrate the performance of a high precision beam shaper to make flattop beams and other spatial profiles with similarly low spatial frequency content. The digital micromirror device (DMD) was imaged through a telescope containing a pinhole low-pass filter. An error diffusion algorithm was used to design the initial DMD pixel pattern based on the input beam profile. This pattern was iteratively refined based on output image measurements. We demonstrate forming a variety of beam profiles including flattop beams and beams with 1-D linear intensity variation, both with square and circular cross-sections. Produced beams had less than 0.25% root-mean-square (RMS) error with respect to the target profile and nearly flat phase.

The two approaches presented in this paper consist of splitting the tracking action into two sub-systems. The decoupling of local scanning and global scanning functions is an alternative solution to the use of fast-steering, power-consuming galvanometric scanner. Applications targeted are multi-object tracking and 3D perception in safe condition. This paper presents more specifically an approach based on a Risley prism configuration steering a laser pattern dynamically shaped by a DMD allowing a good compromise for the refresh rate and the precision.

Programmable array microscopes (PAMs) use "multi-pinhole" masks in confocal image planes to introduce illumination and block the "out-of-focus light". Compared to traditional confocal microscopes (CM), PAM systems have higher efficiency in utilizing the signal light and faster image acquisition speed. However, these advantages are gained at the cost of using more complicated optics and detectors. Compressive sampling (CS) measurement patterns can be used as pinhole masks in PAM systems. With CS patterns, the light collected after the detector mask can be summed up and used to reconstruct the imaging scene via solving an l₁-minimization problem. Only a simple relay-lens and a singlepixel detector are needed to measure the intensity of the summed light. Therefore the optical complexity associated with conventional PAM systems can be reduced. Since only a single-pixel detector is needed, this system can also be called a single-pixel PAM or SP-PAM system. In this work, we introduce the design and fabrication of a prototype SP-PAM system. In this system, scrambled-block Hadamard ensembles (SBHE) are used as CS measurement patterns and a digital micromirror device (DMD) is employed to realize these patterns.

The EUCLID mission from the European Space Agency (ESA) will study the dark universe by characterizing a very high number of galaxies in shape and in spectrum. The high precision spectra measurements could be obtained via multi-object spectroscopy (MOS) using Digital Micromirror Devices (DMD). These devices would act as object selection reconfigurable masks. ESA has engaged with Visitech and LAM in a technical assessment of the DMD from Texas Instruments that features a 2048 x 1080 mirrors and a 13.68μm pixel pitch for space applications. For EUCLID, the device should work in vacuum, at low temperature, and each MOS exposure lasts 1500s with micromirrors held in a static state (either ON or OFF) during that duration. A specific thermal / vacuum test chamber has been developed for test conditions down to -40°C at 10^-5 mbar vacuum. Imaging capability for resolving each micromirror has also been developed for determining any single mirror failure. Dedicated electronics and software permit to hold any pattern on the device for a duration as long as 1500s. Our first tests reveal that the DMD remains fully operational at -40°C. A 1038 hours life test, in EUCLID conditions (temperature and vacuum) has been successfully completed. Total Ionizing Dose (TID) radiation tests have been completed, establishing between 10 and 15 Krads, the level of TID that the DMD can tolerate; at mission level, this limitation could most likely be overcome by a proper shielding of the device. Finally, thermal cycling, vibration tests and MOS-like tests are under way.

Time resolved 3D-microscopy using DMD-arrays utilizes the principles of confocal microscopy. Application fitted patterns optimize optical imaging of reflective, transparent, and fluorescent objects. Diffraction limited spatial resolution is achieved at simultaneously high temporal resolution due to fast DMD controlling. This enables to visualize and track processes in vivo within living biocells as well as fast structural volume and surface mapping.

The Use of DMD based Rapid Manufacturing Systems has proven to be very advantageous in the production of highly accurate plastic based components for use in mass customization market such as hearing aids, and dental markets. The voxelization process currently afforded with the DLP technology eliminates any layering effect associated with all existing additive Rapid Manufacturing technologies. The smooth accurate surfaces produced in an additive process utilizing DLP technology, through the voxelization approach, allow for the production of custom finished products. The implementation of DLP technology in rapid prototyping and rapid manufacturing systems allow for the usage of highly viscous photopolymer based liquid and paste composites for rapid manufacturing that could not be used in any other additive process prior to implementation of DLP technology in RP and RM systems. It also allowed for the greater throughput in production without sacrificing quality and accuracy.

The development of the Digital Micromirror Device (DMD) by Texas Instruments has made a significant breakthrough in 3D micro-manufacturing, and in particular, in the area of additive layer-based manufacturing. One area of particular interest for using DMD technology is microstereolithography; a technology that builds 3D shapes through successive photopolymerization of individual thin 2D layers that are stacked vertically. A DMD-based projection microstereolithography system and a robust micro-manufacturing process have been developed. This system and various micro-fabricated 3D structures with features on the order of 10 microns, including recent advancements in multimaterial micro-fabrication, will be presented and described.

A key parameter in evaluating the performance of photovoltaic (PV) solar cells is characterization of electrical response to various incident source spectra. Conventional techniques utilize monochromators that emit single band-passes across a spectral region of interest. Since many solar cells respond differently at different broadband source light levels, a white bias light source that raises the overall light level to simulate the sun's broadband emission is typically introduced. However, such sources cannot render realistic solar continua. We present some initial results demonstrating how a spectrally-dispersed broadband source modulated with Texas Instruments' Digital Light Projection (DLP®) technology can be used to more faithfully synthesize solar spectra for this application.

The DMD™ (Digital Micromirror Device) has become an integral part of the instrumentation for many applications. Prior characterization of this device has been focused on its use in DLP™ (TI Digital Light Processing) projector applications where a collimated wavefront impinges on the DMD. The results of such investigations are not applicable to using DMDs at the focal plane of an optical system where it is used as a slit mask (e.g. in a multi-object spectrometer). In order to study the DMD scattering function in this second case, a subpixel spot scanning system has been assembled. The scattered light collected from this system allowed a subpixel scattering function to be determined for the DMD when illuminated by a converging beam.