Extracorporeal membrane oxygenators with light-diffusing fibers for treatment of carbon monoxide poisoning: Experiments, mathematical modeling, and performance assessment with unit cells.

Unlabelled: BACKGROUND AND OBJECTIVES: Approximately 50,000 emergency department visits per year due to carbon monoxide (CO) poisoning occur in the United States alone. Tissue hypoxia can occur at very low CO concentration exposures because CO binds with a 250-fold higher affinity than oxygen to hemoglobin. The most effective therapy is 100% hyperbaric oxygen (HBO) respiration.

In vitro comparison between the image obtained using PSP plates and Kodak E-speed films.

Objectives: The aim of this study was to compare the intra-oral radiographic images obtained by a PSP digital radiography system ("Orex", Israel) with that obtained using Kodak Ultra speed films in terms of image quality, radiation dosage and diagnostic value.

Methods: The physical measurement of image quality was conducted with an aluminum step-wedge. Radiation dosage was measured with a dosimeter.

Nonuniform sampling, image recovery from sparse data and the discrete sampling theorem.

In many applications, sampled data are collected in irregular fashion or are partly lost or unavailable. In these cases, it is necessary to convert irregularly sampled signals to regularly sampled ones or to restore missing data. We address this problem in the framework of a discrete sampling theorem for band-limited discrete signals that have a limited number of nonzero transform coefficients in a certain transform domain.

Superresolution in color videos acquired through turbulent media.

Color videos acquired with a single CCD through turbulent media can be enhanced in their resolution beyond the limit defined by the image sampling rate. We provide a mathematical justification for this claim, present an efficient superresolution algorithm and its experimental verification on a real-life video, and finally, discuss its potentials and limitations.

Input-image homogenization as a method to improve a correlator's discrimination capability.

We propose an input-image preprocessing method consisting of homogenization of the image to improve the discrimination capability of a correlation-based recognition process. This method is an approximation of the optimal filter. It offers the advantage that correlation with the preprocessed images can easily be implemented in an optical correlator working with phase-only spatial light modulators.

Integration in the Fourier domain for restoration of a function from its slope: comparison of four methods.

In some measurement techniques the profile, f(x), of a function should be obtained from the data on measured slope f(?)(x) by integration. The slope is measured in a given set of points, and from these data we should obtain the profile with the highest possible accuracy. Most frequently, the integration is carried out by numerical integration methods [Press et al.

Superresolution in turbulent videos: making profit from damage.

It is shown that one can make use of local instabilities in turbulent video frames to enhance image resolution beyond the limit defined by the image sampling rate. We outline the processing algorithm, present its experimental verification on simulated and real-life videos, and discuss its potentials and limitations.

Stochastic nonlinear dynamics pattern formation and growth models.

Stochastic evolutionary growth and pattern formation models are treated in a unified way in terms of algorithmic models of nonlinear dynamic systems with feedback built of a standard set of signal processing units. A number of concrete models is described and illustrated by numerous examples of artificially generated patterns that closely imitate wide variety of patterns found in the nature.

Image processing for a high-resolution optoelectronic retinal prosthesis.

In an effort to restore visual perception in retinal diseases such as age-related macular degeneration or retinitis pigmentosa, a design was recently presented for a high-resolution optoelectronic retinal prosthesis having thousands of electrodes. This system requires real-time image processing fast enough to convert a video stream of images into electrical stimulus patterns that can be properly interpreted by the brain. Here, we present image-processing and tracking algorithms for a subretinal implant designed to stimulate the second neuron in the visual pathway, bypassing the degenerated first synaptic layer.

Redundancy of stereoscopic images: Experimental evaluation.

With the recent advancement in visualization devices over the last years, we are seeing a growing market for stereoscopic content. In order to convey 3D content by means of stereoscopic displays, one needs to transmit and display at least 2 points of view of the video content. This has profound implications on the resources required to transmit the content, as well as demands on the complexity of the visualization system.

Frequency responses and resolving power of numerical integration of sampled data.

Methods of numerical integration of sampled data are compared in terms of their frequency responses and resolving power. Compared, theoretically and by numerical experiments, are trapezoidal, Simpson, Simpson-3/8 methods, method based on cubic spline data interpolation and Discrete Fourier Transform (DFT) based method. Boundary effects associated with DFT- based and spline-based methods are investigated and an improved Discrete Cosine Transform based method is suggested and shown to be superior to all other methods both in terms of approximation to the ideal continuous integrator and of the level of the boundary effects.

Algorithm for reconstruction of digital holograms with adjustable magnification.

A new algorithm that allows for reconstruction of digital holograms with adjustable magnification is proposed. The algorithm involves two reconstruction steps implemented by a conventional single Fourier-transform algorithm. The advantages of the algorithm lie in its adaptability to various object sizes and recording distances as well as in its capability to maintain the pitch of a reconstructed image, independent of the reconstruction distance and wavelength for objects larger than a CCD.

Boundary effect free and adaptive discrete signal sinc-interpolation algorithms for signal and image resampling.

The problem of digital signal and image resampling with discrete sinc interpolation is addressed. Discrete sine interpolation is theoretically the best one among the digital convolution-based signal resampling methods because it does not distort the signal as defined by its samples and is completely reversible. However, sinc interpolation is frequently not considered in applications because it suffers from boundary effects, tends to produce signal oscillations at the image edges, and has relatively high computational complexity when irregular signal resampling is required.

Nonlinearity optimization in nonlinear joint transform correlators.

Three types of nonlinear transformations of the joint spectrum in nonlinear joint transform correlators (NLJTC's) are investigated with the purpose of achieving the highest discrimination capability in target location in a cluttered background: logarithmic transformation and the (1/k)th law transformation in combination with the limitation of the signal dynamic range and binarization by thresholding. By computer simulation carried out on a set of test images, it is shown that application of these transformations in NLJTC's may considerably improve the correlator's capacity to locate and recognize properly small objects on a cluttered background, provided there is proper selection of nonlinearity parameters. It is also shown that a moderate blur of the joint spectrum in such NLJTC's before nonlinear transformation is permissible, which simplifies the requirements of correlator optical alignment, the resolution power of correlator electronic components, or both.

Efficient algorithm for discrete sinc interpolation.

A new computing method for discrete-signal sinc interpolation suitable for use in image and signal processing and the synthesis of holograms is described. It is shown to be superior to the commonly used zero-padding interpolation method in terms of interpolation accuracy, flexibility, and computational complexity.

A Fourier based algorithm for tracking SPAMM tags in gated magnetic resonance cardiac images.

A method is described for automatically tracking spatial modulation of magnetization tag lines on gated cardiac images. The method differs from previously reported methods in that it uses Fourier based spatial frequency and phase information to separately track horizontal and vertical tag lines. Use of global information from the frequency spectrum of an entire set of tag lines was hypothesized to result in a robust algorithm with decreased sensitivity to noise.

Color pattern recognition with circular component whitening.

Polychromatic object recognition based on circular whitening preprocessing of red-green-blue components and multichannel matched filtering is described. Computer simulations and experimental results are provided to facilitate recognizing a color target among objects of similar shape but with different color contents. Experimental results are obtained with an optical correlator with two spatial light modulators, one to introduce the scene and the second one to introduce the filter.

Optical correlators with (-k)th-law nonlinearity: optimal and suboptimal solutions.

A computer simulation of nonlinear correlators with (-k)th-law nonlinearity has been implemented. The nonlinearity is applied to the input-image power spectrum, with either a matched filter or a phase-only filter representing the reference object. Optimal correlators (with an exactly known power spectrum of the background-image component) and suboptimal correlators have been studied in order to establish potential limits and achievable figures for the correlator's discrimination capability in a target location in a cluttered background.

Convolution-based interpolation for fast, high-quality rotation of images.

This paper focuses on the design of fast algorithms for rotating images and preserving high quality. The basis for the approach is a decomposition of a rotation into a sequence of one-dimensional translations. As the accuracy of these operations is critical, we introduce a general theoretical framework that addresses their design and performance.

Optimal filter approximation by means of a phase-only filter with quantization.

Approximate filters based on a phase-only filter for reliable recognition of objects are proposed. Good light efficiency and discrimination capability close to that of the optimal filter can be obtained. Computer simulation results are presented and discussed.

Deconvolution of multiple images of the same object.

Deconvolution of images of the same object from multiple sensors with different point spread functions as suggested by Berenstein [Proc. IEEE 78, 723 (1990); Stochastic and Neural Methods in Signal Processing, Image Processing, and Computer Vision, S. Chen, ed.

Computer-assisted technologies in lung cancer diagnosis and staging.

A paradigm for digital image processing in radiological diagnosis and an appropriate algorithmic instrumentation toolset for the implementation of image processing methods on inexpensive computers and workstations are outlined briefly. Examples of computer-assisted technologies for lung cancer differential diagnosis are given that exhibit considerable increase in diagnostic accuracy. Multimodal image processing and data fusion in lung cancer diagnosis are discussed and a 'road map' for examining lung cancer patients is suggested on the basis of clinical experience in the use of different modalities for lung cancer staging.

Target location measurement by optical correlators: a performance criterion: comment.

Fleisher et al. [Appl. Opt.