Collagen fibers and their component fibrils make up the protenaceous " backbone" of most tissues and provide the majority of their resistance to tensile loading. Spatial orientation of collagen fibrils is an important factor in determining tissue properties. This is particularly true in ligament tissue, since ligaments must be loose enough to allow joints to move but tight enough to prevent joint surfaces from separating. A method is presented here to reproducibly quantify this collagen arrangement, which should be useful in studies on ligament healing and growth.

A Fourier Domain Directional Filterng Method for Analysis of Collagen Alignment in Ligaments

Various optical data-processing techniques are reviewed in this article Both coherent and incoherent optical systems are considered Coherent systems are described in terms of spatial filtering concepts and two principal methods for implementing a general linear integral operator are discussed: one using space-domain reference function masks and one using frequency-domain spatial filters Incoherent systems are described in terms of geometrical optics

A Review of Optical Data-processing Techniques

and many different ways in which the results may be used within systematics and evolutionary biology. The methods range from the use of a measurement and univariate statistics, to holographic techniques. The forms to be characterized may be the external dimensions of some simple biological object, the complex internal patterns revealed by such methods as dissection and radiography, or the complicated and multidimensional "structure" of data relevant to a biological problem. Problems of systematics and evolution may be attacked through straightforward descriptions of organisms on the one hand, or, on the other, through elucidation of the conceptual patterns associated with ontogenetic, genetic, phylogenetic, functional, environmental, populational, geographic, and other issues. At the beginning of the century when the science of morphometrics was still in its infancy, Karl Pearson prophesied that "Twenty years hence our successors, working by improved methods and with better training, will no doubt reach fitter definitions and more exact values for vital coefficients." He added that by this time, morphometric methods will not "have to justify themselves to a non-mathematical biological world; mathematical knowledge will seem to be as much a part of the biologist's equipment as today of the physicist." Yet in spite of what may appear to be an enormous spate of papers using morphometric approaches, seventy years later it is still scarcely appropriate to review the contributions of morphometric techniques to biological thought. Many of the

One Biologist's View of Morphometrics

In the middle and late 1960s, holography, applied to acoustics, generated a considerable upsurge of activity in the already mature acoustic imaging technology. It brought both coherent optics and digital data processing to bear upon the problems of acoustic imaging and introduced fresh approaches to the visualization of sound fields. These developments are reviewed and the wide range of potential applications for acoustic holography is discussed. In most cases, the status is that of proved feasibility awaiting broader application.

Acoustic holography

Primary reflections in seismic records are often obscured by coherent noise making processing and interpretation difficult. Trapped water modes, surface waves, scattered waves, air waves, and tube waves to name a few, must be removed early in the processing sequence to optimize subsequent processing and imaging. The authors have developed a noise canceling algorithm that effectively removes many of the commonly encountered noise trains in seismic data. All currently available techniques for coherent noise attenuation suffer from limitations that introduce unacceptable signal distortion sand artifacts. Also, most of those techniques impose the dual stringent requirements of equal and fine spatial sampling in the field acquisition of seismic data. Their technique takes advantage of characteristics usually found in coherent noise such as being localized in time, high aliased, nondispersive (or only mildly so), and exhibit a variety of moveout patterns across the seismic records. When coherent noise is localized in time, a window much like a surgical mute is drawn around the noise. The algorithm derives an estimate of the noise in the window, automatically correcting for amplitude and phase differences, and adaptively subtracts this noise from the window of data. This signal estimate is then placed back in the record.more » In a model and a land data example, the algorithm removes noise more effectively with less signal distortion than does f-k filtering or velocity notch filtering. Downgoing energy in a vertical seismic profile (VSP) with irregular receiver spacing is also removed.« less

A procedure for optimally removing localized coherent noise

When coherent light from a laser beam is passed through a transparent reduction of a variable‐density or variable‐area record section, the seismic signals act as an optical grating to produce a diffraction pattern which is the two‐dimensional Fourier transform of the section itself. With suitable lenses the diffraction pattern can be converted back into an image of the original section. By obstructing portions of the pattern corresponding to particular frequencies or dips on the section one can remove such frequencies or dips from the reconstructed image. The equipment developed for this processing incorporates special design features to combine high optical resolution, precise discrimination of moveouts and frequencies, limitation in the length of the overall optical path to permit the use of a short optical bench, and visual monitoring by use of a microscope or a closed‐circuit TV system. Filter elements consist of wedges mounted on a rotary stand for velocity rejection, wires of various diameters for b...

Velocity and frequency filtering of seismic data using laser light

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Velocity and frequency filtering of seismic data using laser light