People do pattern recognition differently from current optical computers, but we can learn from them. This is one sense of `personal.'' The other is that I have sacrificed thoroughness and completeness to cut to the heart of what one person (I) believes to be the key current research issues. It is the kind of paper this person likes to read from others

The quantitative analysis of human corneal endothelial cell patterns is analyzed with Fourier transform methods. The optical or digital Fourier transform of the pattern of endothelial cell borders is analyzed to yield the average cell area and the coefficient of variation of the average cell area. The more difficult problem of cell shape characterization is still under investigation. The advantage of the Fourier transform analysis is the parallel processing of the optical Fourier transform and the potential development of a hybrid digital-optical device for the rapid analysis of large numbers of endothelial specular photomicrographs

Optical coherence domain reflectometry is applied here to the study of diffusive biological tissue. This non-contact technique allows us to probe the light reflected at a tissue interface, and the back scattered light through the tissue thickness, with very fine spatial resolution and large dynamics. We present such measurements performed on an arterial wall, with a spatial resolution of 15 micrometers and a dynamic of 110 dB, and deduce from these measurements an attenuation coefficient (Sigma) t equals 19 cm-1 through the arterial wal

This paper describes a new optical microscope that can simultaneously acquire images with differential phase and differential intensity contrast. The instrument has a confocal response, thereby eliminating flare from features out of the plane of focus, and an existing capability of actively controlling the microscope transfer function electronically. Images are shown that demonstrate the operation of the system

A new coherent optical correlator system has been developed for intended application to breast cancer screening. Such a system must have an inherent capability to deal with patterns that have high degrees of similarity between the desired and rejected classes, due to the overall similarity between benign and malignant cells. Consequently, effort has been directed toward achieving this goal. This paper presents an optical configuration that contains two coherent optical processors (COPs) working in parallel and utilizes phase-stepping detection at the output to multiply the two correlation signals. It is shown how this scheme offers an excellent compromise between good discrimination and immunity from noise added in the input plane

Novel techniques and corresponding equipment for observation of the internal space of the eye and for monitoring of the pupil''s response to various external influences are proposed. These techniques are based on utilization of specially designed infrared-sensitive videocameras with the possibility of image processing. The proposed techniques enable one to increase the contrast of the image and to obtain dimensions of the pupil in a digital form convenient for further computer processing

Double exposure holograms taken at different wavelengths can be replayed at one wavelength. This is usually called `two wavelength holography.'' With photorefractive holography, the two wavelengths can directly interfere. We explore this phenomenon here

In this paper we discuss the use of holography for recording biomedical properties. A holographic stereogram, system holography camera, and holographic television are presented for this purpose

Some new experiments concerning holographic endoscopy are presented. The quantitative measurements of deformations of objects are obtained by the double-exposure and double- reference beam method, using either a cw-laser or a pulsed laser. Qualitative experiments using an argon laser with time-average holographic endoscopy are also presented. A video film on real-time endoscopic holographic interferometry was recorded with the help of a frequency-doubled YAG-laser working at 25 Hz for the first time.

A holographic continuous exposure method is proposed for studying the dynamic and structure characteristics of the Brownian motion of unicellular algae. The measured algae velocity and size distribution functions are reported.

The successful development of total hip replacement as an effective surgical technique has been one of the most significant advances in modern orthopaedics. The method has superseded the traditional forms of treatment for hip fractures which involve extensive nailing across the site of the break. However, clinical experience has highlighted failures in both the implant and surrounding bone which have often been attributed to mechanical causes. The problem of optimizing the performance of an implant is very complex and includes a number of interrelated factors: fixation to the bone, strength of the prosthesis itself, wear of articulating surfaces, kinematic requirements, energy absorption, effect of implant position and bone structure in the surrounding area. This paper reports attempts to establish a test facility which can accurately model these parameters and monitor their effects with the intention of providing information for the orthopaedic field. Areas of interest that are intended to be examined include: the effect of bone preservation methods on the bone's strength and weight-bearing characteristics, the effects of medical conditions on bone strength, such as osteoporosis, and the effect of the patient's diet on bone character.

The mechanism of speckle interferometer output signal forming for biovibration measurements is discussed. Statistical characteristics analysis of output signal amplitude is carried out. The factors creating parasitic amplitude-phase modulation of the output signal are investigated. The possibility of differential homodyne speckle interferometers application in Tibetan pulse diagnostics is shown.

Holographic nondestructive testing (HNDT) is used to investigate the complex structures of bones of various shapes and sizes subjected to forces. During the course of the present study three antlered deer skulls of different species were investigated, and significant species- specific differences were observed. The HNDT method was also used to verify the advanced healing of an osteosynthetized sheep jawbone. Radioulnar bones of normal and orphaned moose calves were subjected to the bending test. Different bending dynamics were observed.

The effects of unilateral simulated masseter muscle activity on the dorsal and lateral skull bone surfaces of a European moose have been investigated in this study by means of holographic nondestructive testing (HNDT). These effects could be seen over the whole of the skull surface with varying intensity depending on the stability of bone and suture structures. Areas of rapid surface movements were observed rostrally from the masseter muscle attachment surface and around the nasofrontal junction. It was concluded that there may be a causative connection between masseter forces and the variation of nasal region bone structures of the European moose not observed in other mammal species.

To compare the elasticity of bones covered with soft tissue and the elasticity of defleshed and dried bones we used sampling screws to make the surface movements of the bones visible through the soft tissue. We compared fresh and dry European moose skulls with antlers before and after skinning. External forces were focused on the skull bones through the antlers and on the metatarsal bones through the distal epiphysis. A high correlation in fringe orientation was observed in the case of thick skull bone structures with rigid interdigited sutures. We also compared compression dynamics of fresh and dry moose antler cubes.

The unilateral axially dynamic fixator (Orthofix) was mounted on a sheep tibial shaft. Three fixation modes: static, dynamic controlled, and dynamic free were examined by means of double exposure holographic interferometry. Simultaneously, the acceleration was measured by an accelerometer and displayed on the monitor together with loading characteristics. The first exposure was made before the acting force was applied to the tibia plateau. The second one after the moment when the acceleration wave started to propagate through the specimen. We stated that in the case of dynamization less torsion occurs at the fracture site. So far, we have not been able to determine any correlation between results of holographic and accelerometric measurements.

Displacement of a ceramic bimorph, due to the converse piezoelectric effect, has been observed using real-time, phase-stepped holographic interferometry. The observed bending obeys the theoretical solution. From the bending, the relevant piezoelectric constant was determined. The measured value, d₃₁ equals 279 +/- 9.5 pm/V, agrees with the commercial value of d₃₁ equals 274 +/- 55 pm/V. Displacement measurements for bone, however, were not repeatable. It appears that results for bone previously reported by us may have been experimental artifact.

Endoscopic holography or endoholography combines the features of endoscopy and holography. It can be utilized in holographic imaging or interferometry inside natural cavities of the body. In imaging, the ability to view a three-dimensional, large focal depth, faithful rendition of internal organs and tissue may greatly enhance the detection of disease and abnormality. Contact Denisyuk holography makes it possible to obtain a high-resolution holographic recording which can be examined microscopically. In the case of endoholographic interferometry, new diagnostic techniques can emerge; e.g., the measurement of compliance of the wall of the bladder or of the arteries may provide diagnostic indicators of early stages of disease.

High resolution dynamic holographic interferometry based on coupled-wave theory in gyroanisotropic photorefractive crystal group 23 has been performed using the reflecting hologram grating. This method creates the non-linear optical transformation and resolution of optical signal. The highly effective technique of visualization in cryoultrasonic surgical instruments in real-time is presented. A dynamic optical speed-filter to test the moving biological object in vivo is proposed.

A combination of optical methods and holographic interferometry was applied to study spatial features of illexines I₁ and I₂ and the mode of their interaction with DNA.

The large amount of new materials like amalgams and techniques of finishing and polishing in operative dentistry has stimulated interest for simple non-destructive methods of surface roughness evaluation. We studied an optical method based on the scattering of coherent light upon reflection on prepared samples of composite resins submitted to different surface treatments. The method should be able to discriminate the degree of flatness for the samples thus enabling a classification procedure according to a figure of merit to be defined. The diffraction properties of such moderately rough surfaces has been correlated with mechanical profilometric measurements of the residual granular structure after polishing. Different surface treatments of composite resins result in distinctive levels of surface flatness, and it is shown that a relation between the intensity of the normalized specular reflection of a beam of coherent light and the rms surface roughness can be established for characterization purposes.

An overview of the moire techniques most frequently used for three-dimensional human form measurements is given. The spatial-carrier phase-shifting method for automatic fringe pattern analysis in moire topography is introduced. The multipurpose system for shape determination using both temporal and spatial phase-shifting method is presented.

A new method for reconstructing 3-D corneal curvature is proposed which makes use of polynomials to represent the profile of the human cornea. It is shown that the anterior surface of the human cornea can be represented by a group of polynomials, and hence the corneal radius of the curvature can be derived without the assumption of an elliptical or spherical model.

A noncontact method for determining particle concentration and size distribution functions is proposed. Results on erythrocyte sizes and concentrations are reported which are in good agreement with independent microscopic measurements.

The effect of lecithin concentration on the refractive index behavior in a perturbed water- lecithin system is investigated using a polarization interferometer. It is found that the time variations of the refractive index for different lecithin concentrations can be used to assess the state of the lecithin in water, i.e., detect micelles, single and double molecular layers, etc.

As neuroprostheses become smaller, the need for superior quality control becomes vital. For such devices, Van der Lugt optical correlation (VLOC) techniques, involving Fourier transform holography, offer the potential of superseding conventional leak testing methodologies -- in that working with light is cleaner, faster, more sensitive, and eliminates the disadvantages of tracer gas introduced through backfilling or `bombing.' Current leak testing methods often prove inadequate for very small and delicate devices, as they sometimes involve inordinate stress on the package, or introduce undesirable results due to chemical considerations. In the case of very small packages, gross leaks are often missed by conventional means, since minute quantities of tracer gas introduced into the package may have disappeared by the time the test is run. VLOC techniques have been shown to overcome many of these limitations. The preliminary studies reported here indicate that VLOC techniques are capable of detecting leaks in the range of 10^-6 and above in large aluminum-enclosed electronic packages. Furthermore, the method has been proven capable of automation through the use of a thermoplastic recording camera.

Some biological structures like chromosomes, mitochondria, cell walls, and living cells were observed with the computer-aided phase microscope (CPM) `Airyscan' having spatial resolution 5 - 20 nm. We succeeded in obtaining new information about dynamic processes in living cells and micro-organisms by a new registering method. Some of the possible applications in the areas of medicine and biology are discussed.

We present both a theoretical and experimental analysis of dynamic holographic interferometry using a reflection grating geometry in Bi₁₂TiO₂₀.

The temporal fluctuations in the laser speckle pattern produced by scattering from moving objects obey the same statistics as the spatial variations of the stationary speckle pattern. These statistics can be used to measure the movement of the scattering particles, a technique of particular value in biomedical science. Potential applications include monitoring blood flow, motility, and intra-cellular activity.

A heterodyne hologram interferometry method for quantitative studies of tissue and bone responses to stimuli is described. Fundamental mathematical relationships between the holographic parameters and the displacement vectors are presented. Biomedical applications of the method are discussed and their implementation is illustrated by representative quantitative examples.