3.4 Holographic Research Methods in Biology and Medicine
271
production. A possible solution to this problem is to create a recording of interferogram sequence. Photorefractive crystals are especially useful for these purposes
as except for good line resolution they do not require much time for processing
and are optically erasable. The main purpose is to develop a double-exposure holographic interferometer with high repetition frequency based on photorefractive crystals; that is why the argon-ion laser has been widely used. The obtained samples of
the interferograms should be computer-estimated to provide the best effectiveness.
The work [222] points out that miniaturization of the devices becomes an urgent
problem in production of contemporary optical equipment, especially in the sphere
of endoscopy. Implementation of this technique together with holography provides
a number of advantages, for example, 3D-documentation, and a display with high
zooming capacity, as well as metrology in the form of holographic interferometry
of objects, which are difficult to be optically reached. Basically, implementation of
holographic metrology in the sphere of endoscopy is a step forward to creation of
the metrological base for quantitative diagnostics in body cavities that opens new
possibilities in medical diagnosis and environmental research. Moreover, miniature
holographic endoscopic equipment requires a miniature illumination system and an
image forming system as well as a small recording device. Usage of photorefractive
crystals provides the possibility of development of such a holographic memory unit
with high repetition frequency and line resolution.
Recently, the concept of virtual reality has appeared, and the study was conducted
in the sphere of “vision” and “motion” of two most important human functions,
which underlie such technologies [223]. This study includes: (1) perception model,
which explains how a person mentally reproduces three-dimensional forms from a
two-dimensional image projected on the retinal; (2) research of tight interconnection
between different types of perception, for example, between the auditory and visual
perception, visual information and stimuli of muscle motion. An illustrative example
of practical application of this technology is measurement of eye motion in order to
detect the Alzheimer’s disease on the first stages. Also, main problems are discussed,
which occur during the creation of flat 3D-displays.
The work [224] shows the possibility of using holographic methods to determine biomechanical characteristics of vessels and their prostheses for the purpose
of comparative evaluation.
Medical and biological practice is often in need of motion pictures of fast
processes. It is connected with great informativity and possibility to observe the
development of different processes in dynamics.
Registration of objects in motion (holographic movie) plays a special role among
holographic methods. The works [225–229] are dedicated to this issue. One of the
variants of the creation of a 3D movie is described in the article [227]. Motion is
realized in the following way: Consequent positions of the object are recorded on
one hologram at different angles. During reconstruction, the hologram is illuminated
by the same sources and under the same angles. Seven images were recorded on one
hologram using the overlap method. During reconstruction, the plate was gradually
turning and repeating the angles of the reference beam, and it created an impression
of motion. The work [228] describes the obtaining of consequent holographic frames
271
production. A possible solution to this problem is to create a recording of interferogram sequence. Photorefractive crystals are especially useful for these purposes
as except for good line resolution they do not require much time for processing
and are optically erasable. The main purpose is to develop a double-exposure holographic interferometer with high repetition frequency based on photorefractive crystals; that is why the argon-ion laser has been widely used. The obtained samples of
the interferograms should be computer-estimated to provide the best effectiveness.
The work [222] points out that miniaturization of the devices becomes an urgent
problem in production of contemporary optical equipment, especially in the sphere
of endoscopy. Implementation of this technique together with holography provides
a number of advantages, for example, 3D-documentation, and a display with high
zooming capacity, as well as metrology in the form of holographic interferometry
of objects, which are difficult to be optically reached. Basically, implementation of
holographic metrology in the sphere of endoscopy is a step forward to creation of
the metrological base for quantitative diagnostics in body cavities that opens new
possibilities in medical diagnosis and environmental research. Moreover, miniature
holographic endoscopic equipment requires a miniature illumination system and an
image forming system as well as a small recording device. Usage of photorefractive
crystals provides the possibility of development of such a holographic memory unit
with high repetition frequency and line resolution.
Recently, the concept of virtual reality has appeared, and the study was conducted
in the sphere of “vision” and “motion” of two most important human functions,
which underlie such technologies [223]. This study includes: (1) perception model,
which explains how a person mentally reproduces three-dimensional forms from a
two-dimensional image projected on the retinal; (2) research of tight interconnection
between different types of perception, for example, between the auditory and visual
perception, visual information and stimuli of muscle motion. An illustrative example
of practical application of this technology is measurement of eye motion in order to
detect the Alzheimer’s disease on the first stages. Also, main problems are discussed,
which occur during the creation of flat 3D-displays.
The work [224] shows the possibility of using holographic methods to determine biomechanical characteristics of vessels and their prostheses for the purpose
of comparative evaluation.
Medical and biological practice is often in need of motion pictures of fast
processes. It is connected with great informativity and possibility to observe the
development of different processes in dynamics.
Registration of objects in motion (holographic movie) plays a special role among
holographic methods. The works [225–229] are dedicated to this issue. One of the
variants of the creation of a 3D movie is described in the article [227]. Motion is
realized in the following way: Consequent positions of the object are recorded on
one hologram at different angles. During reconstruction, the hologram is illuminated
by the same sources and under the same angles. Seven images were recorded on one
hologram using the overlap method. During reconstruction, the plate was gradually
turning and repeating the angles of the reference beam, and it created an impression
of motion. The work [228] describes the obtaining of consequent holographic frames