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62 OPTOINFORMATICS’05 Substantial advantage <strong>of</strong> the proposed method above known consists in possibility <strong>of</strong> conducting the quantitative non-destructive control <strong>of</strong> pitting corrosion process on the studied specimen surface. The other advantage consists in possibility <strong>of</strong> the real time data acquisition about the beginning <strong>of</strong> pitting and development <strong>of</strong> microcrack. Presentation <strong>of</strong> this paper was partially supported by ICO travel-grant program. 1. І.М. Дмитрах, В.В. Панасюк, Вплив корозійних середовищ на локальне руйнування металів біля концентраторів напружень, Львів: Вид. ФМІ НАН України, 341, (1999). 2. M. Sjödahl, Some Recent Advances in Electronic Speckle Photography // Opt. Las. Eng., 29, 125-144, (1998).
SAINT-PETERSBURG, October 17 – 20, 2005 63 THE ANALYSIS OF RESOLUTION CAPABILITY OF THE OPTICAL COHERENT TOMOGRAPH K.L. Khohlov, V.K. Sokolov Baltic State Technical University, 1 st Krasnoarmeyskaya str.1, 198005, St.Petersburg, Russia E-mail: xkl1478@mail.ru In the report questions <strong>of</strong> resolution enhancement <strong>of</strong> a coherent laser optical tomograph <strong>of</strong> high-resolution capability in short-range infrared a band are considered. The tomograph focused on use for early diagnostics <strong>of</strong> pathological modification in a thyroid gland <strong>of</strong> the human. Traditional methods <strong>of</strong> ultrasonic do not provide in this case, the required resolution in tens micron, and X-ray methods cannot be used because <strong>of</strong> their harm for the patient. The carried out analysis <strong>of</strong> methods <strong>of</strong> an optical tomography has shown, that to the most suitable for the solution <strong>of</strong> a task in view, the method optical coherent tomography with use optical heterodyne. The method allows to detect the ballistic photons forming the shadow image <strong>of</strong> a stratum <strong>of</strong> tissue, similar to the X-ray image. At use short-range infrared areas (700-1300 nanometers), relevant to a spectral window <strong>of</strong> the s<strong>of</strong>t tissue <strong>of</strong> the human, depth <strong>of</strong> penetration can achieve 10-12 cm. Magnifications <strong>of</strong> the resolution can be achieved in two stages: 1. The diameter <strong>of</strong> fibers in sourcing and detecting arrays can be reduced. It allows to reduce scanning aperture. The accessible type <strong>of</strong> fibers and length <strong>of</strong> waves restrict resolution capability. 2. Realization posterior processing <strong>of</strong> the received images, implemented electronic or optoelectronic processor working in actual time. We use the optical processor which represents the television system covered with an optical back coupling and implementing algorithm inverse filtering. At the given stage <strong>of</strong> our work we analyzes with help <strong>of</strong> mathematical models the opportunities <strong>of</strong> the first method. The inverse filtration means gathering some additional information on a transfer function <strong>of</strong> imaging system and about properties <strong>of</strong> the object <strong>of</strong> observation. The dependences <strong>of</strong> the resolution on a standing <strong>of</strong> an objective plane concerning a plane <strong>of</strong> the image and source, dependence <strong>of</strong> the resolution on character <strong>of</strong> allocation <strong>of</strong> complex amplitudes under the aperture <strong>of</strong> a fibril are analysed. The model allows to take into account influence <strong>of</strong> the size <strong>of</strong> the aperture <strong>of</strong> an emitter, the receiver on the resolution <strong>of</strong> a tomograph. The criterion <strong>of</strong> the resolution is diameter <strong>of</strong> a spot <strong>of</strong> the image is formed in a image plane. The boundary <strong>of</strong> a spot is defined or on the first minimum in the diffraction pattern, or on a level exp 1 − . Further we plan measuring coefficients <strong>of</strong> absorption and dispersion <strong>of</strong> medium <strong>of</strong> observation and improvement <strong>of</strong> a model, terminating connection <strong>of</strong> a transfer function <strong>of</strong> figuring system and definition <strong>of</strong> methods <strong>of</strong> its compensation. 1. Edited by Steve Webb. “The Physics <strong>of</strong> Medical Imaging”. M.:”Mir”, 1991 - 408с. 2. F. Stuart Foster, Charles J. Pavlin “Advances in ultrasound biomicroscopy”: Ultrasound in Med. and Biol., vol. 26, No. 1, pp. 1-27, 2000. 3. V.I.Danilenko, A.A.Shmarin. ”New morphological spheroids objects and a morphgenesis <strong>of</strong> pathological body height <strong>of</strong> tissues”.
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