RU2428096C2 - Visualisation method of inner object cavity filled with diffusing medium - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention refers to various fields of machine-building industry, instrument-making industry and medicine and is intended to control inner walls of cavities and pipelines filled with or transporting muddy diffusing liquids. Method involves introduction of light source to investigated cavity, lighting of cavity with light, reception of reflected optic signal and formation of video image of inner walls of the cavity on the basis of reflected optic signal. Lighting of cavity is performed with certain parallax between axes of receiving-transmitting system, which is calculated depending on index of dispersion of fluid medium filling the cavity with length of wave, which is chosen from spectral intervals corresponding to minimum total light absorption and dispersion coefficient of fluid medium. Reception of reflected signal characterising the state of walls of the investigated cavity is performed in close proximity to the image, converted to video signal and it is recorded outside the object.

EFFECT: use of this invention will allow increasing resolution capability and improving perception of the image as whole entity.

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Description

The invention relates to various fields of engineering, instrumentation and medicine and is intended to control the internal walls of cavities and pipelines filled or transporting turbid, dispersing liquids, for example milk, pharmaceutical solutions and, in particular, for medical diagnosis of the walls of blood vessels and blood-containing cavities.

A known method of intravascular endoscopy [1], including the introduction of an endoscope into a blood vessel, illuminating the cavity of the vessel with a light source with a wavelength that causes the fluorescence of the molecules of the substance of the atherosclerotic plaque, and receiving an inverse fluorescence signal from the tissue of the vessel. The reflected signal is recorded by the receiving device in the form of a light flare, by which a change in the vessel wall is judged.

The disadvantage of this method is the inability to build a video image of the inner wall of the vessel, as well as the lack of selectivity of the method, since in some cases the reverse fluorescent signal can be obtained from the vessel wall, which does not have structural changes.

A known method of obtaining images of blood-containing cavities [2], including the introduction of an endoscope into the cavity under investigation, illumination of the cavity with light, and the formation of an image of the cavity under study reflected on the boundary of the media. In this case, the field of view is provided by temporarily scattering the blood with physiological solution introduced through the distal end of the endoscope. The resulting image can be photographed or recorded on a VCR.

The disadvantage of this method is that to obtain an image of an object (vascular wall), it is necessary to replace the blood with an optically transparent liquid, in particular saline, for the duration of the study.

Closest to the invention in technical essence is a method [3] for acquiring an image of blood-containing cavities, including introducing an endoscope into the cavity under investigation, illuminating the cavity with light through moving blood, receiving a reflected optical signal with an endoscope, filtering the background noise signal caused by moving blood, and generating based on the filtered optical signal.

The disadvantages of this method are insufficiently high resolution, grid structure, other elements that interfere with the perception of the image as a whole and can hide small details and / or media interface elements.

Known methods for acquiring an image of the internal cavity due to the remote location of the receiver relative to the surface under study and large losses in the transmission path can lead to errors in determining structural changes.

The claimed invention is aimed at solving the problem of increasing resolution and improving the perception of the image as a whole.

The result is achieved in that in a method for visualizing an internal cavity of an object filled with a scattering medium, including introducing a light source into the cavity, illuminating the cavity with light, receiving a reflected optical signal and generating a video image of the internal walls of the cavity based on the reflected optical signal, the cavity is illuminated with a certain parallax between the axes of the transceiver system, calculated depending on the scattering index of the liquid medium filling the cavity, with a wavelength, selected from spectral ranges corresponding to the minimum total coefficient of absorption and scattering of light by a liquid medium, the reception of the reflected signal characterizing the state of the walls of the cavity under study is carried out in the immediate vicinity of the image, converted into a video signal and recorded outside the object.

Figure 1 shows a device for implementing the method of visualizing the internal cavity of an object, figure 2 is a view along arrow A.

The research results prove the feasibility of applying the proposed method.

Example

When the scattering index of the liquid medium filling the cavity is 100 ÷ 200 mm ^-1 , with a wavelength λ≈0.6 ÷ 0.64 μm, selected from the spectral ranges corresponding to the minimum total absorption and scattering coefficient of light by the liquid medium, the parallax between the axes transceiver system is 0.1 ÷ 2.0 mm.

To implement the proposed method, a device was developed where the light source introduced into the studied cavity 1 is made in the form of LEDs 2 located on the circumference 3 of the concentric axis of the lens of the receiver 4, the output signal of which is transmitted to an image processing unit (not shown) installed outside the investigated cavity.

The transceiver system (source and TV receiver) is introduced into the cavity, and the luminous flux of the backlight radiation is controlled by changing the current strength of the power source. The radiation of the backlight through the flow of the scattering liquid is directed to the inner walls of the cavity, and the wavelength of the radiation of the backlight is chosen so that the refractive index is minimal. The reflected signal is recorded by a TV camera located inside the cavity, and is transmitted to the image processing unit and the TV monitor as an electric signal. Depending on the scattering index, the parallax of the optical axes of the transceiver system is calculated, and with an increase in the refractive index, the parallax increases.

This method can be implemented at enterprises of the Russian Federation on equipment manufactured in the Russian Federation, and meets the criterion of "industrial applicability".

Information sources

1. US patent No. 5217456, CL. A61B 17/32, published 1993

2. US patent No. 4934339, CL. A61B 1/04, published 1989

3. RF patent №2168927, cl. A61B 1/04, published June 20, 2001

Claims (1)

A method for visualizing the internal cavity of an object filled with a scattering medium, including introducing a light source into the cavity, illuminating the cavity with light, receiving a reflected optical signal and generating, based on the reflected optical signal, a video image of the internal walls of the cavity, characterized in that the cavity is illuminated with a certain parallax between the axes transceiver system, calculated depending on the scattering index of the liquid medium filling the cavity, with a wavelength selected from spectral intervals corresponding to the minimum total coefficient of absorption and scattering of light by a liquid medium, the reception of the reflected signal characterizing the state of the walls of the cavity under study is carried out in the immediate vicinity of the image, converted into a video signal and recorded outside the object.

Images