RU2386956C1 - Radiooptical endoscope - Google Patents

Abstract

FIELD: physics. ^ SUBSTANCE: radiooptical endoscope comprises body with X-ray and optical channels arranged in it, besides radiooptical endoscope additionally contains the second colour CCD-matrix with B*B size installed on axis of optical channel lens in plane of its image, in front of optical channel lens symmetrically to it there are the following components installed coaxially - circular matrix with diametre D from N microlasers, optical axes of which are parallel to each other and axis of optical channel lens, which os used to generate image of laser spots circular structure on object surface, and circular structure diametre equals inlet parametre of focon and remains constant as distance from object to focon changes, and circular matrix from M light diodes with diametre Dc>D, angle of radiation of which is selected based on the conditon W=arctg(B/2f), and length of their radiation wave Y2 is selected with account of provision of maximum contrast of spots images from microlasers with radiation wave length Y1, besides video information from both CCD-matrices arrives to inlet of computer with colour display, with the possibility of simultaneous or serial view of X-ray and optical images of object in various modes of their digital processing and matching on display screen. ^ EFFECT: invention provides for the possibility to match substantially different characteristics of X-ray and optical channels with the help of single CCD-matrix. ^ 3 dwg

Description

The invention relates to the field of non-destructive testing of materials and products, and more specifically to devices for x-ray and / or isotope defectoscopy of objects located in inaccessible cavities.

A known x-ray optical endoscope, which consists of two channels located in a single housing and structurally combined - x-ray and optical. The device allows you to generate, transmit and play simultaneously or sequentially x-ray and optical images of the object using a single television system [1].

The disadvantages of this device are the difficulty of matching substantially different spectral, scale, brightness, sharpness and other characteristics of the x-ray and optical channels using one CCD matrix. In addition, when an object is illuminated by a weakly diverging x-ray beam, which is most often used in practice, the size of the object region visualized by the X-ray luminescent transducer and obviously equal to the input diameter of the focon remains practically constant. At the same time, the size of the linear field of view of the objective of the optical channel linearly depends on this distance, which makes it difficult to compare the results of fluoroscopic and visual control.

The purpose of the invention is the elimination of these disadvantages.

For this, the device for complex x-ray and optical monitoring of objects located in hard-to-reach cavities, containing a housing with x-ray and optical channels located in it, the x-ray channel contains an x-ray source, a focon with an x-ray phosphor located at its end, and a highly sensitive black-and-white CCD matrix size A × A and two lenses whose optical axes coincide with the axis of the focon, and the focal planes are aligned respectively with the output end of the focon and the plane but-white CCD, the focal lengths of these lenses are f ₁ and f ₂ are in a ratio f ₁ / f ₂ = d / A, where d - exit diameter of focon, and between the lenses there telecentric beam path, the optical path comprises a mirror from Plexiglas installed on the focon axis under the angle of 45 ° to it at the intersection point of this axis with the axis of the lens of the optical channels, the object illumination unit, an additional second color CCD matrix of VhV size is introduced, mounted on the axis of the lens of the optical channel in the image plane, focal length f of this lens, f is selected taking into account the relation f = L × B / D, where L is the minimum distance from the input end of the focon to the object, D is the diameter of this end, and a coaxially ring matrix is mounted symmetrically relative to it in front of the lens of the optical channel diameter D of N microlasers, the optical axes of which are parallel to each other and the axis of the lens of the optical channel, with which an image of the ring structure of laser spots is formed on the surface of the object, the diameter of which is equal to the input diameter of the focon D and etsya constant with changes in the distance from the object to the focon, and an annular array with diameter D _C> D of M svetotodiodov, whose optical axes are parallel to each other and the optical channel of the lens axis of the radiation angle of the LED is chosen from the condition of W = 2arctg (B / 2f) , and the radiation wavelength Y2, is selected taking into account the maximum contrast of stain images from microlasers with the radiation wavelength Y1, video information from both CCDs is fed to the input of a computer with a color display, with the possibility of simultaneous or sequential on view X-ray and optical images of the object in different modes of digital processing and combination of the display screen.

The scheme of the endoscope is illustrated by the drawing (figure 1), which shows the source of x-ray radiation 1, the investigated object 2 and the elements of the x-ray and optical ropes.

The X-ray channel consists of a focon 6 with an X-ray phosphor 5 located on its end, protected by a foil 4, a collimator lens 7 with a focal length f ₁ , the focal plane of which coincides with the output end of the focon 6, a second lens 8 with a focal length f ₂ and a highly sensitive black and white CCD array 9 mounted in the focal plane of the lens 8.

The optical channel consists of a lens 10 with a focal length f, in the image plane of which there is a color CCD matrix 11 of size B × B, and a mirror of plexiglass 3 mounted on the axis of the focal angle at an angle of 45 ° to it at the intersection of this axis with the axis of the lens 10. The combination and image processing of the optical and x-ray channels is carried out using a computer 12 with a display 13. Two ring arrays 14 and 15 are arranged in front of the lens 10. The matrix 14 contains N microlasers with a radiation wavelength of Y1. Matrix 15 contains M LEDs with a radiation wavelength of Y2. The optical axis of the microlasers and LEDs are parallel to each other and the axis of the objective of the optical channel. The emission angle of the LEDs is selected taking into account the condition W> 2arctg (B / 2f) for uniform illumination of the field of view of the lens 10. The radiation power of the microlasers and LEDs is selected taking into account the spectral sensitivity of the CCD matrix 11. The number of microlasers N is selected taking into account the ergonomic characteristics of visual perception. Usually, at N> 8, a clear fixation of the boundaries of the control region is achieved. The figure 2 shows the design of the ring matrix.

X-ray endoscope works as follows. When the source of x-ray radiation on the X-ray phosphor 5, an image of the internal structure of object 2 appears, which, with the help of focon 6, lenses 7 and 8, enters the CCD matrix 9, the video signal from which enters the computer 12 and is visualized on the display 13 after processing.

The focal lengths of the lenses 7 and 8 are chosen so that the image of the output end of the focon with a diameter of d fits completely into the raster of the CCD matrix 9, that is, the ratio f ₁ / f ₂ = d / A takes place, which is valid for the telecentric path of the rays between lenses 7 and 8 .

During visual inspection, object 2 is illuminated by a matrix of LEDs 15 using a mirror 3. An image of object 2 using a mirror 3 and a lens 10 is formed on a CCD matrix 11, enters the computer 12 and is observed on the display 13. At the same time, it is possible to observe on the display the pattern of laser spots from matrices of world-lasers 14, outlining the boundaries of the region of the object, translucent x-ray radiation. This allows you to bind fragments of the fluoroscopic image to the corresponding fragments of the optical image. By changing the distance from the focon to the object by moving the entire endoscope, it is possible to achieve the equality of the linear fields of view of the X-ray and optical channels, which greatly facilitates the interpretation of the control results. It is clear that in this case, the annular structure of the laser spots should be fully inscribed in the raster of the CCD matrix 11. The structure of the laser spots can be made not only of a ring shape, but of any other configuration, in accordance with the shape of the input end face of the applied focus.

The figure 3 presents the calculation scheme for determining the focal length of the lens 10. The distance L from the object 2 to the lens 10 is selected taking into account the minimum distance from the input end of the focon to the inner surface of the object 2, which is determined from structural considerations, taking into account the shape of the object, the geometric blur of x-ray an image depending on the size of the focal spot of the applied x-ray tube, the distance from the focon to the object, and other factors.

The size of the control zone of the x-ray channel, obviously, is equal to the diameter of the input end of the focon. The focal length of the lens 10 is chosen so that the image of this zone fits completely into the raster of the CCD matrix 11 of size B. Therefore, the magnification of the lens should be equal to M = B / D. The lens 10 should not shield the x-ray beam incident on the input of the focon 6, and should be located outside the propagation zone of the x-ray beam incident on the focon. In addition, usually to exclude the operation of refocusing the lens when changing the distance from the object to the focal point in endoscopes use short-focus lenses with a large depth of field, for which f << L. Therefore, Z - the distance from the object to the front focus of the lens 10 can be taken equal to L. Moreover, in accordance with the laws of geometric optics Z = f × M, a Z '<< f (2). Equating these equations, we finally obtain f = B × D / L.

The angle of radiation of the illuminator W, which is necessary for complete illumination of the area illuminated by x-ray radiation, is selected from the obvious ratio W = 2arctg (B / 2f).

The program for processing these images is selected taking into account the maximum defectoscopic information in each of them.

Literature

1. RF patent 2168166.

2. Apenko M.I. Zadachnik on Applied Optics, Moscow, Higher School, 2003, 591 pp.

Claims (1)

A device for complex x-ray and optical monitoring of objects located in hard-to-reach cavities, comprising a housing with x-ray and optical channels located therein, the x-ray channel contains an x-ray source, a focon with an x-ray phosphor located at its end, a highly sensitive black-and-white CCD matrix of size A × A, and two lenses, the optical axes of which coincide with the axis of the focon, and the focal planes are aligned respectively with the output end of the focon and the plane of black and white P C-matrix, wherein the focal lengths of these lenses are f ₁ and f ₂ are in a ratio f ₁ / f ₂ = d / A, where d - exit diameter of focon, and between the lenses there telecentric beam path, an optical path composed of a lens with a focal length f and Plexiglas mirrors mounted on the axis of the focal angle at an angle of 45 ° to it at the intersection of this axis with the axis of the lens, characterized in that it additionally introduces a second color CCD matrix of size B × B mounted on the axis of the lens of the optical channel in the plane of his image, focal the distance f of this lens f is selected taking into account the relation f = L · B / D, where L is the minimum distance from the input end of the focon to the object, D is the diameter of this end, and a coaxial ring matrix with a diameter D of N made symmetrically relative to it microlasers, the optical axes of which are parallel to each other and the axis of the lens of the optical channel, with the help of which an image of the ring structure of laser spots is formed on the surface of the object, the diameter of which is equal to the input parameter of the focal area and remains constant when the distance from the object to the focus changes, and the ring matrix of M LEDs with a diameter of D _C > D, the emission angle of which is selected from the condition W = arctan (B / 2f), and the wavelength of their radiation Y2 is selected taking into account the maximum contrast of the spots from microlasers with a radiation wavelength of Y1, and video information from both CCDs is fed to a computer input with a color display, with the possibility of simultaneous or sequential viewing of x-ray and optical images of an object in various modes of their digital processing and combining on the display screen.

Images