CN101866031A

CN101866031A - Optical readout method utilizing fiber optics bundle to carry out modulation

Info

Publication number: CN101866031A
Application number: CN201010190301A
Authority: CN
Inventors: 赵跃进; 郭玉婷; 董立泉; 刘小华; 于晓梅; 武红; 龚诚; 张琳琳
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2010-06-03
Filing date: 2010-06-03
Publication date: 2010-10-20
Anticipated expiration: 2030-06-03
Also published as: CN101866031B

Abstract

The invention discloses an optical readout method utilizing a fiber optics bundle to carrying out modulation, belonging to an application of fiber optics in the technical field of optical readout type infrared focal plane thermal imaging, and solving the problem of filtering difficulty due to inconsistent zero-order spectrums caused by different initial attitudes of the imaging units of the optical readout type infrared focal plane array. The scheme can replace a knife edge (or an aperture) to carry out optical filtering; and meanwhile, stray light generated due to limited environment conditions has better inhibitory action, thereby improving the quality of output images. The main process is as follows: ray is transmitted in fiber according to the total reflection principle; the fiber has rigid requirement on the incidence angle of the ray, thus the ray (such as the stray light in environment) which does not satisfy the incidence angle can not be totally reflected in the fiber but is refracted into a cladding, i.e. the fiber optics bundle can not transmit the ray, thereby inhibiting the stray light; and the ray (such as beam expanding collimation light source) satisfying the incidence angle can be transmitted to the rear end surface of the fiber optics bundle by means of the total reflection principle. When a focal plane array arranged on the rear end surface deflects because of being heated so as to change the angle of the ray entering the fiber from the end surface, thus the angle of the ray emitted from the front end surface also changes; and luminous energy received from an optical receiver changes and is embodied by the light and shade change on the image.

Description

The optical reading method that utilizes fibre bundle to modulate

Technical field

The present invention is that the optical read that a kind of optics is read formula infrared focal plane array thermal imaging system goes out treatment technology, utilizes this technology can replace the edge of a knife or aperture that system is carried out filtering, has simplified the structure of system; And the parasitic light in the environment there is significant inhibitory effect, makes the subsequent image processing process can obtain better effect, improve picture quality.

Background technology

In recent years, along with continuous progress in science and technology, the non-refrigeration type infra-red thermal imaging system has been obtained develop rapidly, following several reading methods have progressively been formed: 1. electricity reading method: the heat energy that infrared energy is changed into probe unit on the focal plane, local temperature variation causes that the physical parameter surveyed of focal plane detection unit changes, for example electrical impedance changes, and reads temperature variation with the electric signal that flows into the probe unit array again, thereby provides heat picture.Adopting the advantage of the non-refrigeration focal surface array infra-red thermal imaging system of electricity reading method is to need not to be equipped with refrigerating plant, and focal plane arrays (FPA) technology and IC process compatible, replaces traditional refrigeration mode system gradually, becomes the main flow of current thermal imaging system.Shortcoming is it except little manufacture difficulty of reading array circuit, its probe unit is connected with the lead of substrate, reduced the insulation effect of probe unit, and allow electric current flow through probe unit itself to have understood heat effect, influence the temperature measurement accuracy of unit, in addition, the outstanding gap between substrate and the probe unit makes the conduction of heat of air layer can not ignore, thereby require FPA must place the vacuum chamber of condition of high vacuum degree (0.01Pa), thereby increased technical difficulty.2. optical reading method: the heat energy that infrared energy is changed into probe unit on the focal plane, temperature variation causes the corner of focal plane detection unit or acoplanarity displacement to change, detect the variation of probe unit output spectrum by optical pickup system and understand out the variation and the distribution of the corner or the acoplanarity displacement of focal plane probe unit, thereby provide the heat picture of infrared radiation object.Than the electricity playback mode, its advantage is that ground unrest is low, and is simple in structure low with cost, begins in recent years to receive publicity.There is how tame mechanism to put in the world successively in the middle of this important function for of research, wherein mainly comprise U.S.'s Oak Ridge National Laboratory, University of California Berkeley, Sarcon/Sarnoff microsystems, multispectral imaging company, Agiltron company, the Nikon company of Japan, Beijing Institute of Technology, Peking University, Microelectronics Institute of the Chinese Academy of Sciences and China Science ﹠ Technology University etc.The high speed optical that U.S. Agiltron company makes is read focal plane arrays (FPA), and it is surveyed noise equivalent temperature difference and has reached 120mK, array sizes 280x240, and output can reach 1000 frame per seconds.But this technology is ripe not enough at present, also has certain distance from commercialization, still rests on the experimental study stage.

The optical reading technique of focal plane arrays (FPA) mainly is the technology that the miniature deformation of focal plane arrays (FPA) surface cell under the infra-red heat effect is changed into the image that can directly detect by an unaided eye.The focal plane arrays (FPA) thermal deformation mainly is based on the mechanism of double-material beam temperature distortion, the yardstick of array element is about tens micron dimensions, each inside, unit is all comprising one or several two material composite cantilevers, two kinds of material thermal expansion coefficients that constitute semi-girder differ greatly, for the ease of visible light detecting, can be fixedly on the double-material beam structure material of high reflectance reflecting surface or the reflecting body made, at ultrared heat effect lower cantalever beam small bending can take place, drive reflecting surface deflection and change the phase place of incident light.

Optical fiber is relevant permutation clocklike in the fibre bundle, and every optical fiber is in full accord in the geometric position of incident end and exit end, can with high fidelity transmit the image of high definition, be the photoelectronic imaging and the image transfer element of superior performance.Every fiber in the fibre bundle can independently transmit a pixel, has the good optical insulating property, and the biography light time can not be subjected to the influence of fiber on every side.

Summary of the invention

The biography that the objective of the invention is to utilize fibre bundle is as characteristic, to modulating through the light of focal plane array column unit reflection, reads the be heated information of back unit deflection of focal plane arrays (FPA); The filtering appts parasitic light suppresses noise.

The objective of the invention is to realize: when 1. not having the infrared radiation object in the environment by following technical scheme, each unit of focal plane arrays (FPA) does not all deflect, collimated light enters into fibre bundle with special angle, shining focal plane array through total reflection repeatedly lists, after the focal plane arrays (FPA) reflection, partial reflection light enters into fibre bundle once more, and optical receiver receives this part luminous energy, and as benchmark.When 2. having object to send infrared radiation in the environment, focal plane arrays (FPA) deflects owing to double material effect, the reflection angle that is radiated at the light that focal plane array lists will change, the angle of fibre bundle front end face emergent ray will be along with the variation of end face angle of incident light thereafter and is changed like this, the luminous energy that receives on the optical receiver can increase or reduce, and can obtain the heat picture of radiation object after " subtracting each other " with benchmark.

Beneficial effect

Employing the present invention can substitute the existing edge of a knife or the aperture filter element carries out filtering, simplied system structure; Utilize the biography light characteristic of optical fiber, reduce in the environment parasitic light, suppress noise, improve output image quality the influence of system imaging; Utilize fibre bundle, can carry out long-distance transmissions, avoid the electromagnetic interference (EMI) of signal.

Description of drawings

Fig. 1 is for classifying the thermal imaging system principle schematic of core based on of the present invention as with focal plane array,

Fig. 2 is the end pattern of fibre bundle,

Fig. 3 does not have radiation source and the transmission contrast of light in fibre bundle under two kinds of situations of radiation source is arranged in the environment, wherein (a) (b) is the situation that has infrared origin in the environment for there not being the situation of infrared origin in the environment,

Wherein: the 1-light source, the 2-half-reflecting half mirror, the extraneous incident infrared of 3-, 4-Infrared Lens, the 5-focal plane arrays (FPA), the 6-fibre bundle, 7, the 8-fourier lense, the 9-camera, the 10-Digital Image Processor, the 11-display, the 21-both ends of the surface are the fibre bundle on plane, and end face of 22-has the fibre bundle at inclination angle.

Embodiment

Below in conjunction with accompanying drawing the present invention is described further:

Fig. 1 is the optical system schematic diagram.The light that light source 1 sends is radiated on the fibre bundle 5 by half-reflecting half mirror 2 through collimation, and is transferred on the focal plane arrays (FPA) 6 by fibre bundle 5, and the light of array 6 reflections is imaged on the camera 9 by

fourier lense

7 and 8 again after 5 transmission.When not having infrared radiation in the environment, gather a two field picture by Digital Image Processor 10 and also preserve as a setting; When in the environment infrared radiation being arranged, extraneous incident infrared 3 focuses on the focal plane arrays (FPA) 6 through Infrared Lens 4, because double material effect, each unit of 6 can deflect, incide on 6 light through 6 the reflection after, light also will deflect, and through the transmission of fibre bundle 5, image received on the camera 9 also will change thereupon.Digital Image Processor 10 subtracts each other back output with the image of current collection and the background image of preserving before and is presented on the display 11, promptly obtains visible target temperature field distribution.

Two end faces of fibre bundle can be parallel, shown in Fig. 2 (a); Also can be uneven, promptly one of them end face be vertical with optical fiber, another end face then with the optical fiber out of plumb, shown in Fig. 2 (b).

Light when Fig. 3 (a) is not heated for focal plane arrays (FPA) and the transmission situation of process focal plane arrays (FPA) light reflected in fibre bundle.Suppose to incide light on the fibre bundle and be perpendicular to planar end surface, through repeatedly total reflection, light will be transferred on another end face (inclined end face) of fibre bundle, reflection through the focal plane arrays (FPA) metal level, light will incide with specific angle on the inclined end face of fibre bundle, planar end surface will with

The angle outgoing.Fig. 3 (b) produces the transmission situation of light in optical fiber behind the deflection angle δ for focal plane arrays (FPA) is subjected to extraneous infrared radiation.By the light of fibre bundle planar end surface ejaculation and the angle of end face will no longer be at this moment

And become In fact, fibre bundle end face output to be one be the light cone shape light field of cone apex angle with the emergent light angle, after focal plane arrays (FPA) produces the thermic corner, the cone apex angle of light field can become big or diminish, the luminous energy that receives on the CCD also can change thereupon like this, and being embodied on the image is the variation of bright-dark degree.

Claims

1. optical reading method that utilizes fibre bundle to modulate is characterized in that: utilize fibre bundle to modulating through the light of focal plane array column unit reflection, read the be heated information of back unit deflection of focal plane arrays (FPA); Utilize fibre bundle filtering appts parasitic light, realize suppressing the purpose of noise.

2. the optical reading method that utilizes fibre bundle to modulate as claimed in claim 1, it is characterized in that: after the focal plane array column unit is heated generation thermic corner, the angle of fibre bundle front end face beam projecting will change with the angle of fibre bundle rear end face light incident, and the luminous energy that receives on the optical receiver will respective change.The reflected light that is the focal plane array column unit is modulated by fibre bundle.

3. the optical reading method that utilizes fibre bundle to modulate as claimed in claim 1, it is characterized in that: light transmits in optical fiber need follow total reflection principle, optical fiber has strict requirement to the incident angle of light, total reflection does not take place but is refracted in the covering in the light that does not satisfy the incident angle requirement in optical fiber, promptly do not transmit the light that this part does not meet the demands, suppressed system's parasitic light.

4. the optical reading method that utilizes fibre bundle to modulate as claimed in claim 1 is characterized in that: the both ends of the surface of fibre bundle both can be the planes, also can be the inclined-planes that an end has the inclination angle.

5. the optical reading method that utilizes fibre bundle to modulate as claimed in claim 1 is characterized in that: modulate used element, be not limited to regularly arranged fibre bundle, also can adopt fibre faceplate.