CN101943605B - Three-dimensional temperature measurement imaging system and measuring method thereof - Google Patents

Abstract

The invention provides a low-cost three-dimensional temperature measurement imaging system. The system avoids the problem of synchronization discrepancy caused by multiple imaging elements, and can reconstruct the three-dimensional structure of medium and high temperature objects. The three-dimensional temperature measurement imaging system comprises at least three optical lens sets, an image transmission fiber, an imaging element and a signal processor, wherein the imaging element is a monolithic chromatic CCD or CMOS imaging element. The non-contact high-low-temperature object surface imaging temperature measurement system and method based on heat source radiation can compare multiple image signals so as to detect the temperature measurement boundary of the object, calculate the surface temperature of an object to be measured by using the multiband heat source radiation temperature algorithm and the system features, and characterize the temperature field of the surface of the measured object in a three-dimensional mode.

Description

Three-dimensional temperature measuring imaging system and measuring method thereof

Technical field

The present invention relates to a kind of three-dimensional temperature measuring imaging system and measuring method thereof.

Background technology

At present common temperature measuring imaging system is based on infrared photo-sensitive cell, and its structure mainly comprises optical lens, infrared imaging photo-sensitive cell and signal processing unit, and the induction light wavelength of photo-sensitive cell is usually more than 1 micron.The advantage of this class temperature measuring imaging system is to survey lower temperature, even comprises that normal temperature object, shortcoming are that cost is higher, and this mainly is because the cost of infrared imaging photo-sensitive cell is high more a lot of than other visible lights and near infrared imaging element.

In recent years based on the temperature measuring imaging system of CCD mostly based on a plurality of CCD cameras or many CCD element, with the radiation signal beam split to a plurality of CCD cameras, utilize the radiation temperature measurement principle to carry out temperature computation, this makes temp measuring system comparatively complicated, simultaneously because the synchronization discrepancy problem that a plurality of image-forming components bring, increase the difficulty of system calibration and demarcation, also improved the cost of temp measuring system.

Computer reconstruction to the object dimensional structure, present common methods is to mark a lot of unique points or utilize the existing unique point of body surface in object surfaces, adopt a plurality of CCD cameras to be made a video recording simultaneously in a plurality of surfaces of object, perhaps this object different surfaces is taken a series of image, utilize that each identical surface characteristics point comes profiling object surface is rebuild on the object different images with single CCD camera.But this method for heating middle high temp objects, there is not unique point substantially in its surface, can't mark unique point on its surface yet, so this method be difficult to be suitable for.

Summary of the invention

Technical matters to be solved by this invention provides a kind of three-dimensional temperature measuring imaging system cheaply, and the synchronization discrepancy problem of having avoided a plurality of image-forming components to bring also can be carried out the three-dimensional structure reconstruction by the centering high temp objects simultaneously.

The present invention also will provide a kind of measuring method of above-mentioned three-dimensional temperature measuring imaging system.

The technical scheme that technical solution problem of the present invention is adopted is: three-dimensional temperature measuring imaging system, comprise optical lens group, image conduction optical fiber, image-forming component, signal processor along light path, described optical lens group comprises at least three group optical lens groups, and described image-forming component is monolithic colour CCD or cmos imaging element.

Further, described optical lens group comprises convex lens and noise reduction aperture.

Further, described optical lens group adopts four groups to be the arrangement of tetrahedron shape, and the angle with the testee center between per two groups of optical lens groups is 109.4 degree.

Further, the group number of described image conduction optical fiber is identical with the group number of optical lens group.

Further, before described signal processor, also be provided with signal processing converter.

The measuring method of three-dimensional temperature measuring imaging system, this method may further comprise the steps:

1) the optical lens group is collected by each surface emissivity signal of thermometric object, and signal is carried out noise reduction, collimation;

2) image conduction optical fiber image signal transmission that the optical lens group is collected is to several zoness of different on same colored CCD or CMOS image element 3 surfaces;

3) colored CCD or cmos imaging element are converted into picture signal with the spectral signal of each image conduction Optical Fiber Transmission; Signal processing converter is a digital signal with electrical signal conversion, and transfers to signal processor;

4) signal processor carries out data processing and temperature field calculating.

Further, described each picture signal of step 3 comprises three to four broadband light signals.

Further, the described temperature field of step 4 is calculated and is: the border or the specified threshold value border that utilize luminance threshold and brightness step distribution Auto-Sensing object, according to the multiband temperature-measurement principle temperature of each point of testee surface is calculated, simultaneously according to the body surface of delimiting a bit or the temperature field in a certain zone calculate.

Further, the described temperature field of step 4 is calculated and is: utilize the border of the coordinate and the captured image of four groups of optical lens groups, the 3D shape of this testee is reduced, and then the temperature data that it is surperficial is characterized in the three-dimensional model surface.

The invention has the beneficial effects as follows: the system and method that the present invention is based on contactless, the middle high temp objects surface imaging thermometric of thermal source radiation, thereby can compare the thermometric border that detects object to a plurality of picture signals, utilize multiband thermal source radiation temperature algorithm and system performance that object surface temperature is calculated, also the temperature field on testee surface can be carried out three-dimensional simultaneously and characterize.Single CCD that the present invention is contained or CMOS, many images thermometric and surperficial characterization technique can conveniently be applied to all kinds of middle high temperature fields, synchronization discrepancy problem that a plurality of image-forming components bring and drawback such as expensive have been avoided in the application of single CCD or CMOS, can select specific wavelength to improve the accuracy of measurement according to the surface nature of testee simultaneously, also can reduce the influence of natural light reflection measurement result.The invention provides a kind of system and method that (middle high temperature thermal objects) carries out the 3-D solid structure reduction to object under harsh conditions, because catching of at least three group images is to carry out synchronously, avoided carrying out sequential picture and caught the nonsynchronous problem of bringing of body surface temperature data, also do not needed that body surface is carried out unique point simultaneously and indicate with single CCD camera.

Description of drawings

Fig. 1 is the structural representation of system of the present invention.

The 3 D stereo synoptic diagram that Fig. 2 makes up with four groups of images.

Embodiment

As shown in Figure 1, system of the present invention comprises following assembly along light path:

1) the optical lens group 1: comprise at least three group optical lens groups 1, every group of optical lens group 1 comprises convex lens and noise reduction aperture, optical lens group 1 is collected by each surface emissivity signal of thermometric object, and signal carried out noise reduction, collimation, at least three group optical lens groups be installed on respectively testee around, preferably adopt four groups to be the arrangement of tetrahedron shape, the angle with the testee center between per two groups of optical lens groups 1 is 109.4 degree.Four groups of optical lens groups 1 can contain the radiation information of object all surface, can obtain simultaneously 3 D stereo and rebuild necessary spatial information, and three groups of optical lens groups 1 are rebuild spatial information if obtain necessary 3 D stereo, can only contain the surface of object 7/8 at most.Unnecessary more than 1 of four groups of optical lens group, what Fig. 1 expressed is four groups of optical lens groups 1;

2) image conduction optical fiber 2: image conduction optical fiber 2 is mainly by glass optical fiber Shu Zucheng, can select the resolution of image conduction optical fiber according to practical application, the group number of image conduction optical fiber 2 is identical with the group number of optical lens group 1, and the image signal transmission that image conduction optical fiber 2 is collected optical lens group 1 is several zoness of different on same colored CCD or CMOS image element 3 surfaces extremely;

3) colored CCD or cmos imaging element 3 and signal processing converter 4: the spectral signal of each image conduction Optical Fiber Transmission is converted into picture signal, each picture signal comprises three to four broadband light signals, the quantity of wave band depends on the colored filter on colored CCD or CMOS surface usually, is generally RGB or YeMaCy; The effect of signal processing converter 4 is to be digital signal with electrical signal conversion, and transfers to signal processor;

4) signal processor 5: the border or the specified threshold value border that can utilize luminance threshold and brightness step distribution Auto-Sensing object, and each image has all comprised multi-wave signal, this just can calculate the temperature of each point of testee surface according to the multiband temperature-measurement principle, simultaneously can according to the body surface of delimiting a bit or the temperature field in a certain zone calculate.Utilize the border of the coordinate and the captured image of four groups of optical lens groups, can reduce, and then the temperature data that it is surperficial is characterized in the three-dimensional model surface the 3D shape of this testee.

The temperature computation process:

The present invention utilizes testee surface each point when different temperatures, and the difference of radiation signal on different light-wave bands is to recently calculating the temperature of this point.

Under optimal situation, the relation of the temperature of the digital signal strength of each pixel and testee can be expressed as equation one on CCD or the cmos imaging element:

$Q=\mathrm{\α}\·\frac{\mathrm{\π}}{4}\·{\left(\frac{D}{d}\right)}^2\·f\left(g\right)\·\frac{a}{X}\·\mathrm{\Δt}\·\underset{{\mathrm{\λ}}_1}{\overset{{\mathrm{\λ}}_2}{\∫}}{\mathrm{\ϵ}}_{\mathrm{\λ}}{\mathrm{\τ}}_{\mathrm{\λ}}{\mathrm{\ψ}}_{\mathrm{\λ}}{S}_{\mathrm{\λ}}\·\frac{C_1\·{\mathrm{\λ}}^{-5}}{e^{C_2/\mathrm{\λ}\·T}-1}\·\mathrm{d\λ}$

In the formula: the signal intensity of each pixel of Q=;

F (g)=CCD or CMOS gain;

The Δ t=time shutter;

After system of the present invention calibrates and demarcates, two images can be chosen wantonly, following correlation two can be obtained:

$\frac{Q_i}{Q_j}=\frac{\underset{{\mathrm{\λ}}_{i,1}}{\overset{{\mathrm{\λ}}_{i,2}}{\∫}}{\mathrm{\ϵ}}_{\mathrm{\λ}}{\mathrm{\τ}}_{\mathrm{\λ}}{\mathrm{\ψ}}_{i,\mathrm{\λ}}{S}_{\mathrm{\λ}}\·\frac{C_1\·{\mathrm{\λ}}^{-5}}{e^{C_2/\mathrm{\λ}\·T}-1}\·\mathrm{d\λ}}{\underset{{\mathrm{\λ}}_{j,1}}{\overset{{\mathrm{\λ}}_{j,2}}{\∫}}{\mathrm{\ϵ}}_{\mathrm{\λ}}{\mathrm{\τ}}_{\mathrm{\λ}}{\mathrm{\ψ}}_{j,\mathrm{\λ}}{S}_{\mathrm{\λ}}\·\frac{C_1\·{\mathrm{\λ}}^{-5}}{e^{C_2/\mathrm{\λ}\·T}-1}\·\mathrm{d\λ}}$

In the formula: i, in many wavelength of j=and the image any two;

ε _λThe spectral emittance of=testee, this emissivity often are constant in close wavelength coverage.

In correlation two, if spectral emittance is considered as constant, then can simplify this correlation, thereby obtain a reduced equation that has only a known variables (testee is in the temperature of this location of pixels), and then obtain the temperature data on this surface, place according to the ratio of different-waveband signal intensity on same pixel; On the other hand, if the spectral emittance of testee can not handle by constant, if but roughly know the value of its emissivity at different-waveband, also can calculate temperature data accurately according to the polychrome temperature-measurement principle.

(is example with four groups of images) restored in the 3 D stereo temperature field:

Utilize pixel threshold and pixel intensity gradient to carry out after object boundary surveys four groups of images, can obtain four groups of image borders, utilize the particular orientation of these four groups of image skeletons and four groups of optical lens groups, utilize interpolation method to determine the projection profiles of this object on four direction, thereby construct the stereo profile of this object, Figure 2 shows that the synoptic diagram of this 3 D stereo building process.Wherein four solid lines (not comprising outline line) among the figure are that each two dimensional image profile is in three-dimensional reduction.Further utilize space residual error interpolation method to carry out resurfacing again, will utilize then that measured temperature data reappears on constructed 3 D stereo surface on the two dimensional image, obtain whole object surfaces three dimension temperature and distribute.

The present invention is mainly used in the wide width of cloth surface temperature measurement on larger object surface or the three-dimensional surface temperature survey and the 3-d reproduction of whole object.

Claims (5)

1. three-dimensional temperature measuring imaging system, comprise optical lens, image conduction optical fiber (2), image-forming component, signal processor (5) along light path, it is characterized in that: described image-forming component is monolithic colour CCD or cmos imaging element (3), described optical lens adopts four groups of optical lens groups (1) and is the tetrahedron shape and arranges, angle with the testee center between per two groups of optical lens groups (1) is 109.4 degree, and the group number of described image conduction optical fiber (2) is identical with the group number of optical lens.

2. three-dimensional temperature measuring imaging system as claimed in claim 1 is characterized in that: described optical lens group (1) comprises convex lens and noise reduction aperture.

3. three-dimensional temperature measuring imaging system as claimed in claim 1 is characterized in that: at the preceding signal processing converter (4) that also is provided with of described signal processor (5).

4. the measuring method of three-dimensional temperature measuring imaging system, it is characterized in that: this method may further comprise the steps:

1) the optical lens group is collected by each surface emissivity signal of thermometric object, and signal is carried out noise reduction, collimation;

2) image conduction optical fiber transfers to the radiation signal of optical lens group collection several zoness of different on same colored CCD or CMOS image element 3 surfaces;

3) colored CCD or cmos imaging element are converted into picture signal with the radiation signal of each image conduction Optical Fiber Transmission; Signal processing converter is a digital signal with electrical signal conversion, and transfers to signal processor;

4) signal processor carries out data processing and temperature field calculating, calculate in described temperature field: the border or the specified threshold value border that utilize luminance threshold and brightness step distribution Auto-Sensing object, according to the multiband temperature-measurement principle temperature of each point of testee surface is calculated, simultaneously according to the body surface of delimiting a bit or the temperature field in a certain zone calculate; Utilize the border of the coordinate and the captured image of four groups of optical lens groups, the 3D shape of this testee is reduced, and then the temperature data that it is surperficial is characterized in the three-dimensional model surface.

5. the measuring method of the described three-dimensional temperature measuring imaging system of claim 4, it is characterized in that: described each picture signal of step 3) comprises three to four broadband light signals.

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