CN103335727A - Thermal imaging image processing method based on setting of multiple emissivities for visible light divided area - Google Patents

Abstract

The invention discloses a thermal imaging image processing method based on setting of multiple emissivities for visible light divided areas, which comprises the following steps: S1, a visible light image and an infrared thermal image are shot; S2, by utilizing the visible light image, a target object is divided into n areas by adopting the division algorithm, wherein n is equal to or greater than 2, and corresponding emissivities are arranged for the n areas so as to obtain n outlines; S3, the infrared thermal image is delimitated or divided by utilizing the n outlines in the step S2 so as to n areas of the infrared thermal image, the n areas of the infrared thermal image are spliced or composed, after splicing or composing is performed, gap exists, and smoothing processing is performed to the gap in virtue of heat conduction property. Via the processing of the steps, after the shot images of the irregular objects (the shape, roughness and texture are different) with the same temperature are changed via pseudo color, the color of the images tends to accordance, and temperature variance of various areas is reduced; the distribution of measured temperature is more accurate for the objects with different temperature.

Description

A kind of graphic images disposal route that many emissivity are set of cutting apart based on the visible region

Technical field

The present invention relates to a kind of graphic images disposal route that many emissivity are set of cutting apart based on the visible region.

Background technology

External infrared imagery technique starting is morning, and therefore, infrared temperature-test technology on this basis also develops rapidly.Just take to the development of infrared measurement of temperature product abroad the twenties from eighties of last century, Yan Zhi pyrometer implementation method is by the target under the selected wavelength being compared its brightness ratio, eliminating because the error that the difference of emissivity produces true temperature the earliest.This method is not too suitable to general most of materials, can cause bigger error, and is still for the measurement of grey body, still relatively effective.The development of the infrared temperature-test technology of China also mainly develops based on this general principle of work, obtain the infrared radiation that object sends by optical system, filtration through camera lens, the light of infrared wavelength range is seen through, enter infrared focus plane, infrared focus plane is converted into voltage signal to the infrared radiation that detects, and arrives digital signal by handling again, thereby has obtained heat picture and the temperature information of object.

The thermal imaging thermometric is a kind of emerging non-contact temperature measuring technology, also possesses functions such as target identification, temperature early warning in the two-dimension temperature field distribution of obtaining target in real time.Emissivity is one of factor that influences the thermal imaging thermometric, all is at the single emissivity of the solid of comparison rule under the laboratory environment.When practice, object is often irregular, and has many emissivity situation, continues to use the method in the laboratory of this " idealizing ", will cause inevitable error.

Summary of the invention

Technical matters solved by the invention is to provide a kind of and cuts apart the graphic images disposal route that many emissivity are set based on the visible region, thereby solves the problem in the above-mentioned background technology.

Technical matters solved by the invention realizes by the following technical solutions:

A kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, comprise the steps:

S1, employing visible light planar array detector and thermal infrared imager are taken target object under same visual field, same resolution, obtain visible light figure and infrared chart;

S2, based on visible light figure and the many complementary characteristics of infrared chart, utilize visible light figure, adopt partitioning algorithm to cut apart to target object, be divided into n regional, n 〉=2, n zone arranges corresponding emissivity respectively:

$T_0=T_r/\sqrt[n]{\mathrm{\ϵ}}---\left(1\right)$

T _rBe probe temperature, T ₀Be true temperature, ε is emissivity.

Obtain n profile, wherein, partitioning algorithm is including but not limited to Candy, watershed method, threshold method, Otsu and combination thereof;

S3, utilize n profile among the step S2 that infrared chart is defined or divides, obtain n zone of infrared chart, and with n of infrared chart zone splicing or synthetic, can there be break joint after splicing or synthesizing, to break joint by thermal conduction characteristic, carry out smoothing processing, the method for processing is including but not limited to based on heat-conduction equation:

$u(x,t)=\frac{\sin \left(2\right)}{2}+\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}{A}_n\cos \left(\mathrm{n\πx}\right)\exp \left({-\mathrm{kn}}^2{\mathrm{\π}}^{2}t\right)---\left(2\right)$

Wherein $A^n=2{\∫}_0^1\cos \left(2x\right)\cos \left(\mathrm{n\πx}\right)\mathrm{dx}={(-1)}^n\frac{-4\sin \left(2\right)}{n^2{\mathrm{\π}}^2-4}$

And the distortion or derive, the radial diffusion method

Radial diffusion algorithm thought is: outline line is expanded to n width (original is that 1 pixel is wide), and n is odd number, and the concrete numeral of n determines the actual n=5 of this paper by covering when there is free shortcoming in the splicing place; Circulate along the pointwise of original contour line, asking i point place is that (the node coordinate ecto-entad of Li is: Ci1 for the line segment Li of n perpendicular to the length of outline line ... Cin, outline line is at midpoint Cin/2+1), established by topic and can get TCi1=T2, TCin=T1, line segment Li is carried out the n-1 five equilibrium, can release the temperature of other point.

Through the processing of above step, for the irregularly shaped object (shape, roughness, texture difference) of isothermal, the thermal map of taking, behind pseudo-color conversion, color reaches unanimity, and each regional temperature variance reduces; For anisothermal object, the Temperature Distribution that records is more accurate.

Among the present invention, described visible light planar array detector and thermal infrared imager all require consistent on the physical form of focal length, camera lens, optical characteristics.

Among the present invention, the on-line monitoring thermal infrared imager that the preferred Zhuhai of thermal infrared imager more than one monitoring science and technology are produced.

Among the present invention, the wavelength that thermal infrared imager adapts to is 2～14 μ m.

Among the present invention, described visible light planar array detector adopts colored CCD or black-white CCD.

Among the present invention, among the step S2, preferably utilize the canny detecting device that visible light figure is cut apart.

Among the present invention, among the step S3, when break joint is carried out smoothing processing, preferably adopt the radial diffusion method to handle.

Owing to adopted above technical scheme, the present invention has following beneficial effect:

Irregular target object exists many emissivity to cause the bigger method of measured temperature error thereby main contents of the present invention provide a cover improvement, is used for the thermal imaging thermometric to the complex target object.

When instrument is set to single emissivity, no matter calculate still from the effect of actual observation from the reason human relations, when the emissivity height that the actual transmission rate sets than instrument, measured temperature can be higher, and vice versa, is called for short Gao Genggao, lower.When the known isothermal of object, its infrared chart (pseudo-coloured silkization back) should be same color in the ideal case, if when the emissivity in a zone is higher than the emissivity of setting, when another regional emissivity is lower than the emission that sets, bigger aberration can appear in its infrared chart, shown in figure (2).The colour temperature of this moment can not reflect the real temperature of object.The scheme taked of invention is to same object under test, cuts apart to use based on visible light a kind ofly by the zone method of many emissivity to be set, in order to make the object of known isothermal take the infrared chart of isochrome.This method is intended to by the region growing algorithm after improving, according to different zones corresponding emissivity is set, in view of the algorithm self characteristics, can make regional adjacent not fit together perfectly, the present invention adopts the radial diffusion method to make intersection seamlessly transit according to thermal conduction characteristic.Thereby make more even the smoothing to of thermal map be close to an integral body, objective evaluation is consistent with the subjective assessment effect.Final thermography reflects the true temperature of target object more accurately.

This method is suitable for the diseases and pests of agronomic crop diagnosis, also can be applicable in commercial unit thermometric and the medical diagnosis, can avoid or reduce the mistaken diagnosis erroneous judgement; In the atural object infrared telemetry, can make the easier differentiation identification of ground thing.

Description of drawings

Fig. 1 is the VI figure of the aluminium block of the 20*10*5mm specification of taking under the common laboratory environment;

Fig. 2 is the IR figure of the aluminium block of the 20*10*5mm specification of taking under the common laboratory environment;

Fig. 3 is given in the outline map of taking the canny detecting device to extract under the MATLAB environment;

Fig. 4 is the design sketch after Fig. 2 stacking diagram 3 carries out region deviding;

Fig. 5 is because the fit equation of detector gray scale and temperature is different with Fig. 6, revises back gray scale thermal map again through being converted to two kinds of design sketchs of pcolor under same detector;

Fig. 7 is the stacking diagram of Fig. 5 and Fig. 6;

Fig. 8 has provided the design sketch after " colour temperature " seamlessly transits under the MATLAB environment, i.e. the final effect figure of this method.

Embodiment

For technological means, creation characteristic that the present invention is realized, reach purpose and effect is easy to understand, below in conjunction with specific embodiment, further set forth the present invention.

A kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, comprise the steps:

S1, employing visible light planar array detector and thermal infrared imager are taken target object under same visual field, same resolution, wherein, the visible light planar array detector adopts colored CCD, the on-line monitoring thermal infrared imager that thermal infrared imager adopts Zhuhai more than one monitoring science and technology to produce, both all require consistent on the physical form of focal length, camera lens, optical characteristics, the wavelength that thermal infrared imager adapts to is 2～14 μ m, obtains visible light figure and infrared chart, and is as follows:

On-line monitoring thermal infrared imager (the Flir movement that uses Zhuhai more than one monitoring science and technology to produce, Daheng's processor), the default transmit rate is 0.95, the color output mode is elected Fusion as, indoor is the common laboratory environment, indoor temperature is 20 ℃, and relative humidity is 65%, and door and window closes and is considered as indoor no cross-ventilation.Aluminium block is of a size of 20*10*5mm, surperficial frosted, and the centre is painted and is painted irregularly shapedly, (is considered as the heat interchange balance) in indoor placement after 2 hours, takes with the visual field.But Fig. 1 and Fig. 2 be exactly clap under the same visual field light light figure and infrared chart, resolution is 320*240;

S2, many mutually by characteristic based on visible light figure and infrared chart utilizes visible light figure, adopts partitioning algorithm to cut apart to target object, is divided into n zone, n 〉=2,

N zone arranges corresponding emissivity respectively:

$T_0=T_r/\sqrt[n]{\mathrm{\ϵ}}---\left(1\right)$

T _rBe probe temperature, T ₀Be true temperature, ε is emissivity, n=4 herein, and this is reason human relations foundations, company derives out by heat radiation.

Obtain n profile, wherein, partitioning algorithm more than is algorithm known including but not limited to Candy, watershed method, threshold method, Otsu and combination thereof;

As follows:

By experiment condition aluminium block each several part equality of temperature as can be known, the controlled temperature bar just can apparently find out that middle black paint temperature partly is than white space is obviously high on every side through range estimation, instrument shows that the temperature difference reaches 4.4 ℃, and this is because the different institute of the emissivity in two zones causes.Use following method, can be so that the object of known isothermal be taken the infrared chart of isochrome;

Utilize the canny detecting device to realize cutting apart of black region among Fig. 1.Black paint (emissivity Es=1) is uniformly sprayed on the target object surface, by adjusting the thermal infrared imager emissivity, identical with the lacquered surface temperature or approaching up to the surface temperature of not spraying paint then, get the non-paint of target object emissivity partly.Can draw non-paint part emissivity Er=0.92 with above-mentioned experimental technique, oppositely derive revised gray scale thermal map according to two different emissivity Es, Er and original gray-scale map, be converted to pcolor then, the paint part can be to blue shift, non-paint part can be to orange skew, effect is shown in Fig. 5,6, the stack back is Fig. 7, estimating two regional aberration obviously reduces, pcolor color trend is consistent, but boundary obviously has incompleteness, and this is that pixel by intersection neither belongs to Fig. 5 and also do not belong to Fig. 6 and cause.

S3, utilize n profile among the step S2 that infrared chart is defined or divides, obtain n zone of infrared chart, and with n of infrared chart zone splicing or synthetic, can there be break joint after splicing or synthesizing, to break joint by thermal conduction characteristic, carry out smoothing processing, the method for processing is including but not limited to based on heat-conduction equation:

$u(x,t)=\frac{\sin \left(2\right)}{2}+\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}{A}_n\cos \left(\mathrm{n\πx}\right)\exp \left({-\mathrm{kn}}^2{\mathrm{\π}}^{2}t\right)---\left(2\right)$

Wherein $A^n=2{\∫}_0^1\cos \left(2x\right)\cos \left(\mathrm{n\πx}\right)\mathrm{dx}={(-1)}^n\frac{-4\sin \left(2\right)}{n^2{\mathrm{\π}}^2-4}$

And the distortion or derive, the radial diffusion method,

Radial diffusion algorithm thought is: outline line is expanded to n width (original is that 1 pixel is wide), and n is odd number, and the concrete numeral of n determines when there is free shortcoming in the splicing place by covering; Circulate along the pointwise of original contour line, asking i point place is that (the node coordinate ecto-entad of Li is: Ci1 for the line segment Li of n perpendicular to the length of outline line ... Cin, outline line is at midpoint Cin/2+1), established by topic and can get TCi1=T2, TCin=T1, line segment Li is carried out the n-1 five equilibrium, can release the temperature of other point.

As follows:

The situation of Fig. 7 uses heat transfer process to be modeled as: the heat conduction has reached to a certain stable state, being the high-temperature region no longer changes to the transitional zone temperature of low-temperature space, suppose the high-temperature in the corresponding paint of T2 district, the low temperature in the corresponding non-paint of T1 district, the temperature of that zone of transition should be to carry out the transition to T1 by T2 along the curve smoothing of heat-conduction equation from inside to outside, choosing which section of curve can't determine as for the curve that selects which time point, because the difference of T1 and T2 is smaller, can adopt the radial diffusion method to realize seamlessly transitting along outline line.Back effect such as Fig. 8 dispose.

With reference to the characteristic attribute of texture statistics, reference information entropy, standard deviation, smoothness, contrast Third moment, Consistency come the gray component of evaluation map 2 and Fig. 8.Adopt the crops digital image analysis system (V2.0) of Agricultural Information research institute of Agricultural University Of Hunan exploitation to record table (1)

Table 1 evaluating test comparison table

The result draws Fig. 8 comparison diagram 2, and entropy diminishes, and standard deviation diminishes, and contrast diminishes, smoothness diminishes, and three rank are apart from diminishing, and consistance increases, and illustrates that thermal map is more even more level and smooth more consistent, namely by the aluminium block thermal map after the zone setting emissivity, be close to an integral body, objective evaluation is estimated consistent with the master.

Through the processing of above step, for the irregularly shaped object (shape, roughness, texture difference) of isothermal, the thermal map of taking, behind pseudo-color conversion, color reaches unanimity, and each regional temperature variance reduces; For anisothermal object, the Temperature Distribution that records is more accurate.

More than show and described ultimate principle of the present invention and principal character and advantage of the present invention.The technician of the industry should understand; the present invention is not restricted to the described embodiments; that describes in above-described embodiment and the instructions just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.

Claims (7)

1. cut apart the graphic images disposal route that many emissivity are set based on the visible region for one kind, it is characterized in that: comprise the steps:

S1, employing visible light planar array detector and thermal infrared imager are taken target object under same visual field, same resolution, obtain visible light figure and infrared chart;

S2, many mutually by characteristic based on visible light figure and infrared chart, utilize visible light figure, adopt partitioning algorithm to cut apart to target object, be divided into n zone, n 〉=2, n zone arranges corresponding emissivity respectively and obtains n profile, and wherein, partitioning algorithm is including but not limited to Candy, watershed method, threshold method, Otsu and combination thereof;

S3, utilize n profile among the step S2 that infrared chart is defined or divides, obtain n zone of infrared chart, and with n of infrared chart zone splicing or synthetic, can there be break joint after splicing or synthesizing, to break joint by thermal conduction characteristic, carry out smoothing processing, the method for processing including but not limited to based on heat-conduction equation and distortion thereof or derive, the radial diffusion method.

2. according to claim 1ly a kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, it is characterized in that: described visible light planar array detector and thermal infrared imager all require consistent on the physical form of focal length, camera lens, optical characteristics.

3. according to claim 1ly a kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, it is characterized in that: the on-line monitoring thermal infrared imager that thermal infrared imager selects for use Zhuhai more than one monitoring science and technology to produce.

4. according to claim 1ly a kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, it is characterized in that: the wavelength that thermal infrared imager adapts to is 2～14 μ m.

5. according to claim 1ly a kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, it is characterized in that: described visible light planar array detector adopts colored CCD or black-white CCD.

6. according to claim 1ly a kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, it is characterized in that: among the step S2, utilize the canny detecting device that visible light figure is cut apart.

7. according to claim 1ly a kind ofly cut apart the graphic images disposal route that many emissivity are set based on the visible region, it is characterized in that: among the step S3, when break joint is carried out smoothing processing, adopt the radial diffusion method to handle.

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