CN1112574C - High-temperature luminous body temperature and temperature distribution measuring method based on three primary colors - Google Patents

Abstract

The present invention discloses a method for measuring the temperature and the distribution of objects through the luminescence color of an object at high temperature. In the method, a digital color video camera or an analog type color video camera and an image acquisition card or a camera and a color picture scanner or a colored shooting videoplayer, a videotape and an image acquisition card are used for digitizing shot color images of objects at high temperature and inputting the digitized shot color images of objects at high temperature to a computer; corresponding color system numbers of color pixel points are read out according to the trichromatic theory for obtaining the monochromatic radiance expression and the temperature of objects and the initial values of undetermined parameters; the color system numbers of luminescence colors of the objects at high temperature are computed according to the color system number equation; temperature data is computed by a least square method; results can be displayed, printed or used as control signals.

Description

Measure the method for high temperature luminous object temperature and distribution thereof based on three primary colors

The present invention relates to color, adopt computing machine to carry out the method for temperature and distribution measuring thereof according to the high temperature luminous object.

For the object that meets Planck's law of radiation, when himself temperature surpasses more than 600 ℃ behind the high temperature, will send the light of naked eyes visible color, along with the rising of temperature, color can by kermesinus to yellow, change to red white again.According to the luminous color that shows of object self Yin Gaowen, experienced master worker can estimate the roughly temperature of object.

Contactless radiation temperature measurement technology is adopted in existing measurement to high-temperature temperature usually.As leucoscope, its measured temperature is the brightness temperature under 0.66 micron wave length, and need make the true temperature that just can obtain object after the correction according to the data of object monochromatic radiance under this wavelength; The OS-900 series infrared thermometer produced of Britain Omega technology company for another example, reception be the heat radiation of object in the region of ultra-red emission, to know that equally also the data of object radiation rate are proofreaied and correct, could accurately obtain the true temperature of object; The common defects of above-mentioned two kinds of temperature measurement technologies is: object radiation rate data will according to circumstances be selected to determine by the tester, have certain subjectivity, therefore often because of giving the inaccurate error that causes, even so, then difficult more concerning amateur survey crew to professional survey crew; Existing in addition measuring method often only can be made measurement to the radiation of a certain very small region of object.The TVS-2000ST series thermal imaging system that Japan produces, though can measure the radiation profiles of object, in order to obtain the accurate data of Temperature Distribution, the radiance data that still need to provide object are proofreaied and correct.In fact, because the object radiation rate is the function of object temperature and wavelength, when object exists Temperature Distribution, its radiance exists distribution too, but thermal imaging system can only be according to given some radiance data, temperature distributing measuring data to the whole audience are made a kind of correction, and its accuracy is very restricted.It is worthy of note: adopt above-mentioned various radiation temperature measurement technology, what directly record only is the radiation intensity of object, and can not directly make measurement to the radiance of object, said radiance data in order to Tc must provide in other mode, thereby often do not match or the inaccurate error that causes because of selection.In addition, above-mentioned various radiation temperature measurement technology all need be carried out temperature calibration, set up the output valve of surveying instrument and the mutual relationship between the radiation intensity by demarcation.

The invention provides a kind of method of measuring high temperature luminous object temperature and distribution thereof based on three primary colors, for the high temp objects that meets Planck's law of radiation, according to its glow color, adopt computing machine to calculate the temperature or the radiance of object automatically, thereby avoid existing radiation temperature measurement technology often because of the unknown of object radiation rate data or estimate the inaccurate thermometric error that causes; This measurements and calculations simultaneously can be carried out each pixel pointwise of forming the high temp objects chromatic image, thereby can obtain the distribution of the temperature or the radiance of object.

This method of measuring high temperature luminous object temperature and distribution thereof based on three primary colors, it is characterized in that: by the chromatic image of picture pick-up device picked-up object because of the luminous formation of self high temperature, to import computing machine after this chromatic image digitizing, computing machine is according to the calculation procedure of being worked out, count measurement data with regard to the three primary colours colour system that its image color provided, directly calculate temperature, radiance and the distribution thereof of object;

Described picture pick-up device is colour TV camera or color camera;

Described chromatic image digitizing can directly be adopted digital colour TV camera or the high temp objects chromatic image information of colour TV camera picked-up directly is sent to image pick-up card or the high temp objects chromatic image information stores of colour TV camera picked-up broadcasted image pick-up card by colored player with image again or adopts camera picked-up high temp objects photochrome by the coloured image scanner photochrome to be scanned input and realize on record-reproduce head;

The calculation procedure of described establishment is: freeze and the measurement colour system that reads in the object chromatic image red, green, blue three primary colours of specifying color pixel cell is counted F _R, F _G, F _BCount equation according to colour system, obtain calculated value R, G, the B of high temp objects colour system number, do normalized respectively after, find the solution the Temperature numerical that this color pixel cell shows by least square method again; Described colour system is counted equation: $R=\underset{380}{\overset{780}{\∫}}r\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $G=\underset{380}{\overset{780}{\∫}}g\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $B=\underset{380}{\overset{780}{\∫}}b\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$

In the formula: C ₁----Planck first constant;

C ₂----Planck second constant;

E (λ, T)----monochromatic radioactive intensity;

T----absolute temperature;

ε _λ----monochromatic radiance;

λ----wavelength;

R, G, B----are respectively red, green, blue colour system number;

R (λ), g (λ), b (λ)----count function for the distribution colour system of the unified regulation of International Commission on Illumination (CIE).

The present invention is based on the measuring method of three primary colors, it is characterized in that taking following operation steps by computer realization colored shooting temperature and distribution thereof:

(1) with the input of the object high-temperature color signal of video signal after digitizing computing machine;

(2) execution is freezed to object high-temperature color image frame, reads the measurement colour system that constitutes the red, green, blue three primary colours of a certain specified pixel point in the object chromatic image and counts F _R, F _G, F _B

(3) expression formula and the Planck's law of radiation substitution colour system that will contain the object monochromatic radiance of one or two undetermined parameter counted equation, provides the initial value of undetermined parameter and temperature, obtains calculated value R, G, the B of high temp objects colour system number;

(4) will measure the gained colour system and count F _R, F _G, F _BCount R, G, B with calculating gained colour system and do the linear normalization processing respectively, get the trichromatic units vector f _R, f _G, f _BAnd f _r, f _g, f _b, import the Least Square in Processing program then, solve the temperature value of specified pixel point;

(5) repeat the process of (2) → (4), the colour system logarithmic data of the chromatic image that can be revealed because of pyrometric scale by taking the photograph object is found the solution calculating by pointwise, obtains the object temperature distribution field.

Described object monochromatic radiance expression formula can be consulted relevant documents and materials and be obtained.For example to luminous flame, its monochromatic radiance expression formula can be checked in by SAE document [SAE Paper 790491 (1979)]: ${\mathrm{\ϵ}}_{\mathrm{f\λ}}=1-\exp (-\mathrm{KL}/{\mathrm{\λ}}^{\mathrm{\α}})$ In the formula: ε _{F λ}Monochromatic radiance for luminous flame; KL is a undetermined parameter; α=138.

It below is the process flow diagram that program is calculated in computer color temperature survey used in the present invention.

Measuring method of the present invention is based on following principle:

To general object, its radiation and distribution thereof are described by Planck law: ${E(\mathrm{\λ},T)=\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}$

In the formula: C ₁----Planck first constant;

C ₂----Planck second constant;

E (λ, T)----monochromatic radioactive intensity;

T----absolute temperature;

ε _λ----monochromatic radiance;

λ----wavelength.

Following formula provides the spectral distribution of object radiation.In visible-range, this spectral distribution shows as visual color effect.

On the other hand, the color of object can reappear by the three primary colors principle, and this is the principle of work of colour TV camera, colour television set and color scanner.In the face of the chromatic image of a panel height temperature object, the colour system number of its three primary colours can be calculated by following system of equations: $R=\underset{380}{\overset{780}{\∫}}r\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $G=\underset{380}{\overset{780}{\∫}}g\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $B=\underset{380}{\overset{780}{\∫}}b\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ In the formula, R, G, B are respectively red, green, blue colour system number; R (λ), g (λ), b (λ) are that the distribution colour system of the unified regulation of International Commission on Illumination (CIE) is counted function.

General object depends on the radiation spectrum of object because of the color that self hyperthermia radiation showed.Conversely, the color that shows of high temp objects has comprised the information of temperature and radiance.Therefore,, and find the solution above-mentioned system of equations, can calculate the temperature and the radiance of object simultaneously by measurement to the high temp objects color coefficient.The inventive method is compared with the existing measureing method of high-temperature, owing to considered finding the solution of radiance simultaneously in measurements and calculations, therefore the temperature data that draws is more accurate.

Thermometry involved in the present invention is suitable for the high-temperature temperature measurement that the object monochromatic radiance is described the object that one to two undetermined constant is arranged in the formula.

Since the present invention by object because of the luminous color that produces of self high temperature (more than 600 ℃), adopt the computing machine automatic calculation to calculate the temperature of object, really realized technically " distinguish look know temperature ", and not only can record the temperature of specified point, can also provide the Temperature Distribution of a certain high-temperature area; Because considered simultaneously finding the solution of object radiation rate when calculating automatically, therefore the temperature data that draws accurately and reliably.

Adopt the inventive method can directly measure the Temperature Distribution of luminous object, this existing temp measuring method is difficult to accomplish; The present invention can provide comprehensive, complete metrical information, even this is to adopt many single-point temperature measurers also unapproachable by picked-up high temp objects chromatic image; The present invention compares with radiation temperature measurement technology such as existing leucoscope, Radiation Temperature Measurement Instrument, has the characteristics of measurement of full field; Compare with thermal imaging system, have low, the easy to use and visual characteristics such as human vision custom that meet of price; The present invention can directly be presented at the temperature that calculates by suitable mode (as: isotherm, etc. warm colour etc.) on the screen of computing machine or output to other device by computing machine, the demonstration of its result of calculation has intuitive and integrality, and the output of result of calculation has great convenience.

Compare with existing temp measuring method, two outstanding features of the present invention are:

(1) temperature measuring equipment that adopts the inventive method to construct relates to the next corresponding corresponding temperature of color that object high temperature luminescent spectrum is showed, so need not demarcate;

(2) adopt the inventive method, can pass through colour TV camera or color camera, with the high temp objects chromatic image be recorded in video-tape or and photochrome on after calculate thermometric again, the operation format of this measurement is simple, implement easily, especially under the very universal condition of camera and video camera, make thermometric become very easy, and can realize " strange land measurement " easily.

Adopt the inventive method,, also can solve the temperature of high temp objects and accurately the measuring of distribution thereof of the monochromatic radiance expression formula that contains two above undetermined parameters if three primary colors is suitably expanded to many primary colours.

Further describe below in conjunction with embodiment:

Embodiment 1 is for adopting a kind of direct measurement embodiment of the inventive method.

Accompanying drawing 2 is the overall construction drawing of a kind of measurement mechanism of using the inventive method and constructing.

The chromatic image vision signal of colourful CCD video camera 2 (IVC-83PN) picked-up high temp objects 1 is delivered to color image capture card 3, and this color image capture card 3 can adopt (VIDEO PLUS) finished product, is inserted in the expansion slot of computing machine 4 (PC/486).Vision signal deposits among the DRAM after image collection card 3 digitizings, and capture card 3 exports the digital video signal among the DRAM in the display of computing machine 4 again via display card simultaneously, forms the colorful visual image of high temp objects 1 on screen.And then carry out following operation:

The first step: with regard to above-mentioned high temp objects chromatic image on computer display screen, its each color pixel point of forming picture all can decomposite the colour system number of three kinds of primary colours of red, green, blue.The colour system number of remembering the color pixel point that certain is gathered is F _R, F _G, F _B

Second step: consult relevant documents and materials, measured object is provided its radiance expression formula, notice that the unknown parameter in this expression formula must not be more than 2.For example to luminous flame, its monochromatic radiance expression formula can check in ε by SAE document [SAE Paper 790491 (1979)] _{F λ}=1-exp (KL/ λ ^α), in the formula: ε _{F λ}Be the monochromatic radiance of luminous flame, KL is a undetermined parameter, α=1.38.Provide the initial value of undetermined parameter and temperature then, find the solution the calculated value of high temp objects color colour system number according to following formula, $R=\underset{380}{\overset{780}{\∫}}r\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $G=\underset{380}{\overset{780}{\∫}}g\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $B=\underset{380}{\overset{780}{\∫}}b\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$

In the formula, R, G, B--are respectively red, green, blue colour system number;

R (λ), g (λ), b (λ)--for the distribution colour system of the unified regulation of International Commission on Illumination (CIE) is counted function;

ε _λ--the object monochromatic radiance;

C ₁, C ₂--first, second constant of Planck;

λ--wavelength, μ m;

T--absolute temperature, K.

The 3rd step: with the measured value F of three primary colours _R, F _G, F _BCarry out linear normalization respectively with calculated value R, G, B and handle, get the trichromatic units vector f _R, f _G, f _BAnd f _r, f _g, f _bValue is handled with least square method then, just temperature or radiance data computation that this pixel showed can be come out.

The 4th step: temperature or radiance calculated value are presented on the screen, or output on other device.And then next pixel repeated above-mentioned same operation and calculating, until whole calculating of finishing high temp objects chromatic image temperature or radiance, obtain the temperature field or the radiance field of object.

Also can take the reconnaissance calculation mode, operation steps is the same.

One width of cloth picture carries out the high temp objects temperature of next width of cloth picture or the calculating of radiance and distribution thereof after calculating and finishing again.Finish the thermometric overall process of colored shooting thus.

Adopt the direct metering system of present embodiment as follows to the measurement of a concrete blackbody temperature:

Blackbody radiation source is placed the position of accompanying drawing high temp objects, provides different blackbody temperatures respectively, obtain measurement data and be listed in the table below:

Measure sequence number	The blackbody temperature value, K	Measured temperature, K	Measuring error (%)
				1	1053	1053.0	0
2	1573	1573.1	0.006
				3	1953	1921.3	1.623
4	2073	2069.0	0.193
				5	2293	2239.9	2.316
6	2313	2271.9	1.777

Measuring error in the last table can reach desired measuring accuracy scope by the improvement of calculation procedure.

Embodiment 2 adopts the inventive method to carry out a kind of embodiment that the strange land is measured indirectly.

Accompanying drawing 3 is the overall construction drawing of the another kind of measurement mechanism that uses the inventive method and construct.

The colored picture pick-up device here adopts camera 5 (OLYMPUS), takes the photochrome 6 of high temp objects 1 down, and color image scanner 7 is read into the photochrome 6 of high temp objects 1 in the computing machine 4; Perhaps adopt video camera 5, the variation chromatic image of high temp objects 1 is filmed, and records on the video-tape 6, the image of shooting with video-corder is inputed to the image collection card 3 that is installed in computing machine 4 expansion slot with player 7 then.The digital signal of the high temp objects chromatic image 6 that obtains exports to via display card in the display of computing machine 4, forms the colorful visual image of high temp objects 1 on screen.

And then carry out the above-mentioned operation steps that goes on foot from the first step to the four, finish measurement to high temp objects temperature and distribution thereof.

Adopt the indirect metering system of present embodiment 2 as follows to the concrete practical measuring examples of a flame temperature:

Adopt the measurement mechanism shown in the accompanying drawing 3, with the diesel oil flame 1 that burns under the free state, take into earlier photochrome 6, with colour picture scanner 7 photochrome 6 is scanned in the computing machine 4 then, get fire different measuring points in the flame photo obtains measurement data and is listed in the table below:

The measurement of flame temperature

The measurement point numbering	R	C	B	Measured temperature, K
					1	146	90	100	3030.9
2	158	143	72	2314.8
					3	158	143	72	2314.8
4	141	114	70	2846.4
					5	127	101	51	2736.9

Claims (2)

1. method of measuring high temperature luminous object temperature and distribution thereof based on three primary colors, it is characterized in that: by the chromatic image of picture pick-up device picked-up object because of the luminous formation of self high temperature, to import computing machine after this chromatic image digitizing, computing machine is according to the calculation procedure of being worked out, count measurement data with regard to the three primary colours colour system that its image color provided, directly calculate temperature, radiance and the distribution thereof of object;

Described picture pick-up device is colour TV camera or color camera;

Described chromatic image digitizing can directly be adopted digital colour TV camera or the high temp objects chromatic image information of colour TV camera picked-up directly is sent to image pick-up card or the high temp objects chromatic image information stores of colour TV camera picked-up broadcasted image pick-up card by colored player with image again or adopts camera picked-up high temp objects photochrome by the coloured image scanner photochrome to be scanned input and realize on record-reproduce head;

The calculation procedure of described establishment is: freeze and the measurement colour system that reads in the object chromatic image red, green, blue three primary colours of specifying color pixel cell is counted F _R, F _G, F _BCount equation according to colour system, obtain calculated value R, G, the B of high temp objects colour system number, do normalized respectively after, find the solution the Temperature numerical that this color pixel cell shows by least square method again; The colour system logarithmic data of the chromatic image that is revealed because of pyrometric scale by taking the photograph object is found the solution calculating by pointwise, obtains the object temperature distribution field;

Described colour system is counted equation: $R=\underset{380}{\overset{780}{\∫}}r\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $G=\underset{380}{\overset{780}{\∫}}g\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$ $B=\underset{380}{\overset{780}{\∫}}b\left(\mathrm{\λ}\right){\mathrm{\ϵ}}_{\mathrm{\λ}}\frac{C_1}{{\mathrm{\λ}}^5[\exp \left(\frac{C_2}{\mathrm{\λT}}\right)-1]}\mathrm{d\λ}$

In the formula: C ₁----Planck first constant;

C ₂----Planck second constant;

E (λ, T)----monochromatic radioactive intensity;

T----absolute temperature;

ε _λ----monochromatic radiance;

λ----wavelength;

R, G, B----are respectively red, green, blue colour system number;

R (λ), g (λ), b (λ)----count function for the distribution colour system of the unified regulation of International Commission on Illumination (CIE).

2. one kind based on the measuring method of three primary colors by computer realization colored shooting temperature and distribution thereof, it is characterized in that taking following operation steps:

(1) with the input of the object high-temperature color signal of video signal after digitizing computing machine;

(2) execution is freezed to object high-temperature color image frame, reads the measurement colour system that constitutes the red, green, blue three primary colours of a certain specified pixel point in the object chromatic image and counts F _R, F _G, F _B

(3) expression formula and the Planck's law of radiation substitution colour system that will contain the object monochromatic radiance of one or two undetermined parameter counted equation, provides the initial value of undetermined parameter and temperature, obtains calculated value R, G, the B of high temp objects colour system number;

(4) will measure the gained colour system and count F _R, F _G, F _BCount R, G, B with calculating gained colour system and do the linear normalization processing respectively, get the trichromatic units vector f _R, f _G, f _BAnd f _r, f _g, f _b, import the Least Square in Processing program then, solve the temperature value of specified pixel point;

(5) repeat the process of (2) → (4), the colour system logarithmic data of the chromatic image that can be revealed because of pyrometric scale by taking the photograph object is found the solution calculating by pointwise, obtains the object temperature distribution field.

Images