CN107843193B - A kind of high-speed displacement measuring method and measuring device based on infrared thermal imaging technique - Google Patents
A kind of high-speed displacement measuring method and measuring device based on infrared thermal imaging technique Download PDFInfo
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- CN107843193B CN107843193B CN201710809940.9A CN201710809940A CN107843193B CN 107843193 B CN107843193 B CN 107843193B CN 201710809940 A CN201710809940 A CN 201710809940A CN 107843193 B CN107843193 B CN 107843193B
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- metal derby
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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Abstract
The present invention provides a kind of high-speed displacement measuring method based on infrared thermal imaging technique, metal derby is set on swing rod as emission source, its movement locus is captured by camera lens, it is converted into image, the thermal image feature of metal block mark is come out with background separation, the movement locus of the thermal image of metal derby is exactly the displacement that intelligent detecting instrument is occurred in the high speed processes of strike sample, to directly, precisely measure out intelligent detecting instrument in each sampling instant strike sample high-speed displacement, better authenticity, reliability, so as to calculate the impact absorbing energy of test button in each sampling instant.
Description
Technical field
The invention belongs to the analysis and test fields of dynamic fracture-mechanics performance, more particularly to one kind being based on infrared thermal imaging
The high-speed displacement measuring method and measuring device of technology.
Background technology
The security evaluation of hardware service condition tries metal using intelligent detecting instrument with the detection of its anti-break capability
Sample applies loading force to complete, and intelligent detecting instrument implements dynamic load to mechanics sample, and acquires dynamic force, time letter simultaneously
Number, data processing and last dynamic fracture-mechanics performance evaluation are completed by data processing system.
Traditional dynamic testing machine is common Charpy impact machine tester, can only record the suction of the impact after sample once interrupts
Work(is received, the fracture process of sample under the conditions of dynamic loading can not be recorded, it is even more impossible to obtain the Dynamic Fracture Toughness of material.
In order to meet the research needs of new material, meet the needs of engineering design and security evaluation, not only to record and interrupt
The impact absorbing energy of sample, at the same record thrust during sample power-displacement curve, the curve can be used for analyze sample
Fracture process under dynamic load effect.
There are not very good method, the displacement measurement of intelligent detecting instrument to use load-time graph the measurement of displacement
It obtains indirectly, is not result measured directly.It is the particularity of limitation and displacement signal due to measurement means to trace it to its cause.
It mostly uses rotary encoder for the development of the displacement sensor of intelligent detecting instrument both at home and abroad to segment through frequency multiplication, with load
Lotus senser sampling circuit synchronous acquisition, i.e., acquisition is believed by the angle that rotary encoder generates while carrying out load sampling
Number, then displacement is obtained by l=w*R, but have following disadvantage by the displacement that l=w*R is obtained：
(1) sub-circuit is highly susceptible to the influence of interference signal, and 1 times of subdivision will not be interfered, but 2 times, 4 times of subdivisions
It is just highly susceptible to interfere, mess code occurs in sub-circuit, causes data inaccurate.
(2) R is pendulum length, is the geometry centre of percussion of shock machine, and real impact testing machine is in processing and manufacturing process
In barycenter often more or less to deviate R, R ' is actual pendulum length, and R ' is obtained by single pendulum measurement, so R ' inherently exists
Certain error.
Invention content
To solve the above problems, the present invention provides a kind of high-speed displacement measuring method based on infrared thermal imaging technique,
Copper billet is permeated on swing rod as emission source, its movement locus is captured by camera lens, is converted into image, the thermal image of copper billet mark is special
Sign comes out with background separation, and the movement locus of the thermal image of copper billet is exactly intelligent detecting instrument institute in the high speed processes of strike sample
The displacement of generation, to precisely measure out high-speed displacement.
A kind of displacement measurement method based on infrared thermal imaging technique, includes the following steps：
Step 1：Metal derby is set on the body of rod on the movement swing rod of displacement intelligent detecting instrument, while in movement swing rod
Pendulum is arranged in free end, and as infrared imaging emission source, pendulum is used for hitting to be placed below movement swing rod wherein metal derby
Test button；
Step 2：Released movement swing rod, when moving the angle between swing rod and test button more than set angle threshold value,
Acquire and store the benchmark infrared image of metal derby；Angle between movement swing rod and test button is equal to set angle threshold value
When, the original infrared image sequence of metal derby is acquired and stored in chronological order, and wherein acquisition time is at least 30ms；
Step 3：By the metal derby profile in the benchmark infrared image of the original infrared image sequence of metal derby and metal derby
It compares, retains same section, reject different piece, obtain the metal derby infrared image sequence after denoising；
Step 4：Since the first frame infrared image of the infrared image sequence after metal derby denoising, adjacent two frame is differentiated successively
The displacement that metal derby is occurred in infrared image, to obtain the strike position generated during final pendulum strike test button
It moves.
Further, the displacement for differentiating that metal derby is occurred in adjacent two frames infrared image successively, to obtain most
The strike displacement generated during whole pendulum strike test button, specific method are：
First frame infrared image is the starting point of displacement measurement, and the infrared image of the latter sampling instant is subtracted previous adopt
The infrared image at sample moment, wherein pixel value difference are background no more than the pixel of given threshold, and pixel value difference is more than setting threshold
The pixel of value is metal derby pixel, counts the number of the metal derby pixel in every a line in kick positive direction, then calculates
In kick positive direction in all rows metal derby number of pixels average value, the average value be adjacent two frames infrared image in metal derby
The relative displacement of generation, wherein kick positive direction are adopted for metal derby in the infrared image of the latter sampling instant relative to previous
The moving direction of metal derby in the infrared image at sample moment；Analogized with secondary, until calculating institute in metal derby infrared image sequence
All relative displacements, are then added by the relative displacement for having the metal derby between consecutive frame to generate, and obtain final pendulum strike gold
Belong to the strike displacement generated in specimen.
Further, the benchmark infrared image and original infrared image sequence are obtained by infrared camera scan.
Further, the metal derby is copper billet.
Further, the copper block surface does oxidation processes.
A kind of measuring device of the displacement measurement method based on infrared thermal imaging technique, including displacement intelligent detecting instrument, gold
Belong to block, synchronizing generator and thermal imaging system；
The metal derby is fixed on the movement swing rod of displacement intelligent detecting instrument；
The synchronizing generator under the action of synchronous triggering signal of displacement intelligent detecting instrument, adopt by driving thermal imaging system
Collect the original infrared image sequence of metal derby, wherein acquisition time is at least 30ms；
The camera lens face metal derby of the thermal imaging system.
Advantageous effect：
1, the present invention provides a kind of high-speed displacement measuring method based on infrared thermal imaging technique, and metal is arranged on swing rod
Block captures its movement locus as emission source, by camera lens, is converted into image, by the thermal image feature of metal block mark and background point
It separates out and, the movement locus of the thermal image of metal derby is exactly the position that intelligent detecting instrument is occurred in the high speed processes of strike sample
Move, to directly, precisely measure out intelligent detecting instrument in each sampling instant strike sample high-speed displacement, more very
Reality, reliability, so as to calculate the impact absorbing energy of test button in each sampling instant；
The infrared imagery technique that the present invention uses, infrared to be better than visible light to environmental suitability, penetration power is strong, anti-interference
It is good, under night and adverse weather condition, it can measure high-speed displacement of the intelligent detecting instrument in hitting specimen；
The high-speed displacement measuring method high resolution of the present invention, identifies that the ability of target is strong, when target and environment have temperature
When degree difference, target can display on the image, can obtain the target image of high-resolution.
2, high-speed displacement measuring method of the invention is met《ISO 14556-2015 metal material Charpy v-notch is put
Hammering blow experiment-instrumentation test method》The needs of standard, the present invention directly measure intelligent measurement using infrared thermal imaging technique
The displacement of instrument can be manufactured into infrared displacement sensor, and sensor bulk is small, low in energy consumption, can be used in specially measuring intelligence
The displacement of detector, solve traditional displacement cannot problem measured directly, to fill up the blank in this field.
Specific implementation mode
With reference to embodiment, the present invention is described in detail.
It,, will be continuous due to the presence of its internal warm-up movement when the temperature of object is higher than absolute zero in nature
Radiated electromagnetic wave around, wherein just containing wave band is located at 0.75 μm~1000 μm of infrared ray, the maximum spy of infrared ray
Point is at given temperature and wavelength, and there are one maximum values for the radiation energy of object emission.Infrared imagery technique is realized people
The infrared band that eye cannot respond to is converted to the function of visible image.Object temperature is higher, and infra-red radiation is stronger, and wavelength is got over
It is short.
The incidence of different metal material is different, and emissivity is increased with the raising of temperature.The emissivity of metal with
Surface state is related, and when surface forms oxide layer after oxidation processes, emissivity is at tens times of increase.The transmitting of object
Rate changes with the variation of radiation wavelength, but variation amplitude is little, it is considered that emissivity is one in certain local wave bands
Constant.Object emission rate is related with coating material and thickness, and after body surface is plated or coated with other materials, object emission rate is only
It is related with the radiation characteristic of surfacing, and it is unrelated with the radiance of radiator itself.The basic principle of this patent is i.e. by base
In the radiation characteristic principle of metal material.
A kind of high-speed displacement measuring method based on infrared thermal imaging technique, includes the following steps：
Step 1：Metal derby is set on the movement swing rod of displacement intelligent detecting instrument, as infrared imaging emission source；It is described
Metal derby is copper billet, and copper block surface does oxidation processes, to generate maximum emissivity so that copper billet emissivity is apparently higher than
The emissivity of background；
The copper billet size is long 50mm, wide 30mm, thickness 2mm；Copper billet is connected with linking for swing rod using screw；
Step 2：The temperature radiation thermal imagery image for initially setting up copper billet, since the emissivity of copper billet is higher than the transmitting of background
Rate, then the thermal image feature performance of copper billet is apparent；Thermal camera face is moved into swing rod, and moves swing rod and is with distance of camera lens
1000mm；On-test, movement swing rod accelerate, and the sent out infrared light of copper billet is acquired by camera lens；Copper billet is embedded into movement
On swing rod, movement swing rod moves in hitting specimen, generates displacement, and with movement swing rod same position occurs for copper billet
It moves, the displacement of copper billet is the displacement that intelligent detecting instrument is occurred during strike sample, application load；
Therefore strike angle of the present invention between movement swing rod and test button vertical direction is more than set angle threshold value
When, the benchmark infrared image of infrared camera scan metal derby；Strike between movement swing rod and test button vertical direction
When angle is equal to set angle threshold value, synchronous triggering signal is triggered, thermal camera acquires and stores metal derby in chronological order
Original infrared image sequence, wherein acquisition time at least 30ms；
Infrared light reaches by camera lens on the non-refrigeration focal surface inside displacement displacement sensor, and focal plane generates electric current
Signal is integrated to form infrared image signal by amplification, and infrared image signal is uploaded to computer in the form of analog signal,
By the infrared image of Computer display displacement；
The control logic sequential of non-refrigeration focal surface is designed using FPGA circuitry, is reached and is passed with displacement intelligent detecting instrument load
The pattern that sensor works at the same time；
Step 3：Metal derby profile in the benchmark infrared image of the original infrared image sequence of metal derby and metal derby is made
Comparison retains same section, rejects different piece, and wherein different piece is the hangover that metal derby generates in image acquisition process,
To obtain the metal derby infrared image sequence after denoising；
Step 4：After first frame infrared image is positioned (time is the K moment), next sampling instant (time is the K+1 moment)
It is kick on edge with the previous thermal imagery radiation image using the moment (K moment), kick just generates larger image
The positive direction of kick, the heat when starting with the K moment when the K+1 moment terminates are directed toward in Edge difference, the direction of Edge difference
Displacement spatially has occurred in image, that is, produces maximum kick and become, maximum sudden change point is found out, maximum sudden change point generally occurs
In boundary, floor projection is displacement, and this method is dynamic edge thermal imagery method of identification；
Control software stores the infrared image of metal derby in chronological order, and by the thermal image of displacement in infrared image
It is detached with background, background image is changeless, and the thermal image of displacement is variation, to obtain shift value；
Therefore, the present invention differentiates phase successively since the first frame infrared image of the infrared image sequence after metal derby denoising
The displacement that metal derby is occurred in adjacent two frame infrared images, wherein first frame infrared image is the starting point of displacement measurement, specially：
The infrared image of the latter sampling instant is subtracted to the infrared image of previous sampling instant, wherein pixel value difference not
Pixel more than given threshold is background, and the pixel that pixel value difference is more than given threshold is metal derby pixel, and statistics is prominent
Then the number for jumping each row metal block pixel in positive direction calculates the flat of in kick positive direction all row metal block number of pixels
Mean value, then the average value is the displacement that metal derby generates in two frame infrared images, when wherein kick positive direction is that the latter samples
Moving direction of the metal derby relative to metal derby in the infrared image of previous sampling instant in the infrared image at quarter；Class successively
It pushes away, then the displacement generated until calculating the metal derby in metal derby infrared image sequence between all consecutive frames will own
Displacement is added, and obtains the strike displacement generated during final pendulum strike test button.
A kind of measuring device of the displacement measurement method based on infrared thermal imaging technique, including displacement intelligent detecting instrument, gold
Belong to block, synchronizing generator and thermal imaging system；
The metal derby is fixed on the movement swing rod of displacement intelligent detecting instrument；
The synchronizing generator under the action of synchronous triggering signal of displacement intelligent detecting instrument, adopt by driving thermal imaging system
Collect the original infrared image sequence of metal derby, wherein acquisition time is at least 30ms；
The camera lens face metal derby of the thermal imaging system.
Certainly, the invention may also have other embodiments, without deviating from the spirit and substance of the present invention, ripe
It knows those skilled in the art and makes various corresponding change and deformations, but these corresponding changes and change in accordance with the present invention
Shape should all belong to the protection domain of appended claims of the invention.
Claims (6)
1. a kind of displacement measurement method based on infrared thermal imaging technique, which is characterized in that include the following steps：
Step 1：Metal derby is set on the body of rod on the movement swing rod of displacement intelligent detecting instrument, while in the freedom of movement swing rod
As infrared imaging emission source, pendulum is used for hitting the metal being placed below movement swing rod for end setting pendulum, wherein metal derby
Sample；
Step 2：Released movement swing rod, when moving the angle between swing rod and test button more than set angle threshold value, acquisition
And store the benchmark infrared image of metal derby；When moving the angle between swing rod and test button equal to set angle threshold value,
The original infrared image sequence of metal derby is acquired and stored in chronological order, and wherein acquisition time is at least 30ms；
Step 3：Metal derby profile in the benchmark infrared image of the original infrared image sequence of metal derby and metal derby is opposed
Than retaining same section, rejecting different piece, obtain the metal derby infrared image sequence after denoising；
Step 4：Since the first frame infrared image of the infrared image sequence after metal derby denoising, differentiate that adjacent two frame is infrared successively
The displacement that metal derby is occurred in image, to obtain the strike displacement generated during final pendulum strike test button.
2. a kind of displacement measurement method based on infrared thermal imaging technique as described in claim 1, which is characterized in that it is described according to
The secondary displacement for differentiating that metal derby is occurred in adjacent two frames infrared image, during obtaining final pendulum strike test button
The strike displacement of generation, specific method are：
First frame infrared image is the starting point of displacement measurement, when the infrared image of the latter sampling instant is subtracted previous sampling
The infrared image at quarter, wherein pixel value difference are background no more than the pixel of given threshold, and pixel value difference is more than given threshold
Pixel is metal derby pixel, counts the number of the metal derby pixel in every a line in kick positive direction, then calculates in kick
In positive direction in all rows metal derby number of pixels average value, the average value be adjacent two frames infrared image in metal derby generate
Relative displacement, wherein kick positive direction be the latter sampling instant infrared image in metal derby relative to previous sampling when
The moving direction of metal derby in the infrared image at quarter；Analogized with secondary, until calculating all phases in metal derby infrared image sequence
All relative displacements, are then added by the relative displacement that the metal derby between adjacent frame generates, and obtain final pendulum strike metal examination
The strike displacement generated during sample.
3. a kind of displacement measurement method based on infrared thermal imaging technique as described in claim 1, which is characterized in that the base
Quasi- infrared image and original infrared image sequence are obtained by infrared camera scan.
4. a kind of displacement measurement method based on infrared thermal imaging technique as described in claim 1, which is characterized in that the gold
Category block is copper billet.
5. a kind of displacement measurement method based on infrared thermal imaging technique as claimed in claim 4, which is characterized in that the copper
Do oxidation processes in block surface.
6. a kind of measuring device for realizing the displacement measurement method described in claim 1 based on infrared thermal imaging technique, special
Sign is, including displacement intelligent detecting instrument, metal derby, synchronizing generator and thermal imaging system；
The metal derby is fixed on the movement swing rod of displacement intelligent detecting instrument；
The synchronizing generator is under the action of the synchronous triggering signal of displacement intelligent detecting instrument, driving thermal imaging system acquisition gold
Belong to the original infrared image sequence of block, wherein acquisition time is at least 30ms；
The camera lens face metal derby of the thermal imaging system.
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| CN109946188A (en) * | 2019-03-25 | 2019-06-28 | 莱州市电子仪器有限公司 | Flaky material is detected by the device and method of metal melt flow thermal shock resistance properties |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1815168A (en) * | 2006-02-14 | 2006-08-09 | 钢铁研究总院 | Dynamic fracture-mechanics testing system |
| CN106017695A (en) * | 2016-07-20 | 2016-10-12 | 上海航天控制技术研究所 | Adaptive infrared non-uniformity calibration method based on motion state estimation |
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| MY136233A (en) * | 2002-11-18 | 2008-08-29 | Univ Putra Malaysia | Pendulum impact test rig |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1815168A (en) * | 2006-02-14 | 2006-08-09 | 钢铁研究总院 | Dynamic fracture-mechanics testing system |
| CN106017695A (en) * | 2016-07-20 | 2016-10-12 | 上海航天控制技术研究所 | Adaptive infrared non-uniformity calibration method based on motion state estimation |
Non-Patent Citations (1)
| Title |
|---|
| 摆锤试验机冲击吸收功的计算机测量方法;洪刚 等;《物理测试》;20050131;第23卷(第1期);第31-33页 * |
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