CN102706458B - Infrared thermal imaging coordinate positioning method - Google Patents

Abstract

The invention discloses an infrared thermal image coordinate positioning method, which comprises the following steps: (1) selecting an infrared thermal image positioning plate, the infrared thermal image positioning plate includes a base plate and a plurality of cooling columns vertically arranged on the base plate; (2) uniformly Heating the infrared thermal image positioning plate; (3) shooting the infrared thermal image of the infrared thermal image positioning plate; (4) finding out the low temperature point in the infrared thermal image of the infrared thermal image positioning plate; (5) according to the infrared thermal image The position parameters of the heat dissipation column on the mid-infrared thermal image positioning board are used to calculate the actual coordinate position of each pixel in the infrared thermal image; (6) remove the infrared thermal image positioning board after shooting, and take the infrared thermal image of the sample to be analyzed According to the image diagram, the actual coordinate position of each part of the sample to be analyzed is determined according to the positional relationship between the converted cooling column and the sample to be analyzed. The method is simple, has high precision, can quickly determine the location of the abnormal temperature point, is applicable to various occasions, and has strong practicability.

Description

A Coordinate Positioning Method of Infrared Thermal Image

technical field

The invention belongs to the technical field of infrared thermal imaging, and in particular relates to an infrared thermal imaging coordinate positioning method.

Background technique

Because infrared thermal imaging technology can perform non-contact, high-resolution temperature imaging, generate high-quality images, provide a lot of information on measurement targets, and make up for the lack of human eyes, it has been used in power systems, civil engineering, Automobile, metallurgy, petrochemical, medical and many other industries have been widely used, and the future development prospect is even more limitless. With the development of the application of infrared thermal imaging technology, it has higher requirements for the speed and accuracy of infrared image analysis. At present, most of the infrared image analysis is to determine the position of the temperature anomaly point by comparing the profile of the infrared image with the profile of the sample. Such a method has low precision and slow speed. If the emissivity and temperature of the object are not much different from the background, it will be difficult to determine the position of the temperature anomaly.

Contents of the invention

The purpose of the present invention is to provide an infrared thermal image coordinate positioning method that can quickly and accurately find the actual position coordinates corresponding to the pixels from the thermal image. It can be applied to various occasions and has strong practicability.

The above object of the present invention is achieved by the following method: a method for positioning infrared thermal image coordinates, comprising the following steps:

(1) selecting an infrared thermal image positioning plate, the infrared thermal image positioning plate includes a base plate and a plurality of heat dissipation columns vertically arranged on the base plate;

(2) Heating the infrared thermal image positioning board evenly;

(3) Use an infrared thermal imager to shoot an infrared thermal image of the infrared thermal image positioning board;

(4) Find out the low temperature point in the infrared thermal image of the infrared thermal image positioning plate;

(5) Calculate the actual coordinate position of each pixel in the infrared thermal image according to the position parameters of the cooling column on the infrared thermal image positioning plate in the infrared thermal image;

(6) After taking the infrared thermal image of the infrared thermal image positioning plate, remove the infrared thermal image positioning plate, take the infrared thermal image of the sample to be analyzed, and determine the positional relationship between the heat dissipation column and the sample to be analyzed according to the positional relationship between the converted cooling column and the sample to be analyzed The actual coordinate position of each part of the sample.

In the above steps:

The bottom plate in the step (1) of the present invention is made of a material with poor heat dissipation, and the material with poor heat dissipation is preferably but not limited to plastic, wood or ceramics.

The size of the bottom plate in step (1) of the present invention is preferably but not limited to 1 cm ² ~1 m ² .

The cooling post in the step (1) of the present invention is made of a metal material with good heat dissipation, and the metal material is preferably but not limited to iron, copper, aluminum, tungsten, tin or nickel.

The number of cooling columns described in step (1) of the present invention is preferably but not limited to 1-100.

One end of the cooling column described in step (1) of the present invention is vertically embedded in the bottom plate of the infrared thermal image positioning plate, and the other end is preferably but not limited to 0.1-20 cm higher than the surface of the bottom plate.

The infrared thermal image positioning plate adopted in the present invention includes a bottom plate and a heat dissipation column vertically arranged on the bottom plate, which is a plate with a heat dissipation column nailed on the surface, and the base plate is made of a material with poor heat dissipation capacity, such as: Plastic, boards with thermal insulation coating on the surface, etc.; the heat dissipation column is made of materials with good heat dissipation capabilities, such as: various metal materials, and the heat dissipation column is vertically fixed on the surface of the bottom plate.

The main principle of the infrared thermal image positioning board is: after the positioning board is evenly heated, since the heat dissipation column is larger than the bottom plate in terms of specific surface area and material heat dissipation characteristics, the heat dissipation speed of the heat dissipation column is much faster, and it can be photographed within a certain period of time. There will be a significant low temperature point in the infrared thermal image. By comparing the distance and position relationship between the measured multiple heat dissipation columns with the relationship of the low temperature point in the infrared thermal image, the actual coordinate position represented by each pixel in the infrared thermal image can be calculated through program calculation.

In step (4) of the present invention, the low temperature point in the infrared thermal image of the infrared thermal image positioning plate can be found out through human eye recognition or computer recognition program;

In the step (6) of the present invention, for small samples, the infrared thermal image positioning plate is placed on the device with the limiting structure, the infrared thermal imager and the device with the limiting structure are adjusted on the same straight line, and the infrared thermal image is positioned after shooting After taking the infrared thermal image of the plate, remove the infrared thermal image positioning plate, place the small sample to be analyzed at the same position, and determine the actual coordinate position of each part of the small sample by taking the infrared thermal image of the small sample.

In step (6) of the present invention, for a large sample, the infrared thermal image positioning plate is fixed on the large sample, and the large sample and the infrared thermal imager are adjusted on the same straight line, and after the infrared thermal image of the infrared thermal image positioning plate is taken, Remove the infrared thermal image positioning plate, take an infrared thermal image of the large sample to be analyzed, and determine the actual coordinate position of each part of the large sample.

As an embodiment of the present invention, for small samples, it is generally placed on a device with a limit structure to take infrared thermal images, and after one positioning, multiple thermal images of samples can be taken and analyzed. The process is as follows:

(1) Fix the infrared thermal imager and the device with a limit structure on the same straight line;

(2) Place the infrared thermal image positioning plate on the limited structure with the limit structure device;

(3) Heating the infrared thermal image positioning board evenly;

(4) Shoot the infrared thermal image of the infrared thermal image positioning board;

(5) Find the low temperature point, and calculate the actual coordinate position of each pixel in the infrared thermal imaging image of the infrared thermal image positioning board according to the positional relationship of the cooling column;

(6) Remove the infrared thermal image positioning plate, place the small sample to be analyzed in the same position, and determine the actual coordinate position of each part of the small sample by taking the infrared thermal image of the small sample.

Then the sample can be replaced, photographed and analyzed, and after one positioning, thermal images of multiple samples can be taken and analyzed.

As an embodiment of the present invention, for large samples, the samples are generally taken directly, and the infrared thermal imager and the sample are placed on the same straight line. Each sample needs to be positioned once before shooting and analysis. The specific process is as follows:

(1) Place the thermal imaging camera and the sample on the same straight line;

(2) Fix the infrared thermal image positioning plate on certain positions of the sample, such as the right-angle frame or the center;

(3) Heating the infrared thermal image positioning board evenly;

(4) Shoot the infrared thermal image of the infrared thermal image positioning board;

(5) Find the low temperature point, and calculate the actual coordinate position of each pixel in the infrared thermal image according to the positional relationship of the cooling column;

(6) Remove the infrared thermal image positioning plate, take and analyze the infrared thermal image of a large sample;

Finally, replace the sample and repeat the above steps (1)~(6) to obtain the actual coordinate positions of various parts of other large samples.

Compared with prior art, the present invention has following advantage:

(1) The present invention can customize the size of the heat dissipation column according to the image resolution of the infrared thermal imager, so that the low temperature point only occupies one or a few pixels, which can avoid the occurrence of the problem when the low temperature point is selected by the human eye. If the subjective deviation is too large, it can also reduce the difficulty of selecting a low-temperature program for the computer and reduce the possibility of program errors;

(2) The infrared thermal image positioning plate of the present invention is simple to manufacture, does not need any electrical equipment, and has low cost;

(3) According to the shape of the sample and the resolution of the infrared thermal imager, the present invention can further improve the coordinate positioning accuracy and reduce the difficulty and system error of the calculation program by arranging different numbers of cooling columns and relative positional relationships;

(4) Through the method of the present invention, whether it is the test and analysis of large batches of small samples on the production line or the detection of large samples at large construction sites, the actual coordinate position of the pixel of the infrared thermal image can be determined quickly and accurately, thereby quickly and Accurately analyze and repair the defects and abnormal points in the sample.

Description of drawings

Fig. 1 is the pictorial diagram of the infrared thermal image positioning plate adopted in the embodiment 1 of the present invention;

2 is a schematic diagram of applying the infrared thermal imaging coordinate positioning method to the field of defect analysis of crystalline silicon solar cells in Embodiment 1 of the present invention;

Fig. 2a is a top view of the placement position of the positioning plate in Fig. 2;

Fig. 3 is a schematic diagram of an infrared thermal image positioning plate used in Embodiment 2 of the present invention;

Fig. 4 is the schematic diagram of placing the positioning plate on the furnace wall of the kiln in Example 2 of the present invention;

Fig. 4a is a schematic diagram of using an infrared thermal image positioning board to overhaul a large kiln wall in embodiment 2;

5 is a schematic diagram of an infrared positioning board used in Embodiment 3 of the present invention;

Fig. 6a is a schematic diagram of placing the infrared positioning plate on the bracket for infrared coordinate positioning in embodiment 3 of the present invention;

Fig. 6b is a schematic diagram of the structure of the infrared positioning plate placed on the bracket in Fig. 6a;

Fig. 6c is a schematic diagram of placing an automobile tire on a bracket for infrared coordinate positioning in Example 3 of the present invention;

Fig. 6d is a schematic diagram of placing a car tire on a support in Example 3 of the present invention;

Among them: 11. Bottom plate; 12. Cooling column; 1. Test bench; 2. Limiting bar; 3. Positioning plate (cooling column not shown) or test sample; 4. Infrared thermal imager; 21. Positioning plate; 22. Kiln wall; 23. Infrared camera.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Example 1

The infrared thermal image coordinate positioning method is applied to the field of defect analysis of crystalline silicon solar cells. The infrared thermal image positioning plate is shown in Figure 1, including a base plate 11 and a heat dissipation column 12 vertically arranged on the base plate 11. The base plate 11 is made of a plastic plate. In this embodiment, the size is 156mm×156mm×3mm, and the heat dissipation column 12 is made of stainless steel, with a diameter of 1mm and a height of 20mm, but in fact the above is not to limit the size of the bottom plate and the heat sink, and it can be determined according to the different analysis objects. Corresponding adjustments are enough. The number of heat dissipation columns is three, distributed on the three vertices of a right triangle. The side lengths of the right triangle are 120mm and 100mm, and the vertices of the right angle are located at (10mm, 10mm) in the positioning board coordinate system ( The coordinate system takes the right-angled vertex of the bottom plate as the origin O, and the sides parallel to the two sides of the right-angled triangle as the xy axis, as shown in Figure 1). The distribution method of the cooling column mainly uses these three points to establish a rectangular coordinate system. The actual coordinate position of the pixel point in the thermal image can be easily calculated through the transformation formula of the rectangular coordinate system. At the same time, the relationship between the three points is simple. Whether it is to distinguish by human eyes or through image recognition programs, it is quite simple, and the probability of error is low.

The specific implementation steps of this example are as follows:

(1) Put the above-mentioned infrared thermal image positioning plate on the measuring platform, the measuring platform has fixed squares perpendicular to each other as a limit device to fix the position of the positioning plate in the middle of the field of view of the infrared thermal imager, adjust the infrared The thermal imager and the measuring platform are on the same straight line, as shown in Figure 2 and 2a;

(2) Use a hair dryer to blow hot air to the infrared thermal image positioning plate, so that the bottom plate of the infrared thermal image positioning plate is evenly heated;

(3) Use the real-time shooting function of the infrared thermal imager, wait for three obvious low-temperature points distributed at right angles to appear in the infrared thermal image, and then take the infrared thermal image;

(4) Use the positioning program to call out the infrared thermal image, use the mouse to select the positions of the three low-temperature points in the infrared thermal image, and then calculate the three low-temperature points through the program and transform them into the positions in the base plate coordinate system where the heat dissipation column is located The coordinate transformation formula is used to calculate the actual coordinate position of each pixel in the infrared thermal image on the bottom plate of the infrared thermal image positioning board through the coordinate transformation formula;

(5) Remove the positioning plate, put the 156mm×156mm solar cell to be analyzed at the same position, and take the infrared thermal image after corresponding processing, and then analyze the corresponding position of the defect in the cell.

Example 2

The infrared thermal image coordinate positioning method is applied to the field of large-scale kiln wall maintenance. The infrared thermal image positioning board used is shown in Figure 3, including the bottom plate 1 and the cooling column 2 vertically arranged on the bottom plate 1. Due to the temperature of the kiln wall Higher, so the bottom plate 1 uses a high temperature resistant ceramic plate with a size of 1000mm×1000mm×20mm, and the heat dissipation column 2 uses tungsten with better thermal stability, with a diameter of 10mm and a height of 10mm, but in fact the above is not for the bottom plate and The size of the heat sink is limited, and it can be adjusted according to the different analysis objects. The number of cooling columns is four, and the distribution is shown in Figure 3. The side lengths of the right triangle are 8000mm and 8000mm, and the vertices of the right angle are located at Position (100mm, 100mm) of the positioning plate coordinate system (the coordinate system takes the right angle vertex of the bottom plate as the origin O, and the side parallel to the two sides of the right triangle is the xy axis, as shown in Figure 1). Using such a distribution method of cooling columns mainly uses these four points to establish a rectangular coordinate system, in which one more cooling column in the middle of the vertical side has two functions: 1. Identify the xy axis; 2. Improve the resolution of the vertical direction and the y axis Accuracy (Since the refractory bricks on the furnace wall are laid flat, the vertical direction requires higher precision than the horizontal direction to determine which brick has a problem)

The specific implementation steps of this example are as follows:

(1) As shown in Figure 3, the above-mentioned infrared thermal image positioning plate 21 is placed on the lower left corner of the kiln wall 22, and the left edge and the lower edge of the infrared thermal image positioning plate 21 are aligned with the lower left edge of the kiln wall 22;

(2) The infrared thermal image positioning plate is close to the furnace wall. Due to the high temperature of the furnace wall, the infrared thermal image positioning plate is evenly heated through heat conduction;

(3) Use the real-time shooting function of the infrared thermal imager 23 to take the infrared thermal image of the infrared thermal image positioning plate after four obvious low temperature points distributed at right angles appear in the infrared thermal image;

(4) Use the positioning program to call up the infrared thermal image of the infrared thermal image positioning board, use the mouse to select the positions of four low-temperature points in the infrared thermal image, and then calculate the four low-temperature points through the program and transform them into the location of the cooling column The coordinate transformation formula of the position in the bottom plate coordinate system, the actual bottom plate coordinate position relative to each pixel point in the infrared thermal image is calculated by the coordinate transformation formula;

(5) Remove the infrared thermal image positioning plate, and re-take the infrared thermal image of the furnace wall. After calculating the pixel position of the abnormal temperature point in the picture, the position where the refractory brick needs to be replaced can be calculated, and the kiln can be carried out accordingly. Wall maintenance.

Example 3

The infrared thermal image coordinate positioning method is applied to the performance test of automobile tires. The infrared thermal image positioning board used is shown in Figure 5, including the bottom plate and the cooling column vertically arranged on the bottom plate, because the tire needs to be fixed on a bracket for testing and The main object of the study is the rubber part of the outer ring, so the positioning plate used is a circular ring. Taking the outer diameter of the ring as 190.5mm and the inner diameter as 25.0mm as an example, the thickness of the positioning plate is consistent with the tire to be tested. The same thickness is convenient to be fixed on the bracket, and the bottom plate of the positioning plate is made of wood, which is because the wood is easy to process and light in weight, so it is more suitable as a positioning plate for tire testing. The heat dissipation column is made of stainless steel. In this embodiment, the diameter is 5mm, the height is 10mm as an example, the number of heat dissipation columns is 15, and the distribution is shown in Figure 5. Using this distribution method, a polar coordinate system can be easily established, and different numbers of heat dissipation columns are distributed every 60 degrees. Even if there is an error in the artificial determination of the low temperature point, the position of the origin of the polar coordinates can be determined more accurately through the algorithm of the least squares method, and at the same time, the pixel of the infrared thermal imager image can be avoided by comparing the intervals of different cooling columns. The error in determining the actual coordinates caused by the distribution of rectangular coordinates.

The specific implementation steps of this example are as follows:

(1) As shown in Figures 6a-6b, fix the above-mentioned infrared thermal image positioning plate on the test bracket;

(2) Use hot air to heat or soak in hot water to heat the positioning plate evenly;

(3) Use the real-time shooting function of the infrared thermal imager, wait for 15 low-temperature spots to appear in the infrared thermal image, and then shoot the infrared thermal image;

(4) Use the positioning program to call out the infrared thermal image, use the mouse to select the positions of 15 low-temperature points in the infrared thermal image, and then calculate the 15 low-temperature points through the program and transform them into the positions in the base plate coordinate system where the heat dissipation column is located The coordinate transformation formula is used to calculate the actual coordinate position of the base plate relative to each pixel in the infrared thermal image;

(5) Remove the positioning plate, fix the tire to be tested on the bracket as shown in Figure 6c-6d, and after the experiments such as rotation friction or stress test, use the infrared thermal imager to take the thermal image, after the thermal image By calculating the pixel position of the temperature abnormal point, the actual position can be calculated, so as to study the performance of the tire, and use this as a basis to find problems and improve the design.

The present invention has been described by citing specific examples above. It should be pointed out that the above examples are only used to further illustrate the present invention, and do not represent the protection scope of the present invention. Non-essential modifications and adjustments made by others according to the hints of the present invention still belong to the protection scope of the present invention.

Claims (2)

1. an infrared thermal imagery coordinate location method, is characterized in that containing following steps:

(1) choose infrared thermal imagery location-plate, described infrared thermal imagery location-plate comprises base plate and is vertical at the multiple thermal columns on base plate;

(2) homogeneous heating infrared thermal imagery location-plate;

(3) adopt thermal infrared imager to take the Infrared Thermogram of infrared thermal imagery location-plate;

(4) find out the low warm spot in the Infrared Thermogram of infrared thermal imagery location-plate;

(5), according to the location parameter of thermal column on infrared thermal imagery location-plate in Infrared Thermogram, calculate the real coordinate position of each pixel in Infrared Thermogram;

(6) take off the infrared thermal imagery location-plate of having taken, take the Infrared Thermogram of sample to be analyzed, according to the position relationship of conversion thermal column and sample to be analyzed, determine the real coordinate position at the each position of sample to be analyzed;

Described in step (1), base plate is made up of the material of poor radiation, and the material of described poor radiation is plastics, timber or pottery;

Described in step (1), thermal column is made up of the good metal material of thermal diffusivity, and described metal material is iron, copper, aluminium, tin, tungsten or nickel.

2. infrared thermal imagery coordinate location method according to claim 1, is characterized in that: described in step (1), the size of base plate is 1cm ²~ 1m ².

3. infrared thermal imagery coordinate location method according to claim 1, is characterized in that: described in step (1), the quantity of thermal column is 1 ~ 100.

4. infrared thermal imagery coordinate location method according to claim 1, is characterized in that: described in step (1), one end of thermal column is vertically embedded in the base plate of infrared thermal imagery location-plate, and the other end exceeds backplate surface 0.1 ~ 20cm.

5. infrared thermal imagery coordinate location method according to claim 1, it is characterized in that: in step (6) for small sample, infrared thermal imagery location-plate is placed on the device with position limiting structure, the device of adjusting thermal infrared imager and have position limiting structure is on same straight line, take after the Infrared Thermogram of infrared thermal imagery location-plate, take off infrared thermal imagery location-plate, place small sample to be analyzed in same position, by taking the Infrared Thermogram of small sample, determine the real coordinate position at each position of this small sample.

6. infrared thermal imagery coordinate location method according to claim 1, it is characterized in that: in step (6) for large-scale sample, infrared thermal imagery location-plate is fixed on large-scale sample, adjust large-scale sample and thermal infrared imager on same straight line, take after the Infrared Thermogram of infrared thermal imagery location-plate, take off infrared thermal imagery location-plate, take the Infrared Thermogram of large-scale sample to be analyzed, determine the real coordinate position at this each position of large-scale sample.

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