Infrared temperature measuring device automatic calibration method and system

Abstract

The present application relates to a kind of infrared temperature measuring equipment automatic calibration method and system, comprising: setting scanning path, traversing scanning, obtaining temperature response rate correction matrix, calibration.The present application utilizes infrared temperature measuring equipment scanning movement, clear blackbody image can traverse all pixels of infrared temperature measuring equipment, avoid the rigorous requirement of traditional calibration method to blackbody everywhere constant temperature, infrared temperature measuring equipment is always in clear imaging state in the calibration process of different temperature measuring distance, overcome the influence of refractive index non-uniform distribution and lens face shape processing inconsistency of infrared lens on calibration result, calibration data is handled by computer terminal, convenient operation, high degree of automation, calibration result is more accurate.

Description

Technical Field

[0001] This invention relates to a calibration method and system, and more particularly to an automatic calibration method and system for infrared temperature measurement equipment. Background Technology

[0002] An infrared camera is a device that images objects radiating infrared light. The higher the object's temperature, the stronger the infrared energy it radiates. The intensity of energy at the imaging point reflects the object's temperature; therefore, infrared cameras are also widely used as temperature measurement devices. The temperature obtained from an infrared camera is the radiated temperature of the object's surface, not its actual temperature. Its value is equal to the actual temperature of a blackbody radiating the same energy. Therefore, in actual temperature measurement, the thermal imager must first be calibrated using a high-precision blackbody. Secondly, due to the differences in temperature responsivity between pixels of the infrared detector, calibration is needed to correct for these differences. A common method for temperature responsivity calibration is to create a constant-temperature blackbody. For example, CN113375814A discloses an infrared temperature measurement calibration method, device, electronic equipment, and storage medium. In this embodiment, a square metal heating plate with a side length of 80 mm is used as the blackbody, placed in front of the infrared camera so that the blackbody fills the entire camera's field of view. The temperature responsivity of the infrared detector pixels is calibrated by monitoring the difference between the measured temperature and the actual temperature of the blackbody. Traditional calibration methods require two prerequisites. The first prerequisite is that the blackbody is at a constant temperature and the temperature is equal everywhere. Therefore, in CN113375814 A, materials with high thermal conductivity, such as graphene coating or adhesive tape, are used to increase thermal conductivity and maintain the uniformity of the blackbody surface temperature. However, in actual operation, it is impossible to achieve equal temperature everywhere on the surface of an ordinary blackbody or a square metal blackbody with a side length of 80 mm. The second prerequisite is that the blackbody is a diffuse emitter, that is, the energy density radiated to all angles of space is equal. Ordinary blackbodies, even with complex internal cavity structure design, still cannot achieve complete diffuse emission. The square metal blackbody involved in CN113375814 A, as a plane, does not have the condition of diffuse emission. In addition, the calibration of temperature measuring equipment is affected not only by the non-uniformity of the detector but also by the lens manufacturing process. The focusing process of temperature measurement requires rotating the lens to make the image clear. The infrared lens is composed of spherical and aspherical lenses. The non-uniformity of the refractive index of the infrared lens and the deviation in the precision of the manufacturing process will cause the blackbody radiation energy distribution on the detector to change when the lens is rotated. In the traditional calibration process, in order to fill the entire field of view of the camera, the infrared camera needs to be close to the blackbody. The radiation of the blackbody will cause temperature changes in the infrared lens and the infrared camera itself. Especially when calibrating at high temperatures, calibration performed in a changing temperature field will lead to inaccurate calibration results. Summary of the Invention

[0003] The technical problem solved by this invention is to construct an automatic calibration method and system for infrared temperature measurement equipment, overcoming the technical problem that the calibration of existing technologies is greatly affected by external factors and cannot be automatically calibrated.

[0004] The technical solution of this invention is: to construct an automatic calibration method for infrared temperature measurement equipment, comprising the following steps:

[0005] Set the scanning path: Based on the distance between the infrared temperature measuring device under test and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device under test, the pixel size, and the size of the constant-temperature area of ​​the blackbody, set the scanning path of the infrared temperature measuring device so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device.

[0006] Traversal scanning: At the set distance between the infrared temperature measuring device and the constant temperature blackbody and at the constant temperature of the constant temperature blackbody, a motion command is received, and the infrared temperature measuring device moves according to the set scanning path so that the blackbody image it acquires can traverse all pixels of the infrared temperature measuring device.

[0007] Obtain the temperature response rate correction matrix: Set the constant temperatures T0, T1...T of the isothermal blackbody respectively. p (p>0), set the distances L0, L1...Ln (n>0) between the infrared temperature measuring device and the constant-temperature blackbody, respectively, and obtain the distances at constant-temperature blackbody temperatures T0, T1...Tn. p The temperature response rate correction matrix of the infrared temperature measuring device detector under the distances L0, L1...Ln between the infrared temperature measuring device and the isothermal blackbody. Construct a temperature response rate correction matrix array M;

[0008] Calibration: Interpolate the vector of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel value of the infrared temperature measurement device and the actual temperature of the object being measured.

[0009] A further technical solution of the present invention is: based on the distance between the infrared temperature measuring device and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device, the pixel size a, and the size of the constant-temperature region of the blackbody, the scanning angle step θ0 is calculated, and the infrared temperature measuring device is rotated to scan according to the scanning angle step θ0.

[0010] A further technical solution of the present invention is: when the infrared temperature measuring device rotates to a specified position, it stays for a time t, obtains the pixel coordinates covered by the black body, and records the pixel value of the corresponding coordinate pixel. After completing the traversal, the full-frame pixel value of the infrared temperature measuring device is obtained.

[0011] A further technical solution of the present invention is: the position of the blackbody is fixed, and the infrared temperature measuring device is set on the rotating component. The infrared temperature measuring device is rotated so that the acquired constant temperature blackbody image can traverse all pixels of the infrared temperature measuring device.

[0012] A further technical solution of the present invention is: to obtain the correspondence between the pixel value of the infrared detector and the true temperature of the object being measured by interpolation calculation based on the row vector or column vector of the temperature response rate correction matrix array M.

[0013] The technical solution of this invention is as follows: An automatic calibration system for an infrared temperature measuring device is constructed, comprising a computer, a moving part, and a constant-temperature blackbody. The infrared temperature measuring device to be tested is mounted on the moving part. The computer connects the moving part and the infrared temperature measuring device. The computer includes a scan path setting module, a temperature response rate correction matrix construction module, and a calibration module. The scan path setting module sets the scan path of the infrared temperature measuring device based on the distance between the infrared temperature measuring device and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device, the pixel size, and the size of the constant-temperature region of the constant-temperature blackbody. This scan path allows the acquired blackbody image to traverse all pixels of the infrared temperature measuring device. At the set distance between the infrared temperature measuring device and the constant-temperature blackbody and at the constant temperature of the constant-temperature blackbody, the moving part receives a motion command and drives the infrared temperature measuring device to move along the set scan path, so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device. The temperature response rate correction matrix construction module sets the constant temperatures T0, T1…T of the constant-temperature blackbody. p (p>0), the distances L0, L1...Ln (n>0) between the infrared temperature measuring device and the constant-temperature blackbody are set respectively. The temperature response rate correction matrix construction module obtains the distances at constant-temperature blackbody temperatures T0, T1...Tn respectively. p The temperature response rate correction matrix of the infrared temperature measuring device detector under the distances L0, L1...Ln between the infrared temperature measuring device and the isothermal blackbody. A temperature response rate correction matrix array M is constructed; the calibration module performs interpolation calculations on the vectors of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel values ​​of the infrared temperature measurement device and the actual temperature of the object being measured.

[0014] A further technical solution of the present invention is: the moving part includes an azimuth motion module, a pitch motion module and an installation module, the azimuth motion module causes the infrared temperature measuring device to move in the azimuth direction, the pitch motion module causes the infrared temperature measuring device to move in the pitch direction, and the installation module installs the infrared temperature measuring device.

[0015] A further technical solution of the present invention is: the installation module includes an angle rotation module and an angle tilt module, the angle tilt module is disposed on the angle rotation module, the angle tilt module adjusts the tilt angle of the infrared temperature measuring device, and the angle rotation module adjusts the pitch of the infrared temperature measuring device.

[0016] A further technical solution of the present invention is that the computer is connected to the constant-temperature blackbody via a serial port.

[0017] A further technical solution of the present invention is: the calibration module performs interpolation calculations on the row vectors or column vectors of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel values ​​of the infrared temperature measurement device and the actual temperature of the object being measured.

[0018] The technical effect of this invention is: to provide an automatic calibration method and system for infrared temperature measuring devices. The automatic calibration method for infrared temperature measuring devices includes the following steps: Setting a scanning path: Based on the distance between the infrared temperature measuring device and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device, the pixel size, and the size of the constant-temperature region of the blackbody, a scanning path for the infrared temperature measuring device is set so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device. Traversal scanning: At the set distance between the infrared temperature measuring device and the constant-temperature blackbody and the constant temperature of the blackbody, a motion command is received, and the infrared temperature measuring device moves according to the set scanning path so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device. Obtaining a temperature response rate correction matrix: The constant temperatures T0, T1...T of the constant-temperature blackbody are set respectively. p (p>0), set the distances L0, L1...Ln (n>0) between the infrared temperature measuring device and the constant-temperature blackbody, respectively, and obtain the distances at the constant-temperature blackbody temperatures T0, T1...Tn. p The temperature response rate correction matrix of the infrared thermometer detector is given by the distances L0, L1...Ln between the infrared thermometer and the blackbody. A temperature response rate correction matrix array M is constructed. Calibration is performed: interpolation calculations are performed on the vectors of the temperature response rate correction matrix array M to obtain the correspondence between the pixel values ​​of the infrared detector and the true temperature of the object being measured. This invention provides a method and system for automatic calibration of infrared temperature measuring equipment. Utilizing the scanning motion of the infrared temperature measuring equipment, a clear blackbody image can traverse all pixels of the infrared temperature measuring equipment, avoiding the stringent requirement of constant temperature for the blackbody itself in traditional calibration methods. During calibration at different temperature measuring distances, the infrared temperature measuring equipment remains in a clear imaging state, overcoming the influence of non-uniform refractive index distribution and inconsistent lens surface processing on the calibration results. Calibration data is processed through a computer terminal, making operation convenient, highly automated, and resulting in more accurate calibration results. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the pixel scanning path of the traversing infrared temperature measurement device of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0022] The specific implementation of this invention is as follows: An automatic calibration method for infrared temperature measurement equipment is constructed, comprising the following steps:

[0023] Set the scanning path: Based on the distance between the infrared temperature measuring device under test and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device under test, the pixel size, and the size of the constant-temperature region of the blackbody, set the scanning path of the infrared temperature measuring device so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device.

[0024] The specific implementation process is as follows: Based on the distance L between the infrared temperature measuring device to be tested and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device to be tested, the pixel size a, and the size of the constant-temperature region of the blackbody, the scanning path of the infrared temperature measuring device is set, and the blackbody image obtained by the infrared temperature measuring device can traverse all pixels of the infrared temperature measuring device.

[0025] Traversal scanning: At the set distance between the infrared temperature measuring device and the constant-temperature blackbody and at the constant temperature of the constant-temperature blackbody, a motion command is received, and the infrared temperature measuring device moves according to the set scanning path so that the blackbody image it acquires can traverse all pixels of the infrared temperature measuring device.

[0026] The specific implementation process is as follows: When the infrared temperature measuring device moves to a designated position, it stays for time t, obtains the pixel coordinates covered by the blackbody, and records the pixel value of the corresponding coordinate pixel; then, it moves according to the set path, stays for time t at the designated position, and obtains the pixel coordinates covered by the blackbody, until the traversal is completed and the full-frame pixel value is obtained. The temperature response rate correction matrix of the infrared temperature measuring device detector is then calculated when the blackbody temperature is T0 and the blackbody distance is L0.

[0027] Obtain the temperature response rate correction matrix: Set the constant temperatures T0, T1...T of the isothermal blackbody respectively. p (p>0), set the distances L0, L1...Ln (n>0) between the infrared temperature measuring device and the constant-temperature blackbody, respectively, and obtain the distances at constant-temperature blackbody temperatures T0, T1...Tn. p The temperature response rate correction matrix of the infrared temperature measuring device detector under the distances L0, L1...Ln between the infrared temperature measuring device and the isothermal blackbody. Construct a temperature response rate correction matrix array M.

[0028] The specific implementation process is as follows: Set the constant temperatures of the constant-temperature blackbody to T0, T1...T... respectively. p (p>0), set the distances L0, L1…Ln (n>0) between the infrared temperature measuring device and the constant-temperature blackbody, respectively. Based on a set constant temperature of the constant-temperature blackbody, adjust the distances L0, L1…Ln between the infrared temperature measuring device and the constant-temperature blackbody, and obtain the temperature response rate correction matrix for each distance L0, L1…Ln between the infrared temperature measuring device and the constant-temperature blackbody. Alternatively, based on a certain distance between the infrared temperature measuring device and the constant-temperature blackbody, set the constant temperature T0, T1…Tn of the constant-temperature blackbody. p The constant temperatures T0, T1...T of the isothermal blackbody are obtained respectively. p The temperature response rate correction matrix is ​​obtained, and a temperature response rate correction matrix array M is constructed based on all the obtained temperature response rate correction matrices. That is, the temperature response rate correction matrix array M can be obtained at p different blackbody temperatures and n different blackbody distances.

[0029]

[0030] Calibration: Interpolate the vector of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel value of the infrared temperature measurement device and the actual temperature of the object being measured.

[0031] Example:

[0032] In a specific embodiment, the motion unit includes a gimbal capable of orthogonal motion along two axes. The infrared temperature measurement device is placed on this gimbal, which is capable of orthogonal motion along both pitch and azimuth axes. The infrared temperature measurement device is adjusted so that the horizontal center line of the image is perpendicular to the horizontal rotation axis of the gimbal, and the vertical center line of the image is perpendicular to the pitch rotation axis of the gimbal. To traverse all pixels of the infrared temperature measurement device, the scanning path is set to a horizontal-then-tilt pattern. The angle α subtended by the detector pixel with respect to the infrared lens is:

[0033] α = actan(a / f)

[0034] If the isothermal region of a blackbody is a square with side length h, then the horizontal and vertical angles subtended by the blackbody with respect to the infrared lens of an infrared thermometer are equal, denoted as β:

[0035] β = actan(h / L0)

[0036] Let d = floor(β / α), where floor is the floor function. Then the number of pixels that the blackbody can cover on the infrared temperature measuring device detector in the horizontal and vertical directions is d × d. When d < 1, we take d = 1.

[0037] The scanning step size θ0 is an integer multiple of α. Let θ0 = q × α, where q is an integer and q ≤ d;

[0038] Let the size of the infrared detector pixel array be k. h ×k v Then the number of horizontal scanning steps is S. h :

[0039] S h =ceil(k h / q)-1

[0040] ceil is the mathematical rounding up, and the vertical scan step number is S. v :

[0041] S v =ceil(k v / q)-1

[0042] The pan-tilt unit (PTZ) begins scanning. When the PTU moves to a designated position, it remains stationary for time t to obtain the pixel coordinates covered by the blackbody and records the pixel values ​​at those coordinates. After completing the traversal, the full-frame pixel values ​​are obtained, and the temperature response rate correction matrix of the infrared thermometer detector is calculated when the blackbody temperature is T0 and the blackbody distance is L0.

[0043] The specific implementation process is as follows: The gimbal begins scanning. After the gimbal reaches a designated position, it remains stationary for a time t, during which the computer terminal records and processes the data. Given the gimbal's step size θ0 = q × α, for each step the gimbal takes, it needs to record and process q × q pixels located at the center of the blackbody imaging region. Figure 2 As shown; when k h When the number of horizontal pixels is not divisible by q, when the pan-tilt unit scans to the horizontal edge of the detector pixel array, the number of horizontal pixels processed is less than q, but q', where q' = mod(k). h / q), mod is the mathematical modulo operation; similarly, when k v When the number of vertical pixels is not divisible by q, when the pan-tilt unit scans to the vertical edge of the detector pixel array, the number of vertical pixels processed is less than q, but q" instead, where q" = mod(k v / q); The pan-tilt unit completes the scan, and the blackbody imaging area traverses the detector pixel array. The computer terminal obtains the pixel values ​​of the detector pixel array. Based on the blackbody temperature T0 at this time, the mapping relationship between the pixel value and temperature of each pixel of the infrared thermometer detector at the temperature measurement distance L0 is obtained, which is denoted here as the temperature response rate correction matrix. The elements in the array correspond one-to-one with the detector pixels, therefore The size is the same as the detector pixel array, which is one k h ×k v Array, temperature response correction matrix The method of obtaining the elements is a mature technology, and will not be elaborated here;

[0044] By changing the distance value to L1, the temperature responsivity correction matrix of the infrared thermometer detector is obtained when the blackbody temperature is T0 and the blackbody distance is L1. Similarly, the temperature response rate correction matrix is ​​obtained when the blackbody temperature is T0 and the blackbody distances are L0, L1, ... Ln.

[0045] When the blackbody temperature is T0 and the blackbody distance is L0, the temperature responsivity correction matrix of the infrared thermometer detector is obtained. Then, without changing the blackbody temperature, only the distance between the blackbody and the infrared thermometer is changed. The blackbody is placed at a distance L1 directly in front of the infrared thermometer, and the lens of the infrared thermometer is rotated to adjust the focal plane of the lens so that the blackbody can be clearly imaged. The angle subtended by the detector pixels with respect to the infrared lens remains α, and the horizontal and vertical angles subtended by the blackbody with respect to the infrared lens are β':

[0046] β' = actan(h / L1)

[0047] d' = floor(β' / α), the number of pixels that the blackbody can cover on the infrared temperature measuring device detector in the horizontal and vertical directions is d' × d'. When d' < 1, we take d' = 1; scanning is done in a horizontal-then-tilt manner, with a scanning step size θ0 = q' × α, where q' is an integer and q' ≤ d'; the number of horizontal scanning steps is S. h '=ceil(k h / q'), the vertical scan step number is S v '=ceil(k v / q'); For each step the pan-tilt unit moves, it needs to record and process q'×q' pixels at the center of the blackbody imaging region. This process is repeated to traverse the detector pixel array across the blackbody imaging region. The computer obtains the pixel values ​​of the detector pixel array. Based on the blackbody temperature T0 at this time, the mapping relationship between the pixel value and temperature of each pixel of the infrared thermometer detector at a temperature measurement distance L1 is obtained, denoted as . Similarly, the temperature response rate correction matrix is ​​obtained when the blackbody temperature is T0 and the blackbody distances are L0, L1, ... Ln. The obtained correction matrix is ​​denoted as row vector Row0.

[0048] Set the blackbody temperature to T. 1, Obtain the temperature responsivity correction matrix when the blackbody temperature is T1 and the blackbody distances are L0, L1, ... Ln. By analogy, we can obtain an array M of temperature responsivity correction matrices for p different blackbody temperatures and n different blackbody distances. The row vectors of M are the temperature responsivity correction matrices obtained at the same blackbody temperature, and the column vectors of M are the temperature responsivity correction matrices obtained at the same blackbody distance.

[0049]

[0050] The temperature of the isothermal blackbody is set to T1. The blackbody temperature can be gradually reached and maintained at T1 using a temperature regulation device. Similarly, the same distance values ​​L0, L1, ... Ln are set, and the same pan-tilt scanning method and data recording and processing method are used to obtain the temperature response rate correction matrix when the blackbody temperature is T1 and the blackbody distance is L0, L1, ... Ln. remember Following this logic, by setting p different blackbody temperatures T0, T1, ..., Tp, we can obtain p row vectors Row0, Row1, ..., Rowp, each with n elements. Merging these p row vectors along their column directions yields a p×n temperature responsivity correction matrix array M.

[0051]

[0052] The row vector of M is the temperature response rate correction matrix obtained at the same blackbody temperature, and the column vector of M is the temperature response rate correction matrix obtained at the same blackbody distance.

[0053] By interpolating the vector of the temperature response rate correction matrix array M, the correspondence between the pixel value of the infrared detector and the true temperature of the object being measured can be obtained.

[0054] The specific implementation process is as follows: Denote the column vector This represents the mapping relationship between the pixel values ​​of each pixel on the detector and the blackbody temperature under the condition of a temperature measurement distance of L0. Similarly, let Col1, Col2, ... … Coln represents the temperature measurement distances L1, L2, and L3. … Under condition Ln, the mapping relationship between pixel values ​​and blackbody temperature of each pixel on the detector; assuming L0 < L1 < … If Ln and L0≤Lx≤L1, then the temperature responsivity correction matrix Colx with blackbody distance Lx can be obtained by interpolation of Col0 and Col1, that is:

[0055]

[0056] This represents the mapping relationship between pixel values ​​and blackbody temperature of each pixel on the detector under the condition of a temperature measurement distance of Lx. Both are k h ×k vThe matrix of the array, where k h k is the number of rows in the pixel array of the infrared detector. v Let [x] be the number of columns in the infrared detector pixel array; for any pixel coordinate [x]... i ,y i The pixel value at position ] is taken from the coordinates of all elements in Colx, i.e. Median coordinates [x i ,y i The value at [] is val0. Median coordinates [x i ,y i The value at position ] is val1, and so on, to obtain [val0, val1, ... val1]. p ], representing the temperature responsivity correction value of the pixel at that location under the blackbody temperature [T0, T1, ..., Tp]. Since the temperature values ​​are discrete, the mapping relationship between the pixel's temperature responsivity and continuous temperature values ​​can be obtained through piecewise linear interpolation. For example, let T0 < T1 < ... … If <Tp, then val0 < val1 < ... < val p In the interval valx∈[val0,val1], the mapping relationship between valx and Tx is as follows:

[0057]

[0058] If the row vectors of the temperature response rate correction matrix array M are interpolated, the same steps as those for the column vectors above can be used to obtain the correspondence between the pixel values ​​of the infrared detector and the true temperature of the object being measured.

[0059] like Figure 1As shown, a specific embodiment of the present invention is as follows: An automatic calibration system for an infrared temperature measuring device is constructed, including a computer 1, a moving part, and a constant-temperature blackbody 4. The infrared temperature measuring device 6 to be tested is mounted on the moving part. The computer connects the moving part and the infrared temperature measuring device 6. The computer 1 includes a scan path setting module 11, a temperature response rate correction matrix construction module 12, and a calibration module 13. The scan path setting module 11 determines the calibration based on the distance between the infrared temperature measuring device 6 and the constant-temperature blackbody 4, the focal length f of the lens of the infrared temperature measuring device 6, the pixel size, and the constant-temperature blackbody 4. The size of the constant temperature region is set, and the scanning path of the infrared temperature measuring device 6 is configured so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device 6. At the set distance between the infrared temperature measuring device 6 and the constant temperature blackbody 4, and at the constant temperature of the constant temperature blackbody, the moving part receives a motion command to drive the infrared temperature measuring device 6 to move along the set scanning path, so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device 6. The temperature response rate correction matrix construction module 12 sets the constant temperatures T0, T1…T of the constant temperature blackbody 4. p (p>0), the distances L0, L1...Ln (n>0) between the infrared temperature measuring device 6 and the constant-temperature blackbody 4 are set respectively. The temperature response rate correction matrix construction module 12 obtains the distances at constant-temperature blackbody temperatures T0, T1...Tn respectively. p The temperature response rate correction matrix of the detector of the infrared temperature measuring device 6 is given by the distances L0, L1...Ln between the infrared temperature measuring device 6 and the constant-temperature blackbody 4. A temperature response rate correction matrix array M is constructed; the calibration module 13 performs interpolation calculations on the vectors of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel values ​​of the infrared temperature measuring device 6 and the actual temperature of the object being measured.

[0060] like Figure 1 As shown, the specific implementation process of this invention is as follows: An automatic calibration system for an infrared temperature measurement device is constructed. In a specific embodiment, the moving part includes a pan-tilt unit capable of orthogonal motion along two axes. The infrared temperature measurement device is placed on a pan-tilt unit capable of orthogonal motion along both pitch and azimuth axes. The infrared temperature measurement device is adjusted so that the horizontal center line of the image is perpendicular to the horizontal rotation axis of the pan-tilt unit, and the vertical center line of the image is perpendicular to the pitch rotation axis of the pan-tilt unit. To traverse all pixels of the infrared temperature measurement device, the scanning path is set to a horizontal-then-tilt method. The angle α subtended by the detector pixel with respect to the infrared lens is:

[0061] α = actan(a / f)

[0062] If the isothermal region of a blackbody is a square with side length h, then the horizontal and vertical angles subtended by the blackbody with respect to the infrared lens of an infrared thermometer are equal, denoted as β:

[0063] β = actan(h / L0)

[0064] Let d = floor(β / α), where floor is the floor function. Then the number of pixels that the blackbody can cover on the infrared temperature measuring device detector in the horizontal and vertical directions is d × d. When d < 1, we take d = 1.

[0065] The scanning step size θ0 is an integer multiple of α. Let θ0 = q × α, where q is an integer and q ≤ d;

[0066] Let the size of the infrared detector pixel array be k. h ×k v Then the number of horizontal scanning steps is S. h :

[0067] S h =ceil(k h / q)-1

[0068] ceil is the mathematical rounding up, and the vertical scan step number is S. v :

[0069] S v =ceil(k v / q)-1

[0070] The pan-tilt unit (PTZ) begins scanning. When the PTU moves to a designated position, it remains stationary for time t to obtain the pixel coordinates covered by the blackbody and records the pixel values ​​at those coordinates. After completing the traversal, the full-frame pixel values ​​are obtained, and the temperature response rate correction matrix of the infrared thermometer detector is calculated when the blackbody temperature is T0 and the blackbody distance is L0.

[0071] The specific implementation process is as follows: The gimbal begins scanning. After the gimbal reaches a designated position, it remains stationary for a time t, during which the computer terminal records and processes the data. Given the gimbal's step size θ0 = q × α, for each step the gimbal takes, it needs to record and process q × q pixels located at the center of the blackbody imaging region. Figure 2 As shown; when k h When the number of horizontal pixels is not divisible by q, when the pan-tilt unit scans to the horizontal edge of the detector pixel array, the number of horizontal pixels processed is less than q, but q', where q' = mod(k). h / q), mod is the mathematical modulo operation; similarly, when k v When the number of vertical pixels is not divisible by q, when the pan-tilt unit scans to the vertical edge of the detector pixel array, the number of vertical pixels processed is less than q, but q" instead, where q" = mod(k v / q); The pan-tilt unit completes the scan, and the blackbody imaging area traverses the detector pixel array. The computer terminal obtains the pixel values ​​of the detector pixel array. Based on the blackbody temperature T0 at this time, the mapping relationship between the pixel value and temperature of each pixel of the infrared thermometer detector at the temperature measurement distance L0 is obtained, which is denoted here as the temperature response rate correction matrix. The elements in the array correspond one-to-one with the detector pixels, therefore The size is the same as the detector pixel array, which is one k h ×k v Array, temperature response correction matrix The method of obtaining the elements is a mature technology, and will not be elaborated here;

[0072] By changing the distance value to L1, the temperature responsivity correction matrix of the infrared thermometer detector is obtained when the blackbody temperature is T0 and the blackbody distance is L1. Similarly, the temperature response rate correction matrix is ​​obtained when the blackbody temperature is T0 and the blackbody distances are L0, L1, ... Ln.

[0073] When the blackbody temperature is T0 and the blackbody distance is L0, the temperature responsivity correction matrix of the infrared thermometer detector is obtained. Then, without changing the blackbody temperature, only the distance between the blackbody and the infrared thermometer is changed. The blackbody is placed at a distance L1 directly in front of the infrared thermometer, and the lens of the infrared thermometer is rotated to adjust the focal plane of the lens so that the blackbody can be clearly imaged. The angle subtended by the detector pixels with respect to the infrared lens remains α, and the horizontal and vertical angles subtended by the blackbody with respect to the infrared lens are β':

[0074] β' = actan(h / L1)

[0075] d' = floor(β' / α), the number of pixels that the blackbody can cover on the infrared temperature measuring device detector in the horizontal and vertical directions is d' × d'. When d' < 1, we take d' = 1; scanning is done in a horizontal-then-tilt manner, with a scanning step size θ0 = q' × α, where q' is an integer and q' ≤ d'; the number of horizontal scanning steps is S. h '=ceil(k h / q'), the vertical scan step number is S v '=ceil(k v / q'); For each step the pan-tilt unit moves, it needs to record and process q'×q' pixels at the center of the blackbody imaging region. This process is repeated to traverse the detector pixel array across the blackbody imaging region. The computer obtains the pixel values ​​of the detector pixel array. Based on the blackbody temperature T0 at this time, the mapping relationship between the pixel value and temperature of each pixel of the infrared thermometer detector at a temperature measurement distance L1 is obtained, denoted as . Similarly, the temperature response rate correction matrix is ​​obtained when the blackbody temperature is T0 and the blackbody distances are L0, L1, ... Ln. The obtained correction matrix is ​​denoted as row vector Row0.

[0076] Set the blackbody temperature to T. 1, Obtain the temperature responsivity correction matrix when the blackbody temperature is T1 and the blackbody distances are L0, L1, ... Ln. By analogy, we can obtain an array M of temperature responsivity correction matrices for p different blackbody temperatures and n different blackbody distances. The row vectors of M are the temperature responsivity correction matrices obtained at the same blackbody temperature, and the column vectors of M are the temperature responsivity correction matrices obtained at the same blackbody distance.

[0077]

[0078] The temperature of the isothermal blackbody is set to T1. The blackbody temperature can be gradually reached and maintained at T1 using a temperature regulation device. Similarly, the same distance values ​​L0, L1, ... Ln are set, and the same pan-tilt scanning method and data recording and processing method are used to obtain the temperature response rate correction matrix when the blackbody temperature is T1 and the blackbody distance is L0, L1, ... Ln. remember Following this logic, by setting p different blackbody temperatures T0, T1, ..., Tp, we can obtain p row vectors Row0, Row1, ..., Rowp, each with n elements. Merging these p row vectors along their column directions yields a p×n temperature responsivity correction matrix array M.

[0079]

[0080] The row vector of M is the temperature response rate correction matrix obtained at the same blackbody temperature, and the column vector of M is the temperature response rate correction matrix obtained at the same blackbody distance.

[0081] By interpolating the vector of the temperature response rate correction matrix array M, the correspondence between the pixel value of the infrared detector and the true temperature of the object being measured can be obtained.

[0082] The specific implementation process is as follows: Denote the column vector This represents the mapping relationship between the pixel values ​​of each pixel on the detector and the blackbody temperature under the condition of a temperature measurement distance of L0. Similarly, let Col1, Col2, ... … Coln represents the temperature measurement distances L1, L2, and L3. … Under condition Ln, the mapping relationship between pixel values ​​and blackbody temperature of each pixel on the detector; assuming L0 < L1 < …If Ln and L0≤Lx≤L1, then the temperature responsivity correction matrix Colx with blackbody distance Lx can be obtained by interpolation of Col0 and Col1, that is:

[0083]

[0084] This represents the mapping relationship between pixel values ​​and blackbody temperature of each pixel on the detector under the condition of a temperature measurement distance of Lx. Both are k h ×k v The matrix of the array, where k h k is the number of rows in the pixel array of the infrared detector. v Let [x] be the number of columns in the infrared detector pixel array; for any pixel coordinate [x]... i ,y i The pixel value at position ] is taken from the coordinates of all elements in Colx, i.e. Median coordinates [x i ,y i The value at position ] is val0, R 1 x Median coordinates [x i ,y i The value at position ] is val1, and so on, to obtain [val0, val1, ... val1]. p ], representing the temperature responsivity correction value of the pixel at that location under the blackbody temperature [T0, T1, ..., Tp]. Since the temperature values ​​are discrete, the mapping relationship between the pixel's temperature responsivity and continuous temperature values ​​can be obtained through piecewise linear interpolation. For example, let T0 < T1 < ... … If <Tp, then val0 < val1 < ... < val p In the interval valx∈[val0,val1], the mapping relationship between valx and Tx is as follows:

[0085]

[0086] like Figure 1 As shown, a preferred embodiment of the present invention is as follows: the motion unit includes an azimuth motion module 3, a pitch motion module 2, and a mounting module 5. The azimuth motion module 1 causes the infrared temperature measuring device 6 to move in the azimuth direction, the pitch motion module 2 causes the infrared temperature measuring device 6 to move in the pitch direction, and the mounting module 5 mounts the infrared temperature measuring device 6. The motion unit includes a pan-tilt unit with orthogonal motion along two axes. The infrared temperature measuring device is placed on a pan-tilt unit capable of orthogonal motion along the pitch and azimuth axes. The infrared temperature measuring device is adjusted so that the horizontal center line of the image is perpendicular to the horizontal rotation axis of the pan-tilt unit, and the vertical center line of the image is perpendicular to the pitch rotation axis of the pan-tilt unit.

[0087] Specifically: The two-axis gimbal includes an azimuth motion module 3, a pitch motion module 2, and a mounting module 5. The azimuth motion module 3 enables rotation in the azimuth direction of the gimbal; that is, the pitch motion module 2 and the equipment mounting platform 203 rotate around the azimuth axis under the drive of the azimuth motion module 3. The pitch motion module 2 enables rotation in the pitch direction of the gimbal; that is, the equipment mounting platform 203 rotates around the pitch axis under the drive of the pitch motion module 2. The mounting module 5 consists of an angle rotation module 53, an angle tilt module 52, and a clamp 51. The angle tilt module 52 is fixed to the angle rotation module 53, and the clamp 51 is fixed to the angle rotation module 53. The infrared temperature measuring device 4 is fixed to the clamp 51. The angle tilt module... Module 52 adjusts the tilt angle of the horizontal center line of the infrared temperature measuring device 4's image, making the horizontal center line of the infrared temperature measuring device 4's image perpendicular to the horizontal rotation axis of the pan-tilt unit; module 53 adjusts the line-of-sight direction of the infrared temperature measuring device 4, making the vertical center line of the infrared temperature measuring device 4's image perpendicular to the pan-tilt unit's pitch rotation axis; the video data of the infrared temperature measuring device 4 is exported to computer 1 via the network port, and the control of the two-axis pan-tilt unit 2 is connected to computer 1 via the TTL serial port. Computer 1 can control the two-axis pan-tilt unit 2 to scan in the azimuth and pitch directions through software programming; a constant-temperature blackbody 5 is placed in front of the infrared temperature measuring device 4. The temperature of the constant-temperature blackbody 5 is adjustable, and different temperatures can be achieved by setting different temperatures for the constant-temperature blackbody 5.

[0088] An automatic calibration device for infrared temperature measurement equipment is constructed, comprising a computer 1, a two-axis gimbal 2, a mounting module 5, an infrared temperature measurement device 5, and a constant-temperature blackbody 4. The computer 1 controls the movement of the two-axis gimbal 2 via a serial port and obtains video data from the infrared temperature measurement device 4 via an image and video interface. The two-axis gimbal 2 can rotate in two orthogonal directions: pitch and horizontal. The mounting module 5 is used to fix the infrared temperature measurement device 4 and can adjust the attitude of the infrared temperature measurement device 4 so that the horizontal center line of the image is perpendicular to the horizontal rotation axis of the gimbal, and the vertical center line of the image is perpendicular to the pitch rotation axis of the gimbal. The infrared temperature measurement device 4 is an infrared camera to be calibrated, capable of acquiring infrared video images and transmitting them to the computer 1 via a video interface. The constant-temperature blackbody 5 is a constant-temperature radiation source capable of uniformly radiating infrared energy into space.

[0089] like Figure 1As shown, the specific implementation process of the present invention is as follows: The two-axis gimbal 2 includes an azimuth motion device 200, a pitch motion module 2, and an equipment mounting platform 202. The azimuth motion device 200 realizes the rotation of the gimbal in the azimuth direction, that is, the pitch motion module 2 and the equipment mounting platform 203 will rotate around the azimuth axis under the drive of the azimuth motion device 200; the pitch motion module 2 realizes the rotation of the gimbal in the pitch direction, that is, the equipment mounting platform 203 will rotate around the pitch axis under the drive of the pitch motion module 2; the mounting module 5 consists of an angle rotation module 53, an angle tilt module 52, and a clamp 51, wherein the angle tilt module 52 is fixed on the angle rotation module 53, and the clamp 51 is fixed on the angle rotation module 53; the infrared temperature measuring device 4 is fixed on the clamp. 51. The tilt module 52 adjusts the tilt angle of the horizontal center line of the infrared temperature measuring device 4's screen, making the horizontal center line of the infrared temperature measuring device 4's screen perpendicular to the horizontal rotation axis of the pan-tilt unit; the rotation module 53 adjusts the line of sight of the infrared temperature measuring device 4, making the vertical center line of the infrared temperature measuring device 4's screen perpendicular to the pitch rotation axis of the pan-tilt unit; the video data of the infrared temperature measuring device 4 is exported to computer 1 via the network port, and the control of the two-axis pan-tilt unit 2 is connected to computer 1 via the TTL serial port. Computer 1 can control the two-axis pan-tilt unit 2 to scan in the azimuth and pitch directions through software programming; a constant temperature blackbody 5 is placed in front of the infrared temperature measuring device 4. The temperature of the constant temperature blackbody 5 is adjustable. By setting different temperatures, a constant temperature blackbody 5 with different temperatures can be achieved;

[0090] A preferred embodiment of the present invention is as follows: the temperature of the constant-temperature blackbody 5 can be set via a serial port connected to a computer 1. The computer 1 automatically sets or acquires the set blackbody temperature, and temperature regulation is automated through programming.

[0091] The calibration module performs interpolation calculations on the row vectors or column vectors of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel values ​​of the infrared temperature measurement device and the actual temperature of the object being measured.

[0092] The technical effect of this invention is: to provide an automatic calibration method and system for infrared temperature measuring devices. The automatic calibration method for infrared temperature measuring devices includes the following steps: Setting a scanning path: Based on the distance between the infrared temperature measuring device and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device, the pixel size, and the size of the constant-temperature region of the blackbody, a scanning path for the infrared temperature measuring device is set so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device. Traversal scanning: At the set distance between the infrared temperature measuring device and the constant-temperature blackbody and the constant temperature of the blackbody, a motion command is received, and the infrared temperature measuring device moves according to the set scanning path so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device. Obtaining a temperature response rate correction matrix: The constant temperatures T0, T1...T of the constant-temperature blackbody are set respectively. p(p>0), set the distances L0, L1...Ln (n>0) between the infrared temperature measuring device and the constant-temperature blackbody, respectively, and obtain the distances at the constant-temperature blackbody temperatures T0, T1...Tn. p The temperature response rate correction matrix of the infrared thermometer detector is given by the distances L0, L1...Ln between the infrared thermometer and the blackbody. A temperature response rate correction matrix array M is constructed. Calibration is performed: interpolation calculations are performed on the vectors of the temperature response rate correction matrix array M to obtain the correspondence between the pixel values ​​of the infrared detector and the true temperature of the object being measured. This invention provides a method and system for automatic calibration of infrared temperature measuring equipment. Utilizing the scanning motion of the infrared temperature measuring equipment, a clear blackbody image can traverse all pixels of the infrared temperature measuring equipment, avoiding the stringent requirement of constant temperature for the blackbody itself in traditional calibration methods. During calibration at different temperature measuring distances, the infrared temperature measuring equipment remains in a clear imaging state, overcoming the influence of non-uniform refractive index distribution and inconsistent lens surface processing on the calibration results. Calibration data is processed through a computer terminal, making operation convenient, highly automated, and resulting in more accurate calibration results.

[0093] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An infrared temperature measurement device automatic calibration method, characterized in that, Includes the following steps: Set the scanning path: Based on the distance L between the infrared temperature measuring device under test and the constant-temperature blackbody, the focal length f of the lens of the infrared temperature measuring device under test, the pixel size, and the size of the constant-temperature area of ​​the blackbody, set the scanning path of the infrared temperature measuring device so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device. Traversal Scanning: At the set distance between the infrared temperature measuring device and the constant-temperature blackbody, and under the constant temperature of the blackbody, a motion command is received. The infrared temperature measuring device moves along a set scanning path so that the acquired blackbody image can traverse all pixels of the infrared temperature measuring device, obtaining full-frame pixel values. The mapping relationship between the pixel value and temperature of each pixel of the infrared temperature measuring device detector is calculated when the blackbody temperature is T0 and the blackbody distance is L0. This is denoted here as the temperature response rate correction matrix. ; Obtain the temperature response rate correction matrix: Set the constant temperatures T0, T1...T of the isothermal blackbody respectively. p The distances L0, L1...Ln between the infrared thermometer and the constant-temperature blackbody are set respectively, and the temperatures at the constant-temperature blackbody T0, T1...Tn are obtained respectively. p The temperature response rate correction matrix of the infrared temperature measuring device detector under the distances L0, L1...Ln between the infrared temperature measuring device and the isothermal blackbody. , ... Construct a temperature response rate correction matrix array M: ； Calibration: Interpolate the vector of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel value of the infrared temperature measurement device and the actual temperature of the object being measured.

2. The automatic calibration method for infrared temperature measuring equipment according to claim 1, characterized in that, Based on the distance between the infrared temperature measuring device and the constant-temperature blackbody, the focal length f of the infrared temperature measuring device lens, the pixel size a, and the size of the constant-temperature region of the blackbody, the scanning angle step θ0 is calculated, and the infrared temperature measuring device is rotated to scan according to the scanning angle step θ0.

3. The automatic calibration method for infrared temperature measuring equipment according to claim 1, characterized in that, When the infrared temperature measuring device rotates to a designated position, it stays for a time t, obtains the pixel coordinates covered by the blackbody, and records the pixel value of the corresponding coordinate pixel. After completing the traversal, the full-frame pixel value of the infrared temperature measuring device is obtained.

4. The automatic calibration method for infrared temperature measuring equipment according to claim 1, characterized in that, With the blackbody position fixed, the infrared temperature measuring device is mounted on the rotating component. Rotating the infrared temperature measuring device allows the acquired constant-temperature blackbody image to traverse all pixels of the infrared temperature measuring device.

5. The automatic calibration method for infrared temperature measuring equipment according to claim 1, characterized in that, Interpolation calculations are performed on the row or column vectors of the temperature response rate correction matrix array M to obtain the correspondence between the pixel values ​​of the infrared detector and the true temperature of the object being measured.

6. An automatic calibration system for infrared temperature measurement equipment, characterized in that, The system includes a computer, a motion unit, and a constant-temperature blackbody. The infrared thermometer to be tested is mounted on the motion unit. The computer connects the motion unit and the infrared thermometer. The computer includes a scan path setting module, a temperature response rate correction matrix construction module, and a calibration module. The scan path setting module sets the scan path of the infrared thermometer based on the distance L between the infrared thermometer and the constant-temperature blackbody, the focal length f of the lens of the infrared thermometer, the pixel size, and the size of the constant-temperature region of the blackbody. This ensures that the acquired blackbody image can traverse all pixels of the infrared thermometer. Under the set distance between the infrared thermometer and the constant-temperature blackbody and the constant temperature of the blackbody, a motion command is received, and the infrared thermometer moves along the set scan path so that the acquired blackbody image can traverse all pixels of the infrared thermometer, obtaining full-frame pixel values. The mapping relationship between the pixel value and temperature of each pixel of the infrared thermometer detector is calculated when the blackbody temperature is T0 and the blackbody distance is L0. This is denoted as the temperature response rate correction matrix. At the set distance between the infrared temperature measuring device and the constant-temperature blackbody, and under the constant temperature of the constant-temperature blackbody, the moving part receives a motion command and drives the infrared temperature measuring device to move along a set scanning path, so that the blackbody image acquired by the infrared temperature measuring device can traverse all pixels of the infrared temperature measuring device; the temperature response rate correction matrix construction module sets the constant temperature of the constant-temperature blackbody T0, T1...T... p The distances L0, L1...Ln between the infrared thermometer and the constant-temperature blackbody are set respectively. The temperature response rate correction matrix construction module obtains the distances at constant-temperature blackbody temperatures T0, T1...Tn respectively. p The temperature response rate correction matrix of the infrared temperature measuring device detector under the distances L0, L1...Ln between the infrared temperature measuring device and the isothermal blackbody. , ... Construct a temperature response rate correction matrix array M: ； The calibration module performs interpolation calculations on the vector of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel values ​​of the infrared temperature measurement device and the actual temperature of the object being measured.

7. The automatic calibration system for infrared temperature measurement equipment according to claim 6, characterized in that, The moving part includes an azimuth motion module, a pitch motion module, and a mounting module. The azimuth motion module causes the infrared temperature measuring device to move in the azimuth direction, the pitch motion module causes the infrared temperature measuring device to move in the pitch direction, and the mounting module mounts the infrared temperature measuring device.

8. The automatic calibration system for infrared temperature measurement equipment according to claim 7, characterized in that, The installation module includes an angle rotation module and an angle tilt module. The angle tilt module is mounted on the angle rotation module. The angle tilt module adjusts the tilt angle of the infrared temperature measuring device, and the angle rotation module adjusts the pitch of the infrared temperature measuring device.

9. The automatic calibration system for infrared temperature measurement equipment according to claim 6, characterized in that, The computer is connected to the constant-temperature blackbody via a serial port.

10. The automatic calibration system for infrared temperature measurement equipment according to claim 6, characterized in that, The calibration module performs interpolation calculations on the row vectors or column vectors of the temperature response rate correction matrix array M to obtain the correspondence between the detector pixel values ​​of the infrared temperature measurement device and the actual temperature of the object being measured.

Images