A method and device for focusing a thermal reflection microscopic thermal imaging system and an electronic device

Abstract

The present application provides a kind of heat reflection microthermal imaging system's follow focus method, device and electronic equipment.The method includes: obtaining initial image, first image, second image.Calculating the image definition of initial image, each first image and each second image respectively.If first average definition is greater than second average definition, object distance is adjusted to initial object distance minus preset step.If first average definition is less than or equal to second average definition, object distance is adjusted to initial object distance plus preset step.Adjusted object distance is used as initial object distance.The present application is by preset step alternately adjusting object distance, collecting image, comparing the average image definition under two adjacent object distances, after adjusting object distance by preset step, again with adjusted object distance as reference continue alternately adjusting object distance collection image and adjusting object distance.It can be executed in the process of heat reflection microthermal imaging system test temperature, real-time adjustment object distance, continuously keep image definition, realize continuous real-time follow focus.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal reflection microscopic thermal imaging, and in particular to a focusing method and device of a thermal reflection microscopic thermal imaging system and an electronic device. BACKGROUND

[0002] Thermal reflection temperature measurement technology is a non-contact temperature measurement technology, and its basis is thermal reflection. The basic feature of thermal reflection is that the reflectivity of an object changes with the temperature of the object. The basic principle of thermal reflection temperature measurement is to derive the temperature change AT by measuring the relative change AR / R0 of the reflectivity R. By using the above thermal reflection phenomenon, the thermal reflection microscopic thermal imaging system can collect the image of the measured object, and thermal reflection microscopic thermal imaging temperature measurement can be realized.

[0003] Thermal reflection microscopic thermal imaging generally includes a three-axis nanometer displacement table and an imaging microscope. The measured object is fixed on the three-axis nanometer displacement table, and the imaging microscope collects the image of the measured object. The distance between the measured object and the lens center of the imaging microscope is the object distance. By adjusting the Z-axis direction of the three-axis nanometer displacement table, the object distance can be adjusted and clear imaging can be achieved. In actual testing, the position of the measured object in the Z-axis direction will move and deviate from the focal point due to factors such as temperature change and external vibration, resulting in blurred imaging. Therefore, during testing, the object distance needs to be continuously adjusted to achieve clear imaging by using a focusing algorithm.

[0004] The existing methods include a defocusing depth method and a focusing depth method. The defocusing depth method has poor accuracy, while thermal reflection temperature measurement is highly sensitive to defocusing, and the imaging microscope has a small focal depth, so the defocusing depth method cannot guarantee the testing accuracy. The focusing depth method collects images at different object distances, evaluates the sharpness, and fits a focusing evaluation curve to determine the peak point as the best object distance position. The larger the object distance range and the more images collected, the more accurate the object distance determined by the focusing depth method. The focusing depth method can achieve higher focusing accuracy, but it needs to determine the focusing position in a large focusing range. When the focal point deviates too much, for example, beyond the focal depth, the image is blurred. Thermal reflection temperature measurement generally needs to collect images continuously, so the focusing depth method has a too large focusing range and cannot continuously maintain clear images, which is not suitable for continuous real-time focusing in thermal reflection temperature measurement applications. SUMMARY

[0005] The embodiments of the present application provide a focusing method, device and electronic equipment of a thermal reflection microscopic thermal imaging system to solve the problem that the focusing range of the focusing depth method is too large when the thermal reflection microscopic thermal imaging system tests the temperature of the measured object, and the image cannot be continuously maintained clear, which is not suitable for continuous real-time focusing.

[0006] In a first aspect, the embodiments of the present application provide a focusing method of a thermal reflection microscopic thermal imaging system, comprising:

[0007] acquiring an initial image, wherein the initial image is an image captured at an initial object distance.

[0008] acquiring a first image, wherein the first image is an image captured after adjusting the object distance from the initial object distance to a first object distance, the first object distance being the initial object distance minus a preset step length.

[0009] acquiring a second image, wherein the second image is an image captured after adjusting the object distance from the first object distance back to the initial object distance.

[0010] repeating the acquiring of the first image and the acquiring of the second image to obtain a plurality of sets of the first image and the second image.

[0011] calculating the image sharpness of the initial image, each first image and each second image respectively.

[0012] if the first average sharpness is greater than the second average sharpness, adjusting the object distance to the initial object distance minus the preset step length, wherein the first average sharpness is an average of the image sharpness of each first image, and the second average sharpness is an average of the image sharpness of the initial image and each second image.

[0013] if the first average sharpness is less than or equal to the second average sharpness, adjusting the object distance to the initial object distance plus the preset step length.

[0014] using the adjusted object distance as the initial object distance to repeatedly capture images, calculate average sharpness and adjust the object distance.

[0015] In a possible implementation, before the acquiring of the initial image, the method further includes: acquiring a first step length of a preset fixed length as the preset step length, the first step length being less than the focal depth of the thermal reflection microscopic thermal imaging system.

[0016] In a possible implementation, before the acquiring of the initial image, the method further includes: acquiring a second step length and a third step length, wherein the second step length is less than the focal depth of the thermal reflection microscopic thermal imaging system, and the third step length is greater than the second step length. When the thermal reflection microscopic thermal imaging system is used to test the measured object at a constant temperature, the second step length is used as the preset step length. When the thermal reflection microscopic thermal imaging system is used to test the measured object at a variable temperature, the third step length is used as the preset step length, wherein the third step length is proportional to the variable temperature amplitude.

[0017] In a possible implementation, after the using of the adjusted object distance as the initial object distance to repeatedly capture images, calculate average sharpness and adjust the object distance, the method further includes: if the directions of the object distance adjustment in two consecutive cycles are the same, increasing the length of the preset step length. If the directions of the object distance adjustment in two consecutive cycles are opposite, decreasing the length of the preset step length.

[0018] In a possible implementation, the calculating the image sharpness of the initial image, each first image and each second image respectively comprises: calculating the image sharpness of the initial image, each first image and each second image respectively based on the following formula:

[0019]

[0020]

[0021]

[0022] wherein c i is a gray value of each pixel of the image, P is a total pixel number of the image, and s is the image sharpness.

[0023] In a possible implementation, after the initial image is acquired, the method further comprises: calculating the image sharpness based on the initial image. Correspondingly, the acquiring the first image comprises: if the image sharpness of the initial image is lower than a preset threshold, acquiring the first image.

[0024] In a second aspect, an embodiment of the present application provides a focusing device of a thermal reflection microscopic thermal imaging system, the device comprising:

[0025] a first acquiring module configured to acquire an initial image, wherein the initial image is an image collected at an initial object distance.

[0026] a second acquiring module configured to acquire a first image, wherein the first image is an image collected after the object distance is adjusted to a first object distance from the initial object distance, and the first object distance is the initial object distance minus a preset step length.

[0027] a third acquiring module configured to acquire a second image, wherein the second image is an image collected after the object distance is adjusted back to the initial object distance from the first object distance.

[0028] a first circulating module configured to repeatedly execute the acquiring the first image and the acquiring the second image to obtain a plurality of groups of the first image and the second image.

[0029] a sharpness calculating module configured to calculate the image sharpness of the initial image, each first image and each second image respectively.

[0030] a first adjusting module configured to, if a first average sharpness is greater than a second average sharpness, adjust the object distance to the initial object distance minus the preset step length, wherein the first average sharpness is an average value of the image sharpness of each first image, and the second average sharpness is an average value of the image sharpness of the initial image and each second image.

[0031] a second adjusting module configured to, if the first average sharpness is less than or equal to the second average sharpness, adjust the object distance to the initial object distance plus the preset step length.

[0032] The second loop module is configured to loop image acquisition, average sharpness calculation and object distance adjustment by taking the adjusted object distance as the initial object distance.

[0033] In a possible implementation, the apparatus further includes a step length acquisition module configured to acquire a first step length of a preset fixed length as the preset step length before the initial image is acquired, the first step length being smaller than the focal depth of the thermal reflection microscopic thermal imaging system.

[0034] In a third aspect, an embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the method according to the first aspect or any possible implementation of the first aspect when executing the computer program.

[0035] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executable by a processor to implement the steps of the method according to the first aspect or any possible implementation of the first aspect.

[0036] The embodiment of the present application provides a focusing method, device and electronic equipment of a thermal reflection microscopic thermal imaging system. The method comprises the following steps: acquiring an initial image, wherein the initial image is an image collected at an initial object distance; acquiring a first image, wherein the first image is an image collected after the object distance is adjusted to a first object distance from the initial object distance, and the first object distance is the initial object distance minus a preset step length; acquiring a second image, wherein the second image is an image collected after the object distance is adjusted back to the initial object distance from the first object distance; repeatedly performing the steps of acquiring the first image and acquiring the second image to obtain a plurality of groups of first images and second images; calculating the image definition of the initial image, each first image and each second image respectively; if the first average definition is greater than the second average definition, adjusting the object distance to the initial object distance minus the preset step length; wherein the first average definition is the average value of the image definition of each first image, and the second average definition is the average value of the image definition of the initial image and each second image; if the first average definition is less than or equal to the second average definition, adjusting the object distance to the initial object distance plus the preset step length; and taking the adjusted object distance as the initial object distance to cyclically collect images, calculate the average definition and adjust the object distance. The present application adjusts the object distance by a preset step length alternately at the initial object distance position and the position adjacent to the initial object distance, collects images, compares the average image definition at the two adjacent object distances, determines the adjustment direction of the object distance, adjusts the object distance by the preset step length, and then continues to adjust the object distance alternately, confirms the adjustment direction and adjusts the object distance based on the adjusted object distance. In the focusing process, the range of the object distance adjustment is within the preset step length, the deviation from the initial object distance is small, that is, the deviation from the focal point is small, and the image definition can be ensured. The method can be cyclically performed in the temperature test process of the thermal reflection microscopic thermal imaging system, the object distance can be adjusted in real time, the image definition can be continuously maintained, and continuous real-time focusing is realized. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0038] Figure 1 is a typical structure schematic diagram of a thermal reflection microscopic thermal imaging system;

[0039] Figure 2 is an implementation flowchart of the focusing method of the thermal reflection microscopic thermal imaging system provided by the embodiment of the present application;

[0040] Figure 3 is a continuous image collection method schematic diagram;

[0041] Figure 4 is an alternating object distance image collection method schematic diagram provided by the embodiment of the present application;

[0042] Figure 5 is a structural schematic view of a focusing device of a thermal reflection microscopic thermal imaging system provided by an embodiment of the present application;

[0043] Figure 6 is a schematic view of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0044] In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, circuits, and

[0045] In order to make the objects, technical solutions, and advantages of the present application clearer, the following will be described in conjunction with the accompanying drawings and specific embodiments.

[0046] Thermal reflection thermometry is a non-contact thermometry technique, which is based on thermal reflection phenomenon. The basic characteristic of thermal reflection phenomenon is that reflectivity of an object changes with temperature of the object. The change of reflectivity with temperature can be considered as linear, and thus can be characterized by a change rate coefficient, usually referred to as thermal reflection coefficient or thermal reflection calibration coefficient, denoted as C TR , and defined as:

[0047]

[0048] In the formula, R is reference reflectivity, ΔR is reflectivity change, and ΔT is temperature change.

[0049] For most metals and semiconductor materials, C TR usually ranges from (10 -2 ~ 10 -5 ) K -1 , and is related to material, incident light wavelength, and incident angle. If the object surface has a multi-layer structure, material composition of each layer and interference of light between the multi-layer materials will also directly affect the value of C TR . The usual practice is to select a suitable measurement wavelength for each (type or model) sample, and to determine C TR , usually referred to as C TR calibration, and to use the determined C TR for temperature measurement.

[0050] In the case where C TR is known, temperature can be calculated according to the following formula by measuring change of reflectivity of the object

[0051]

[0052] In formula (2), T x is the temperature to be measured, T0 is the reference temperature, R x is the reflectivity at the temperature to be measured, and R0 is the reflectivity at the reference temperature.

[0053] Since the change rate of reflectivity (R x -R0) / R0 is actually concerned, temperature measurement can be achieved by projecting a probe light (incident light) onto the surface of the measured object and then measuring the change rate of the reflected light intensity, which is the implementation of the thermal reflection thermometry technology. Assuming that the probe light intensity is constant, the change rate of reflectivity in formula (2) can be equivalent to the change rate of the detector reading, i.e., formula (2) is changed into

[0054]

[0055] In formula (3), c x is the detector reading at the temperature to be measured, and c0 is the detector reading at the reference temperature.

[0056] In order to realize high spatial resolution microscopic thermal imaging, a microscopic light reflection thermal imaging device is usually constructed based on a high-performance optical microscope. The illumination system of the optical microscope is used to provide the probe light, a high-performance camera is used to record the microscopic imaging, and the output camera reading is used as the measurement value c.

[0057] Since the value of c TR is low, in order to ensure the measurement accuracy, multiple frames of images are usually taken to obtain c0 and c x , and the total number of frames is denoted as N, and there is

[0058]

[0059]

[0060]

[0061] From the above principle, it can be known that the data on each pixel of the camera and the spatial position of the measured surface should have a stable corresponding relationship during the entire measurement process. If the corresponding relationship is disturbed, the accuracy of the temperature measurement result will be affected. There are several times of temperature change during the test, and the corresponding thermal expansion will cause the measured object to deviate from the focal point, i.e., defocus, resulting in blurred images. Therefore, focusing needs to be performed multiple times during the test, and the consistency of the focusing should be good enough to ensure that the above-mentioned corresponding relationship is stable and consistent. Otherwise, additional errors will be introduced.

[0062] Figure 1 is a typical structural schematic diagram of a thermal reflection microscopic thermal imaging system. Referring to Figure 1The typical thermal reflection micro-thermal imaging system comprises an imaging microscope, a temperature control table, a three-axis nanometer displacement table, a computer, and the like. The measured object is fixed on the three-axis nanometer displacement table, and the imaging microscope collects the image of the measured object. The distance between the measured object and the lens optical center of the imaging microscope is the object distance. The object distance can be adjusted by adjusting the Z-axis direction of the three-axis nanometer displacement table to achieve clear imaging. In actual testing, the position of the measured object in the Z-axis direction will move and deviate from the focal point due to the influence of factors such as temperature change and external vibration, resulting in blurred imaging. Therefore, the object distance needs to be continuously adjusted to achieve clear imaging by using a focusing algorithm during testing.

[0063] The existing methods include a defocusing depth method and a focusing depth method. The defocusing depth method has poor accuracy, and the thermal reflection temperature measurement is highly sensitive to defocusing, and the focal depth of the imaging microscope is small, so the defocusing depth method cannot guarantee the testing accuracy. The focusing depth method collects images at different object distances, evaluates the sharpness, fits a focusing evaluation curve to determine the peak point as the best object distance position. The larger the object distance range and the more the collected images, the more accurate the object distance determined by the focusing depth method. The focusing depth method can achieve higher focusing accuracy, but it needs to determine the focusing position in a large focusing range. When the focal point deviates too much, for example, beyond the focal depth, the image is blurred. The thermal reflection temperature measurement generally needs to collect images continuously, so the focusing depth method has a too large focusing range and cannot continuously maintain clear images, and is not suitable for continuous real-time focusing in the thermal reflection micro-thermal imaging system.

[0064] Embodiments of the present application provide a focusing method, device and electronic equipment of a thermal reflection micro-thermal imaging system to solve the problem that the focusing range of the focusing depth method is too large when the thermal reflection micro-thermal imaging system tests the temperature of the measured object, and the image cannot be continuously maintained clear, which is not suitable for continuous real-time focusing.

[0065] Figure 2 is the implementation flowchart of the focusing method of the thermal reflection micro-thermal imaging system provided by the embodiments of the present application. Referring to Figure 2 , the above method comprises:

[0066] S1, obtaining an initial image, wherein the initial image is an image collected at an initial object distance.

[0067] Illustratively, the image of the measured object is collected by the imaging microscope of the thermal reflection micro-thermal imaging system to obtain the initial image. Illustratively, the initial image is obtained by collecting the image at the initial object distance. When the image is collected, the measured object is usually at the focal point, and the initial object distance can be the object distance when the focal point is deviated. The initial object distance can also be the object distance when the focal point is deviated due to the influence of various factors.

[0068] S2, obtaining a first image, wherein the first image is an image collected after the object distance is adjusted from the initial object distance to a first object distance, and the first object distance is the initial object distance minus a preset step length.

[0069] After adjusting the object distance from the initial object distance to the first object distance, an image is collected to obtain a first image. The first object distance can also be the initial object distance plus a preset step length, for example. The object distance represents the relative distance between the three-axis nanometer displacement stage and the imaging microscope. The object distance can be adjusted by controlling the movement of the Z-axis of the three-axis nanometer displacement stage, for example. The relative distance between the measured object and the imaging microscope is the actual object distance of the measured object. The relative distance between the measured object and the three-axis nanometer displacement stage can change due to thermal expansion, and the relative distance between the three-axis nanometer displacement stage and the imaging microscope cannot completely represent the relative distance between the measured object and the imaging microscope. The present solution can adjust the object distance by controlling the movement of the Z-axis of the three-axis nanometer displacement stage, offset the change in the relative distance between the measured object and the three-axis nanometer displacement stage, and keep the measured object in the focal position of the imaging microscope, i.e., realize focus tracking.

[0070] S3, obtaining a second image, wherein the second image is an image collected after adjusting the object distance from the first object distance back to the initial object distance.

[0071] After collecting the first image, the object distance can be adjusted from the first object distance back to the initial object distance, and an image is collected to obtain a second image, for example. Although the initial image and the second image are both collected at the initial object distance, the relative distance between the measured object and the three-axis nanometer displacement stage continues to change, i.e., the position of the measured object drifts, so the initial image and the second image are not necessarily the same image.

[0072] S4, repeatedly performing the steps of obtaining the first image and obtaining the second image to obtain a plurality of groups of first images and second images.

[0073] The above steps S2 and S3 are repeatedly performed, and a group of first image and second image is obtained each time the loop is executed. A plurality of groups of first images and second images are obtained by repeatedly executing the loop multiple times. The focal length returns to the initial focal length position each time the loop is executed, for example. The above steps S2 and S3 are executed at least twice to obtain at least two groups of first images and second images, for example.

[0074] S5, calculating the image sharpness of the initial image, each first image, and each second image, respectively.

[0075] The image sharpness can be calculated by a sharpness evaluation function, for example. The sharpness evaluation function, also known as a focus evaluation function, includes image gray value variance, image gray value standard deviation, Tenengrad function, and Laplace function, etc.

[0076] S6, if the first average sharpness is greater than the second average sharpness, adjusting the object distance to the initial object distance minus a preset step length. The first average sharpness is the average of the image sharpness of each first image, and the second average sharpness is the average of the image sharpness of the initial image and each second image.

[0077] Exemplarily, the image sharpness of each first image is arithmetically averaged to obtain a first average sharpness. The first average sharpness represents the average sharpness of each image captured at the first object distance position. Exemplarily, the higher the sharpness value is, the sharper the image is, and the lower the sharpness value is, the blurrier the image is.

[0078] If the first average sharpness is greater than the second average sharpness, that is, if the image sharpness at the first object distance position is higher than the sharpness at the initial object distance position, the object distance is adjusted to the initial object distance minus the preset step length, that is, the object distance is adjusted from the initial object distance to the first object distance, so as to realize the adjustment of the object distance from the blur position to the sharp position. The adjustment direction of the object distance is the decreasing direction, or the negative direction.

[0079] S7, if the first average sharpness is less than or equal to the second average sharpness, the object distance is adjusted to the initial object distance plus the preset step length.

[0080] If the first average sharpness is less than or equal to the second average sharpness, that is, if the image sharpness at the first object distance position is less than or equal to the sharpness at the initial object distance position, the object distance is adjusted to the initial object distance plus the preset step length, so as to realize the adjustment of the object distance from the blur position to the sharp position. The adjustment direction of the object distance is the increasing direction, or the positive direction.

[0081] Exemplarily, in steps S2 and S3, if the first object distance is the initial object distance plus the preset step length, then step S6 is that, if the first average sharpness is greater than the second average sharpness, the object distance is adjusted to the initial object distance plus the preset step length. Correspondingly, step S7 is that, if the first average sharpness is less than or equal to the second average sharpness, the object distance is adjusted to the initial object distance minus the preset step length.

[0082] S8, the adjusted object distance is taken as the initial object distance to cyclically capture images, calculate average sharpness and adjust the object distance.

[0083] The object distance adjusted in step S6 or step S7 is taken as the initial object distance, and steps S1 to S7 are re-executed based on the initial object distance. Steps S1 to S8 are cyclically executed to continuously determine the adjustment direction of the object distance and adjust the object distance based on the initial object distance, so as to realize the focus.

[0084] The embodiment of the present application determines the adjustment direction of the object distance by alternately adjusting the object distance by a preset step length at the initial object distance position and the position adjacent to the initial object distance, collecting images, and comparing the average image definition under the two adjacent object distances, adjusts the object distance by the preset step length, and then continues to alternately adjust the object distance based on the adjusted object distance, collects images, confirms the adjustment direction, and adjusts the object distance. The range of the object distance adjustment in the focusing process is within the preset step length, and the deviation from the initial object distance is small, that is, the deviation from the focus is small, so that the image definition can be ensured. The method can be cyclically executed during the temperature test of the thermal reflection microscopic thermal imaging system, the object distance can be adjusted in real time, the image definition can be continuously maintained, and continuous real-time focusing can be realized.

[0085] Exemplarily, the relative distance change between the measured member and the three-axis nanometer displacement table can include two cases. Case one: the relative distance between the measured member and the three-axis nanometer displacement table changes and then remains unchanged. Case two: the relative distance between the measured member and the three-axis nanometer displacement table in the Z-axis direction continuously changes, that is, the measured member is always in position drift. The embodiments of the present application are applicable to the above two cases.

[0086] In case one, the embodiments of the present application can cyclically execute steps S1 to S8 multiple times, and the object distance is continuously adjusted until the object distance is adjusted to the vicinity of the focus point. Finally, the object distance can be repeatedly adjusted in the vicinity of the focus point.

[0087] In case two, the embodiments of the present application can collect images multiple times at the positions of the object distance alternately when the measured member continuously and slowly drifts. Due to the position drift of the measured member, the image definition collected at the same object distance position at different times can be different. Figure 3 is a schematic diagram of a continuous image collection method. Referring to Figure 3 , the horizontal axis represents the object distance, the vertical axis represents the definition of the image, the solid line curve represents the definition curve at the initial position at the initial time, and each dashed line represents the definition curve at each time after the initial time. With the passage of time, the definition curve continuously drifts to the right. The solid triangles represent the time of collecting images and the object distance position. The left three solid triangles represent collecting images three times in succession at the same object distance position. The right four solid triangles represent collecting images four times in succession after changing the object distance position. The average definition corresponding to the left three solid triangles is higher than the average definition of the right four solid triangles, and actually, the definition will be higher after increasing the object distance to the right.

[0088] Figure 4 is a schematic diagram of an image collection method provided by the embodiment of the present application. Referring to Figure 4, solid dots represent the time and the object distance position of the collected image. In time sequence, the solid curve corresponds to the object distance (initial object distance) at the initial time, and then the object distance is reduced by d (i.e. a preset step length) to collect the image, and then the object distance is returned to the initial object distance position to collect the image. The cycle is executed, and the image is collected at the alternate object distance position. By comparing the average sharpness of the images collected at the two object distance positions, the judgment error of the object distance adjustment direction caused by the continuous drift of the measured object position during the focusing process can be avoided.

[0089] In a possible implementation, before the initial image is acquired, the method further includes: acquiring a first step length as the preset step length, the first step length being smaller than the depth of focus of the thermal reflection microscopic thermal imaging system.

[0090] During the cycle execution of steps S1 to S8, the preset step length can be a fixed value. The first step length can be acquired as the preset step length before step S1. For example, the first step length is smaller than the depth of focus of the thermal reflection microscopic thermal imaging system. When the object distance is changed by a distance of the first step length, the image can still be clear. For example, the first step length is greater than the object distance difference corresponding to the noise level of the sharpness curve. That is, when the object distance is moved by a preset step length near the focal point, the change in image sharpness is greater than the noise of the sharpness curve.

[0091] When the object distance is near the focal point, the preset step length with the shortest length can ensure that the image remains clear during the adjustment of the object distance during the focusing process, and the focusing accuracy is high. In practical application of the thermal reflection microscopic thermal imaging system, the object distance can deviate from the focal point by a large distance. A smaller preset step length can reduce the range of the object distance adjustment after each cycle execution of steps S1 to S8, and the efficiency of the object distance adjustment to the focal point is low.

[0092] In a possible implementation, before the initial image is acquired, the method further includes: acquiring a second step length and a third step length, wherein the second step length is smaller than the depth of focus of the thermal reflection microscopic thermal imaging system. The third step length is greater than the second step length. When the thermal reflection microscopic thermal imaging system is used for constant temperature testing of the measured object, the second step length is used as the preset step length. When the thermal reflection microscopic thermal imaging system is used for variable temperature testing of the measured object, the third step length is used as the preset step length, wherein the third step length is proportional to the variable temperature amplitude.

[0093] The second step length is small and the third step length is large. When the thermal reflection micro-thermal imaging system is used to test the measured object at constant temperature, the thermal expansion of the measured object is small, the position of the measured object drifts small, and the second step length is small, which can ensure the accuracy of the focusing. When the thermal reflection micro-thermal imaging system is used to test the measured object at variable temperature, the thermal expansion of the measured object is large, the position of the measured object drifts large, and the third step length is large, which can ensure the efficiency of the focusing. For example, the third step length can be a variable value. For example, the third step length can be proportional to the variable temperature amplitude. For example, the third step length is 5 to 10 times of the second step length. For example, the variable temperature test includes heating or cooling the measured object to change the temperature of the measured object. For example, the variable temperature test can also include applying different voltages or currents to the measured object to change the working temperature of the measured object.

[0094] The embodiment of the present application sets a small second step length and a large third step length to monitor the working state of the thermal reflection micro-thermal imaging system, wherein the working state includes constant temperature test and variable temperature test. Different lengths of preset step lengths are selected based on different working states. In each cycle of steps S1 to S8, a small step length or a large step length is selected based on the application scenario, and the accuracy and efficiency of the focusing are considered.

[0095] In a possible implementation, after the adjusted object distance is used as the initial object distance to cyclically collect images, calculate the average sharpness, and adjust the object distance, the method further includes: if the directions of the object distance adjustment in the two consecutive cycles are the same, increasing the length of the preset step length. If the directions of the object distance adjustment in the two consecutive cycles are opposite, decreasing the length of the preset step length.

[0096] For example, in the cyclic execution of steps S1 to S8, the direction of the object distance adjustment includes the increasing direction and the decreasing direction. For example, the directions of the object distance adjustment in the two consecutive cycles are the same, including that the directions of the object distance adjustment in the two consecutive cycles of steps S1 to S8 are both increasing directions or both decreasing directions.

[0097] For example, the directions of the object distance adjustment in the two consecutive cycles are opposite, including that the directions of the object distance adjustment in the two consecutive cycles of steps S1 to S8 are the increasing direction and the decreasing direction in turn, or the decreasing direction and the increasing direction in turn.

[0098] For example, if the directions of the object distance adjustment in the two consecutive cycles are the same, the length of the preset step length is increased by a preset coefficient. d' = αd, α > 1, d' represents the adjusted object distance, d represents the adjusted object distance, and α represents the preset coefficient. If the directions of the object distance adjustment in the two consecutive cycles are the same, it can be indicated that the object distance is not adjusted to the peak point of the sharpness curve, and the length of the preset step length can be increased to improve the efficiency of the focusing.

[0099] For example, if the directions of the object distance adjustment in two consecutive cycles are opposite, the length of the preset step is reduced by a preset coefficient. d' = βd, β < 1, d' represents the adjusted object distance, d represents the object distance before adjustment, and β represents the preset coefficient. If the directions of the object distance adjustment in two consecutive cycles are opposite, it can be indicated that the object distance is repeatedly adjusted on both sides of the peak point of the sharpness curve. Reducing the length of the preset step can improve the accuracy of the focus.

[0100] In a possible implementation, the calculating the image sharpness of the initial image, each first image and each second image respectively comprises: calculating the image sharpness of the initial image, each first image and each second image respectively based on the following formula:

[0101]

[0102]

[0103]

[0104] wherein c i is the gray value of each pixel of the image, P is the total number of pixels of the image, and s is the image sharpness.

[0105] The embodiment of the application determines the sharpness based on the gray value of the collected image, the image is the sharpest at the focus position, and the sharpness value is the largest. The output of the sharpness calculation method is theoretically not affected by the change of the illumination intensity, so the influence of the illumination intensity drift can be effectively suppressed, and better focus effect can be obtained.

[0106] In a possible implementation, after the initial image is acquired, the method further comprises: calculating the image sharpness based on the initial image. Correspondingly, the acquiring the first image comprises: if the image sharpness of the initial image is lower than a preset threshold, acquiring the first image.

[0107] The embodiment of the application determines whether the object distance needs to be adjusted based on the current image sharpness, that is, whether the steps S1 to S8 are executed to adjust the object distance.

[0108] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the application.

[0109] The following is a device embodiment of the application. For details not described in detail, reference can be made to the corresponding method embodiments described above.

[0110] Figure 5 A structure schematic diagram of a focus device of a thermal reflection microscopic thermal imaging system provided by the embodiment of the application is shown. For ease of illustration, only parts related to the embodiment of the application are shown, and the details are as follows:

[0111] As shown in Figure 5 A follow focus device 5 of a thermal reflection microscopic thermal imaging system comprises:

[0112] A first acquisition module 51 is configured to acquire an initial image, wherein the initial image is an image collected at an initial object distance.

[0113] A second acquisition module 52 is configured to acquire a first image, wherein the first image is an image collected after the object distance is adjusted to a first object distance from the initial object distance, and the first object distance is the initial object distance minus a preset step length.

[0114] A third acquisition module 53 is configured to acquire a second image, wherein the second image is an image collected after the object distance is adjusted back to the initial object distance from the first object distance.

[0115] A first loop module 54 is configured to repeatedly perform the acquisition of the first image and the acquisition of the second image to obtain a plurality of groups of the first image and the second image.

[0116] A definition calculation module 55 is configured to calculate the image definition of the initial image, each first image and each second image, respectively.

[0117] A first adjustment module 56 is configured to adjust the object distance to the initial object distance minus the preset step length if a first average definition is greater than a second average definition, wherein the first average definition is an average value of the image definition of each first image, and the second average definition is an average value of the image definition of the initial image and each second image.

[0118] A second adjustment module 57 is configured to adjust the object distance to the initial object distance plus the preset step length if the first average definition is less than or equal to the second average definition.

[0119] A second loop module 58 is configured to take the adjusted object distance as the initial object distance to repeatedly collect images, calculate average definitions and adjust the object distance.

[0120] The embodiment of the present application adjusts the object distance by a preset step length alternately at the initial object distance position and the position adjacent to the initial object distance, collects images, compares the average image definition at the two adjacent object distances, determines the adjustment direction of the object distance, adjusts the object distance by the preset step length, and then continues to adjust the object distance alternately, confirms the adjustment direction and adjusts the object distance based on the adjusted object distance. The range of the adjustment of the object distance in the follow focus process is within the preset step length, and the deviation from the initial object distance is small, i.e., the deviation from the focus point is small, which can ensure the image definition. The process can be repeatedly performed during the temperature test of the thermal reflection microscopic thermal imaging system, the object distance can be adjusted in real time, the image definition can be continuously maintained, and continuous real-time follow focus is achieved.

[0121] In a possible implementation, the apparatus further includes a step length obtaining module configured to, before obtaining the initial image, obtain a first step length of a preset fixed length as the preset step length, the first step length being smaller than a focal depth of the thermal reflection microscopic thermal imaging system.

[0122] In a possible implementation, before obtaining the initial image, the apparatus further includes obtaining a second step length and a third step length, wherein the second step length is smaller than the focal depth of the thermal reflection microscopic thermal imaging system, and the third step length is greater than the second step length. When the thermal reflection microscopic thermal imaging system is used to test a test piece at a constant temperature, the second step length is used as the preset step length. When the thermal reflection microscopic thermal imaging system is used to test the test piece at a variable temperature, the third step length is used as the preset step length, wherein the third step length is proportional to a variable temperature amplitude.

[0123] In a possible implementation, after the adjusted object distance is used as the initial object distance to cyclically collect images, calculate the average sharpness, and adjust the object distance, the apparatus further includes: if the directions of the object distance adjustment in two consecutive cycles are the same, increasing the length of the preset step length. If the directions of the object distance adjustment in two consecutive cycles are opposite, decreasing the length of the preset step length.

[0124] In a possible implementation, the calculating the image sharpness of the initial image, each first image, and each second image respectively includes: calculating the image sharpness of the initial image, each first image, and each second image respectively based on the following formula:

[0125]

[0126]

[0127]

[0128] wherein c i is a gray value of each pixel of the image, P is a total number of pixels of the image, and s is the image sharpness.

[0129] In a possible implementation, after the initial image is obtained, the apparatus further includes calculating the image sharpness based on the initial image. Correspondingly, the obtaining the first image includes: if the image sharpness of the initial image is lower than a preset threshold, obtaining the first image.

[0130] Figure 6 is a schematic diagram of an electronic device provided by an embodiment of the present application. As shown in Figure 6 The electronic device 6 of this embodiment includes a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. The processor 60 implements the steps in each of the follow-up focusing methods of the thermal reflection microscopic thermal imaging system embodiments when executing the computer program 62, for example Figure 2The steps S1-S8 are shown. Alternatively, the processor 60 implements the functions of the modules / units in the above-mentioned apparatus embodiments when executing the computer program 62, for example Figure 5 The functions of the modules 51-58 are shown.

[0131] The computer program 62 can be segmented into one or more modules / units for example, which are stored in the memory 61 and executed by the processor 60 to complete the present application. The one or more modules / units can be a series of computer program instruction segments capable of completing a specific function, which are used to describe the execution process of the computer program 62 in the electronic device 6. For example, the computer program 62 can be segmented into Figure 5 The modules 51-58 are shown.

[0132] The electronic device 6 can be a desktop computer, a notebook, a palm computer, a cloud server and other computing devices. The electronic device 6 can include, but is not limited to, the processor 60, the memory 61. Those skilled in the art can understand that Figure 6 The electronic device 6 is only an example and does not constitute a limitation on the electronic device 6, which can include more or fewer components than shown, or combine certain components, or different components, for example, the electronic device can also include an input / output device, a network access device, a bus, etc.

[0133] The processor 60 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0134] The memory 61 can be an internal storage unit of the electronic device 6, for example, a hard disk or a memory of the electronic device 6. The memory 61 can also be an external storage device of the electronic device 6, for example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 6. Further, the memory 61 can include both the internal storage unit and the external storage device of the electronic device 6. The memory 61 is used to store the computer program and other programs and data required by the electronic device. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0135] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the unit and module in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0136] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0137] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0138] In the embodiments of the present application, it should be understood that the disclosed apparatus / equipment and method can be implemented in other manners. For example, the described apparatus / equipment embodiments are merely schematic. The division of the modules or units is merely logical function division. There can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0139] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0140] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically, or two or more units can be integrated into one unit. The integrated unit can be implemented in the form of hardware, or in the form of a software functional unit.

[0141] The integrated module / unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, all or part of the flow of the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. When the processor executes the computer program, the steps of each follow-up method embodiment of the above-mentioned thermal reflection micro-thermal imaging system can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0142] The above-described embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A focusing method for a thermal reflection microscopy thermal imaging system, characterized in that, include: Acquire an initial image, wherein the initial image is an image acquired at an initial object distance; Acquire a first image, wherein the first image is an image acquired after adjusting the object distance from the initial object distance to the first object distance, and the first object distance is the initial object distance minus a preset step size; Acquire a second image, wherein the second image is an image acquired after adjusting the object distance from the first object distance back to the initial object distance; Repeat the process of acquiring the first image and acquiring the second image to obtain multiple sets of the first image and the second image; Calculate the image sharpness of the initial image, each first image, and each second image respectively; If the first average sharpness is greater than the second average sharpness, the object distance is adjusted to the initial object distance minus a preset step size; wherein, the first average sharpness is the average of the image sharpness of each first image, and the second average sharpness is the average of the image sharpness of the initial image and each second image; If the first average sharpness is less than or equal to the second average sharpness, adjust the object distance to the initial object distance plus the preset step size; The adjusted object distance is used as the initial object distance to continuously acquire images, calculate the average sharpness, and adjust the object distance accordingly. Before acquiring the initial image, the method further includes: acquiring a first step length of a preset fixed length as the preset step length, wherein the first step length is less than the depth of focus of the thermal reflection microscopy thermal imaging system; Alternatively, a second step size and a third step size can be obtained, wherein the second step size is less than the depth of focus of the thermal reflection microscopy system; the third step size is greater than the second step size; when the thermal reflection microscopy system is used to test the test piece at a constant temperature, the second step size is used as the preset step size; when the thermal reflection microscopy system is used to test the test piece at a variable temperature, the third step size is used as the preset step size, wherein the third step size is proportional to the temperature change amplitude.

2. The focusing method of the thermal reflection microscopy thermal imaging system according to claim 1, characterized in that, After using the adjusted object distance as the initial object distance to cyclically acquire images, calculate the average sharpness, and adjust the object distance, the process further includes: If the direction of the object distance adjustment is the same in two consecutive cycles, the preset step size is increased. If the object distance is adjusted in opposite directions in two consecutive cycles, the preset step size is reduced.

3. The focusing method of the thermal reflection microscopy thermal imaging system according to claim 1, characterized in that, The calculation of image sharpness for the initial image, each first image, and each second image includes: The image sharpness of the initial image, each first image, and each second image are calculated based on the following formulas: in, These are the grayscale values ​​of each pixel in the image. The total number of pixels in the image. Image sharpness.

4. The focusing method of the thermal reflection microscopy thermal imaging system according to claim 1, characterized in that, After obtaining the initial image, the process also includes: Calculate image sharpness based on the initial image; Accordingly, acquiring the first image includes: If the image clarity of the initial image is lower than a preset threshold, then the first image is obtained.

5. A focusing device for a thermal reflection microscopy thermal imaging system, characterized in that, include: The first acquisition module is used to acquire an initial image, wherein the initial image is an image acquired at an initial object distance; The second acquisition module is used to acquire a first image, wherein the first image is an image acquired after adjusting the object distance from the initial object distance to the first object distance, and the first object distance is the initial object distance minus a preset step size. The third acquisition module is used to acquire a second image, wherein the second image is an image acquired after adjusting the object distance from the first object distance back to the initial object distance; The first loop module is used to repeatedly execute the steps of acquiring the first image and acquiring the second image to obtain multiple sets of the first image and the second image. The image sharpness calculation module is used to calculate the image sharpness of the initial image, each first image, and each second image respectively. The first adjustment module is used to adjust the object distance to the initial object distance minus a preset step size if the first average sharpness is greater than the second average sharpness; wherein, the first average sharpness is the average image sharpness of each first image, and the second average sharpness is the average image sharpness of the initial image and each second image; The second adjustment module is used to adjust the object distance to the initial object distance plus a preset step if the first average sharpness is less than or equal to the second average sharpness. The second loop module is used to acquire images cyclically using the adjusted object distance as the initial object distance, calculate the average sharpness, and adjust the object distance. The step size acquisition module is used to acquire a first step size of a preset fixed length as a preset step size before acquiring the initial image, wherein the first step size is less than the depth of focus of the thermal reflection microscopy system; or, to acquire a second step size and a third step size, wherein the second step size is less than the depth of focus of the thermal reflection microscopy system and the third step size is greater than the second step size; when the thermal reflection microscopy system is used to test the test piece at a constant temperature, the second step size is used as the preset step size; when the thermal reflection microscopy system is used to test the test piece at a variable temperature, the third step size is used as the preset step size, wherein the third step size is proportional to the temperature change amplitude.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the focusing method of the thermal reflection microscopy thermal imaging system as described in any one of claims 1 to 4.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the focusing method of the thermal reflection microscopy thermal imaging system as described in any one of claims 1 to 4.

Images