Laser spot image processing method, automatic focusing method and medium

Abstract

The invention provides a laser spot image processing method, an automatic focusing method and a medium. The processing method comprises the following steps: acquiring a plurality of laser spot images corresponding to different laser energy; based on the reflectivity of the surface area of the object to be measured and / or the pixel value of the laser spot image, dividing the laser spot image to obtain first data meeting a first condition and second data not meeting the first condition; based on the first data and the second data, screening a first pixel range and a second pixel range which meet imaging requirements; the imaging requirement is that a light spot exists in a laser spot image corresponding to the first data, and a light spot exists in a laser spot image corresponding to the second data; laser energy ranges corresponding to the first pixel range and the second pixel range are used as effective exposure conditions. Based on the effective exposure condition, the first effective data and the second effective data are determined, and a fusion means is adopted, so that the problem that a light spot image of an area with large reflectivity difference cannot be accurately obtained by the same laser energy is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to a laser spot image processing method, an automatic focusing method and a medium. Background Art

[0002] Optical microscopes use lenses to magnify the surface of an object under test. To obtain a meaningful image, the microscope objective must be precisely focused on the sample surface. However, the depth of field of high-magnification microscopes is typically only a few microns, requiring operators to spend considerable time manually adjusting the distance between the objective and the object under test to achieve focus. Microscope autofocus technology uses feedback signals to calculate the current defocus value of the objective lens and converts this into a motion signal for the motor, which then drives the objective lens to automate the focusing process.

[0003] Depending on the type of feedback signal, microscopic autofocus technology can be divided into image-based autofocus and laser-based autofocus. Image-based autofocus uses an image clarity evaluation function to determine the current defocus value using a quantified clarity value. This determination depends on the state of the captured image and is easily affected by the lighting environment. It also results in slower focusing speeds and a smaller focus range.

[0004] Laser-based autofocus technology adds a laser signal to a conventional microscope. By calculating the laser spot shape (including its center of mass, radius, and curvature), the defocus value of the object under test is determined. The objective lens's movement direction and distance are controlled based on this defocus value, ensuring that the distance between the microscope objective and the surface of the object under test falls within the objective's depth of field, thereby achieving autofocus. This technology offers a wider focus range and faster focusing speed, making it widely used in industrial inspection applications.

[0005] Generally speaking, for various reflectivity conditions, the laser exposure strategy (such as exposure time, exposure distance, laser energy, etc.) can be appropriately adjusted according to the reflectivity to make the spot image clearer and improve processing efficiency during the detection and focusing process of the object to be tested. For example, Chinese patent CN119291910A dynamically adjusts the laser power, camera exposure time and gain settings, and sets the minimum threshold for the linear spot width to accurately control the scanning step size and pause time of the focus motor to achieve fast and stable focusing effects in response to different sample surface characteristics and lighting conditions.

[0006] If the surface of the object to be measured has various reflectivities, and the reflectivities differ greatly, precise focusing on the surface of the object to be measured cannot be achieved simply by adjusting the laser exposure strategy of the microscope autofocus system (such as adjusting the exposure time, exposure distance, laser energy, etc.).

[0007] For example, if a high-exposure strategy (such as increasing laser energy and exposure time) is adopted, there will be a clear spot in the laser spot image corresponding to the low-reflectivity area, but the laser spot image corresponding to the high-reflectivity area will be overexposed. Conversely, if a low-exposure strategy (such as reducing laser energy and exposure time) is adopted, there will be a clear spot in the laser spot image corresponding to the high-reflectivity area, but there will be no clear spot in the laser spot image corresponding to the low-reflectivity area, and effective data cannot be obtained for relevant calculations.

[0008] Therefore, for the surface of the object to be tested with multiple reflectivity areas, it is possible that the focus cannot be locked or the focus is unstable by simply adjusting the exposure strategy, so that the defocus amount of the surface of the object to be tested is calculated inaccurately, and the focusing requirements of the surface of the object to be tested with multiple refractive indices cannot be met.

[0009] Chinese patent CN105578009A discloses a spot imaging device and proposes a method for calculating the center of a laser spot imaged by an overexposed CCD linear array photosensor in laser triangulation. This method enables laser scanning vision systems to obtain high-precision measurement results in environments with a wide dynamic range. This patent involves the principle of laser triangulation, which differs from the imaging principle of this solution, and the technical means employed in this solution are also different from those of this solution.

[0010] Chinese patent CN116088130A discloses a line laser focusing method, apparatus, optical device, and storage medium. This patent determines the zoom position corresponding to the focus lens based on the spot image and performs a first focusing operation. It then performs segmented detection of the line laser based on the spot image to determine the focus area of ​​the line laser on the surface of the object to be measured, thereby controlling the focus lens to perform a second focusing operation on the object to be measured, thereby accurately determining the focus point of different objects to be measured. This patent differs from the technical approach of this application.

[0011] The journal article "Laser Autofocus Method Based on Light Field Computation and Image Processing Algorithms" (doi: 10.3788 / gzxb20245311.1132002) proposes a method for determining the focus position based on the relationship between the spot diameter and the acquisition position. Combined with light field distribution calculations, this paper solves the problem of quantitatively finding the focus position in femtosecond laser 3D machining. This paper uses a different technical approach from the present application. Summary of the Invention

[0012] The present invention provides a laser spot image processing method, an automatic focusing method and a medium, which at least solve one of the above-mentioned technical problems.

[0013] To achieve the above objectives, the present invention proposes the following technical solutions: A method for processing a laser spot image, comprising: Acquire several laser spot images corresponding to different laser energies; the laser spot images are formed by reflection from the surface of the object to be measured, and there are at least two areas with different reflectivity on the surface of the object to be measured; Divide the laser spot image based on the reflectivity of the surface area of ​​the object to be measured and / or the pixel value of the laser spot image to obtain first data that meets the first condition and second data that does not meet the first condition; The first condition is that the reflectivity is greater than a set value and / or the pixel value is greater than a division threshold; Based on the first data and the second data, a first pixel range and a second pixel range that meet the imaging requirement are screened; the imaging requirement is that a light spot exists in the laser spot image corresponding to the first data and a light spot exists in the laser spot image corresponding to the second data; The laser energy ranges corresponding to the first and second pixel ranges are used as effective exposure conditions.

[0014] Furthermore, it also includes: Based on the first pixel range, assigning pixel values ​​not greater than the first valid threshold to fixed values ​​to form first valid data; Based on the second pixel range, assigning pixel values ​​not less than the second valid threshold to fixed values ​​to form second valid data; Taking the maximum value of the first valid data and the second valid data at any pixel point as the pixel value of the pixel point, and obtaining the valid data; The second effective threshold is smaller than the first effective threshold, and the fixed value is smaller than the current pixel value.

[0015] Furthermore, it also includes: fusing a pixel value corresponding to any pixel point in the first data at any laser energy value in the first energy range with a pixel value corresponding to the pixel point at any laser energy value in the second energy range to obtain first fused data; fusing a pixel value corresponding to any pixel point in the second data at any laser energy value within the first energy range with a pixel value corresponding to the pixel point at any laser energy value within the second energy range to obtain second fused data; Calculating effective data using the first fused data and the second fused data; Among them, the laser energy values ​​of the first energy range selected by the first data and the second data are the same, and the laser energy values ​​of the second energy range selected are the same; the laser energy range corresponding to the first pixel range is the first energy range, and the laser energy range corresponding to the second pixel range is the second energy range.

[0016] Furthermore, it also includes: the difference between the minimum value of the reflectivity corresponding to the first data and the maximum value of the reflectivity corresponding to the second data is greater than the reflectivity threshold; and / or the difference between the minimum value of the pixel value in the first data and the maximum value of the pixel value in the second data is greater than the pixel threshold.

[0017] Furthermore, the pixel range that meets the imaging requirements includes: A first pixel range, which is an intersection of a pixel range in the first data having pixel values ​​less than a first threshold and a pixel range in the second data having pixel values ​​greater than a second threshold and less than the first threshold; A second pixel range, which is an intersection of a pixel range in the second data whose pixel values ​​are greater than the second threshold and less than the first threshold, and a pixel range in the first data whose pixel values ​​are not less than the first threshold; The first threshold is used to filter out overexposed image data, and the second threshold is smaller than the first threshold.

[0018] Furthermore, the effective exposure conditions include a first energy range corresponding to the first pixel range and a second energy range corresponding to the second pixel range; the minimum value of the laser energy in the second energy range is greater than the maximum value of the laser energy in the first energy range.

[0019] Furthermore, the second threshold is a pixel value corresponding to the second data when the first data is equal to the laser energy value corresponding to the first threshold for the first time.

[0020] Furthermore, it also includes: The laser energy-pixel value curves corresponding to the first data and the second data are fitted respectively, and the pixel range that meets the imaging requirements is determined by using the first threshold and the second threshold. Based on the response relationship between reflectivity and light intensity, the first energy range and the second energy range are selected as effective exposure conditions. The present application also proposes an autofocus method, comprising: Based on the same inventive concept, the present application also proposes an autofocus method, comprising: Using the above-mentioned processing method to obtain valid data; Calculate the effective data spot centroid, obtain the defocus value of the surface of the object to be measured, and realize autofocus.

[0021] On the other hand, the present invention further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the method described above.

[0022] The beneficial effects of the embodiments of the present invention are as follows: This embodiment utilizes the difference in sensitivity of different reflectivity areas on the surface of the object to be measured to light intensity, and proposes dividing the acquired laser spot image into high reflectivity and low reflectivity by reflectivity and / or pixel value to obtain first data and second data.

[0023] Because there are at least two areas with different reflectivity on the surface of the object to be measured, the micro automatic focusing system cannot achieve accurate focusing. Therefore, to achieve focusing control on the surface of the object to be measured, the effective exposure conditions corresponding to different reflectivity areas should be analyzed, that is, in the effective exposure conditions corresponding to any reflectivity, the light spot in the light spot image reflected by the reflectivity area is clear. In this way, accurate focusing of any reflectivity area can be achieved, or based on the exposure parameter analysis of the above appropriate conditions, the balance condition is obtained to achieve accurate focusing of the surface of the object to be measured.

[0024] In order to further exclude the image data in the first data and the second data that does not meet the imaging requirements, the embodiment filters the pixel range in the first data and the second data that meets the imaging requirements by analyzing the pixel change process.

[0025] Based on the difference in sensitivity of different reflectivity to light and the change process of pixel value in the laser light spot image, the embodiment determines the pixel range that meets the imaging requirements by analyzing the overexposed image data in the first data and the second data.

[0026] Because of the difference in sensitivity of different reflectivity areas to light intensity, in the effective exposure condition of the light spot image reflected by the high reflectivity area, the light spot image reflected by the low reflectivity area may have no light spot (there may be pixel data but no light spot, not no pixel data) or weak light spot; similarly, in the effective exposure condition of the light spot image reflected by the low reflectivity area, the light spot image reflected by the high reflectivity area is overexposed.

[0027] In the embodiment, based on the analysis of the existence of light spots in the light spot images reflected by the low and high reflectivity areas, the pixel value is taken as the screening condition to obtain the effective exposure conditions corresponding to the existence of light spots in the light spot images reflected by the low and high reflectivity areas.

[0028] According to the first energy range and the second energy range, the embodiment sequentially filters out the laser energy meeting the requirements of the high reflectivity area and the laser energy meeting the requirements of the low reflectivity area from the above energy ranges, adjusts the exposure according to the laser energy meeting the requirements of the high reflectivity area and the laser energy meeting the requirements of the low reflectivity area, determines the first effective data and the second effective data, and based on the pixel values in the high reflectivity area and the low reflectivity area in the first effective data and the second effective data, uses fusion means to obtain the light spot images under at least two reflectivities of the surface of the object to be measured, solves the problem that the same laser energy cannot accurately obtain the light spot image of the area with large reflectivity difference, and avoids the problem of overexposure or underexposure on the surface of the object to be measured.

[0029] This embodiment, based on the characteristics of the first data and the second data, screens the pixel values ​​corresponding to the laser energy values ​​in the first energy range and the pixel values ​​corresponding to the laser energy values ​​in the second energy range in the first data, and performs fusion calculation to obtain first fused data corresponding to the high reflectivity area; similarly, the second data is screened to calculate second fused data corresponding to the low reflectivity area; and valid data is finally obtained by using the first fused data and the second fused data, thereby solving the problem of the inability to accurately obtain spot images of areas with large reflectivity differences using the same laser energy, thereby avoiding the problem of overexposure or underexposure on the surface of the object to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the optical principle diagram of the laser-based microscopic autofocus technology; Figure 2 is a flow chart of the laser spot image processing method of the present invention; Figure 3 is a schematic diagram of a laser energy-pixel value curve in an embodiment of the present invention; Figure 4 is a flow chart of a method for obtaining valid data in an embodiment of the present invention; Figure 5 is a flow chart of a method for obtaining valid data in an embodiment of the present invention; Figure 6 It is a flow chart of the automatic focusing method in the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0032] like Figure 1 As shown in the figure, the optical principle of laser-based microscopic autofocus technology is as follows: Laser unit 1 emits a parallel laser beam, which is modulated by cylindrical lens 2 into an asymmetric beam that diverges in the direction of curvature of cylindrical lens 2 and is collimated in the non-curvature direction. The asymmetric beam loses half of its energy when passing through baffle 3 and propagates only on one side of the optical axis. After being reflected by reflector 4, first beam splitter 5, and second beam splitter 6, it enters microscope objective 7, where it converges onto the surface of object under test 8.

[0033] The laser beam reflected from the surface of the object under test 8 passes through the microscope objective 7, the second beam splitter 6, and the first beam splitter 5 before being converged by the focusing lens 9 onto the surface of the first sensor, forming a laser spot. The first sensor captures the laser spot image (also known as the "spot image") reflected from the object under test. The first sensor is a black and white sensor, and the laser spot image is a grayscale image, with pixel values ​​equal to grayscale values.

[0034] The image processing unit calculates the defocus amount according to the shape of the laser spot in the spot image, and converts the defocus amount into a control signal of the driving unit, so that the driving unit drives the microscope objective lens 7 to move and realize automatic focusing.

[0035] The illumination light source 10 forms a coaxial illumination light path with the third beam splitter 11, the second beam splitter 6 and the microscope objective 7. The tube lens 12, the second sensor and the microscope objective 7 form an imaging light path. The second sensor is used to collect the focused surface image of the object to be measured 8.

[0036] Preferably, the laser unit 1 can be a line laser or a point laser. If it is a point laser, in order to ensure that the laser unit emits a parallel laser beam, a collimating lens is also required to obtain a parallel beam.

[0037] Preferably, the driving unit may be a driving device such as an electric motor, so as to achieve precise movement control of the microscope objective lens 7 .

[0038] Based on the above-mentioned microscopic autofocus system, the first sensor collects the spot image reflected by the surface of the object to be measured, and the pixel value of each pixel in the spot image represents the average brightness information of each pixel.

[0039] like Figure 2 As shown, in order to achieve focus control on the surface of the object to be measured with multiple reflectivity regions so that the second sensor can capture images with high-quality visual effects, the present application proposes a method for processing laser spot images, including: Several laser spot images corresponding to different laser energies are obtained; the laser spot images are formed by reflection from the surface of the object to be measured, and there are at least two areas with different reflectivity on the surface of the object to be measured.

[0040] There are at least two areas with different reflectivity on the surface of the object to be measured, and the reflectivity difference is large. As a result, using only exposure strategies (such as adjusting one or more of exposure time, exposure distance, and laser energy) cannot achieve automatic focusing on the surface of the object to be measured.

[0041] There may be some defects on the surface of the object to be measured, resulting in different reflectivities of the laser in different areas of the surface.

[0042] The surface of the object to be measured can be composed of materials with different reflectivities, such as semiconductor wafers; or optical films or special coatings, which may have multiple areas of different reflectivities due to their material properties; or optical films or special coatings of different thicknesses may also result in multiple areas of different reflectivities on the surface to be measured.

[0043] To obtain laser spot images with different laser energies, an initial energy value may be set, and the laser energy may be increased in sequence by equal amounts to obtain a number of laser spot images under multiple exposure conditions corresponding to the laser energy as a variable.

[0044] Among them, in the laser spot image corresponding to the initial energy value, the laser spot image corresponding to the low reflectivity area may have pixel data but no spot, or may have no pixel data; the laser spot image corresponding to the high reflectivity area has a spot.

[0045] Laser light is the stimulated emission of light by atoms. The principle of laser light generation is that electrons in atoms absorb energy, transition from a low energy level to a high energy level, and then release the energy as photons when they fall back down from the high energy level. As a result, the resulting photon beam (laser light) has highly consistent optical properties, resulting in monochromaticity, excellent directionality, and higher brightness than conventional light sources.

[0046] Compared with ordinary light sources, lasers have strong directionality and high brightness. According to actual measurement experience, adjusting the exposure distance and exposure time in the laser exposure strategy does not significantly improve imaging.

[0047] Therefore, this application chooses to analyze the influence of laser energy on the imaging of laser spot image to obtain the effective exposure conditions corresponding to different reflectivity areas to achieve autofocus control.

[0048] Dividing the laser spot image based on the reflectivity of the surface area of ​​the object to be measured and / or the pixel value of the laser spot image to obtain first data that meets the first condition and second data that does not meet the first condition; The first condition is that the reflectivity is greater than a set value and / or the pixel value is greater than a division threshold.

[0049] Preferably, the reflectivity of the surface of the object to be measured can be measured and calculated by a device such as a laser energy detector.

[0050] Or the reflectivity corresponding to the material of the surface of the object to be measured is known.

[0051] The set value is set according to multiple reflectivities of the surface of the object to be measured, and can be the median of multiple reflectivities, the average of any two reflectivities, or other calculation methods.

[0052] If the reflectivity of the surface of the object to be measured is known, it can be classified as high reflectivity (reflectivity greater than the set value) or low reflectivity (reflectivity not greater than the set value) based on the set value to facilitate subsequent calculations. The terms high reflectivity and low reflectivity are relative terms and are only used to describe the magnitude relationship of the known reflectivities.

[0053] The image data of the laser spot image corresponding to the high reflectivity region is used as the first data; and the image data of the laser spot image corresponding to the low reflectivity region is used as the second data.

[0054] Preferably, only the partial reflectivity greater than the set value can be selected to select the image data of the laser spot image corresponding to the partial reflectivity area as the first data; similarly, the partial reflectivity less than the set value can be selected to determine the second data.

[0055] For applications where the surface of the object under test has more than two reflectivity regions, this embodiment divides the laser spot images corresponding to the multiple reflectivity regions into first data and second data based on the reflectivity to facilitate subsequent calculations. To ensure the accuracy and effectiveness of the image processing method proposed in this embodiment, this embodiment stipulates that there must be a certain difference between any reflectivity corresponding to the first data and any reflectivity corresponding to the second data. This ensures that the pixel values ​​of the first and second data are different, effectively distinguishing between high-reflectivity and low-reflectivity regions.

[0056] To ensure the effectiveness of the processing method proposed in this embodiment, this embodiment adds the following limiting conditions: The difference between the minimum value of the reflectivity corresponding to the first data and the maximum value of the reflectivity corresponding to the second data is greater than the reflectivity threshold; and / or the difference between the minimum value of the pixel value in the first data and the maximum value of the pixel value in the second data is greater than the pixel threshold.

[0057] If the reflectivity is known, the difference between the minimum reflectivity corresponding to the first data and the maximum reflectivity corresponding to the second data is greater than the reflectivity threshold, so that the processing method proposed in this embodiment is applicable.

[0058] The reflectivity threshold is an empirical value and is set according to actual application requirements.

[0059] In addition, due to the difference in laser energy received by the low reflectivity area and the high reflectivity area on the surface of the object to be measured, the light intensity reflected to the surface of the first sensor from different reflectivity areas is also different, that is, the pixel values ​​of different reflectivity areas in the spot image collected by the first sensor are different.

[0060] If the pixel value of the laser spot image is used as the screening condition for the first data and the second data, the first condition is that the pixel value is greater than the division threshold.

[0061] If the reflectivity is known, the first data and the second data can be further limited by pixel values ​​based on the reflectivity screening.

[0062] Preferably, based on the acquired laser spot image, the pixel value is used as a screening condition to determine the first data and the second data, specifically including: setting a division threshold, and taking the pixel points in the laser spot image with a pixel value greater than the division threshold as the first data; otherwise, as the second data.

[0063] The division threshold is used to distinguish the laser spot images corresponding to the high reflectivity area and the low reflectivity area in the laser spot image reflected by the surface of the object to be measured. The specific value of the division threshold can be set according to actual conditions, and this application does not limit the specific value.

[0064] Preferably, the dividing threshold may be an average of the pixel values ​​of the spot image corresponding to the high reflectivity region and the pixel values ​​of the spot image corresponding to the low reflectivity region.

[0065] Preferably, based on the acquired laser spot image, pixel values ​​are used as screening conditions to determine the first data and the second data, and further includes: If the reflectivity of the surface of the object to be measured is unknown, the laser spot image reflected by the surface of the object to be measured can be divided into several areas of equal size, a division threshold is set, and the pixel value of each area is compared with the division threshold one by one. If the number of pixel points with pixel values ​​greater than the division threshold in the current area exceeds 50% of the total number of pixel points in the current area, the image data corresponding to the current area is selected as the first data; or only the image data corresponding to the pixel points with pixel values ​​greater than the division threshold in the current area are selected as the first data (that is, both the quantity and pixel value conditions are met at the same time).

[0066] The sizes of the several regions divided into the laser spot image are smaller than the size of any reflectivity region, so as to ensure that the pixel value screening of each reflectivity region can be applied to the above screening conditions.

[0067] In addition, the quantity restriction condition of 50% is only an example, and other values ​​can be set according to the specific distribution of pixel values ​​in the current laser spot image.

[0068] The above-mentioned screening methods for the first data and the second data can be selected by one or any combination thereof, or other methods can be adopted, depending on the actual application requirements.

[0069] Preferably, only part of the image data that meets the conditions may be selected to form the first data and the second data respectively.

[0070] In the above method for determining the first data and the second data, the difference between the minimum pixel value in the first data and the maximum pixel value in the second data is greater than the pixel threshold, so as to be applicable to the processing method proposed in this embodiment.

[0071] The pixel threshold is an empirical value and is set according to actual application requirements.

[0072] Because the surface of the object under test has at least two regions with different reflectivities, the microscopic autofocus system cannot achieve precise focus. Therefore, to achieve focus control on the object under test, the effective exposure conditions corresponding to each reflectivity region should be analyzed. Specifically, under the effective exposure conditions corresponding to any reflectivity, the spot image reflected from that reflectivity region should be clear. This allows precise focus on any reflectivity region. Alternatively, based on the exposure parameter analysis of these appropriate conditions, a balanced condition can be obtained to achieve precise focus on the object under test.

[0073] Based on the first data and the second data, a first pixel range and a second pixel range that meet the imaging requirements are screened; the imaging requirements are that a light spot exists in the laser spot image corresponding to the first data and a light spot exists in the laser spot image corresponding to the second data.

[0074] Pixel ranges that meet imaging requirements in the first and second data are selected respectively, and the laser energy range corresponding to the pixel range that meets the imaging requirements is used as the effective exposure condition. The imaging requirement is that a light spot exists in the laser spot image corresponding to the first data and a light spot exists in the laser spot image corresponding to the second data.

[0075] The laser energy ranges corresponding to the first and second pixel ranges are used as effective exposure conditions.

[0076] In the laser spot image, the pixel value increases with the increase of laser energy.

[0077] Since the high-reflectivity area has high photosensitivity, as the laser energy increases, the pixel value of the laser spot image corresponding to this area rises rapidly and easily reaches the pixel upper limit (taking an 8-bit image as an example, the pixel upper limit is 255). The spot image of this area appears overexposed; the spot image corresponding to the subsequent increase in laser energy is also overexposed, and both do not meet the imaging requirements.

[0078] The pixel upper limit is the maximum value of the image data range. Taking 8-bit image data as an example, its range is [0, 255]. The maximum value of the 8-bit image data range is 255, which means the pixel upper limit is 255.

[0079] Since the photosensitivity of the low reflectivity area is low, as the laser energy increases, the pixel value of the laser spot image corresponding to this area rises slowly. It is possible that in the laser spot image within a certain energy range, no pixel value changes are shown or no spot is shown at all. In this case, the laser spot image within this energy range does not meet the imaging requirements.

[0080] Therefore, under the same laser energy, the light spot images formed by the reflection of the high-reflectivity area surface and the light spot images formed by the reflection of the low-reflectivity area surface may present different visual effects. In order to obtain the light spots in the light spot images formed by the reflection of the high-reflectivity area surface and the light spots in the light spot images formed by the reflection of the low-reflectivity area surface, it is necessary to obtain the effective exposure conditions for the light spots in the light spot images formed by the reflection of the high-reflectivity area and the effective exposure conditions for the light spots in the light spot images formed by the reflection of the low-reflectivity area.

[0081] Due to the difference in sensitivity to light intensity in areas with different reflectivity, under the effective exposure condition that there is a light spot in the light spot image formed by reflection from the high reflectivity area, there may be no light spot in the light spot image formed by reflection from the low reflectivity area (there may be pixel data but no light spot, not that there is no pixel data) or the light spot is weak; similarly, under the effective exposure condition that there is a light spot in the light spot image formed by reflection from the low reflectivity area, the light spot image formed by reflection from the high reflectivity area may be overexposed or underexposed.

[0082] Based on the analysis of the existence of light spots in the light spot images formed by reflection from low and high reflectivity areas, the pixel value is used as the screening condition to obtain the effective exposure conditions corresponding to the light spots in the light spot images formed by reflection from low and high reflectivity areas.

[0083] Pixel ranges that meet imaging requirements in the first data and the second data are screened respectively, and effective exposure conditions that meet the imaging requirements are screened based on the laser energy ranges corresponding to the first data and the second data respectively.

[0084] The imaging requirement is that a light spot exists in the laser light spot image corresponding to the first data and a light spot exists in the laser light spot image corresponding to the second data.

[0085] In order to further exclude image data that does not meet the imaging requirements in the first data and the second data, this embodiment screens the pixel ranges that meet the imaging requirements in the first data and the second data by analyzing the pixel change process.

[0086] Based on the differences in light sensitivity due to different reflectivities and the change process of pixel values ​​in the laser spot image, this embodiment analyzes the overexposed image data in the first data and the second data to determine the pixel range that meets the imaging requirements.

[0087] The pixel range that meets the imaging requirements includes a first pixel range and a second pixel range. The laser energy range corresponding to the first pixel range is the first energy range, and the laser energy range corresponding to the second pixel range is the second energy range.

[0088] In this embodiment, a first threshold is set to filter out overexposed image data. Taking 8-bit image data as an example, the first threshold can be 255, 250, or any other value, which can be set according to actual needs.

[0089] According to the analysis process of the pixel range that meets the imaging requirement of the first data and the second data, combined with the light sensitivity of different reflectivities, an effective exposure condition that meets the imaging requirement can be determined.

[0090] The effective exposure condition includes a first energy range corresponding to the first pixel range and a second energy range corresponding to the second pixel range, wherein the minimum laser energy in the second energy range is greater than the maximum laser energy in the first energy range.

[0091] In the laser spot image that meets the imaging requirements corresponding to the first energy range, there is a spot in the laser spot image corresponding to the high reflectivity area on the surface of the object to be measured. Overexposed data in the first data is preferentially excluded, that is, the pixel range in the first data whose pixel value is less than the first threshold value has a spot in the corresponding image data.

[0092] To further determine the energy range corresponding to the presence of light spots in high-reflectivity areas, based on the differences in light intensity sensitivity of different reflectivity areas, within the energy range corresponding to the presence of light spots in high-reflectivity areas, low-reflectivity areas may have no light spots (pixel data may exist but no light spots, not the absence of pixel data) or have very weak light spots. In summary, within the energy range corresponding to the presence of light spots in high-reflectivity areas, it is necessary to filter out the energy range corresponding to the presence of light spots in low-reflectivity areas (pixel data may exist but no light spots, not the absence of pixel data) or having very weak light spots as the first energy range.

[0093] Since it is impossible to accurately obtain the pixel value corresponding to the low reflectivity area where there may be no light spot (there may be pixel data but no light spot, not that there is no pixel data) or the light spot is weak, it is impossible to obtain its corresponding energy range; this embodiment takes into account that the low reflectivity area needs to reach a certain laser energy exposure condition to form a laser spot image; therefore, in the energy range corresponding to the presence of the light spot in the high reflectivity area, the energy range corresponding to the low reflectivity area where no laser spot image is formed is excluded, and the first energy range can be obtained.

[0094] Among them, the low reflectivity area does not form a laser spot image, which is manifested as the pixel value of the second data being zero; that is, in the energy range corresponding to the presence of the laser spot in the high reflectivity area, the energy range corresponding to the second data being zero is excluded to obtain the first energy range.

[0095] In this embodiment, since the pixel values ​​corresponding to the high reflectivity region are less than the first threshold, the corresponding energy range is classified as the first energy range. Therefore, when the pixel values ​​of the first data are equal to the energy values ​​corresponding to the first threshold, the pixel values ​​corresponding to the second data are used as the second threshold to classify the laser energy corresponding to the pixel values ​​in the second data into the first energy range or the second energy range.

[0096] At this point, it can be concluded that the pixel range in the first data that meets the imaging requirements (i.e., the first pixel range) is the intersection of the pixel range in the first data whose pixel values ​​are less than the first threshold and the pixel range in the second data whose pixel values ​​are greater than the second threshold and less than the first threshold. The laser energy range corresponding to the first pixel range is then the first laser energy range.

[0097] The second threshold is the pixel value corresponding to the second data at the laser energy value corresponding to the first data first being equal to the first threshold. The laser energy value corresponding to the second data being equal to the second threshold is used as a basis for classifying the laser energy range corresponding to the second data as belonging to the first energy range or the second energy range.

[0098] In addition, since it is impossible to clearly define the presence of a weak spot or no spot in the laser spot image formed by the low reflectivity area, given that when the second data is the second threshold, the laser energy range corresponding to the pixel range in the second data that is smaller than the second threshold has been divided into the first energy range.

[0099] A pixel value range in the second data having a pixel value greater than zero and less than a second threshold value is invalid data of the second data, ie, second invalid data. The first threshold value is greater than the second threshold value.

[0100] Therefore, the second data can be roughly divided by the second threshold. If the second data is smaller than the second threshold, it can be roughly determined that the laser spot image corresponding to the low reflectivity area has pixel data but no spot (not that there is no pixel data); if the second data is larger than the second threshold, it can be roughly determined that there is a spot in the laser spot image corresponding to the low reflectivity area.

[0101] In the laser spot image meeting the imaging requirements corresponding to the second energy range, the laser spot image corresponding to the low reflectivity area on the surface of the object to be measured has a spot, that is, the image data corresponding to the second pixel range has a spot.

[0102] Similarly, in order to further determine the energy range corresponding to the presence of light spots in the low-reflectivity area, based on the differences in sensitivity of different reflectivity areas to light intensity, the high-reflectivity area may be overexposed in the energy range corresponding to the presence of light spots in the low-reflectivity area. In summary, within the energy range corresponding to the presence of light spots in the low-reflectivity area, the energy range corresponding to the possible overexposure of the high-reflectivity area needs to be screened out as the second energy range.

[0103] The energy range corresponding to the possible overexposure of the high reflectivity area corresponds to the laser energy range corresponding to the pixel value in the first data being not less than the first threshold.

[0104] At this point, it can be concluded that the pixel range in the second data that meets the imaging requirements (i.e., the second pixel range) is the intersection of the pixel range in the second data whose pixel values ​​are greater than the second threshold and less than the first threshold, and the pixel range in the first data whose pixel values ​​are not less than the first threshold. The laser energy range corresponding to the second pixel range is then the second laser energy range.

[0105] In addition, this application does not limit the specific method for the analysis process of the pixel range and effective exposure conditions that meet the imaging requirements.

[0106] For example, based on the first data and the second data obtained by the above method, an array of pixel point-energy values ​​is constructed, and according to the first threshold and the second threshold, an array that meets the conditions is screened and obtained, thereby determining the pixel range and effective exposure conditions that meet the imaging requirements.

[0107] Preferably, a pixel value-energy value curve graph may be fitted to the first data and the second data respectively, so as to screen the pixel range and effective exposure conditions that meet the imaging requirements in a more intuitive form of expression.

[0108] This embodiment takes curve fitting as an example to illustrate the analysis process of exposure conditions, which is as follows: In this embodiment, a plurality of laser energy values ​​increasing in equal amounts are set from an initial energy value. At each laser energy value, a microscopic autofocus system is used to enable the first sensor to obtain a plurality of laser spot images corresponding to the plurality of laser energy values.

[0109] Based on the division threshold, the pixel values ​​of several laser spot images are compared one by one, and the pixel points with pixel values ​​greater than the division threshold are composed of the first data, and the pixel points with pixel values ​​less than the division threshold are composed of the second data.

[0110] like Figure 3 As shown, the laser energy-pixel value curves corresponding to the first data and the second data are fitted respectively, and the pixel range that meets the imaging requirements is determined by the first threshold and the second threshold. Based on the response relationship between reflectivity and light intensity, the first energy range and the second energy range are screened as effective exposure conditions.

[0111] Based on each pixel value in the first data and its corresponding laser energy value, the first laser energy-pixel value curve is fitted as f(i,j)=P0+a×ln(LE), which is used to characterize the changing relationship between the pixel value and the laser energy value in the laser spot image corresponding to the high reflectivity area.

[0112] In the formula, f(i,j) represents the pixel value of the pixel point (i,j); P0 is the minimum value of the pixel value in the first data; the first fitting coefficient a is obtained by fitting the pixel value in the first data obtained by experiment and the corresponding laser energy value; LE is the laser energy value.

[0113] Based on the pixel value in the second data and the corresponding laser energy value, the second laser energy-pixel value curve is fitted as , which is used to represent the change relationship between the pixel value in the laser spot image corresponding to the low reflectivity area and the laser energy value.

[0114] In the formula, f(i,j) represents the pixel value of the pixel point (i,j); the second fitting coefficient b is obtained by fitting the pixel value in the second data obtained by experiment and the corresponding laser energy value; LE is the laser energy value, and K is the minimum laser energy value corresponding to the minimum pixel value (greater than zero) in the second data.

[0115] Through the above fitting process, the curve graphs corresponding to the first data and the second data are obtained, which reflect the change process of the pixel value and the laser energy of different reflectivity areas in a more intuitive form, and embody the difference in the light intensity sensitivity of the first data and the second data.

[0116] Based on the above laser spot image processing method, the first energy range and the second energy range can be obtained, and according to the reflectivity of the surface of the current object to be measured, the applicable laser energy range can be determined, which is convenient for focus control of the surface of the single reflectivity object to be measured to obtain an image meeting the imaging requirements.

[0117] Or based on the obtained laser energy range, the corresponding laser spot image in the range is obtained to calculate the focus image of the surface of the object to be measured with multiple reflectivity areas, to calculate the effective data of the current laser spot image, and then calculate the defocus amount to realize automatic control.

[0118] As shown in Figure 4 , based on the above effective exposure condition acquisition process, the embodiment further screens the effective pixel ranges corresponding to the high reflectivity area and the low reflectivity area respectively to obtain the effective data of the laser spot image reflected by the surface of the object to be measured.

[0119] Based on the first pixel range, the pixel value not greater than the first effective threshold value is assigned as a fixed value to form the first effective data; based on the second pixel range, the pixel value not less than the second effective threshold value is assigned as a fixed value to form the second effective data; the maximum value of the first effective data and the second effective data in any pixel point is taken as the pixel value of the pixel point to obtain the effective data.

[0120] The second effective threshold value is less than the first effective threshold value, and the fixed value is less than the current pixel value.

[0121] The first effective threshold is the maximum value of the pixel value in the second data corresponding to the first energy range; the second effective threshold is the minimum value of the pixel value in the first data corresponding to the second energy range.

[0122] This embodiment is based on the above-mentioned laser spot image processing method, and takes the obtained first energy range and second energy range as examples to illustrate the auto-focusing process.

[0123] The above laser spot image processing method can be used to obtain the following: The pixel range in the first data that meets the imaging requirements (ie, the first pixel range) is the intersection of the pixel range in the first data whose pixel values ​​are less than the first threshold and the pixel value range in the second data whose pixel values ​​are greater than the second threshold and less than the first threshold.

[0124] The laser energy range corresponding to the first pixel range is the first laser energy range.

[0125] The pixel range in the second data that meets the imaging requirements (i.e., the second pixel range) is the intersection of the pixel range in the second data whose pixel values ​​are greater than the second threshold and less than the first threshold, and the pixel range in the first data whose pixel values ​​are not less than the first threshold.

[0126] The laser energy range corresponding to the second pixel range is the second laser energy range.

[0127] The first threshold is used to filter out overexposed image data.

[0128] The second threshold is the pixel value corresponding to the second data at the laser energy value corresponding to when the first data first equals the first threshold. The first threshold is greater than the second threshold.

[0129] In summary, the laser spot image corresponding to the first energy range (first pixel range) contains both the first data and the second data. The laser spot image corresponding to the second energy range (second pixel range) also contains both the first data and the second data.

[0130] In order to further obtain a valid image of the surface of the object to be measured, this embodiment sets a first valid threshold value to further exclude a pixel value range with poor pixel value performance in the first pixel range.

[0131] The first effective threshold is set according to the actual application scenario, and this embodiment does not limit the specific value.

[0132] The screening condition is to assign a fixed value h to pixel values ​​not greater than the first effective threshold Y1, where the first effective threshold Y1 is the maximum pixel value in the second data corresponding to the first energy range, and the fixed value is less than the current pixel value.

[0133] The first valid data formed after assignment

[0134] Similarly, in this embodiment, the second effective threshold is set to further remove overexposed data of the first data in the second pixel range, so as to obtain a valid image of the surface of the object to be measured.

[0135] The second effective threshold is set according to the actual application scenario, and this embodiment does not limit the specific value.

[0136] In addition, in order to further exclude the pixel value range with poor pixel value performance in the second pixel range, only the pixel value range from (255-Y2) to Y2 is filtered, and its original pixel value is retained.

[0137] The filtering condition is to assign a fixed value h to pixel values ​​not less than the second effective threshold Y2, where the second effective threshold is the minimum pixel value in the first data corresponding to the second energy range; the fixed value is less than the current pixel value, and the second effective threshold is less than the first effective threshold.

[0138] The second valid data formed after assignment

[0139] Based on the first valid data and the second valid data, the maximum value of the first valid data and the second valid data in any pixel point is used as the pixel value of the pixel point, and finally the valid data C(i, j) is obtained.

[0140] C(i,j)=max(C1(i,j),C2(i,j)) This embodiment excludes the pixel value range with poor pixel value performance in the first pixel range based on the characteristics of the first data and the second data in the first pixel range and forms first valid data in the form of screening and assignment. At the same time, the overexposed data corresponding to the high reflectivity area and the pixel value range with poor pixel performance in some pixels in the second pixel range are excluded to obtain second valid data in the form of screening and assignment. The first valid data and the second valid data are fused to obtain valid data, thereby solving the problem that the same laser energy cannot accurately obtain the spot image of the area with large reflectivity difference, and avoiding the problem of overexposure or underexposure on the surface of the object to be measured.

[0141] like Figure 5As shown, in addition to the above-mentioned calculation method of assignment screening, it is also possible to fuse the pixel value corresponding to any pixel point in the first data at any laser energy value in the first energy range with the pixel value corresponding to the pixel point at any laser energy value in the second energy range to obtain the first fused data; fuse the pixel value corresponding to any pixel point in the second data at any laser energy value in the first energy range with the pixel value corresponding to the pixel point at any laser energy value in the second energy range to obtain the second fused data; and calculate the valid data using the first fused data and the second fused data.

[0142] The first data and the second data have the same laser energy value in the first energy range and the same laser energy value in the second energy range.

[0143] In this embodiment, the image data (first data) corresponding to the high reflectivity area is fused, that is, a pixel point (i, j) is selected from the first data, and the pixel value f(i, j) corresponding to the pixel point under the laser energy value R1 in the first energy range is used. R1 , and the pixel value f(i,j) corresponding to the pixel point under the laser energy value R2 in the second energy range R2 , perform fusion calculation to obtain the first fusion data F1(i,j).

[0144] In order to further obtain a valid image of the surface of the object to be measured, for the pixel value corresponding to any pixel point in the first data at any laser energy value in the first energy range, and the pixel value corresponding to the pixel point at any laser energy value in the second energy range, before performing the fusion calculation, the image data that may be overexposed is excluded to obtain fused data of the valid image.

[0145] The screening condition is to make the fusion coefficient corresponding to the pixel value not greater than the first effective threshold Y1 in the image data corresponding to the first energy range in the first data On the contrary, let the fusion coefficient corresponding to the pixel value greater than the first effective threshold Y1 be .

[0146] The first effective threshold is set according to the actual application scenario, and this embodiment does not limit the specific value.

[0147] Taking 8-bit image data as an example, the specific calculation method of the first fused data F1(i,j) is as follows:

[0148] Wherein, subscript R1 represents any laser energy value within the first energy range; R2 represents any laser energy value within the second energy range; f(i,j) is the pixel value of pixel point (i,j) in the laser spot image, and f(i,j) is the pixel value of pixel point (i,j) in the laser spot image. R1is the pixel value of the corresponding pixel point (i, j) under R1, f(i, j) R2 is the pixel value of the pixel point (i, j) in the laser spot image corresponding to R1.

[0149] Similarly, the image data (second data) corresponding to the low reflectivity area is fused, that is, a pixel point (i, j) is selected from the second data, and the pixel value f(i, j) corresponding to the pixel point under the laser energy value R1 in the first energy range is used. R1 , and the pixel value f(i,j) corresponding to the pixel point under the laser energy value R2 in the second energy range R2 , perform fusion calculation to obtain second fusion data; The energy values ​​of the first energy range selected for the high reflectivity region and the low reflectivity region are both R1, and the energy values ​​of the second energy range are both R2.

[0150] Similarly, for the second data, the pixel value corresponding to any pixel point at any laser energy value in the first energy range and the pixel value corresponding to the pixel point at any laser energy value in the second energy range, before performing the fusion calculation, the image data in which the pixel value changes are not obvious or no light spot is displayed are excluded to obtain the fusion data of the effective image.

[0151] The screening condition is that the fusion coefficient corresponding to the pixel value not less than the second effective threshold value Y2 in the image data corresponding to the second pixel range in the second data is On the contrary, let the fusion coefficient corresponding to the pixel value less than the first effective threshold Y1 be .

[0152] The second effective threshold is set according to the actual application scenario, and this embodiment does not limit the specific value.

[0153] Taking 8-bit image data as an example, the specific calculation method of the second fused data F2(i,j) is as follows:

[0154] Wherein, subscript R1 represents any laser energy value within the first energy range; R2 represents any laser energy value within the second energy range; f(i,j) is the pixel value of pixel point (i,j) in the laser spot image, and f(i,j) is the pixel value of pixel point (i,j) in the laser spot image. R1 is the pixel value of the corresponding pixel point (i, j) under R1, f(i, j) R2 is the pixel value of the pixel point (i, j) in the laser spot image corresponding to R1.

[0155] By analyzing the pixel ranges that meet the imaging requirements in the laser spot images corresponding to the first energy range and the second energy range, the laser spot images corresponding to the high reflectivity area are fused and calculated to obtain the first fusion data, and the laser spot images corresponding to the low reflectivity area are fused and calculated to obtain the second fusion data.

[0156] Based on the first fused data and the second fused data, the effective data F(i,j)=F1(i,j)+F2(i,j) is finally obtained.

[0157] This embodiment, based on the characteristics of the first data and the second data, screens the pixel values ​​corresponding to the laser energy values ​​in the first energy range and the pixel values ​​corresponding to the laser energy values ​​in the second energy range in the first data, and performs fusion calculation to obtain first fused data corresponding to the high reflectivity area; similarly, the second data is screened to calculate second fused data corresponding to the low reflectivity area; and valid data is finally obtained by using the first fused data and the second fused data, thereby solving the problem of the inability to accurately obtain spot images of areas with large reflectivity differences using the same laser energy, thereby avoiding the problem of overexposure or underexposure on the surface of the object to be measured.

[0158] like Figure 6 As shown, based on the above processing method, this application also proposes an autofocus method, including: Using the above-mentioned processing method to obtain valid data; Based on the effective data, the centroid of the light spot of the effective data is calculated, the defocus amount of the surface of the object to be measured is obtained, and automatic focusing is achieved.

[0159] The centroid of the valid data is used as the centroid of the surface of the object to calculate the defocus of the surface, enabling accurate focusing of the surface. This effectively eliminates overexposure in high-reflectivity areas and underexposure in low-reflectivity areas, ensuring defocus calculations for different reflectivity areas.

[0160] Alternatively, the centroid of the low reflectivity area is calculated using the first valid data, and the centroid of the high reflectivity area is calculated using the second valid data, and the corresponding defocus amounts are obtained respectively to achieve automatic focusing of the low reflectivity area or the high reflectivity area.

[0161] Based on the same inventive concept, the present application also proposes a computer-readable storage medium, including a computer program, which implements the above-mentioned method when executed by a processor.

[0162] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0163] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for processing a laser spot image, characterized in that: include: Acquire several laser spot images corresponding to different laser energies; the laser spot images are formed by reflection from the surface of the object to be measured, and there are at least two areas with different reflectivity on the surface of the object to be measured; Divide the laser spot image based on the reflectivity of the surface area of ​​the object to be measured and / or the pixel value of the laser spot image to obtain first data that meets the first condition and second data that does not meet the first condition; The first condition is that the reflectivity is greater than a set value and / or the pixel value is greater than a division threshold; Based on the first data and the second data, a first pixel range and a second pixel range that meet the imaging requirement are screened; the imaging requirement is that a light spot exists in the laser spot image corresponding to the first data and a light spot exists in the laser spot image corresponding to the second data; The laser energy ranges corresponding to the first and second pixel ranges are used as effective exposure conditions.

2. The processing method according to claim 1, characterized in that Also includes: Based on the first pixel range, assigning pixel values ​​not greater than the first valid threshold to fixed values ​​to form first valid data; Based on the second pixel range, assigning pixel values ​​not less than the second valid threshold to fixed values ​​to form second valid data; Taking the maximum value of the first valid data and the second valid data at any pixel point as the pixel value of the pixel point, and obtaining the valid data; The second effective threshold is smaller than the first effective threshold, and the fixed value is smaller than the current pixel value.

3. The processing method according to claim 1, characterized in that Also includes: fusing a pixel value corresponding to any pixel point in the first data at any laser energy value within the first energy range with a pixel value corresponding to the pixel point at any laser energy value within the second energy range to obtain first fused data; fusing a pixel value corresponding to any pixel point in the second data at any laser energy value within the first energy range with a pixel value corresponding to the pixel point at any laser energy value within the second energy range to obtain second fused data; Calculating effective data using the first fused data and the second fused data; Among them, the laser energy values ​​of the first energy range selected by the first data and the second data are the same, and the laser energy values ​​of the second energy range selected are the same; the laser energy range corresponding to the first pixel range is the first energy range, and the laser energy range corresponding to the second pixel range is the second energy range.

4. The processing method according to claim 1, characterized in that Also includes: The difference between the minimum reflectivity value corresponding to the first data and the maximum reflectivity value corresponding to the second data is greater than the reflectivity threshold value; And / or a difference between a minimum pixel value in the first data and a maximum pixel value in the second data is greater than a pixel threshold.

5. The processing method according to claim 1, characterized in that The pixel range that meets imaging requirements includes: A first pixel range, which is an intersection of a pixel range in the first data having pixel values ​​less than a first threshold and a pixel range in the second data having pixel values ​​greater than a second threshold and less than the first threshold; A second pixel range, which is an intersection of a pixel range in the second data whose pixel values ​​are greater than the second threshold and less than the first threshold, and a pixel range in the first data whose pixel values ​​are not less than the first threshold; The first threshold is used to filter out overexposed image data, and the second threshold is smaller than the first threshold.

6. The processing method according to claim 5, characterized in that: The effective exposure conditions include a first energy range corresponding to the first pixel range and a second energy range corresponding to the second pixel range; the minimum value of the laser energy in the second energy range is greater than the maximum value of the laser energy in the first energy range.

7. The processing method according to claim 5, characterized in that The second threshold is the pixel value corresponding to the second data when the first data is equal to the laser energy value corresponding to the first threshold for the first time.

8. The processing method according to claim 5, characterized in that Also includes: The laser energy-pixel value curves corresponding to the first data and the second data are fitted respectively, and the pixel range that meets the imaging requirements is determined by using the first threshold and the second threshold. Based on the response relationship between reflectivity and light intensity, the first energy range and the second energy range are screened as effective exposure conditions.

9. An automatic focusing method, characterized in that: include: Adopting the processing method described in any one of claims 1 to 8 to obtain valid data; Calculate the effective data spot centroid, obtain the defocus value of the surface of the object to be measured, and realize autofocus.

10. A computer-readable storage medium comprising a computer program, characterized in that When the computer program is executed by a processor, the processing method according to any one of claims 1 to 8 and / or the autofocus method according to claim 9 are implemented.

Images