An ultra-depth-of-field microscopic rapid measurement device and measurement method

Abstract

The present invention discloses a super-depth-of-field microscopic rapid measurement device and a measurement method, which includes a measurement frame. An optical component is connected to the measurement frame, and a moving measurement platform is arranged below the optical component. A zoom lens is provided in the optical component. The present invention uses an electric zoom lens or a liquid lens to acquire images of a workpiece within a detection range at different focal lengths, and synthesizes the clear parts in the acquired images to obtain a complete image of the sample, enabling height detection and image acquisition of the sample without adjusting the lens height or the focusing position. At the same time, by displaying the pictures in the form of grayscale images, the efficiency of the software in extracting the height value of the workpiece and subsequent three-dimensional modeling can also be improved, featuring high measurement efficiency and good imaging effect.

Description

Technical Field

[0001] The invention relates to a size measuring device and a measuring method, in particular to a super-depth-of-field microscopic fast measuring device and a measuring method. Background Art

[0002] A measuring microscope converts the image it sees into digital-to-analog form, producing an image on the microscope's built-in screen or on a computer. It also uses high-precision optical focus detection to measure the surface height of the measured point. Current measuring microscopes generally utilize a zoom lens or multiple objective lenses with varying magnifications to achieve stable measurement of the measured point. When inspecting large workpieces, the lens or objective lens reduces its magnification to keep the measured point within its depth of field. Conversely, when image sharpness and size requirements at the measured point increase, the lens or objective lens increases its magnification to improve the image quality. However, increasing the lens magnification also reduces its depth of field, resulting in inability to clearly display all areas of the image simultaneously when inspecting workpieces with height differences. Furthermore, increasing the lens magnification reduces the measuring range of the workpiece, making it impossible for the measuring microscope to fully display the entire image of the workpiece at once. Furthermore, horizontally shifting the workpiece can cause image blur due to height variations at different measured points, requiring refocusing after changing the measured point.

[0003] For workpieces with height differences on their surfaces, the current measurement method involves using a measuring microscope to measure local locations at different heights multiple times. Focus is achieved by manually or electrically adjusting the lens height for each measurement. Finally, the images of each local location are combined to form a complete measurement image. During each focus adjustment, the lens's Z-axis position is measured using a grating ruler and calculated based on the lens' focal length to obtain the height information of the measured point. However, this method requires focusing by adjusting the lens height, and each lens adjustment takes approximately 3 to 5 seconds to raise and lower. This results in a measurement time of approximately 10 seconds for a single measurement point. If the workpiece within the measurement range is at different heights, the measuring microscope must adjust the lens height multiple times within the same measurement range to focus at each height, further reducing the overall measurement efficiency of the workpiece. Furthermore, when the workpiece within the measurement range varies in height, the corresponding focus point must be manually selected, further reducing measurement efficiency. The resulting image also contains blurred portions of the unselected locations, reducing the imaging quality of the measuring microscope.

[0004] Furthermore, to ensure efficient sample measurement, current measuring microscopes reduce image clarity during image acquisition to expand the range of clear image portions captured. This allows the microscope to obtain a complete two-dimensional image of the sample with only a small number of images. This results in a significant decrease in the clarity of the resulting composite image, resulting in poor imaging quality. Furthermore, this reduced image clarity can cause the measuring microscope to record parts of the workpiece with slight height differences as being at the same height when acquiring height information, reducing workpiece inspection accuracy and lowering the accuracy of subsequent 3D modeling.

[0005] Therefore, existing measuring microscopes have the problems of low measurement efficiency and poor imaging effect. Summary of the invention

[0006] The purpose of the present invention is to provide a super-depth-of-field microscopic rapid measurement device and a measurement method, which have the characteristics of high measurement efficiency and good imaging effect.

[0007] The technical solution of the present invention is a super-depth-of-field microscopic rapid measurement device, comprising a measuring frame connected to an optical component, a movable measuring platform provided below the optical component; and a zoom lens provided in the optical component.

[0008] In the aforementioned ultra-depth-of-field microscopic rapid measurement device, the optical assembly includes a camera, a zoom lens, a main lens and an objective lens connected in sequence, and the zoom lens is a liquid lens or an electric zoom lens.

[0009] In the aforementioned ultra-depth-of-field microscopic rapid measurement device, the lower end of the mobile measurement platform is connected to the measurement frame via a shock-absorbing workbench, and a buffer layer is provided at the bottom of the measurement frame.

[0010] In the aforementioned ultra-depth-of-field microscopic rapid measurement device, the measuring frame is connected to the shock-absorbing workbench via a marble bottom plate, and the buffer layer is arranged at the bottom of the marble bottom plate.

[0011] In the aforementioned ultra-depth-of-field microscopic rapid measurement device, an illumination light source is provided on one side of the optical component. The illumination light source is a halogen lamp with a power of 100W or above. The illumination light of the halogen lamp is an annular light or a point light source coaxial light.

[0012] The measurement method based on the aforementioned ultra-depth-of-field microscopic rapid measurement device comprises the following steps:

[0013] A. Place the sample on the mobile measuring platform below the optical assembly, and make sure the sample's measurement range is located at the display center of the optical assembly;

[0014] B. Change the focusing focal length of the zoom lens successively according to a plurality of preset parameter values, and enable the optical component to obtain pictures of the range to be measured after each zoom, so as to obtain multiple pictures of the range to be measured at different focal lengths, obtaining Picture A;

[0015] C. Select the clear parts in each Picture A, and then synthesize the clear parts in all Picture A to obtain a complete clear picture of the range to be measured, obtaining Picture B;

[0016] D. Move the measurement platform to change the range to be measured of the sample successively, and re-obtain the complete clear picture of the range to be measured according to steps B and C after each change of the range to be measured, obtaining multiple complete clear pictures of different ranges to be measured, obtaining Picture C;

[0017] E. Synthesize Picture B and Picture C to obtain a two-dimensional picture of the sample;

[0018] F. Obtain a three-dimensional model of the sample according to the two-dimensional picture of the sample in step E.

[0019] In the foregoing measurement method, the height value of each Picture A in step B is recorded according to the parameter value of the current zoom lens when the picture is obtained; when the clear parts in step C are synthesized, the clear parts are displayed in corresponding gray value pairs according to the height values of the pictures corresponding to the clear parts, obtaining a D gray-scale picture; in step E, the D gray-scale pictures of different ranges to be measured are synthesized to obtain an E gray-scale picture; in step F, the height information of the sample at different positions is obtained according to the gray value of the E gray-scale picture, and then the E gray-scale picture is stretched based on the height information to obtain a three-dimensional model of the sample.

[0020] In the foregoing measurement method, the height value of the picture in step B is calculated according to the parameter value of the zoom lens and a conversion function, and the acquisition method of the conversion function includes the following steps:

[0021] B1. Take the surface to be measured of the test sample at different heights as a standard plane, make the zoom lens in the reference state, and realize the focusing on the test sample at different standard planes by vertically moving the optical component; at the same time, use a grating ruler to record the height information of the optical component at different focusing positions, obtaining height information H;

[0022] B2. Return the optical component to the initial position, and then adjust the parameter value of the zoom lens successively, so that the optical component can focus on standard planes of different heights, and record the parameter value V of the zoom lens in different focusing states at the same time;

[0023] B3. Fit the recorded height information H and parameter value V to obtain a conversion function of H = f(V).

[0024] In the foregoing measurement method, the zoom lens is an electric zoom lens, and the parameter value of the electric zoom lens is the rotation angle value. When the rotation angle value in step B1 is 0°, the zoom lens is in the reference state.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] (1) The present invention selects an electric zoom lens or a liquid lens as the zoom lens in the optical component, and on this basis, through preset parameter values, the zoom lens directly acquires the workpiece images within the measurement range at different focal lengths, so that the present invention does not need to focus on the specified position within the measurement range by lifting the lens, but relies on the pictures obtained at different focal lengths to respectively obtain clear images of different heights within the measurement range, thereby greatly improving the clarity range and imaging effect of the images compared with the existing methods; and since the zoom rate of the liquid lens can reach the microsecond level, and the zoom rate of the electric zoom lens can reach the millisecond level, the present invention can obtain more than 100 measurement pictures within the same measurement range within 0.5 seconds, thus greatly improving the measurement efficiency of the workpiece compared with the existing methods;

[0027] (2) On the above basis, the present invention further optimizes the method for obtaining the height value of the clear part in the picture, so that the present invention can directly convert the height information of different positions in the picture through the parameter value of the zoom lens, and then realize the height measurement of the workpiece and subsequent three-dimensional modeling; at the same time, by recording the height information of the workpiece through the gray value, it can also effectively improve the processing efficiency of the software for subsequent pictures and the rate during three-mode modeling, so that the present invention can complete the synthesis of the two-dimensional picture of the sample within 1 second and complete the three-mode modeling within 2 seconds; and using the present invention, more images can be obtained in one detection process, improving the final imaging effect;

[0028] (3) By optimizing the installation structure of the mobile measurement platform, the present invention can also effectively improve the shock absorption effect on the workpiece, so that when the optical component acquires pictures, it will not vibrate and cause the problem of blurred acquired pictures, thereby avoiding the software from being unable to screen normally due to clarity problems when synthesizing images, making the present invention have good stability and being able to realize the acquisition and height detection of the workpiece images under the condition of magnifying 15 - 800 times;

[0029] Therefore, the present invention has the characteristics of high measurement efficiency and good imaging effect. Description of the Drawings

[0030] Figure 1 is the structural schematic diagram of the present invention;

[0031] Figure 2 is the picture of the measurement range at any focal length in step B;

[0032] Figure 3 is a clear picture of the sample within a range to be measured in step C;

[0033] Figure 4 is a grayscale image of the sample within a range to be measured in step C;

[0034] Figure 5 is the three-dimensional model of the sample obtained by the extraction of the present invention.

[0035] The reference signs in the drawings are: 1 - measuring frame, 2 - moving measurement platform, 3 - zoom lens, 4 - camera, 5 - main lens, 6 - objective lens, 7 - shock-absorbing workbench, 8 - illumination light source. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with the drawings and embodiments, but it shall not be used as a basis for limiting the present invention.

[0037] Embodiment. A super-depth-of-field microscopic rapid measurement device is configured as Figure 1 shown, including a measuring frame 1, an optical component is connected to the measuring frame 1, and a moving measurement platform 2 is arranged below the optical component; a zoom lens 3 is provided in the optical component.

[0038] The optical component includes a camera 4, a zoom lens 3, a main lens 5 and an objective lens 6 connected in sequence. The zoom lens 3 is a liquid lens or an electric zoom lens. The electric zoom lens 6 can be a commercially available STOT-EL-10-30-C type rapid electric zoom focusing lens; the liquid lens can be a C-S-25H0-026 type liquid lens of Corning Inc. of the United States.

[0039] The moving measurement platform 2 can be a high-precision electric XY moving platform. The lower end of the moving measurement platform 2 is connected to the measuring frame 1 through a shock-absorbing workbench 7, and a buffer cushion layer is arranged at the bottom of the measuring frame 1.

[0040] The measuring frame 1 is connected to the shock-absorbing workbench 7 through a marble bottom plate, and the buffer cushion layer is arranged at the bottom of the marble bottom plate.

[0041] An illumination light source 8 is arranged on one side of the optical component. The illumination light source 8 is a halogen lamp with a power of more than 100W. The illumination light of the halogen lamp is annular light or point-source coaxial light; the halogen lamp guides the light to the lower part of the lens through a total reflection optical fiber, and small optical fibers are distributed along the ring on the halogen lamp.

[0042] The measurement method of the super-depth-of-field microscopic rapid measurement device includes the following steps:

[0043] A. Place the sample on the moving measurement platform below the optical component, and make the range to be measured of the sample located at the display center of the optical component;

[0044] B. According to a plurality of preset parameter values, sequentially change the focus focal length of the zoom lens, and enable the optical component to obtain pictures of the range to be measured after each zoom, so as to obtain multiple pictures of the range to be measured at different focal lengths, obtaining Picture A;

[0045] C. Select the clear parts in each Picture A, and then synthesize the clear parts in all Picture A based on the depth-from-focus method to obtain a complete clear picture of the range to be measured, obtaining Picture B;

[0046] D. Sequentially change the range to be measured of the sample by moving the measurement platform, and after each change of the range to be measured, re-obtain a complete clear picture of the range to be measured according to steps B and C, obtaining multiple complete clear pictures of different ranges to be measured, and the pictures of adjacent ranges to be measured partially overlap, obtaining Picture C;

[0047] E. Synthesize Picture B and Picture C to obtain a two-dimensional picture of the sample;

[0048] F. Obtain a three-dimensional model of the sample according to the two-dimensional picture of the sample in step E.

[0049] When each Picture A in step B is obtained, record the height value of the picture according to the parameter value of the current zoom lens; when the clear parts in step C are synthesized, display the clear parts in pairs of corresponding gray values according to the height values of the pictures corresponding to the clear parts, forming an 8-bit gray scale image recording the height information of the sample, obtaining Gray Scale Image D; in step E, synthesize the Gray Scale Image D of different ranges to be measured to obtain a complete picture of the sample displayed in gray values, that is, Gray Scale Image E; in step F, obtain the height information of the sample at different positions according to the gray values of Gray Scale Image E, and then stretch Gray Scale Image E using existing modeling software based on the height information to obtain a three-dimensional model of the sample.

[0050] The height value of the picture in step B is calculated according to the parameter value of the zoom lens and the conversion function, and the acquisition method of the conversion function includes the following steps:

[0051] B1. Use a calibrated standard block with a 45° inclined plane as the test sample. The middle scale of the test sample is at the 0 position. There are n scale lines on both sides of the inclined plane of the test sample above and below the 0 position, and the 2n scale lines are evenly spaced at equal heights along the inclined plane; when the zoom lens is in the reference state, move the optical component vertically to achieve focusing on the 0 position and each scale line of the test sample. When focusing, obtain a unified focusing effect through the image sharpness evaluation function; at the same time, use the grating ruler to record the height information of the optical component at different focusing positions. When the optical component focuses on the 0 position, the grating ruler is set to zero, obtaining the height information H[2n];

[0052] B2. Return the optical component to the 0 position of the grating scale, and then sequentially adjust the parameter values of the zoom lens so that the optical component can focus on different scale lines, and record the parameter values V[2n] of the zoom lens at different scales;

[0053] B3. Fit the 2*n groups of data (H[2n] + V[2n]) obtained by recording to obtain the conversion function of H = f(V).

[0054] The zoom lens is a liquid lens, and the parameter value of the liquid lens is the input voltage value. When the input voltage value in step B1 is 0, the zoom lens is in the reference state.

[0055] The zoom lens is an electric zoom lens, and the parameter value of the electric zoom lens is the rotation angle value. When the rotation angle value in step B1 is 0°, the zoom lens is in the reference state.

[0056] The display effect of any A picture in step B is as Figure 2 shown, the display effect of the B picture in step C is as Figure 3 shown, the display effect of the D grayscale image of the sample in step C is as Figure 4 shown, and the display effect of the three-dimensional model of the sample in step F is as Figure 5 shown.

[0057] The working principle of the present invention: When the present invention is measuring, first manually place the workpiece in the center of the field of view of the optical component, and then adjust the magnification of the main lens 5 or switch the objective lens 6 to make the range to be measured of the workpiece within the field of view of the lens; after the range to be measured of the workpiece is confirmed, the software sequentially adjusts the focal length of the zoom lens according to the preset parameter values, so that the optical component can respectively obtain clear pictures of the workpiece at different heights within the range to be measured, and then select and synthesize the clear parts in the pictures to obtain a clear picture of the range to be measured; when the picture is synthesized, the clear parts obtained by the zoom lens at different focal lengths are separately displayed through different grayscale values, so that each grayscale value can respectively correspond to the height value of the sample, thereby obtaining a grayscale image (i.e., D grayscale image) recording the height information of the sample. Since the present invention does not need to focus by lifting, there is no need to manually adjust the focus position, so that the present invention can greatly save the time for obtaining pictures of the range to be measured; taking a 640*512 pixel photo as an example, the liquid lens can complete the acquisition, analysis and synthesis of 91 pictures within 1 second, so as to obtain the best formed image.

[0058] When the present invention sequentially measures multiple measurement points, by horizontally moving the detection workpiece through the moving measurement platform 2, seamless stitching of micrographs with a small field of view can be achieved, improving its overall imaging effect; through the cooperation of the shock-absorbing workbench 7, the marble base plate and the buffer cushion layer, image jitter of the detection workpiece at a high magnification can be effectively reduced, thereby further improving the measurement speed and image clarity of the present invention.

Claims

1. A super-depth-of-field microscopic rapid measurement method, characterized in that: This measurement method uses a super-depth-of-field microscopic rapid measurement device for measurement. The super-depth-of-field microscopic rapid measurement device includes a measurement frame (1), an optical component is connected to the measurement frame (1), and a moving measurement platform (2) is arranged below the optical component; the optical component includes a camera (4), a zoom lens (3), a main lens (5) and an objective lens (6) connected in sequence, and the zoom lens (3) is a liquid lens or an electric zoom lens; This measurement method includes the following steps: A. Place the sample on the moving measurement platform below the optical component, and make the range to be measured of the sample located at the display center of the optical component; B. According to a plurality of preset parameter values, sequentially change the focusing focal length of the zoom lens, and make the optical component obtain pictures of the range to be measured after each zoom, so as to obtain multiple pictures of the range to be measured at different focal lengths, and obtain Picture A; C. Select the clear parts in each Picture A, and then synthesize the clear parts in all Picture A to obtain a complete clear picture of the range to be measured, and obtain Picture B; D. Sequentially change the range to be measured of the sample through the moving measurement platform, and re-obtain the complete clear picture of the range to be measured according to steps B and C after each change of the range to be measured, so as to obtain multiple complete clear pictures of different ranges to be measured, and the pictures of adjacent ranges to be measured partially overlap, and obtain Picture C; E. Synthesize Picture B and Picture C to obtain a two-dimensional picture of the sample; F. Obtain a three-dimensional model of the sample according to the two-dimensional picture of the sample in step E; In step B, the height value of each Picture A is recorded according to the parameter value of the current zoom lens when the picture is obtained; when the clear parts in step C are synthesized, the clear parts are displayed with corresponding gray values according to the height values of the pictures corresponding to the clear parts, and a D gray-scale image is obtained; in step E, the D gray-scale images of different ranges to be measured are synthesized to obtain an E gray-scale image; in step F, the height information of the sample at different positions is obtained according to the gray values of the E gray-scale image, and then the E gray-scale image is stretched based on the height information to obtain a three-dimensional model of the sample; The height value of the picture in step B is calculated according to the parameter value of the zoom lens and a conversion function. The acquisition method of the conversion function includes the following steps: B1. Take the surface to be measured of the test sample at different heights as a standard plane. When the zoom lens is in the reference state, focus on the test sample at different standard planes by vertically moving the optical component; at the same time, use a grating ruler to record the height information of the optical component at different focusing positions to obtain height information H; B2. Return the optical component to the initial position, and then sequentially adjust the parameter values of the zoom lens so that the optical component can focus on standard planes at different heights, and record the parameter values V of the zoom lens in different focusing states at the same time; B3. Fit the recorded height information H and parameter value V to obtain a conversion function of H = f(V).

2. The super-depth-of-field microscopic rapid measurement method according to claim 1, wherein: The lower end of the moving measurement platform (2) is connected to the measurement frame (1) through a shock-absorbing workbench (7), and a buffer cushion layer is arranged at the bottom of the measurement frame (1).

3. The super-depth-of-field microscopic rapid measurement method according to claim 2, characterized in that: The measuring frame (1) is connected to the shock-absorbing workbench (7) through a marble bottom plate, and the buffer cushion layer is arranged at the bottom of the marble bottom plate.

4. The super-depth-of-field microscopic rapid measurement method according to claim 1, characterized in that: A lighting source (8) is provided on one side of the optical component. The lighting source (8) is a halogen lamp with a power of more than 100W, and the irradiation light of the halogen lamp is annular light or point-source coaxial light.

5. A super-depth-of-field microscopic rapid measurement method according to claim 1, characterized in that: The zoom lens is a liquid lens, and the parameter value of the liquid lens is the input voltage value. When the input voltage value in step B1 is 0, the zoom lens is in the reference state.

6. The super-depth-of-field microscopic rapid measurement method according to claim 1, characterized in that: The zoom lens is an electric zoom lens, and the parameter value of the electric zoom lens is the rotation angle value. When the rotation angle value in step B1 is 0°, the zoom lens is in the reference state.

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