Height measuring device and method

Abstract

The application relates to a height measuring device and method. The height measuring device comprises an imaging module, a displacement mechanism comprising a moving part and a grating ruler, the imaging module being fixed on the moving part, the moving part being used to drive the imaging module to move along the extension direction of the grating ruler, a grating signal converter being fixed on the moving part, the grating signal converter moving synchronously with the imaging module, the grating signal converter being used to read the relative position of the grating ruler, output a grating signal corresponding to the relative position, and transmit the grating signal to a programmable gate array chip, and the programmable gate array chip being electrically connected with the grating signal converter and the imaging module, used to convert the grating signal obtained by the grating signal converter into a height signal, generate a trigger signal based on the height signal, and determine the height of the object to be measured according to a plurality of single-depth images collected by the imaging module and the height signals corresponding to the single-depth images.

Description

Technical Field

[0001] This invention relates to the field of image processing, and more specifically to a height measurement device and method. Background Technology

[0002] Currently, depth-of-field fusion technology is widely used in fields such as chip inspection, microscopic imaging, and precision parts measurement. This technology utilizes image sensors to acquire corresponding single-depth-field images at different focal planes, and then fuses multiple images based on the focusing characteristics of each single-depth-field image to generate a multi-depth-field image in which every region is clearly focused.

[0003] In related technologies, systems for implementing depth-of-field synthesis typically include: an optical system for acquiring optical information of single-depth-of-field images at different focal planes; an imaging system for converting the optical information of single-depth-of-field images into digital information; and a central processing unit for synthesizing the digital information of multiple single-depth-of-field images to generate multi-depth-of-field images.

[0004] However, in related technologies, the acquisition and control of single-depth-of-field images by optical systems often rely on the software scheduling of the central processing unit. As a result, there is a delay in the acquisition process, which leads to a decrease in the accuracy of height measurement of each pixel in the final multi-depth-of-field image. Summary of the Invention

[0005] To overcome the problems existing in related technologies, the present invention provides a height measuring device and method.

[0006] According to a first aspect of the present invention, a height measuring device is provided, the height measuring device comprising:

[0007] Imaging module;

[0008] The displacement mechanism includes a moving component and a grating ruler. The imaging module is fixed to the moving component, and the moving component is used to drive the imaging module to move along the extension direction of the grating ruler.

[0009] A grating signal converter is fixed on the moving part. The grating signal converter moves synchronously with the imaging module. The grating signal converter is used to read the relative position with the grating ruler, output the grating signal corresponding to the relative position, and transmit the grating signal to the programmable gate array chip.

[0010] A programmable gate array (PGA) chip, electrically connected to the grating signal converter and the imaging module, is used to convert the grating signal obtained by the grating signal converter into a height signal, and generate a trigger signal based on the height signal to control the imaging module to acquire single-depth-field images of the object under test. The PGA chip determines the height of the object under test based on the multiple single-depth-field images acquired by the imaging module and the height signal corresponding to each single-depth-field image.

[0011] In some exemplary embodiments, the programmable gate array chip determines whether the imaging module has reached the physical position where a picture needs to be taken based on the converted height signal. If it is determined that the imaging module has reached the physical position where a picture needs to be taken, a trigger signal is generated to control the imaging module to acquire a single depth-of-field image of the object under test, and at the same time record the height signal of the single depth-of-field image.

[0012] In some exemplary embodiments, the displacement mechanism further includes:

[0013] The power source is electrically connected to the programmable gate array chip;

[0014] The programmable gate array chip is also used to send a displacement signal to the power source so that the power source drives the moving component to move along the extension direction of the grating ruler.

[0015] In some exemplary embodiments, the trigger signal and the grating reading are generated synchronously based on the same displacement event of the moving component.

[0016] In some exemplary embodiments, when the displacement of the moving component is a preset displacement, the programmable gate array chip outputs a trigger signal.

[0017] In some exemplary embodiments, when the moving component moves to a preset position, the programmable gate array chip outputs a trigger signal.

[0018] In some exemplary embodiments, the programmable gate array chip is also used to perform depth-sensing synthesis of multiple single-depth images into a multi-depth image.

[0019] In some exemplary embodiments, the programmable gate array chip is further configured to receive profile trajectory data of multi-depth images and form profile height curve data of the object under test based on the grating readings corresponding to the profile trajectory data.

[0020] In some exemplary embodiments, the height measuring device further includes:

[0021] A display, electrically connected to the programmable gate array chip, is used to visualize the single depth-of-field image, the raster reading, the multi-depth-of-field image, the profile trajectory data, and the profile height curve data;

[0022] The display is also used to receive profile trajectory data from the user and output the profile trajectory data to the programmable gate array chip.

[0023] According to a second aspect of the present invention, a height measurement method is provided, applied to a height measurement apparatus as described in the first aspect of the present invention, the height measurement method comprising:

[0024] The moving component, carrying the imaging module and the grating signal converter, is controlled to move along the extension direction of the grating ruler. During the movement, the grating signal converter outputs the grating reading in real time, and the grating reading is used to trigger the imaging module to acquire multiple single depth-of-field images.

[0025] The height of the object to be measured is determined based on the multiple single-depth images acquired by the imaging module and the grating readings corresponding to each single-depth image.

[0026] In some exemplary embodiments, determining the height of the object to be measured based on the plurality of single-depth-field images acquired by the imaging module and the grating readings corresponding to each single-depth-field image includes:

[0027] Multiple single-depth-field images are combined into a multi-depth-field image according to a depth-of-field synthesis algorithm, and each pixel in the multi-depth-field image corresponds to a grating reading.

[0028] Receive the profile trajectory data of the multi-depth image;

[0029] Based on the grating readings corresponding to the pixels of the multi-depth image corresponding to the profile trajectory data, the profile height curve data of the object under test is generated.

[0030] Based on the profile height curve data, the height of the test area of ​​the object under test on the profile trajectory line data is determined.

[0031] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0032] A grating signal converter outputs a grating signal corresponding to the relative position and transmits it to a programmable gate array (PGA) chip. The PGA chip converts the grating signal obtained by the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module to acquire single-depth-field images of the object under test. This ensures that the acquisition of single-depth-field images and the reading of gratings are triggered by the same displacement event, thus avoiding delayed triggering during the single-depth-field image acquisition process. Based on the acquired single-depth-field images and the precisely corresponding grating readings for each single-depth-field image, the PGA chip can accurately measure the height of each pixel in multiple single-depth-field images, thereby improving the height measurement accuracy of the object under test.

[0033] Moreover, in this invention, a programmable gate array chip replaces the judgment and control of the upper-level system, allowing the trigger signal for taking pictures to be sent without stopping the movement, infinitely approaching the true height position, which can improve the authenticity of the data and reduce the measurement time.

[0034] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0036] Figure 1 This is a schematic diagram of the circuit structure of a height measuring device according to a first exemplary embodiment.

[0037] Figure 2-1 This is a schematic diagram of the split structure of a height measuring device along the x-axis direction according to an exemplary embodiment.

[0038] Figure 2-2 This is a schematic diagram of the overall structure of a height measuring device according to an exemplary embodiment.

[0039] Figure 3 This is a schematic diagram of a multi-depth-of-field image and a cross-sectional trajectory line on the multi-depth-of-field image of a height measuring device according to an exemplary embodiment.

[0040] Figure 4 This is a schematic diagram of a cross-sectional height curve of a height measuring device according to an exemplary embodiment.

[0041] Figure 5 This is a schematic diagram of the circuit structure of a height measuring device according to a second exemplary embodiment.

[0042] Figure 6This is a flowchart illustrating a height measurement method according to a third exemplary embodiment.

[0043] Figure 7 This is a schematic flowchart illustrating a height measurement method according to a fourth exemplary embodiment.

[0044] Figure 8 This is a flowchart illustrating a height measurement method according to a fifth exemplary embodiment.

[0045] In the picture:

[0046] 1-Imaging module; 2-Displacement mechanism; 21-Moving component; 22-Raster ruler; 23-Power source; 3-Raster signal converter; 4-Programmable gate array chip; 5-Display; 61-First fixing plate; 62-Second fixing plate; 63-Third fixing plate; 64-Fourth fixing plate. Detailed Implementation

[0047] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of methods consistent with some aspects of the invention as detailed in the appended claims. It should also be understood that the term "and / or" as used in this invention refers to any or all possible combinations comprising one or more of the associated listed items.

[0048] Currently, depth-of-field fusion technology is widely used in fields such as chip inspection, microscopic imaging, and precision parts measurement. This technology utilizes image sensors to acquire corresponding single-depth-field images at different focal planes, and then fuses multiple images based on the focusing characteristics of each single-depth-field image to generate a multi-depth-field image in which every region is clearly focused.

[0049] In related technologies, systems for implementing depth-of-field synthesis typically include: an optical system for acquiring optical information of single-depth-of-field images at different focal planes; an imaging system for converting the optical information of single-depth-of-field images into digital information; and a central processing unit for synthesizing the digital information of multiple single-depth-of-field images to generate multi-depth-of-field images.

[0050] However, in related technologies, the acquisition and control of single-depth-of-field images by optical systems often rely on the software scheduling of the central processing unit. As a result, there is a delay in the acquisition process, which leads to a decrease in the accuracy of height measurement of each pixel in the final multi-depth-of-field image.

[0051] Based on this, the present invention provides a height measurement device. A grating signal converter outputs a grating signal corresponding to the relative position and transmits the grating signal to a programmable gate array (PGA) chip. The PGA chip converts the grating signal obtained by the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module to acquire single-depth-field images of the object under test. This ensures that the acquisition of single-depth-field images and the reading of gratings are triggered by the same displacement event, thus avoiding delayed triggering during the single-depth-field image acquisition process. Based on the acquired single-depth-field images and the precisely corresponding grating readings for each single-depth-field image, the PGA chip can accurately measure the height of each pixel in multiple single-depth-field images, thereby improving the height measurement accuracy of the object under test.

[0052] In one exemplary embodiment, such as Figure 1 , Figure 2-1 and Figure 2-2 As shown, the present invention provides a height measuring device, which includes: an imaging module 1, a displacement mechanism 2, a grating signal converter 3, and a programmable gate array chip 4. The imaging module 1 refers to a structure used for acquiring images, such as an industrial camera, video camera, or photosensitive element.

[0053] The displacement mechanism 2 includes a moving component 21 and a grating ruler 22. The imaging module 1 is fixed to the moving component 21, which drives the imaging module 1 to move along the extension direction of the grating ruler 22. The moving component 21 includes a height-adjustable support structure. The grating ruler 22 is a scale with precise graduations, serving as a reference component for measuring the displacement. The extension direction of the grating ruler 22 is the same as the lifting direction of the moving component 21, both being the z-axis direction.

[0054] A grating signal converter 3, fixed to the moving part 21, moves synchronously with the imaging module 1. The grating signal converter 3 reads the relative position with the grating ruler 22 and outputs the grating reading corresponding to the relative position. It also transmits the grating signal to the programmable gate array (PGA) chip 4. The PGA chip 4 converts the grating signal obtained by the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module 1 to acquire a single-depth-of-field image of the object under test. The imaging module 1 acquires a single-depth-of-field image of the object under test based on the trigger signal from the PGA chip 4. The grating signal converter 3 can be a grating read head or a grating reader, capable of converting the displacement into a grating reading. A single-depth-of-field image refers to a frame image acquired by the imaging module on a single focal plane. In a single-depth-of-field image, only the object area on the current focal plane is clearly imaged, while other areas are out of focus and blurred.

[0055] In one embodiment, the programmable gate array chip 4 determines whether the imaging module has reached the physical position where the image needs to be taken based on the converted height signal. If the imaging module has reached the physical position where the image needs to be taken, a trigger signal is generated to control the imaging module 1 to acquire a single depth-of-field image of the object under test, and at the same time record the height signal of the single depth-of-field image.

[0056] The programmable gate array chip 4, electrically connected to the grating signal converter 3 and the imaging module 1, is used to determine the height of the object under test based on multiple single-depth-field images acquired by the imaging module 1 and the corresponding grating readings for each single-depth-field image. The grating reading corresponding to a single-depth-field image can be understood as the grating reading at the acquisition time of each frame of the single-depth-field image. This grating reading can be used as the relative height value between the grating signal converter 3 and the grating ruler 22 at the acquisition time of the corresponding single-depth-field image, that is, it can represent the relative height value between the imaging module 1 and the grating ruler 22 at the acquisition time of the corresponding single-depth-field image.

[0057] The height measuring device provided in the embodiments of the present invention may have the following beneficial effects:

[0058] The grating signal converter 3 outputs the grating reading and transmits the grating signal to the programmable gate array (PGA) chip 4. The PGA chip 4 converts the grating signal obtained from the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module 1 to acquire single-depth-field images of the object under test. This ensures that the acquisition of single-depth-field images and the reading of grating signals are triggered by the same displacement event, thus avoiding delayed triggering during single-depth-field image acquisition. Based on the acquired single-depth-field images and the precisely corresponding grating readings for each single-depth-field image, the PGA chip 4 can accurately measure the height of each pixel in multiple single-depth-field images, thereby improving the height measurement accuracy of the object under test.

[0059] In one embodiment, the displacement mechanism 2 further includes a power source 23.

[0060] Power source 23 is electrically connected to programmable gate array chip 4;

[0061] The programmable gate array chip 4 is also used to send a displacement signal to the power source 23 so that the power source 23 drives the moving part 21 to move along the extension direction of the grating ruler 22.

[0062] For example, the power source 23 includes at least one of a stepper motor, a servo motor, or a linear motor.

[0063] In this embodiment, the programmable gate array chip 4 controls the power source 23 through a displacement signal, so that the power source 23 drives the movement of the moving part 21, which is beneficial to realize the acquisition of multiple single depth-of-field images and the reading of the grating readings corresponding to each single depth-of-field image.

[0064] In one embodiment, the trigger signal and the grating reading are generated synchronously based on the same displacement event of the moving part 21.

[0065] In this embodiment, the trigger signal and the grating reading are generated synchronously based on the same displacement event of the moving part 21, which can ensure that each single depth-of-field image and its corresponding grating reading are aligned in time, avoiding the time misalignment problem caused by software scheduling in related technologies, and providing an accurate data basis for the height calculation of each pixel, thereby improving the accuracy of height measurement.

[0066] In one embodiment, when the displacement of the moving part 21 is a preset displacement, the programmable gate array chip 4 outputs a trigger signal.

[0067] For example, the preset displacement can be set by the programmable gate array chip 4. When the displacement of the moving part 21 is the preset displacement, the programmable gate array chip 4 outputs a trigger signal.

[0068] For example, when the number of single depth-of-field images is 10, the preset displacement value range can be [1μm, 10μm], and the preset displacement value can be 3μm, 5μm, 7μm or 9μm.

[0069] In this embodiment, when the displacement of the moving part 21 is a preset displacement, the programmable gate array chip 4 outputs a trigger signal, which can realize image acquisition based on the preset displacement interval, so that the focal planes of the acquired multiple single depth-of-field images are equally distributed, which is convenient for subsequent depth-of-field synthesis and height interpolation calculation. On the basis of eliminating delayed triggering, the uniformity and consistency of height measurement are further improved.

[0070] In one embodiment, when the moving part 21 moves to a preset position, the programmable gate array chip 4 outputs a trigger signal.

[0071] For example, the preset position can be set by the programmable gate array chip 4. When the moving part 21 moves to the preset position, the programmable gate array chip 4 outputs a trigger signal.

[0072] For example, there are multiple preset positions, and the multiple preset positions can be equally spaced or unequally spaced, which can be flexibly set according to the actual height of the object to be measured.

[0073] In this embodiment, when the moving part 21 moves to the preset position, the programmable gate array chip 4 outputs a trigger signal, which can realize fixed-point image acquisition based on the preset position as the acquisition position. This allows the acquisition position to be flexibly set according to the actual height of the object to be measured, reducing unnecessary acquisition times and improving the height measurement efficiency.

[0074] In one embodiment, the programmable gate array chip 4 is also used to synthesize multiple single-depth images into a multi-depth image.

[0075] For example, the programmable gate array chip 4 is also used to synthesize multiple single-depth-of-field images into a multi-depth-of-field image, including:

[0076] The programmable gate array chip 4 is also used to calculate the sharpness of each single-depth-of-field image, compare the sharpness of the same pixel position in different single-depth-of-field images, select the pixel position of the same pixel in the multi-depth-of-field image corresponding to the pixel with the highest sharpness, and fuse multiple pixels to generate a multi-depth-of-field image. Each pixel in the multi-depth-of-field image corresponds to a grating reading, and the grating reading of each pixel is the grating reading corresponding to the single-depth-of-field image with the highest sharpness.

[0077] In this embodiment, by combining multiple single-depth-field images into a multi-depth-field image, each pixel of the multi-depth-field image corresponds to a raster reading, thus giving each pixel a height value. Depth-field synthesis is completed directly within the programmable gate array chip 4 without needing to transmit data to an external computer, achieving real-time processing and hardware acceleration of depth-field synthesis and improving measurement efficiency.

[0078] In one embodiment, such as Figure 3 and Figure 4 As shown, the programmable gate array chip 4 is also used to receive profile trajectory data from multi-depth images and to form profile height curve data of the object under test based on the grating readings corresponding to the profile trajectory data. The profile trajectory data on the multi-depth image is as follows: Figure 3 As shown, the profile height curve data is as follows: Figure 4 As shown.

[0079] For example, the profile trajectory data of a multi-depth image includes the coordinate positions of the pixels along the path of the profile trajectory, the size of the corresponding pixel, and the corresponding raster reading.

[0080] In this embodiment, the user can draw any cross-sectional trajectory line on the multi-depth image as cross-sectional trajectory line data. The programmable gate array chip automatically generates the cross-sectional height curve based on the grating readings corresponding to the pixels of the drawn trajectory data, which can realize quantitative height analysis of any cross-section of the object under test.

[0081] In one embodiment, such as Figure 5 As shown, the height measuring device also includes: display 5.

[0082] Display 5, electrically connected to programmable gate array chip 4, is used to visualize single depth-of-field images, raster readings, multi-depth-of-field images, profile trajectory data, and profile height curve data.

[0083] Display 5 is also used to receive profile trajectory data from the user and output profile trajectory data to programmable gate array chip 4.

[0084] In this embodiment, the display 5 can realize data visualization function and also realize the function of collecting user input data. Users can complete the line drawing operation and view the results on the device without the need for an external computer, realizing independent measurement and interaction completely independent of the central processing unit.

[0085] For example, such as Figure 2-1 and Figure 2-2 As shown, the height measuring device also includes a housing.

[0086] The housing includes a first fixing plate 61, a second fixing plate 62, a third fixing plate 63, and a fourth fixing plate 64. The first fixing plate 61 includes a first groove and a second groove. The first groove engages with the second fixing plate 62 to fix its position. The second groove connects to the displacement mechanism 2 and the grating signal converter 3 to support them and allow the moving part 21 to move within it. The grating ruler 22, the power source 23, and the grating signal converter are fixed within the second groove. The second fixing plate 62 includes a third groove for engaging the power source 23. The third fixing plate 63 is threadedly connected to the second fixing plate 62 and includes a fourth groove for engaging the programmable gate array chip 4. The fourth fixing plate 64 is threadedly connected to the third fixing plate 63 and surrounds the programmable gate array chip 4.

[0087] In this embodiment, the various structures are integrated into one unit through the shell, which improves the installation accuracy and stability of each component, thereby improving the accuracy and stability of height measurement.

[0088] In one exemplary embodiment, such as Figure 6 As shown, the present invention provides a height measurement method applied to the above-mentioned height measurement device. The height measurement method includes:

[0089] S610: The control moving part, carrying the imaging module and the grating signal converter, moves along the extension direction of the grating ruler. During the movement, the grating signal converter outputs the grating reading to the programmable gate array chip in real time. The programmable gate array chip converts the grating signal obtained by the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module to acquire a single depth-of-field image of the object under test.

[0090] S620. Determine the height of the object to be measured based on multiple single-depth images acquired by the imaging module and the corresponding grating readings for each single-depth image.

[0091] The height measurement method provided by the embodiments of the present invention may include the following beneficial effects:

[0092] A grating signal converter outputs a grating signal corresponding to the relative position and transmits it to a programmable gate array (PGA) chip. The PGA chip converts the grating signal obtained by the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module to acquire single-depth-field images of the object under test. This ensures that the acquisition of single-depth-field images and the reading of gratings are triggered by the same displacement event, thus avoiding delayed triggering during the single-depth-field image acquisition process. Based on the acquired single-depth-field images and the precisely corresponding grating readings for each single-depth-field image, the PGA chip can accurately measure the height of each pixel in multiple single-depth-field images, thereby improving the height measurement accuracy of the object under test.

[0093] For example, in step S610 above, the control moving component, which carries an imaging module and a grating signal converter, moves along the extension direction of the grating ruler. During the movement, the grating signal converter outputs grating readings in real time, including:

[0094] Whenever the moving component, carrying the imaging module and the grating signal converter, moves along the extension direction of the grating ruler by a preset displacement, the programmable gate array chip 4 outputs a trigger signal; or,

[0095] Whenever the control moving part, carrying the imaging module and grating signal converter, moves to a preset position along the extension direction of the grating ruler, the programmable gate array chip 4 outputs a trigger signal.

[0096] For example, when the number of single depth-of-field images is 10, the preset displacement value range can be [1μm, 10μm], and the preset displacement value can be 3μm, 5μm, 7μm or 9μm.

[0097] There are multiple preset positions, and the spacing between these preset positions can be equal or unequal, which can be flexibly set according to the actual height of the object to be measured.

[0098] In this embodiment, by using two triggering methods, namely equal-interval measurement and fixed-point position measurement, the grating signal converter can flexibly output grating readings according to different measurement requirements. Equal-interval measurement can achieve uniform sampling, while fixed-point position measurement can increase sampling density in areas with drastic height changes, thus improving measurement accuracy.

[0099] In one embodiment, such as Figure 7 As shown, the step S620 above, which determines the height of the object to be measured based on multiple single-depth-field images acquired by the imaging module and the corresponding grating readings for each single-depth-field image, includes:

[0100] S710. Based on the depth-of-field synthesis algorithm, multiple single-depth-field images are synthesized into a multi-depth-field image, and each pixel in the multi-depth-field image corresponds to a grating reading.

[0101] S720 receives profile trajectory data from multi-depth images.

[0102] S730. Generate profile height curve data of the object under test based on the grating readings corresponding to the pixels of the multi-depth image corresponding to the profile trajectory line data.

[0103] S740. Based on the profile height curve data, determine the height of the area to be measured of the object on the profile trajectory line data.

[0104] In this embodiment, a one-to-one correspondence between each pixel in a multi-depth-of-field image and a grating reading is established through depth-of-field synthesis. Then, based on the profile trajectory data defined by the user, the grating readings corresponding to the corresponding pixels are extracted. The grating readings corresponding to the pixels in the trajectory data are automatically generated to form a profile height curve, which can realize quantitative height analysis of any profile of the object under test.

[0105] For example, the step S710 above, which involves synthesizing multiple single-depth-field images into a multi-depth-field image according to a depth-of-field synthesis algorithm, includes:

[0106] Calculate the sharpness of each single depth-of-field image.

[0107] Compare the sharpness of the same pixel position in different single-depth-of-field images, and select the pixel position of the same pixel in the multi-depth-of-field image corresponding to the pixel with the highest sharpness.

[0108] Multiple pixels are merged to generate a multi-depth image.

[0109] In this multi-depth-of-field image, each pixel corresponds to a grating reading, and the grating reading of each pixel is the grating reading of the single-depth-of-field image with the highest sharpness.

[0110] In this embodiment, by comparing the sharpness of the same pixel in different single-depth-of-field images, the pixel with the highest sharpness is selected and fused to generate a multi-depth-of-field image, ensuring that each pixel in the multi-depth-of-field image originates from the single-depth-of-field image that made it the sharpest. Simultaneously, the grating reading of each pixel is determined to be the grating reading corresponding to that single-depth-of-field image, thus establishing a one-to-one correspondence between pixels and grating readings. Therefore, when a user draws a line on the multi-depth-of-field image, the programmable gate array chip can automatically generate a profile height curve based on the grating readings corresponding to each pixel on the drawn trajectory, enabling quantitative height measurement of any profile.

[0111] For example, the profile trajectory data in step S720 above includes: the position of the pixel along the path of the profile trajectory, the size of the corresponding pixel, and the corresponding raster reading.

[0112] In this embodiment, the accurate conversion from profile trajectory data to profile height curve data can be achieved by using the position, size, and raster reading of the pixels along the path profile trajectory line.

[0113] For example, the step S730 above, which generates the profile height curve data of the object under test based on the grating readings corresponding to the pixels of the multi-depth image corresponding to the profile trajectory line data, includes:

[0114] The physical location of the pixels along the profile trajectory line is determined based on the coordinates and size of the pixels along the trajectory line.

[0115] Use the raster reading as the height value of the corresponding pixel;

[0116] Using the physical location of the pixels along the profile trajectory as the abscissa and the corresponding height value as the ordinate, the profile height curve data of the object under test is obtained.

[0117] In this embodiment, the profile trajectory data on multi-depth images is converted into height change curves based on physical distance, allowing users to intuitively view the height distribution of the object under test on any profile, while providing an accurate data basis for subsequent height measurement of the area under test.

[0118] For example, in step S740 above, determining the height of the area to be measured of the object on the profile trajectory line data based on the profile height curve data includes:

[0119] Determine at least two endpoints of the area to be measured on the profile height curve data;

[0120] The difference between the ordinate values ​​of at least two endpoints is taken as the height of the area to be measured.

[0121] In this embodiment, the user only needs to select two endpoints on the profile height curve to quickly obtain the height difference between the two points, realizing rapid quantitative measurement for application scenarios such as chip inspection, microscopic imaging, and precision parts measurement, and simplifying the calculation of height difference.

[0122] For example, the height measurement method further includes:

[0123] Visualize single-depth-of-field images, raster readings, multi-depth-of-field images, profile trajectory data, profile height curve data, the area to be measured, and the height of the area to be measured.

[0124] Receive the user's profile trajectory data and the area to be measured.

[0125] In this embodiment, visualization and human-computer interaction can be achieved during the height measurement process, improving the convenience of measurement operations and the intuitiveness of result display.

[0126] In one exemplary embodiment, such as Figure 8 As shown, the present invention provides a height measurement method applied to the above-mentioned height measurement device. The height measurement method includes:

[0127] S810 controls the moving part, which carries the imaging module and grating signal converter, to move along the extension direction of the grating ruler. During the movement, the grating signal converter outputs grating readings in real time, and the grating readings are used to trigger the imaging module to acquire multiple single depth-of-field images.

[0128] S820. Based on the depth-of-field synthesis algorithm, multiple single-depth-field images are synthesized into a multi-depth-field image, and each pixel in the multi-depth-field image corresponds to a grating reading.

[0129] S830 receives profile trajectory data from multi-depth images.

[0130] S840. Generate profile height curve data of the object under test based on the grating readings corresponding to the pixels of the multi-depth image corresponding to the profile trajectory line data.

[0131] S850. Based on the profile height curve data, determine the height of the area to be measured of the object on the profile trajectory line data.

[0132] The height measurement method provided by the embodiments of the present invention may include the following beneficial effects:

[0133] A grating signal converter outputs a grating signal corresponding to the relative position and transmits it to a programmable gate array (PGA) chip. The PGA chip converts the grating signal obtained by the grating signal converter into a height signal and generates a trigger signal based on the height signal to control the imaging module to acquire a single-depth-field image of the object under test. This ensures that the acquisition of the single-depth-field image and the reading of the grating are triggered by the same displacement event, thus avoiding delayed triggering during the single-depth-field image acquisition process. The PGA chip establishes a one-to-one correspondence between each pixel in the multi-depth-field image and the grating reading through depth synthesis. Then, based on the user-defined profile trajectory data, it extracts the grating reading corresponding to the corresponding pixel and automatically generates a profile height curve from the grating readings corresponding to the pixels in the trajectory data. This enables quantitative height analysis of any profile of the object under test.

[0134] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered illustrative only, and the true scope and spirit of the invention are indicated by the claims.

[0135] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A height measuring device, characterized in that, The height measuring device includes: Imaging module; The displacement mechanism includes a moving component and a grating ruler. The imaging module is fixed to the moving component, and the moving component is used to drive the imaging module to move along the extension direction of the grating ruler. A grating signal converter is fixed on the moving part. The grating signal converter moves synchronously with the imaging module. The grating signal converter is used to read the relative position with the grating ruler, output the grating signal corresponding to the relative position, and transmit the grating signal to the programmable gate array chip. A programmable gate array (PGA) chip, electrically connected to the grating signal converter and the imaging module, is used to convert the grating signal obtained by the grating signal converter into a height signal, and generate a trigger signal based on the height signal to control the imaging module to acquire a single-depth-of-field image of the object under test. The programmable gate array chip determines the height of the object under test based on the multiple single-depth images acquired by the imaging module and the height signal corresponding to each single-depth image.

2. The height measuring device according to claim 1, characterized in that, The programmable gate array chip determines whether the imaging module has reached the physical location where a picture needs to be taken based on the converted height signal. If it is determined that the imaging module has reached the physical position where a picture needs to be taken, a trigger signal is generated to control the imaging module to acquire a single depth-of-field image of the object under test, and at the same time record the height signal of the single depth-of-field image.

3. The height measuring device according to claim 2, characterized in that, The displacement mechanism further includes: The power source is electrically connected to the programmable gate array chip; The programmable gate array chip is also used to send a displacement signal to the power source so that the power source drives the moving component to move along the extension direction of the grating ruler.

4. The height measuring device according to claim 2, characterized in that, The trigger signal and the grating reading are generated synchronously based on the same displacement event of the moving part.

5. The height measuring device according to claim 2, characterized in that, When the displacement of the moving component is equal to a preset displacement, the programmable gate array chip outputs a trigger signal; or When the moving part moves to the preset position, the programmable gate array chip outputs a trigger signal.

6. The height measuring device according to claim 2, characterized in that, The programmable gate array chip is also used to synthesize multiple single-depth images into a multi-depth image.

7. The height measuring device according to claim 6, characterized in that, The programmable gate array chip is also used to receive profile trajectory data of multi-depth images and to form profile height curve data of the object under test based on the grating readings corresponding to the profile trajectory data.

8. The height measuring device according to claim 7, characterized in that, The height measuring device also includes: A display, electrically connected to the programmable gate array chip, is used to visualize the single depth-of-field image, the raster reading, the multi-depth-of-field image, the profile trajectory data, and the profile height curve data; The display is also used to show an interface for user interaction, guide the user to select profile trajectory data through the interface, and output the profile trajectory data to the programmable gate array chip.

9. A height measurement method, characterized in that, The height measurement method, applied to the height measuring apparatus as described in any one of claims 1 to 7, comprises: The moving component, carrying the imaging module and the grating signal converter, is controlled to move along the extension direction of the grating ruler. During the movement, the grating signal converter outputs the grating reading in real time, and the grating reading is used to trigger the imaging module to acquire multiple single depth-of-field images. The height of the object to be measured is determined based on the multiple single-depth images acquired by the imaging module and the grating readings corresponding to each single-depth image.

10. The height measurement method according to claim 9, characterized in that, The step of determining the height of the object under test based on multiple single-depth-field images acquired by the imaging module and the grating readings corresponding to each single-depth-field image includes: Multiple single-depth-field images are combined into a multi-depth-field image according to a depth-of-field synthesis algorithm, and each pixel in the multi-depth-field image corresponds to a grating reading. Receive the profile trajectory data of the multi-depth image; Based on the grating readings corresponding to the pixels of the multi-depth image corresponding to the profile trajectory data, the profile height curve data of the object under test is generated. Based on the profile height curve data, the height of the test area of ​​the object under test on the profile trajectory line data is determined.

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