Line-scan measurement system based on position latching technology and line-scan image splicing method

Abstract

The application discloses a line-scan measurement system based on position latching technology and a line-scan image splicing method, which comprises a moving platform, a grating ruler, a reading head and a line array camera. The moving platform is used for installing a product and adjusting the scanning position of the product along a guide rail through a driving assembly. The grating ruler is parallel to the guide rail. The reading head moves along with the moving platform and corresponds to the grating ruler. The line array camera is suspended above the moving platform. When the moving platform moves to a preset scanning starting point, the line array camera is controlled to start scanning the product according to a preset frequency, and the reading head is controlled to start latching the position data of the grating ruler according to the preset frequency. The application can solve the problem that large-size measurement cannot simultaneously meet the requirements of precision and efficiency. Meanwhile, through the configuration of the line array camera, the functions of multiple area array cameras can be realized by using one set of camera, so that the hardware cost and hardware space are saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precision measurement, in particular to a line scan measurement system based on position latching technology and a line scan image splicing method. BACKGROUND

[0002] The fast measurement of large size and high precision has always been a difficult problem in the measurement industry. In order to achieve high precision, it is necessary to improve the magnification of the optical lens, and the magnification increase means that the measurement picture is reduced. At the same time, increasing the measurement picture range and the optical lens magnification requires a multi-camera solution or increasing the camera specification, which will increase the cost by several times, and also increase the complexity of the mechanism design. Or use a multi-camera solution, but the relative position between the cameras needs to be calibrated, which will result in high cost, and the relative position of the cameras at different temperatures at different times due to environmental changes will deviate, which will cause unstable measurement. SUMMARY

[0003] The present application is to solve the technical problems of high measurement cost or low measurement efficiency in the prior art, and proposes a line scan measurement system based on position latching technology and a line scan image splicing method.

[0004] The technical scheme adopted by the present application is:

[0005] The present application proposes a line scan measurement system based on position latching technology, comprising:

[0006] A motion platform for installing a product and adjusting the position of the product along a guide rail through a driving assembly;

[0007] A grating ruler parallel to the guide rail;

[0008] A reading head moving with the motion platform and corresponding to the grating ruler;

[0009] A line array camera suspended above the motion platform;

[0010] A controller, when the motion platform moves to a preset scanning starting point, controls the line array camera to start scanning the product at a preset frequency, and controls the reading head to start latching the position data of the grating ruler at the preset frequency.

[0011] The controller includes a high-speed counter, a pulse switching module, an input module and an output module, the high-speed counter collects the position data of the grating ruler, the output module is used to trigger the pulse switching module, the pulse switching module is used to control the trigger of the line scan camera, and the input module works with the reading head to latch the position data of the grating ruler.

[0012] The application also comprises a machine table for mounting the guide rail and the grating ruler. Two support seats are mounted on the machine table, a cross beam seat is transversely connected to the top of the two support seats, the side surface of the cross beam seat is provided with a camera sliding rail, and a mounting seat for mounting the linear array camera is arranged on the camera sliding rail. The cross beam seat is perpendicular to the guide rail.

[0013] Preferably, the driving assembly is a linear motor.

[0014] The application also proposes a line-scan image splicing method using the above line-scan measurement system, and specifically comprises the following steps:

[0015] Step 1: the motion platform moves to a preset scanning starting point, the linear array camera is controlled to start scanning the product according to a preset frequency, and the reading head is controlled to start locking the position data of the grating ruler corresponding to each scanning according to the preset frequency;

[0016] Step 2: output a product scanning image, and the position of each scanning pixel point of the product scanning image corresponds to the position data of the grating ruler locked in each scanning.

[0017] Further, the following steps are included:

[0018] Step 3: find two preset feature points on the product scanning image, and calculate the distance parameters of the two preset feature points;

[0019] Step 4: repeat steps 1 to 3 for a preset number of times to obtain a preset number of product scanning images and distance parameters corresponding to each product scanning image.

[0020] Compared with the prior art, the application has the following advantages:

[0021] 1. The problem that large-size measurement cannot simultaneously meet the requirements of accuracy and efficiency can be solved.

[0022] 2. The linear array camera is configured, and the functions of multiple area array cameras can be completed by using one set of camera, thereby saving hardware cost and hardware space.

[0023] 3. The problem of difficult design and high cost for large-size product high-precision measurement application is solved, and the competitiveness of products can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 A schematic diagram of a three-dimensional structure in an embodiment of the present application;

[0026] Figure 2 A flow chart in an embodiment of the present application.

[0027] Linear array camera 1, mounting seat 2, linear motor 3, guide rail 4, motion platform 5, grating ruler 6, reading head 7. DETAILED DESCRIPTION

[0028] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0029] The principles and structures of the present application will be described in detail below in combination with the drawings and embodiments.

[0030] In existing high-precision measurement, whether a large-format camera is used or a multi-camera mode is used, the cost will increase exponentially, and when the size reaches a certain size, the specifications of the camera cannot meet the measurement requirements. The multi-camera solution cannot measure the area outside the camera field of view because the camera can only be installed in a fixed position, and the universality is not high, and only a customized solution can be used for special products. In contrast, the present application proposes a line scanning measurement system based on position latching technology. Based on the position latching technology, the high-precision splicing of multi-picture images is performed through the accurate matching between the motion position and the camera pixel points, to realize the high-precision measurement of a large size range, and the problem that the large size measurement cannot simultaneously meet the precision and efficiency requirements can be solved.

[0031] The present application proposes a line scanning measurement system based on position latching technology, which mainly comprises a machine table, a motion platform 5, a grating ruler 6, a reading head 7, a linear array camera 1 and a controller. The machine table is provided with a guide rail 4 and a mounting bracket horizontally arranged above the guide rail; the motion platform is used for mounting or placing a product to be measured, and the motion platform 5 is installed on the guide rail 4 and can be driven to move linearly along the guide rail 4 by a driving assembly to adjust the scanning position of the product; the grating ruler 6 is arranged on the machine table and is parallel to the guide rail 4; the reading head 7 is installed on the motion platform 5 and moves with the motion platform 5, and the reading head corresponds to the grating ruler 6 and acquires position data in real time; the linear array camera 1 is installed on the mounting bracket above the guide rail 4, the shooting direction is vertically downward, the driving assembly drives the motion platform to move so that the product passes below the linear array camera, and the linear array camera can perform scanning and shooting; the controller can control the reading head to start latching (i.e., recording the position of the reading head on the grating ruler) at a preset frequency when the motion platform reaches a preset scanning starting point.

[0032] The controller specifically comprises a high-speed counter, a pulse switching module, an input module and an output module, the high-speed counter directly collects position data of the grating ruler corresponding to the reading head, and the output module is used for triggering the pulse switching module. When the motion platform moves to the pre-set scanning starting point, the pulse switching module is triggered by the output module, and the pulse switching module triggers the line-scan camera to perform high-frequency scanning at a pre-set frequency. During the scanning process, the input module cooperates with the reading head to latch the grating ruler data of each position in the motion process of the motion platform, and the latching frequency is the same as the triggering frequency of the line-scan camera.

[0033] The mounting bracket specifically comprises a support seat and a cross beam seat, the two support seats are arranged on the two sides of the guide rail, the cross beam seat is transversely connected to the top of the two support seats, is arranged above the guide rail and is perpendicular to the guide rail, the side surface of the cross beam seat is provided with a camera sliding rail, the camera sliding rail is provided with a mounting seat 2 for mounting the line array camera, the line array camera can be adjusted in the scanning position as required, and a driving assembly can also be configured for the line array camera, so that the position of the line array camera is automatically adjusted through the controller. The line array camera can also be installed and fixed through other mounting schemes, as long as the line array camera can be suspended above the track for scanning, and all the mounting schemes are within the protection scope of the application.

[0034] The specific working process of the system is as follows:

[0035] The linear motor is started, and the motion platform starts to move linearly.

[0036] When the motion platform moves to the pre-set scanning starting point, the output module of the controller triggers the pulse switching module, and the pulse switching module starts to trigger the line array camera to work at a high frequency and perform high-frequency scanning; during the scanning process, the input module cooperates with the reading head to latch the grating ruler data of each position in the motion process, and the latching frequency is the same as the triggering frequency of the line-scan camera.

[0037] The scanning ends to obtain a complete product scanning image, and the interval of the pixel points of the product scanning image is matched with the data of the grating ruler. Then, two feature points are found on the image, and the distance parameters of the feature points are calculated. For example, the linear array camera scans a column of pixel points each time, and the position data of the grating ruler is locked each time, that is, the actual position of the grating ruler in this scanning, for example, the n-th scanning corresponds to the locked data of the grating ruler a microns, and the n+1-th scanning corresponds to the locked data of the grating ruler b microns. In the subsequent image splicing, the pixel points of each scanning are matched with the corresponding locked position data of the grating ruler, that is, the column of pixel points of the n-th scanning is arranged at the position of a microns, and the column of pixel points of the n+1-th scanning is arranged at the position of b microns. The interval of the two columns of pixel points is b-a. Because the pixel points of each scanning are arranged according to the actual position of the grating ruler to form a complete product scanning image, the accuracy of the product scanning image is high, and the product scanning image can be used for high-precision data measurement. In addition, the image output speed is fast, and the measurement efficiency is also high.

[0038] The above step is repeated for 10 times of scanning, the distance of the same feature points is recorded, and the repeatability is calculated, so as to verify the accuracy and output the most accurate product scanning image according to multiple groups of data.

[0039] In the preferred embodiment, the driving assembly can be a linear motor, and the driving mode can be a screw rod or other existing driving mode to drive the motion platform to slide along the guide rail. All of them are within the protection scope of the present application.

[0040] The present application also provides a line scanning image splicing method using the above line scanning measurement system, which specifically includes the following steps:

[0041] Step 1: when the motion platform moves to the preset scanning starting point, the linear array camera is controlled to scan at a preset frequency; and the reading head is controlled to read and store the position data of the motion platform during the motion (that is, to lock the scale information on the grating ruler) at a preset frequency;

[0042] Step 2: output a product scanning image, and the position of the pixel points of each scanning of the product scanning image corresponds to the position data of the grating ruler locked each time.

[0043] In order to improve the product image accuracy, multiple scanning can be repeated to verify the repeatability, which specifically includes the following steps:

[0044] Step 3: find two preset feature points on the product scanning image, and calculate the distance parameters of the two preset feature points.

[0045] Step 4, repeat steps 1 to 3 for a preset number of times to obtain a preset number of product scan images and distance parameters corresponding to each product scan image. By calculating the repeatability, both the accuracy can be verified, and the most accurate product scan image can be output according to multiple sets of data.

[0046] In a supplementary embodiment, any one of the product scan images with the equal number of distance parameters can be specifically taken as the output product scan image, because if the distance parameters of the preset two feature points of multiple product scan images are consistent, it means that the scanning accuracy of the product scan images is the highest.

[0047] If there are no two or more product scan images with equal distance parameters, the average value of the distance parameters of the preset number of product scan images is calculated, and the product scan image corresponding to the distance parameter closest to the average value is taken as the output product scan image.

[0048] The above supplementary embodiments are only supplementary embodiments of the present application and do not limit the protection scope of the present application. Those skilled in the art can also use other ways, for example, the actual measured distance parameters of the two feature points can be obtained first, and the product scan image closest to or equal to the distance parameter is selected as the output image, which is within the protection scope of the present application.

[0049] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should be understood that when the term "comprising" and / or "including" is used in the specification, it means that the features, steps, operations, devices, components and / or combinations thereof are present.

[0050] Unless otherwise specifically stated, the relative arrangements of parts and steps, numerical expressions, and numerical values set forth in these embodiments are not limiting on the scope of the application. Also, it is to be understood that the herein shown and discussed examples are merely illustrative of only some of the many possible specific embodiments, which can represent the application. As such, forward citations, such as "preferred," "particularly preferred," "engineered," "engineered and selected," and the like, are not utilized unless otherwise stated. Any specific values cited in this application are not to be interpreted as critical to the application. Thus, other example embodiments can have different values. It is to be noted that like reference numerals and letters refer to like items in the drawings and a discussion of like items does not need to be repeated in subsequent drawings. Thus, once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0051] In the description of the present application, it should be understood that the orientation words such as "front, back, upper, lower, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, without making the opposite statement, these orientation words do not indicate and imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0052] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used herein to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0053] In addition, it should be noted that the use of "first", "second" and the like words to define parts only facilitates the differentiation of corresponding parts, and the above words have no special meaning unless otherwise stated, therefore, it cannot be understood as a limitation on the scope of protection of the present application.

[0054] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for stitching line-scanned images, characterized in that, The line scan image stitching method employs a line scan measurement system based on position latching technology, the line scan measurement system comprising: A motion platform is used to install products and is driven by a drive component to slide along a guide rail to adjust the position of the products. The grating ruler is parallel to the guide rail; The reading head moves with the motion platform and corresponds to the grating ruler; A line scan camera is suspended above the motion platform; The controller controls the various components of the line scan measurement system to implement the line scan image stitching method, including: Step 1: The motion platform moves to the preset scanning starting point, controls the line scan camera to start scanning the product at a preset frequency, so as to acquire a column of pixels in each scan, and controls the reading head to latch the position data of the grating ruler corresponding to each scan at the preset frequency. Step 2: Output a product scan image. When stitching the images, make each column of pixels obtained from each scan correspond one-to-one with the grating ruler position data latched in that scan, and place the column of pixels at the position coordinates determined by the latched grating ruler position data, so that the interval between the two columns of pixels obtained from two adjacent scans in the output product scan image is equal to the difference between the corresponding two latched grating ruler position data. Step 3: Locate two preset feature points on the scanned image of the product and calculate the distance parameter between the two preset feature points.

2. The line scan image stitching method as described in claim 1, characterized in that, The controller includes a high-speed counter, a pulse switching module, an input module, and an output module. The high-speed counter collects the position data of the grating ruler. The output module is used to trigger the pulse switching module, which is used to control the triggering of the line scan camera. The input module works in conjunction with the reading head to latch the position data of the grating ruler.

3. The line scan image stitching method as described in claim 1, characterized in that, It also includes a machine tool for mounting the guide rail and the grating ruler.

4. The line scan image stitching method as described in claim 3, characterized in that, The machine base is also equipped with two support seats, and a crossbeam seat is horizontally connected to the top of the two support seats. A camera slide rail is provided on the side of the crossbeam seat, and a mounting seat for mounting the line scan camera is provided on the camera slide rail.

5. The line scan image stitching method as described in claim 1, characterized in that, The drive component is a linear motor.

6. The line scan image stitching method as described in claim 4, characterized in that, The crossbeam seat is perpendicular to the guide rail.

7. The line scan image stitching method according to any one of claims 1 to 6, characterized in that, It also includes the following steps: Step 4: Repeat steps 1 to 3 a preset number of times to obtain a preset number of product scan images and the distance parameter for each product scan image.

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