Device for calibrating laser leveling instruments

Abstract

The present disclosure relates to a device for calibrating a laser leveler, the device comprising: a base platform, configured to support a laser leveler to be mounted thereon at a first position; a target, arranged at a second position of the base platform and configured to receive laser light; and an image recognition device, configured to obtain an image of the laser projected on the target, and to determine the positions of the laser emitted by the laser leveler on the target before and after rotating a first angle based on image recognition technology, so as to determine the deviation distance, and then determine whether the laser leveler needs to be calibrated based on the deviation data, the distance data determined by the position data of the first position and the second position, and the first angle. The device for calibrating a laser leveler proposed in accordance with the present disclosure calibrates the laser leveler with the aid of an image recognition device, and has a simple structure and high calibration accuracy.

Description

Technical Field

[0001] The present disclosure relates to the field of laser measurement, and more particularly to a device for calibrating a laser leveler. Background Art

[0002] The traditional method of calibrating a laser level usually uses a fixed distance, such as a fixed distance of 5 meters or 10 meters, and then fixes the laser level and the detector at preset positions respectively, and calibrates the laser level at a fixed distance.

[0003] In such a calibration system, a specific laser detector is usually used to detect the height of the plane where the laser emitted by the laser leveler is located. Then, the height difference of the position where the laser is hit on the laser detector after the laser leveler rotates a certain angle is used to identify whether the laser leveler needs to be calibrated. And this height difference must be detected by a laser detector with laser detection function. In this way, the calibration of the laser leveler must use a laser detector, which has great limitations in scenes and instruments, and cannot achieve automatic calibration. Summary of the invention

[0004] In view of a deep understanding of the problems existing in the background technology, the inventors of the present disclosure conceived of designing a method for determining the height difference of the laser on the target formed before and after the laser level is rotated by a certain angle by means of image recognition technology, thereby reducing the cost of the system on the one hand, and on the other hand, due to the high accuracy of image recognition technology, it is possible to improve the calibration accuracy.

[0005] Specifically, the present disclosure proposes a device for calibrating a laser leveler, characterized in that the device includes: a base platform, the base platform is configured to support the laser leveler to be installed thereon at a first position; a target, the target is arranged at a second position of the base platform and is configured to receive laser; and an image recognition device, the image recognition device is configured to obtain an image of the laser projected on the target, and determine the positions of the laser emitted by the laser leveler on the target before and after rotating a first angle based on image recognition technology to determine the deviation distance, and then determine whether the laser leveler needs to be calibrated based on the deviation data, the distance data determined by the position data of the first position and the second position, and the first angle. The device for calibrating a laser leveler proposed in accordance with the present disclosure does not require a detector with a laser height difference recognition function, and can calibrate the laser leveler only with the aid of an image recognition device, and has a simple structure and high calibration accuracy.

[0006] In one embodiment of the present disclosure, the image recognition device is disposed at a third position on the side of the target facing the laser leveler. Those skilled in the art should also understand that the image recognition device is disposed at a third position on the side of the target facing the laser leveler, so that the image recognition device can more easily identify the position of the laser on the target, thereby improving the recognition accuracy.

[0007] In one embodiment of the present disclosure, the image recognition device includes a smart phone, a tablet computer and / or a camera. In this way, the existing equipment owned by the user of the device for calibrating the laser leveler can be reused, further reducing the equipment cost of calibrating the laser leveler.

[0008] In one embodiment of the present disclosure, the base platform further comprises: a rotating device, the rotating device being configured to rotate the laser leveler to the first angle based on a control command received from the image recognition device, thereby enabling the rotation angle of the laser leveler to be controlled in a more precise manner.

[0009] In one embodiment of the present disclosure, the first angle is an angle value among 180 degrees, 90 degrees or 270 degrees. Here, those skilled in the art should understand that the three angles here are only exemplary and not restrictive, and these angles are just convenient for calculating calibration parameters, and other angles can also achieve the purpose of calibration, so the technical solutions of other angles are also included in the scope of the technical solutions claimed for protection by the independent claims of the present disclosure.

[0010] In one embodiment of the present disclosure, when the image recognition device determines that the laser leveler needs to be calibrated, the image recognition device determines a calibration signal based on the distance data, the deviation distance and the first angle, and sends the calibration signal to the laser leveler. Preferably, in one embodiment of the present disclosure, the device further includes an optical path extension device, which is disposed at a fourth position between the laser leveler and the target and is configured to receive the laser emitted by the laser leveler and project it onto the target after being adjusted by the optical path extension device. More preferably, in one embodiment of the present disclosure, the optical path extension device includes: an objective lens, which is configured to receive the laser emitted by the laser leveler; an objective lens focusing lens, which is configured to focus the laser received by the objective lens; and an eyepiece, which is configured to project the laser adjusted by the objective lens focusing lens onto the target. In this way, the laser light can be processed by the objective focusing lens after being received by the objective lens and then projected by the eyepiece onto the target, so that the physical distance between the laser leveler and the target can be optically magnified through the processing of the objective focusing lens.

[0011] In addition, further preferably, in one embodiment according to the present disclosure, the optical path extension device further comprises a crosshair graticule, wherein the crosshair graticule is arranged between the objective lens focusing lens and the eyepiece. Optionally, in one embodiment according to the present disclosure, the objective lens is an objective lens group comprising a group of objective lenses. In one embodiment according to the present disclosure, the optical path extension device has an optical path extension multiple of a first multiple. Preferably, in one embodiment according to the present disclosure, the optical path extension device is constructed as a level, wherein the optical path center of the level is aligned with the laser emitted by the laser leveler.

[0012] In one embodiment according to the present disclosure, there is a wired connection or a wireless connection between the image recognition device and the laser leveler, and the wired connection or the wireless connection is constructed to transmit a calibration signal from the image recognition device to the laser leveler. Optionally, in one embodiment according to the present disclosure, the wireless connection includes at least one of an infrared connection, a Bluetooth connection, or a WiFi connection. In one embodiment according to the present disclosure, the target has any one of a horizontal scale, a black block, a black and white grid scale, a cross scale, and / or a high and low scale.

[0013] In summary, the device for calibrating a laser leveler proposed in the present disclosure can calibrate the laser leveler with the aid of an image recognition device, and has a simple structure and high calibration accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The embodiments are shown and explained with reference to the accompanying drawings. These drawings are used to explain the basic principles, and only the aspects necessary for understanding the basic principles are shown. These drawings are not to scale. In the drawings, the same reference numerals represent similar features.

[0015] Figure 1 A schematic structural diagram of a device 100 for calibrating a laser leveling instrument according to an embodiment of the present disclosure is shown;

[0016] Figure 2 The content of this disclosure is shown Figure 1 A schematic diagram of an embodiment of a target 230 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention;

[0017] Figure 3 The content of this disclosure is shown Figure 1 A schematic diagram of an embodiment of a target 330 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention;

[0018] Figure 4 The content of this disclosure is shown Figure 1 A schematic diagram of an embodiment of a target 430 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention;

[0019] Figure 5 The content of this disclosure is shown Figure 1 A schematic diagram of a target 530 at zero degrees that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention;

[0020] Figure 6 The content of this disclosure is shown Figure 1 A schematic diagram of a target 530 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention when the target 530 is at 180 degrees;

[0021] Figure 7 A schematic diagram showing an angle of a device 700 for calibrating a laser leveling device according to the present disclosure; and

[0022] Figure 8 FIG. 7 is a schematic diagram showing a device 700 for calibrating a laser leveling device according to the present disclosure at another angle.

[0023] Other features, characteristics, advantages and benefits of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0024] In the following specific description of preferred embodiments, reference will be made to the attached drawings that form a part of the present disclosure. The attached drawings show specific embodiments that can implement the present disclosure by way of example. The illustrative embodiments are not intended to be exhaustive of all embodiments according to the present disclosure. It will be appreciated that other embodiments may be utilized, and structural or logical modifications may be made without departing from the scope of the present disclosure. Therefore, the following specific description is not restrictive, and the scope of the present disclosure is limited by the attached claims.

[0025] In order to solve the technical problem in the prior art that a laser detector must be used to sense the height difference when calibrating a laser leveler, the inventor of the present disclosure conceived of designing a method that uses image recognition technology to determine the height difference on the target formed by the laser before and after the laser leveler rotates a certain angle. This can, on the one hand, have a greater possibility of reducing the cost of the system, and on the other hand, due to the high accuracy of image recognition technology, can improve the calibration accuracy, wherein the target can be either a traditional laser detector or a simple target such as a whiteboard.

[0026] Based on the above-mentioned inventive concept, the inventor of the present disclosure conceived of designing a device for calibrating a laser leveler, wherein the device includes an image recognition device, which is constructed to obtain an image of a laser projected on a target, and determine the positions of the laser emitted by the laser leveler on the target before and after rotating by a first angle based on image recognition technology. Then, the corresponding processor can determine whether the laser leveler needs to be calibrated based on the deviation distance determined by the image recognition technology, the distance data determined by the position data of the first position and the second position before and after rotating by the first angle, and the first angle.

[0027] The device for calibrating a laser leveling device according to the present disclosure is further described below in conjunction with the attached drawings.

[0028] Figure 1 FIG. 1 is a schematic diagram showing a structure of a device 100 for calibrating a laser leveling instrument according to an embodiment of the present disclosure. Figure 1 It can be seen that the device 100 for calibrating a laser leveling instrument according to the present disclosure includes: a base platform 110, wherein the base platform 110 is configured to be used in a first position ( Figure 1 The left part in the middle) supports the laser leveling instrument 120 to be installed thereon; the target 130, which is set at the second position ( Figure 1) and is configured to receive the laser emitted by the laser leveler 110; and an image recognition device 140, the image recognition device 140 is configured to obtain an image of the laser projected on the target 130, and determine the positions of the laser emitted by the laser leveler 110 on the target 130 before and after rotating the first angle based on the image recognition technology, so as to determine the deviation distance, and then determine whether the laser leveler 110 needs to be calibrated based on the deviation data, the distance data determined by the position data of the first position and the second position, and the first angle. Here, the image recognition device 140 includes a smart phone, a tablet computer and / or a camera. In this way, the existing equipment owned by the user of the device 100 for calibrating the laser leveler 110 can be reused, further reducing the equipment cost of calibrating the laser leveler 110. The device 100 for calibrating the laser leveler 110 proposed in the present disclosure does not require a detector with a laser height difference recognition function, and can calibrate the laser leveler only with the help of an image recognition device, and has a simple structure and high calibration accuracy.

[0029] Optional, Figure 1 The target 130 used in the method can be in various forms. For example, the target 130 can have no pattern at all or can have various patterns. For example, the target 130 has any one of horizontal scales, black blocks, black and white grid scales, cross scales and / or high and low scales.

[0030] The following first introduces the technical solution without any pattern. When there is no pattern on the target 130, the image recognition device 140 can be implemented by a mobile phone, for example. Assuming that there is a black block on the target 130, the image recognition of the image recognition device 140 uses the threshold, findContours and other functions in the openCV framework to obtain the position information of the black rectangle on the target on the screen, and the coordinates of the upper left corner of the black rectangle are (x, y), and the height is recorded as H; then the height H is sent to the lower computer; then, in a dark environment, the frame with the light spot is binarized into a grayscale image through the findContours and other functions in the openCV framework, and the position of the laser leveling light spot on the screen is obtained, based on the coordinates of the center point of the light spot, recorded as (m, n). In this way, the position of the laser emitted by the laser level 1 on the target 130 can be identified. In addition, there is another possibility, that is, there is no black block on the target 130. At this time, the distance between the image recognition device 140 and the target 130 is required to be constant. At this time, the height of the black block on the screen in the above recognition scheme is also a constant value H. Since the constant value H is known, the height H can also be sent to the lower computer at this time; next, in a dark environment, the frame with the light spot is binarized into a grayscale image through the findContours and other functions in the openCV framework, and the position of the laser leveling light spot on the screen is obtained, based on the coordinates of the center point of the light spot, recorded as (m, n), thereby also being able to identify the position of the laser emitted by the laser level 1 on the target 130.

[0031] Of course, different patterns can also be set on the target 130, and various possible pattern forms are introduced below.

[0032] Figure 2 The content of this disclosure is shown Figure 1 A schematic diagram of an embodiment of a target 230 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention. Figure 2It can be seen that the target 230 can be provided with lines with relevant position marks. At this time, when the laser emitted by the laser level is close to a line or coincides with the line, the height of the laser emitted by the laser level is recorded as the value recorded by the mark associated with the line, and then the laser level is rotated by a certain angle, and the value recorded by the mark associated with another possible line after the rotation by a certain angle is determined again by the same method. For example. Before rotation, it may be associated with the line marked with "+3", and after rotation by a certain angle, it may be associated with the line marked with "-3", then the height difference before and after the rotation by the certain angle is +3-(-3), which is 6. Then, based on the height difference, the angle of rotation, and the distance between the laser level and the target, it can be determined whether the laser level needs to be calibrated, and the specific calibration parameter value can be calculated when calibration is required.

[0033] Figure 3 The present disclosure shows Figure 1 A schematic diagram of an embodiment of a target 330 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention. Figure 3 It can be seen that black and white grids with relevant position marks can be set on the target 330. At this time, when the laser emitted by the laser level is close to a black and white grid or coincides with the black and white grid, the height of the laser emitted by the laser level is recorded as the value recorded by the mark associated with the black and white grid, and then the laser level is rotated by a certain angle, and the value recorded by the mark associated with another black and white grid after the rotation is determined by the same method. For example. Before rotation, it may be associated with the line marked with "+6", and after rotation by a certain angle, it may be associated with the line marked with "+3", then the height difference before and after the rotation is +6-(+3), which is 3. Then, based on the height difference, the angle of rotation, and the distance between the laser level and the target, it can be determined whether the laser level needs to be calibrated, and the specific calibration parameter value can be calculated when calibration is required.

[0034] Figure 4 The content of this disclosure is shown Figure 1 A schematic diagram of an embodiment of a target 430 that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention. Figure 4It can be seen that a cross scale can be set on the target 430. At this time, when the laser emitted by the laser level is close to a scale or coincides with the scale, the height of the laser emitted by the laser level is recorded as the scale, and then the laser level is rotated by a certain angle, and the same method is used to determine the possible other scale after the rotation by a certain angle. For example. Before rotation, it may be associated with the first scale, and after rotation by a certain angle, it may be associated with the second scale. Then the height difference before and after the rotation by the certain angle is the difference between the first scale and the second scale. Then, based on the height difference, the angle of rotation, and the distance between the laser level and the target, it can be determined whether the laser level needs to be calibrated, and the specific calibration parameter value can be calculated when calibration is required.

[0035] Figure 5 The content of this disclosure is shown Figure 1 A schematic diagram of a target 530 at zero degrees that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention. Figure 6 The content of this disclosure is shown Figure 1 A schematic diagram of a target 530 at 180 degrees that can be used in an apparatus for calibrating a laser leveling device according to an embodiment of the present invention. Figure 5 and Figure 6 and Figure 2 The difference is that it not only has a larger horizontal scale, but also divides each horizontal scale into three steps, which further refines the scale and can achieve higher accuracy. Figure 5 and Figure 6 It can be seen that the target 530 can be provided with lines with relevant position marks. At this time, when the laser emitted by the laser leveler is close to a line or coincides with the line, the height of the laser emitted by the laser leveler is recorded as the value recorded by the mark associated with the line, and then the laser leveler is rotated by a certain angle, such as 180 degrees, and the value recorded by the mark associated with another possible line after the rotation by a certain angle is determined again by the same method. For example. Before rotation, it may be associated with the line marked with "+4", and after rotation by a certain angle, it may be associated with the line marked with "+1", then the height difference before and after the rotation by a certain angle is +4-(+1), which is 3. Then, based on the height difference, the angle of rotation, and the distance between the laser leveler and the target, it can be determined whether the laser leveler needs to be calibrated, and the specific calibration parameter value can be calculated when calibration is required.

[0036] In addition, the inventors of the present disclosure took into account the technical problem that the device for calibrating the laser leveler is subject to space limitations, and conceived of designing a method for optically amplifying the physical distance between the laser leveler and the target with the aid of optical devices, thereby amplifying the physical distance within a limited space and thus improving the calibration accuracy.

[0037] Specifically, if Figure 7 and Figure 8 As shown, Figure 7 FIG. 1 is a schematic diagram showing an angle of a device 700 for calibrating a laser leveling instrument according to the present disclosure, and FIG. Figure 8 FIG. 7 is a schematic diagram showing another angle of a device 700 for calibrating a laser leveling instrument according to the present disclosure. Figure 7 and Figure 8 It can be seen that the present disclosure proposes a device 700 for calibrating a laser leveler, including a base platform 710, wherein the base platform 710 is configured to support a laser leveler 720 to be mounted thereon at a first position; in addition, the device 700 also includes a target 730, wherein the target 730 is disposed at a second position of the base platform 710 and is configured to receive laser light; and the device 700 also includes an image recognition device 740, wherein the image recognition device 740 is configured to obtain an image of the laser projected on the target 730, and to determine the positions of the laser emitted by the laser leveler 720 on the target 730 before and after rotating by a first angle based on image recognition technology, so as to determine the deviation distance, and then determine whether the laser leveler 720 needs to be calibrated based on the deviation data, the distance data determined by the position data of the first position and the second position, and the first angle. Figure 7 and Figure 8In the illustrated embodiment, the image recognition device 740 is disposed at a third position on the side of the target 730 facing the laser leveler 720. Those skilled in the art should also understand that the image recognition device 740 is disposed at a third position on the side of the target 730 facing the laser leveler 720, so that the image recognition device 740 can more easily recognize the position of the laser on the target 730, thereby improving the recognition accuracy. The base platform 710 can also include a rotating device (not shown in the figure, which can be, for example, directly below the laser leveler 720), and the rotating device is configured to rotate the laser leveler 720 by the first angle based on the control command received from the image recognition device 740. In this way, the rotation angle of the laser leveler 720 can be controlled in a more accurate manner. In one embodiment according to the present disclosure, the first angle is an angle value among 180 degrees, 90 degrees or 270 degrees. Here, those skilled in the art should understand that the three angles here are merely exemplary and non-restrictive, and these angles are just more convenient for calculating calibration parameters, and other angles can also achieve the purpose of calibration, so the technical solutions of other angles are also included in the scope of the technical solutions claimed for protection by the independent claims of the present disclosure. Optionally, in an embodiment of the present disclosure, when the image recognition device determines that the laser leveler needs to be calibrated, the image recognition device determines a calibration signal based on the distance data, the deviation distance and the first angle, and sends the calibration signal to the laser leveler.

[0038] In addition, the device 700 further includes an optical path extension device 750, which is disposed at a fourth position between the laser leveler 720 and the target 730 and is configured to receive the laser light emitted by the laser leveler 720 and project the laser light onto the target 730 after being adjusted by the optical path extension device 750. More preferably, in an embodiment according to the present disclosure, the optical path extension device 750 includes: an objective lens, which is configured to receive the laser light emitted by the laser leveler; an objective lens focusing lens, which is configured to focus the laser light received by the objective lens; and an eyepiece, which is configured to project the laser light adjusted by the objective lens focusing lens onto the target. In this way, the laser light can be processed by the objective focusing lens after being received by the objective lens and then projected by the eyepiece onto the target, so that the physical distance between the laser leveler and the target can be optically magnified through the processing of the objective focusing lens.

[0039] In addition, further preferably, in one embodiment according to the present disclosure, the optical path extension device 750 also includes a crosshair graticule, wherein the crosshair graticule is arranged between the objective lens focusing lens and the eyepiece, and is used for auxiliary alignment of the laser. Optionally, in one embodiment according to the present disclosure, the objective lens is an objective lens group including a group of objective lenses. In one embodiment according to the present disclosure, the optical path extension device has a first multiple of optical path extension multiple. Preferably, in one embodiment according to the present disclosure, the first multiple is 32 times, or 26 times, and a suitable multiple can be selected according to actual needs. Preferably, in one embodiment according to the present disclosure, the optical path extension device is constructed as a level, wherein the optical path center of the level is aligned with the laser emitted by the laser leveler.

[0040] In one embodiment of the present disclosure, there is a wired connection or a wireless connection between the image recognition device 740 and the laser leveler 720, and the wired connection or the wireless connection is configured to transmit a calibration signal from the image recognition device 740 to the laser leveler 720. Optionally, in one embodiment of the present disclosure, the wireless connection includes at least one of an infrared connection, a Bluetooth connection, or a WiFi connection.

[0041] To sum up, the device for calibrating a laser leveler proposed according to the contents of the present disclosure does not require a laser detector to detect and identify changes in the laser position. A suitable target object can be selected as a target according to the application scenario, and the laser leveler can be calibrated only with the help of an image recognition device. It has a wide range of applications, a simple structure and high calibration accuracy.

[0042] Although different exemplary embodiments of the present disclosure have been described, it will be apparent to those skilled in the art that different changes and modifications can be made that can achieve one or some of the advantages of the present disclosure without departing from the spirit and scope of the present disclosure. For those skilled in the art, other components that perform the same function may be appropriately replaced. It should be understood that the features explained herein with reference to specific figures may be combined with the features of other figures, even in those cases where this is not explicitly mentioned. In addition, the method of the present disclosure may be implemented in a software implementation using all appropriate processor instructions or in a hybrid implementation that utilizes a combination of hardware logic and software logic to obtain the same result. Such modifications to the scheme according to the present disclosure are intended to be covered by the appended claims.

Claims

1. A device for calibrating a laser leveling instrument, characterized in that: The device comprises: a base platform configured to support a laser leveling instrument to be mounted thereon at a first position; a target disposed at a second location of the base platform and configured to receive laser light; The device further comprises an optical path extension device, which is disposed at a fourth position between the laser leveler and the target and is configured to receive the laser emitted by the laser leveler and project the laser onto the target after being adjusted by the optical path extension device, wherein the optical path extension device has an optical path extension factor of a first factor; and An image recognition device is constructed to acquire an image projected by a laser on a target, and determine the positions of the laser emitted by the laser leveler on the target before and after rotating by a first angle based on image recognition technology to determine a deviation distance, and then determine whether the laser leveler needs to be calibrated based on the deviation distance, the position data of the first position and the second position, the distance data determined by the first multiple, and the first angle.

2. The device according to claim 1, characterized in that The image recognition device is arranged at a third position on a side of the target facing the laser leveler.

3. The device according to claim 1, characterized in that The image recognition device includes a smart phone, a tablet computer and / or a camera.

4. The device according to claim 1, characterized in that The base platform also includes: A rotating device is configured to rotate the laser leveler to the first angle based on a control command received from the image recognition device.

5. The device according to any one of claims 1 to 4, characterized in that The first angle is an angle value among 180 degrees, 90 degrees or 270 degrees.

6. The device according to claim 1, characterized in that When the image recognition device determines that the laser leveler needs to be calibrated, the image recognition device determines a calibration signal based on the distance data, the deviation distance, and the first angle, and sends the calibration signal to the laser leveler.

7. The device according to claim 1, characterized in that The optical path extension device comprises: An objective lens, the objective lens being configured to receive the laser emitted by the laser leveling instrument; an objective focusing lens, wherein the objective focusing lens is configured to perform focusing processing on the laser light received by the objective lens; and An eyepiece is configured to project the laser light adjusted by the objective focusing lens onto a target.

8. The device according to claim 7, characterized in that The optical path extension device also includes a crosshair graticule, wherein the crosshair graticule is arranged between the objective focusing lens and the eyepiece.

9. The device according to claim 7 or 8, characterized in that The objective lens is an objective lens group including a group of objective lenses.

10. The device according to claim 1, characterized in that The optical path extension device is configured as a level, wherein the optical path center of the level is aligned with the laser emitted by the laser leveler.

11. The device according to claim 1, characterized in that There is a wired connection or a wireless connection between the image recognition device and the laser sweeper, and the wired connection or the wireless connection is configured to transmit a calibration signal from the image recognition device to the laser sweeper.

12. The device according to claim 11, characterized in that The wireless connection includes at least one of an infrared connection, a Bluetooth connection or a WiFi connection.

13. The device according to claim 1, characterized in that The target has any one of horizontal scales, black blocks, black and white grid scales, cross scales and / or high and low scales.

Images