DE102022111110A1 - Marker device for position determination and method for installing a marker device - Google Patents

Abstract

The invention relates to a marker device (2) for determining position, having at least one user-readable marker (4), which is fixed to a spatial and/or stationary control body and to which a measured spatial coordinate is assigned, which is stored and retrievable in a computer unit, and with at least one machine-readable marker (6), which is arranged directly on the user-readable marker (4) adjacent to the control body, which can be detected by an image capture device assigned to the computer unit and can be identified by the computer unit and to which a marker center in the computer unit can be assigned or assigned, whereby the orientation and the distance of the marker center to the spatial coordinate of the user-readable marker (4) can be stored or stored in the computer unit and can be called up.

Description

The invention relates to a marker device for determining position and a method for installing a marker device.

It is known from the prior art to attach user-readable markers to stationary control bodies for measurement purposes. These are also called control points. The use of these user-readable markers is optimized for manual use by humans. They usually consist of two triangles that indicate the center of the control point and can be precisely measured using measuring equipment. This means that a very precise spatial coordinate can be assigned to the center of the user-readable markers.

With the known marker devices that include user-readable markers, it has proven to be a disadvantage that the user-readable markers cannot be read by machine or can only be read with difficulty and with errors.

Machine-readable markers may include Aruco markers. However, these are difficult to position at an exact spatial coordinate and often have an accuracy of +/- 2.5 cm.

One object of an exemplary embodiment of the invention is to propose a marker device in which the accuracy of a machine-readable position determination is improved.

This object is achieved by a marker device for position determination with at least one user-readable marker, which is fixed to a spatial and/or stationary control body and to which a measured spatial coordinate is assigned, which is stored and retrievable in a computer unit, and with at least one machine-readable marker , which is arranged directly on the user-readable marker adjacent to the control body, which can be detected by an image capture device assigned to the computer unit and identified by the computer unit and to which a marker center in the computer unit can be assigned or is assigned, the orientation and the distance of the marker center from the spatial coordinate of the User-readable marker can be stored or stored in the computer unit and can be accessed.

Because the marker device comprises a user-readable marker, which is fixed to a spatial or stationary control body and to which a measured spatial coordinate is assigned, the spatial coordinate can be measured and determined very precisely.

Because the marker device comprises a machine-readable marker, which is arranged directly on the user-readable marker adjacent to the control body, the machine-readable marker of the marker device can be detected and identified by a machine.

Because the machine-readable marker is arranged directly adjacent to the user-readable marker and the orientation and distance of the marker center from the spatial coordinate can be stored or stored in the computer unit, the measured spatial coordinate of the user-readable marker can be indirectly determined by detecting and identifying the machine-readable marker for machine reading and use be used.

This increases the accuracy of the machine-readable position determination by the marker device compared to the prior art.

Embodiments of the marker device are preferred in which the user-readable marker comprises at least one n-angular, in particular quadrangular, in particular square, cross section with edges of equal length, and at least one image element through which a center point of the user-readable marker can be detected, which is the assigned spatial coordinates corresponds and/or in which the machine-readable marker comprises at least one n-angular, in particular quadrangular, in particular square, cross section with edges of equal length.

If the user-readable marker and the machine-readable marker each comprise a square, in particular square, cross-section, precise positioning, alignment and fixing of the machine-readable marker on the user-readable marker is facilitated.

The image element of the user-readable marker can, for example, comprise a cross or a crosshair, the center of the user-readable marker being arranged at the intersection of at least two lines or being formed by two triangles whose vertices are adjacent and opposite, the point of contact of the triangle vertices being the center of the user-readable marker includes.

The machine-readable marker can comprise any marker that can be detected by a machine, in particular by an image capture device. In embodiments of the marker device, it is provided that the machine-readable marker comprises a QR code, an Aruco marker, an AR tag, a barcode, an RFID tag or another tag.

A QR code is a quick response code, i.e. a two-dimensional code for a “quick answer”. An Aruco marker is a marker in which a bit pattern with a coded ID is arranged within an outer, black edge to identify the marker inside. The matrix arranged within the dark edge includes dark fields and light fields, where dark fields and light fields stand for “0” and “1”, i.e. forming a binary code.

An AR tag is an augmented reality, i.e. an assisted reality, whereby a “tag” includes a label.

An RFID tag includes radio-frequency identification, i.e. identification using electromagnetic waves.

In order to facilitate alignment and orientation of the machine-readable marker with respect to the user-readable marker, it proves to be advantageous if the machine-readable marker comprises, on the side facing the user-readable marker, a user-readable positioning section which comprises a centering element which has a line that is the center point of the user-readable marker connects to the marker center, is aligned or is designed mirror-symmetrically with respect to the line that connects the center of the user-readable marker to the marker center.

In such a case, the machine-readable marker can be arranged centered with respect to the user-readable marker. The line that connects the center of the user-readable marker with the marker center can be understood as a mental or real user-readable line.

In a further development of the last-mentioned embodiment, it is provided that the centering element of the machine-readable marker has a distance from the marker center that can be stored and/or stored and retrieved in the computer unit.

If the distance between the marker center and the centering element is stored in the computer unit, determining the distance between the marker center and the center of the user-readable marker is made easier.

In addition, it proves to be advantageous if the positioning section of the machine-readable marker comprises a user-readable, optically perceptible measuring element through which a side length of the user-readable marker can be detected.

Because the positioning section includes a user-readable, optically perceptible measuring element, the user can record its side length when arranging and fixing the machine-readable marker on the user-readable marker. This means that there is no need to provide additional measuring equipment.

If the user-readable marker comprises a square cross section, the distance from the center of the user-readable marker to the positioning section of the machine-readable marker can be easily determined by detecting the side length of the user-readable marker. If the distance of the centering element on the positioning section to the marker center is stored in the computer unit, the distance from the marker center to the center of the machine-readable marker can be determined without additional aids. As a result, the marker device is simplified and can be installed quickly.

In a further development of the last-mentioned embodiment, it proves to be advantageous if the measuring element is designed to be mirror-symmetrical - with respect to a line through the center and the marker center.

The centering element can be formed, for example, by the center of the measuring element, whereby the marker device is designed to be compact. By arranging the measuring element on the user-readable marker in a mirror-symmetrical manner, the side length of the user-readable marker can also be recorded with the central positioning and alignment of the machine-readable marker.

The measuring element can basically be designed in any way. It proves to be advantageous if the measuring element comprises a user-readable scale or user-readable, optically distinguishable measuring sections that can be assigned to a specific length of the user-readable marker.

If the measuring element comprises a user-readable scale, this can be easily readable by the user, for example in the manner of a tape measure. If the measuring element comprises user-readable, optically distinguishable measuring sections, these measuring sections can, for example, be adapted and aligned to standardized user-readable markers. The optically distinguishable measuring sections can include different colors or be formed by different hatching.

By providing the positioning section, which can include the centering element and/or the measuring element, the machine-readable marker can be easily oriented. In this case, an operator who sets the machine-readable marker on the user-readable marker places the positioning section on the user-readable marker, whereby the machine-readable marker is automatically aligned.

Supporting the positioning section or in embodiments without a positioning section, it proves to be advantageous if the machine-readable marker comprises a user-readable orientation element through which an orientation and/or alignment of the machine-readable marker with respect to the user-readable mark is user-readable.

The orientation element can, for example, include a directional symbol, for example a graphic symbol, a pictogram or a text. For example, if the graphic symbol includes an arrow, the orientation element is formed by a directional arrow pointing in the direction of a user-readable marker.

1. a. Ggf. Festlegen des anwenderlesbaren Markers an einem raum- und/oder ortsfesten Kontrollkörper und Vermessen, Zuordnen und Hinterlegen einer dem anwenderlesbaren Marker zugordneten Raumkoordinate in der Rechnereinheit;
2. b. Positionieren und Festlegen des maschinenlesbaren Markers am Kontrollkörper und am anwenderlesbaren Marker und Zuordnen eines Markerzentrums des maschinenlesbaren Markers in der Rechnereinheit; und
3. c. Hinterlegen einer Orientierung und eines Abstands des Markerzentrums des maschinenlesbaren Markers zur Raumkoordinate des anwenderlesbaren Markers in der Rechnereinheit.

In addition, the object is achieved by a method for installing a marker device for position determination with at least one of the aforementioned features, which has at least one user-readable marker and the at least one machine-readable marker, which is arranged directly on the user-readable marker adjacent to the control body, which is determined by a can be detected by an image capture device assigned to the computer unit and can be identified by a computer unit, with the steps:

1. a. If necessary, fixing the user-readable marker on a spatial and/or stationary control body and measuring, assigning and storing a spatial coordinate assigned to the user-readable marker in the computer unit;
2. b. Positioning and fixing the machine-readable marker on the control body and on the user-readable marker and assigning a marker center of the machine-readable marker in the computer unit; and
3. c. Storing an orientation and a distance of the marker center of the machine-readable marker from the spatial coordinate of the user-readable marker in the computer unit.

Measuring, assigning and storing the user-readable marker can be done using additional measuring equipment. Step a can be carried out “if necessary” if the spatial coordinates are not already stored in the computer unit.

Positioning and fixing the machine-readable marker on the user-readable marker may include aligning the machine-readable marker with the aid of a centering element of a user-readable positioning portion of the machine-readable marker. Here, the centering element and the positioning section can be arranged on a side facing the user-readable marker and aligned with a line that connects the center of the user-readable marker and the marker center. The positioning and fixing can also be done in such a way that the machine-readable marker has its positioning section directly adjacent to the user-readable marker.

Assigning a marker center of the machine-readable marker in the computer unit can include determining the absolute position of the machine-readable marker. In such a case, a measuring element can be provided on the machine-readable marker, with which a side length of the user-readable marker can be detected. If the user-readable marker comprises a square cross section, a distance between the center of the user-readable marker and the machine-readable marker can be determined by the side length. Knowing the distance between the centering element of the machine-readable marker and the marker center, an absolute position of the machine-readable marker can be stored in the computer unit.

This can in particular include storing an orientation of a distance between the marker center of the machine-readable marker and the spatial coordinate of the user-readable marker in the computer unit.

Further features, details and advantages of the invention result from the attached patent claims, from the graphic representation and subsequent description of a preferred embodiment of the marker device and the method.

• 1 Eine Draufsicht auf ein erstes Ausführungsbeispiel einer Markervorrichtung;
• 2 Eine Draufsicht auf ein zweites Ausführungsbeispiel der Markervorrichtung;
• 3 Ein schematisches Ablaufdiagramm eines erfindungsgemäßen Verfahrens.

In the drawing shows:

• 1 A top view of a first embodiment of a marker device;
• 2 A top view of a second embodiment of the marker device;
• 3 A schematic flow diagram of a method according to the invention.

The 1 and 2 show two exemplary embodiments, each of a marker device for position determination, provided overall with the reference number 2. The marker devices 2 each include a user-readable marker 4, which is fixed to a spatial and/or stationary control body (not shown in the figures). A spatial coordinate is assigned to the user-readable marker 4, which is stored in a computer unit and can be called up.

In addition, the marker devices 2 include a machine-readable marker 6, which is fixed directly on the user-readable marker 4 adjacent to the control body. The machine-readable marker 6 can be detected by an image capture device and identified by the computer unit.

A marker center in the computer unit can be assigned to the machine-readable marker 6, the orientation and the distance of the marker center from the spatial coordinate of the user-readable marker 4 being stored or stored in the computer unit and retrievable.

The exemplary embodiments of the 1 and 2 show machine-readable markers 6, which include so-called Aruco markers. These are delimited by an outer closed black frame so that they can be detected as markers by the image capture device. In the exemplary embodiments of the machine-readable markers 6 shown in the figures, there are six columns and six rows within the black frame. These alternate control columns and information columns, with a dark field representing a “1” and a light field representing a “0”, meaning a binary code can be displayed and recorded. Different Aruco markers are stored or can be stored within a library, which means that a pose can be calculated from the four corner points of a camera matrix of unknown marker size.

The exemplary embodiments of the 1 and 2 differ in the user-readable marker used 4.

In the exemplary embodiment according to 1 the user-readable marker 4 is formed by two dark triangles, which meet at their tips at a center point 8 of the user-readable marker 4. The center 8 of the user-readable marker 4 can be directly assigned to the assigned spatial coordinate by a user.

In the exemplary embodiment according to 2 The user-readable marker 4 includes a crosshair, the center point 8 being formed by two intersecting lines.

What both user-readable markers 4 have in common is that they have a square cross section with edges of equal length.

The exemplary embodiments of 1 and 2 What is common is that the machine-readable markers 6 include a positioning section 10 on the side facing the user-readable marker 4. This each comprises a centering element 12 which is aligned with a line through the center 8 of the user-readable marker 4 and through the marker center.

In the exemplary embodiments of 1 and 2 the centering element 12 is realized by a measuring element 14. The measuring element 14 is designed to be mirror-symmetrical with respect to a line through the center point 8 and through the marker center and comprises user-readable measuring sections 16 that are optically distinguishable from one another. The measuring sections 16, which are optically distinguishable from one another, can be detected using different colors or gray levels.

A side length of the user-readable marker 4 comprising a square cross section can be detected by the measuring element 14.

In addition, the exemplary embodiments include the 1 and 2 a user-readable orientation element 18, through which an orientation and/or alignment of the machine-readable marker 6 with respect to the user-readable marker 4 is user-readable. In the exemplary embodiments shown in the figures, the orientation elements 18 are formed by directional arrows.

• In einem ersten Schritt 100, der gegebenenfalls ausgeführt werden kann, wird ein anwenderlesbarer Marker 4 an einem raum- und/oder ortsfesten Kontrollkörper festgelegt und vermessen. Die hierbei durch Vermessen erfasste Raumkoordinate wird dem anwenderlesbaren Marker 4 zugeordnet und in einer Rechnereinheit hinterlegt.

3 shows a schematic flow diagram of the method according to the invention. With the help of the representation of the 1 and 2 the method according to the invention is described below:

• In a first step 100, which can be carried out if necessary, a user-readable marker 4 is fixed and measured on a spatial and/or stationary control body. The spatial coordinate recorded by measurement is assigned to the user-readable marker 4 and stored in a computer unit.

Step 100 is carried out “if appropriate”. For example, the user-readable marker 4 can already be fixed and measured on the control body and a machine-readable marker 6 can be subsequently arranged on the user-readable marker 4.

In a subsequent step 101, a machine-readable marker 6 is positioned and fixed on the control body and on the user-readable marker 4. Here, the measuring element 14 of the positioning section 10 can be used to arrange the machine-readable marker 6 directly adjacent to the user-readable marker 4 and to position, in particular to center, the machine-readable marker 6 with respect to the user-readable marker 4. In addition, in step 101 an assignment of a marker center of the machine-readable marker 6 can take place.

In a subsequent step 102, an orientation and a distance of the marker center of the machine-readable marker 6 from the spatial coordinate, i.e. the center 8, of the user-readable marker 4, can be stored in the computer unit. In this case, the distance can be determined manually by a user of the marker device 2 with the aid of the measuring element 14. The side length of the user-readable marker 4 can be read through the measuring element 14, whereby a distance between the center point 8 of the user-readable marker 4 and the machine-readable marker 6 can be detected with the aid of further measuring elements. Knowing the distance of the measuring element 14 to the marker center, the distance from the marker center to the center point 8 can be recorded and stored in the computer unit without the aid of additional aids.

If the measuring element 14 is fixed flush with the user-readable marker 4 immediately adjacent thereto, the machine-readable marker 6 is aligned with respect to the user-readable marker 4.

The features of the invention disclosed in the above description, in the claims and in the drawing may be essential both individually and in any combination in the implementation of the invention in its various embodiments within the scope of the following claims.

Reference symbol list

2

Marker device

4

user-readable marker

6

machine readable marker

8th

Focus

10

Positioning section

12

Centering element

14

Measuring element

16

Measuring section

18

Orientation element

100-102

Procedural steps

Claims (10)

Marker device (2) for position determination with at least one user-readable marker (4), which is fixed to a spatial and/or stationary control body and to which a measured spatial coordinate is assigned, which is stored and retrievable in a computer unit, and with at least one machine-readable marker (6), which is located directly on the user-readable marker (4) adjacent to the control body, which can be detected by an image capture device assigned to the computer unit and identified by the computer unit and to which a marker center in the computer unit can be assigned or is assigned, the orientation and the Distance of the marker center to the spatial coordinate of the user-readable marker (4) can be stored or stored in the computer unit and can be called up. Marker device (2). Claim 1 , characterized in that the user-readable marker (4) comprises at least one n-angular, in particular quadrangular, in particular square, cross-section with edges of equal length, and at least one image element through which a center point (8) of the user-readable marker (4) can be detected , which corresponds to the assigned spatial coordinates and / or that the machine-readable marker (6) comprises at least one n-angular, in particular quadrangular, in particular square, cross section with edges of equal length. Marker device (2). Claim 1 or 2 , characterized in that the machine-readable marker (6) comprises a QR code, an Aruco marker, an AR tag, a barcode, an RFID tag or another tag. Marker device (2) according to one of the preceding claims, characterized in that the machine-readable marker (6) comprises, on the side facing the user-readable marker (4), a user-readable positioning section (10) which comprises a centering element (12) which has a line , which connects the center point (8) of the user-readable marker (4) to the marker center, is aligned or is designed mirror-symmetrically with respect to the line that connects the center point (8) of the user-readable marker (4) to the marker center. Marker device (2). Claim 4 , characterized in that the centering element (12) of the machine-readable marker (6) to the marker center comprises a distance which is in the Computer unit can be stored and/or stored and accessed. Marker device (2) according to one of the preceding claims, characterized in that the positioning section (10) of the machine-readable marker (6) comprises a user-readable optically perceptible measuring element (14) through which a side length of the user-readable marker (4) can be detected. Marker device (2). Claim 6 , characterized in that the measuring element (14) is designed to be mirror-symmetrical - with respect to a line through the center (8) and the marker center. Marker device (2). Claim 6 or 7 , characterized in that the measuring element (14) comprises a user-readable scale or user-readable optically distinguishable measuring sections (16) which can be assigned to a specific length of the user-readable marker (4). Marker device (2) according to one of the preceding claims, characterized in that the machine-readable marker (6) comprises a user-readable orientation element (18), through which an orientation and/or alignment of the machine-readable marker (6) with respect to the user-readable mark (4) is user-readable is. Method for installing a marker device (2) for position determination according to one of Claims 1 until 9 , the at least one user-readable marker (4) and the at least one machine-readable marker (6), which is arranged directly on the user-readable marker (4) adjacent to the control body, which can be detected by an image capture device assigned to the computer unit and can be identified by a computer unit, with the steps: a. If necessary, fixing the user-readable marker (4) on a spatial and/or stationary control body and measuring, assigning and storing a spatial coordinate assigned to the user-readable marker (4) in the computer unit; b. Positioning and fixing the machine-readable marker (6) on the control body and on the user-readable marker (4) and assigning a marker center of the machine-readable marker (6) in the computer unit; and c. Storing an orientation and a distance of the marker center of the machine-readable marker (6) to the spatial coordinate of the user-readable marker (4) in the computer unit.

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