WO2018147752A1

WO2018147752A1 - System and method for shape and size detection of three-dimensional objects.

Info

Publication number: WO2018147752A1
Application number: PCT/PL2018/050004
Authority: WO
Inventors: Marek Krolikowski; Michal WASKIEWICZ
Original assignee: Marek Krolikowski; Waskiewicz Michal
Priority date: 2017-02-09
Filing date: 2018-02-08
Publication date: 2018-08-16
Also published as: PL420434A1

Abstract

A system and a method for detecting the shape and size of three- dimensional objects. The invention may be used in particular for generating virtual 3D models of objects. The system for detecting the shape and size of three-dimensional objects is characterised in that it comprises at least one set of detection units (101) adapted to be arranged in a physically limited measuring space (A) so as to enable physical contact of each detection unit (101) with at least one other detection unit (101) during measurement, each detection unit (101) having a globally unique identifier (ID) and at least one two-way communication port (104) adapted to transmit/receive at least information on the identifier (ID) to/from the adjacent detection unit (101), each detection unit (101) being adapted to store at least the information on the identifier (ID) of the adjacent detection unit (101), a computing unit (108) in communication with at least one detection unit (101) from at least one set of detection units (101) adapted to collect information on at least pairs of identifiers (ID) of adjacent detection units (101).

Description

System and method for shape and size detection of three- dimensional objects.

[0001] The invention relates to a system and a method for detecting the shape and size of three-dimensional objects. The invention can be used in particular for generating virtual 3D models of objects in reverse engineering, for cataloguing historic objects, in medicine (orthopaedics), for producing spare parts, in non-destructive tests (e.g. in aviation) .

[0002] Systems and methods for detecting the shape and size of three-dimensional objects, in particular those using optical techniques, are known in the art. For example, the document US2016245640 discloses a system for scanning objects in three dimensions that comprises a digital scanning system containing a laser light source, a scanning system, a scanning area, an optical detector and a signal control and processing system. The scanning system can acquire the dimensions of objects, such as the length, width and height of said objects. The scanning area is the area where items can be scanned using a digital scanning system. The optical sensor can be an integral part of the scanning system and can be used to detect objects located below the scanning area. The signal processing and control system can be an integral part of the scanning system and can process the signal generated by the optical sensor.

[0003] However, this system has a disadvantage of not guaranteeing the acquisition of an accurate and comprehensive model of a three-dimensional scanned object, in particular it is impossible to scan the inside of an object when the object is relatively small in relation to the scanning device or the access to the inside is limited.

[0004] An exemplary known optical system for scanning objects in three dimensions also has the disadvantage of being stationary and not suitable to be moved, so that it prevents its use it in several different locations in a short time.

[0005] Therefore, the invention is designed to provide a system and a method for detecting the shape and size of three- dimensional objects that would provide fast, inexpensive and nondestructive scanning of three-dimensional objects, in particular their inside, while ensuring proper precision of the three- dimensional object model.

[0006] The essence according to the invention lies in the fact that the system detecting the shape and size of three-dimensional objects comprises at least one set of detection units adapted to be arranged in a physically limited measuring space so as to enable physical contact of each detection unit with at least one other detection unit during measurement, wherein each detection unit has a globally unique identifier and at least one two-way communication port adapted to transmit/receive at least information on the identifier (ID) to/from the adjacent detection unit, wherein each the detection unit is adapted to store at least the information on the identifier (ID) of the adjacent detection unit, a computing unit in communication with at least one detection unit from at least one set of detection units adapted to collect information on at least pairs of identifiers of adjacent detection units .

[0007] Preferably, the system comprises at least one measuring vessel .

[0008] Preferably, the computing unit is adapted to collect information on pairs of communication ports and/or pairs of identifiers ID of the detection units.

[0009] Preferably, the detection unit further comprises a module for wireless communication with an external computing unit .

[0010] Preferably, the detection unit is of spherical shape.

[0011] Preferably, the detection unit has the shape of a regular polyhedron, in particular a regular dodecahedron.

[0012] Preferably, the detection unit comprises at least one colour detector .

[0013] In another embodiment, the essence according to the invention lies in that the method of detecting the size and shape of three-dimensional objects is characterised in that it comprises: providing a physically limited measuring space A, arranging at least a first set of detection units in the physically limited measuring space A, then receiving, by each detection unit of at least one first set of detection units, information uniquely identifying each of the directly adjacent detection units from at least the first set of detection units, receiving by the computing unit of information collected by at least one detection unit from at least the first set of detection units, processing the collected information so as to obtain a spatial model of the relative position of at least the first set of detection units, using the above as a basis for determining the size and shape of the spatial structure B formed by at least the first set of detection units based on at least information on the size and shape of at least a portion of the spatial structure B formed by at least the first set of detection units, determining the size and shapes of the scanned three-dimensional object.

[0014] Preferably, the physically limited measuring space A is the interior of the object being scanned.

[0015] Preferably, the physically limited measuring space A is the interior of the measuring vessel, and the size and shape of the three-dimensional object being scanned, placed in the measuring vessel is also determined based on the size and shape of the measuring vessel.

[0016] Preferably, the computing unit ( 108 ) receives the information collected by each detection unit from at least the first set of detection units using one of the communications: Bluetooth or NFC.

[0017] Preferably, the information collected by each detection unit from at least the first set of detection units is sent to the computing unit by the communication ports of the detection unit.

[0018] Preferably, the information collected by each detection unit from at least the first set of detection units is sent to the computing unit by the communication ports of the measuring vessel.

[0019] In line with the idea of the structure of a system for detecting the size and shape of a three-dimensional object according to the invention, a three-dimensional object scanning is provided by acquiring its negative image or information on its surface . [0020] The use of a distributed system of a plurality of detection units which freely fill the measurement space allows for scanning objects that have convex and concave portions of surface, in particular internal spaces inaccessible or not easily accessible for other techniques.

[0021] Thus, the use of a distributed system of a plurality of detection units allows for scanning internal surfaces, e.g. openings, recesses, cavities etc.

[0022] Another advantage of the system according to the invention is also the option of partial scanning of three- dimensional objects by partially surrounding them with detection units. This, as needed, allows for reducing the need for computing power of a computing unit and, in another case, the need for a given number of detection units.

[0023] Also, by using the distributed system of a plurality of detection units, it is possible to collect information on the structure formed by these units in parallel, which provides very fast scanning.

[0024] Another advantage of using the distributed system of a plurality of detection units is the option of scanning moving objects. Detection units 'track¹ the movement of the scanned object, aiming to fill the measurement space.

[0025] The provision of a measuring vessel allows for providing a measuring space with a constant and known volume and shape .

[0026] Furthermore, the provision of a measuring vessel allows for providing physical limits of the dispersed measurement system.

[0027] The distributed system of a plurality of detection units performing scanning by contacting the scanned object yields high precision of scanning.

[0028] In addition, many advantages arise from the possibility of easy assembly and disassembly of the system according to the invention. The lack of mechanical connections between system components and the simplicity of the design enable make the scanner easily removable and movable.

[0029] The system for detecting the shape and size of three- dimensional objects according to the invention has been presented in detail in the embodiments with reference to the attached drawings in which: Fig. 1 shows a general view of the system for detecting the shape and size of three-dimensional objects according to the invention; Fig. 2 shows a general view of a single detection unit according to the invention;

Fig. 3 shows a general view of several adjacent detection units according to the invention;

Fig. 4 shows a conceptual diagram of the system for detecting the shape and size of three-dimensional objects according to the invention;

[0030] The terms in the description are to be understood as follows: 'in communication', 'in connection' refers to any type of wired or wireless connection, in particular direct or indirect, i.e. involving another intermediate component/device.

[0031] The system for detecting the shape and size of three- dimensional objects according to the invention can work in various places, e.g. in closed rooms such as laboratories, hospitals, factories, as well as outdoors. This is possible due to its design, which is easy to install and convenient for transport. In particular, the system according to the invention can be used for generating virtual 3D models of objects in reverse engineering, for cataloguing historic objects, in medicine (orthopaedics), for producing spare parts, in non-destructive tests (e.g. in aviation ) .

[0032] Fig. 1 shows a general view of the system for detecting the shape and size of three-dimensional objects. In the first embodiment, it comprises a measuring vessel 2 of any shape, preferably of the cuboid shape. The measuring vessel 2 can be made of any non-conductive material, so as not to interfere with the operation of the other system components. In another embodiment, the measuring vessel 2 can be made of a conductive material. In one variant, the measuring vessel 2 can be closed in a sealed manner. This enables operation in adverse environmental conditions such as dust, moisture, etc. The size and shape of the measuring vessel 2 is adapted to the specific objects to be scanned. The measuring vessel 2 is designed to limit a measurement space A.

[0033] In the measuring vessel 2, an object 3 intended to be scanned and modelled is located in the limited measurement space A. The remainder of the measurement space A is thoroughly filled with a plurality of detection units 101, so that they surround the object being scanned 3. The size of the detection units 101 is small or very small compared to the size of the object being scanned 3. A set of detection units 101 in an established position forms a spatial structure B. A desired three-dimensional model of the object 3 is a complement of the structure B to the measurement space A.

[ 0034 ] Fig. 2 shows details of the detection unit 101. The housing 102 of the detection unit 101 can be made of a conductive or non-conductive material depending on the type of technology used for communication between the detection units 101 and depending on the power supply mode. The housing 102 of the detection unit may have the shape of a sphere or a polyhedron, preferably of a regular polyhedron. Preferably, the housing 102 may be a regular dodecahedron.

[ 0035 ] The detection unit 101 comprises at least a memory 103 for storing a globally unique identifier ID. In the housing 102 of the detection unit 101 there is at least one two-way communication port 104. Preferably, in the case of a polyhedron, the detection unit 101 comprises one communication port on each wall. Preferably, in the case of a tetrahedron, the detection unit 101 comprises four communication ports 104, one on each wall. In the case of a dodecahedron, the detection unit 101 has twelve communication ports 104, also one on each wall. Communication ports 104 can be optical, magnetic or electrical ports. Communication ports 104 are designed for exchanging data between detection units 101, in particular for collecting data on adjacent detection units 101, including information on identifiers ID of adjacent detection units 101. In one variant, each communication port has a unique identifier IDP.

[ 0036] The housing 102 may additionally accommodate a module

105 for wireless communication with an external computing unit 108 in which the data is further processed. This may be for example a Bluetooth module. In another variant, the information from the detection units 101 to the external computing unit 108 can be sent by the communication ports 104. Each detection unit 101 is powered by an internal battery 106 that can be charged for example by physically connecting a charger in the case of large detection units 101 to a dedicated connector in the detection unit 101, or through wireless inductive charging or by energy supplied as light radiation, vibrations or temperature.

[ 0037] As mentioned above, the system for detecting the shape and size of three-dimensional objects comprises a plurality, i.e. several tens, several hundred or more detection units 101, preferably of the same shape and size, which are autonomous devices. In another embodiment, the detection units 101 may have several different known sizes. The detection units 101 freely fill the measurement space A. They form a 3D scanner having a distributed architecture.

[ 0038] Fig. 3 shows a detailed view of a set of several detection units 101 directly adjacent to one another during measurement. In the established relative position of the detection units 101 and with the number of communication ports 104 selected correspondingly with the shape of the housing 102, each communication port 104 of a given detection unit 101 is in communication with at least one communication port 104 of another communication unit 101 that is directly adjacent to a specific detection unit 101. The pre-determined position of the communication ports 104 on the housing 102 and the ability of the communication port 104 to read a unique identifier ID from the adjacent detection unit 101 enables for collecting sufficient information to model the relative position of the detection units 101 and, as a result, to develop a mathematical model of the spatial structure B, which is formed by detection units 101.

[ 0039] For the purpose of creating the model of relative position of the detection units 101, it is possible to use the graph theory. In particular, it is possible to create an adjacency matrix of the detection units 101 and to properly process this information in order to obtain coordinates defining the relative position in space of each detection unit 101. In this variant, it is sufficient to know the unique identifier ID of each detection unit 101.

[ 0040 ] In another variant, when each communication port 104 also has its own unique identifier IDP, memory 103 in each detection unit 101 stores collected unique identifiers IDP of the communication ports 104 that have established communication during the measurement with the communication ports 104 of that specific detection unit 101. In this case, once the computing unit 108 has received data from all the detection units 101, corresponding edge graphs are prepared based on the information on identifiers ID of the detection units 101 and information on IDP port identifiers, i.e. on the pairing of specific communication ports 104. In an embodiment where the communication ports 104 have their unique identifiers IDP, it is possible to improve the precision of the measurement. This is because an unambiguous information on the relative position of these two detection units 101 is obtained. This makes it easier to create the measurement space model B, since it does not require information from a larger number of detection units 101 in order to determine the relative position of the detection units 101 (there is no need to use triangulation or other such methods) .

[0041] Fig. 4 shows a conceptual diagram of the system for detecting the shape and size of three-dimensional objects. All the detection units 101 collect relevant information in their memory 103, including information allowing for the identification of adjacent detection units 101 and their orientation in relation to themselves. Then, they send this information in parallel to the external computing unit 108. In another embodiment, the data transfer process may be partially serial if the data is sent by optical and/or magnetic ports through other detection units 101. The external computing unit 108 may be a laptop or a PC, respectively, or any other device comprising a memory and a processor, respectively. The computing unit 108 is not necessarily physically located close to the detection units 101 - it is possible to use the computing units 108 in the form of remote servers, including distributed architectures.

[0042] To transfer data from the detection units 101 to the computing unit 108 wireless communication can be used such as Bluetooth or NFC. In another embodiment, communication may take place via communication ports 104. For example: the detection unit 101 sends information to other detection units 101 that it is currently in listening mode and can receive data. When another detection unit 101 receives such information, it can then start broadcasting all the information it has about the scan performed, namely the information generated by itself or received from other detection units in a similar communication process. The ports are "closed" when the detection unit 101 does not receive any other information after n notifications about switching to the listening mode. An exemplary diagram of the process of collecting and processing data is shown in fig. 4.

[ 0043 ] In an alternative embodiment, the detection unit 101 may comprise at least one colour detector 106, for example a TAOS3200 or TCS3210 sensor from TAOS, which will allow for detecting the colour of the scanned three-dimensional object 3.

[ 0044 ] In yet another embodiment, the measuring vessel 2 can comprise corresponding optical and/or magnetic and/or NFC ports that allow for transmitting information to the computing unit 108. Additional ports can also improve the precision of the measurement. In addition, it is possible to install a triggering component, for example an illuminator or a flash lamp for triggering measurement - one variant provides for triggering the moment of scan recording by a flash of light or a similar solution. Additionally, it is possible to install shaking means in the measuring vessel 2, designed to improve the arrangement of the detection units 101, improve their contact with each other and contact with the object being scanned. As a result of shaking, it is possible to obtain a plurality of "frames" of the scan, which, through subsequent processing (for example averaging) can contribute to the improvement of the precision of the scan.

[ 0045] The processing unit 108 is designed for processing information collected from the detection units 101. Based on the information on adjacent detection units 101, a model of relative arrangement of all the detection units 101 in relation to each other is created. This provides a three-dimensional negative model of the scanned object 3.

[ 0046] The computing unit 108 performs a series of operations, including algorithms that eliminate the impact of shape imperfections of the housing 102 of the detection units 101, and of the resulting displacements, on the precision of the model.

[ 0047 ] The measurements in the system according to the invention can take place cyclically, almost continuously, which is an advantage if the object 3 being scanned is moving. The distributed system of the detection units 101 allows them to dynamically assume further established positions. Measurement data from successive positions can be read and modelled by the computing unit 108. The computing unit 108 allows for storing the instantaneous states of moving three-dimensional objects 3 or reading the instantaneous moving states stored in the detection units 101, and for subsequently reproducing an animated motion of the three-dimensional object. It is also possible to store moving states in yet another device if it is in communication with the detection units 101.

[0048] The method of detecting the size and shape of three- dimensional objects comprises the following steps. Usually, first a measuring vessel 2 is provided, which is correlated in terms of shape and size to the object 3 being scanned. Where only the inside of the object 3 being scanned is scanned, the object being scanned acts simultaneously as a measuring vessel 2. Then the detection units 101 are arranged in the vessel. Depending on the size of the object 3 being scanned and its shape, positioning of the detection units 101 and the object 3 can take place in multiple steps. For example, at least a first portion of the measuring units 101 is introduced to the measuring vessel 2 so as to cover the bottom and to ensure the presence of the scanner structure on each side of the three-dimensional object 3 being scanned. Next, the object 3 being scanned is placed on at least the first layer of the detection units 101. Next, the remaining space in the measuring vessel 2 is filled with the detection units 101. If necessary, before the last detection units 101 are placed, the three-dimensional object 3 is moved so that the measuring units 101 already located in the vessel adjacently surround said object 3.

[0049] Once the arrangement of the detection units 101 is established in space, the computing unit 108 triggers a scan of a predetermined duration. As mentioned before, each detection unit 101 has a determined number of two-way communication ports 104 evenly distributed over the entire surface of the housing 102. During said scanning, each two adjacent detection units 101 (A and B) exchange their identifiers ID via ports 104 in the vicinity of the interface of the detection units 101 (port X in the detection unit 101a and port Y in the detection unit 101b) . Each detection unit 101 remembers the received identifiers ID together with the information on the ports 104 used ^"during communication, both its own (port X) and that of the other detection unit 101 (Y) . On this basis, the detection unit 101a knows that the detection unit 101b is adjacent with the communication port 104 (Y) to the port X of the detection unit 101a. Once the scanning is over, the detection units 101 can be freely oriented in relation to each other for any period of time.

[0050] The computing unit 108 can read the information stored from each of the detection units 101 and process the said collected information at any time. On the basis of the list of pieces adjacent to each detection unit 101 prepared as above, an orientation model of all the detection units 101 in relation to each other is created, and then a model of space B filled by said detection units. After complementing the model of this space B to the measurement space A, the model C of the object 3 being scanned is obtained. In another embodiment, it is possible to obtain model C of the scanned object 3 based only on information on the contact surface of the detection units 101 and of the scanned object 3.

[0051] The use of a distributed scanning structure in the system in the form of a set of detection units 101 moving relative to each other as a result of the movement of the object being scanned allows for obtaining a scanner of three-dimensional moving objects 3.

[0052]

Reference numbers:

2 - measuring vessel

3 - three-dimensional object to be scanned

100 - system

101 - detection units

102 - housing of a detection unit

103 - memory of a detection unit

104 - communication port of a detection unit

105 - wireless communication module

106 - colour detector

108 - external computing unit

ID - detection unit identifier

IDP - communication port identifier

A - measurement space

B - spatial structure composed of detection units

C - three-dimensional object model

Claims

1. A system for detecting the size and shape of three-dimensional objects, characterised in that it comprises:

- at least one set of detection units (101) adapted to be arranged in a physically limited measuring space (A) so as to enable physical contact of each detection unit (101) with at least one other detection unit (101) during measurement, each detection unit (101) having a globally unique identifier (ID) and at least one two-way communication port (104) adapted to transmit/receive at least information on the identifier (ID) to/from an adjacent detection unit (101), each the detection unit (101) being adapted to store at least the information on the identifier (ID) of the adjacent detection unit (101);

- a computing unit (108) being in communication with at least one detection unit (101) from at least one set of detection units (101) adapted to collect information on at least pairs of identifiers (ID) of adjacent detection units (101);

2. The system according to claim 1, characterised in that it comprises at least one measuring vessel (2) .

3. The system according to claim 1 or claim 2, characterised in that the computing unit (108) is adapted to collect information on pairs of communication ports (104) and/or pairs of identifiers (ID) of the detection units (101).

4. The system according to claim 1 or claim 2 or claim 3, characterised in that the detection unit (101) further comprises a module (105) for wireless communication with an external computing unit (108) .

5. The system according to claim 1 or claim 2 or claim 3, characterised in that the detection unit (101) is of spherical shape .

6. The system according to claim 1 or claim 2 or claim 3 or claim 4, characterised in that the detection unit (101) has the shape of a regular polyhedron, in particular a regular dodecahedron.

7. The system according to claim 1 or claim 2 or claim 3 or claim 4 or claim 5, characterised in that the detection unit (101) comprises at least one colour detector (106) .

8. A method for detecting the size and shape of three-dimensional objects, characterised in that it comprises: providing a physically limited measuring space (A) ,

- arranging at least a first set of detection units (101) in a physically limited measuring space (A) , and then

- receiving by each detection unit (101) from at least the first set of detecting units (101) information uniquely identifying each of the directly adjacent detection units (101) from at least the first set of detection units (101),

- receiving by a computing unit (108) of information collected by at least one detection unit (101) from at least the first set of detection units (101), processing the collected information so as to obtain a spatial model of the relative position of at least the first set of detection units (101) .

- determining based on the above the size and shape of a spatial structure (B) formed by at least the first set of detection units (101),

- based on at least the information on the size and shape of at least a portion of the spatial structure (B) formed by at least the first set of detection units (101), determining the size and shape of a scanned three-dimensional object (3).

9. The method according to claim 8, characterised in that the physically limited measuring space (A) is the interior of the object being scanned (3).

10 The method according to claim 8, characterised in that the physically limited measuring space (A) is the interior of a measuring vessel (2), and the size and shape of the three- dimensional object (3) being scanned, placed in the measuring vessel (2) is also determined based on the size and shape of the measuring vessel (2) .

11. The method according to claim 8 or claim 9 or claim 10, wherein the computing unit ( 108 ) receives the information collected by each detection unit (101) from at least the first set of detection units (101) using one of the communications: Bluetooth or NFC.

12. The method according to claim 8 or claim 9 or claim 10 or claim 11, wherein the information collected by each detection unit (101) from at least the first set of detection units (101) is sent to the computing unit (108) by communication ports (104) of the detection unit (101) .

13. The method according to claim 8 or claim 9 or claim 10 or claim 11, wherein the information collected by each detection unit (101) from at least the first set of detection units (101) is sent to the computing unit (108) by communication ports (104) of the measuring vessel (2) .