A METHOD AND A DEVICE FOR PRODUCING THREE-DIMENSIONAL PHYSICAL REPRODUCTIONS

Abstract: A method and a device for producing three-dimensional physical reproductions from a scan data collection comprising a three-dimensional representation of a scanned area or object, which scan data collection has been obtained by using a remote sensing technique. The scan data of the scan data collection are processed into suitable control data for controlling a processor-controlled machining device for the purpose of producing a three-dimensional physical reproduction associated with the scanned area or object.

Description: A method and a device for producing three-dimensional physical reproductions. In practice the process of producing three-dimensional physical reproductions is used, among others, for converting objects designed by means of CAD (Computer Aided Design) techniques into three- dimensional real physical reproductions. To this end a starting material such as wood, plastic or metal on the basis of the CAD information is processed by means of suitable machining devices by removing material therefrom or adding material thereto in such a manner that a three- dimensional replica of the designed object is obtained. Scale model making is a technique which is used for producing three-dimensional physical reproductions of built-on areas and undeveloped areas, in general topographic and geographic structures. Buildings are reproduced to scale as accurately as possible, for example by mechanically working a starting material, such as wood, on the basis of construction drawings and/or photos. A building may thereby consist of a number of separately reproduced parts, whilst the scale model as a whole is made by assembling the separately made buildings, roads, street furniture, trees, landscapes and the like. It will be appreciated that the production of scale models requires a high degree of expertise, and is generally a time-consuming job. In practice, public and semi-public bodies, administrative bodies (district water boards, the Forestry Commission, polder boards), large construction companies, architects, town and country planners, city developers and property developers, but also museums and the tourist industry appear to have a need for real three-dimensional physical reproductions of topographic and geographic structures, such as city skylines, coastlines, mountains, islands, volcanoes, river areas and the like in the form of, for example, a reduced scale replica of the the areas or objects. In particular for the tourist industry, scale model making is a technique which is too expensive and unsuitable for serial production, whilst the degree of reality or resemblance or the three- dimensional physical reproductions is often inadequate, and wherein an (emotionally) sufficiently recognizable reproduction can only be obtained by making an irresponsibly large effort. Accordingly, it is an object of the present invention to provide a method by means of which (large-scale, if desired) three- dimensional physical reproductions can be made of topographic and/or geographic structures. To that end the invention provides a method which is characterized by the following steps: - providing a scan data collection comprising a three- dimensional representation of a scanned area or object using a remote sensing technique; - processing scan data of the scan data collection into control data suitable for controlling a processor-controlled machining device for the purpose of producing a three-dimensional reproduction associated with the scanned area or object; and - providing the reproduction in a three-dimensional physical shape by means of the machining device. The invention is based on the insight that the current remote sensing techniques, with which height resolutions in the order of 15 cm can be obtained, are capable of providing a scan data collection which can be adapted for controlling a machining device, by means of which three-dimensional physical reproductions can be made. The method according to the invention opens the way for the production (in serial production, if necessary) of replicas of famous skylines, for example Hong Kong, New York, of well-known coastlines, for example Dover, Copacabana, adventurous mountains, such as the Eiger, the Matterhorn, mount Fujiyama, the Mont Blanc, elitist beaches, such as St. Tropez, Monte Carlo, pastoral islands, such as Hawaii, Catalina, Bali, Mont St. Michel, Grand Canaria, ski resorts, such as St. Moritz, Aspen, Zer att, famous volcanoes, among which Vesuvius, Etna, St. Helens, but also picturesque places and famous objects such as the Great Chinese Wall, Niagara Falls, Grand Canyon and the like. These areas or objects can be provided in the form of miniatures, whether or not on a base or pedestal, whereby the base or pedestal and the reproduction in question may be made in one piece. Besides this use for touristic purposes, the method according to the invention is also excellently suited for producing physical reproductions of topographic and/or geographic structures, such as built-on areas and undeveloped areas, river areas, coastal areas and dune areas, water-collection areas, landscapes for use by public bodies and semi-public bodies, landscape administrators, architects, town and country planners, city developers and property developers, etc. The physical reproductions may be used advantageously for planning and providing information on urban renewal , urban expansion, landscaping plans, etc., but also for signposting and cadastral applications. Remote sensing techniques which are suitable for the present invention are known by names such as "3D-aerial laser scanning", "3D-aerial radar scanning", "3D-satellite scanning" or "airborne scanning", whereby a scan data collection in the form of a "cloud" or collection of digital points is provided. The points in the cloud comprise three- dimensional information. In a Cartesian x, y, z coordinate system, the points of a cloud represent a position in the horizontal plane plus the associated height of the respective position relative to the surface of the earth. All points together represent the portion of the earth ' s surface that has been scanned and any buildings and other (natural) objects that are present thereon. For the purpose of the invention it is also possible to use other suitable remote sensing techniques, provided that three- dimensional information of the scanned object and/or area is obtained. The method according to the invention is particularly suitable for producing machined three-dimensional reproductions by subjecting scan data of the scan data collection obtained to processing operations, such as filtering, scaling and/or the addition of data. The processed data can then be used for producing three-dimensional physical reproductions, whereby uneven scaling makes is possible to provide a deliberate misrepresentation, wherein existing objects have been removed or substituted for others, etc. It will be appreciated, that physical reproductions which have been produced in this way are particularly suitable for professional purposes, such as urban renewal , urban expansion, landscape renovation, landscape expansion and the like. It is also possible, however, to provide replicas for touristic and commercial purposes wherein specific buildings or landscape elements are shown in a more pronounced manner or wherein buildings or landscape elements are deliberately misrepresented. Instead of, or in addition to the scan data, also the control data for controlling the machining devices may be subjected to data processing operations such as filtering, scaling and/or the addition of data. The physical reproduction can be provided both as a positive reproduction and as a negative reproduction, analogously to photography, whereby a negative physical reproduction may be used in particular as a mould for producing mouldings. The physical reproduction in question may be made of essentially any suitable material or a combination of materials, such as plastic, wood, ceramics, glass, stone and metal , including brass, stainless steel, copper, bronze, aluminium, whether or not in various colours. The invention furthermore relates to a device for producing three-dimensional physical reproductions, which device comprises processor means and mechanical machining means controlled by the processor means, comprising processing means for processing scan data obtained by remote sensing into control data for the processor means for the purpose of producing a three-dimensional physical reproduction of a scanned area or object being represented by the scan data. The invention will now be explained with reference to figures illustrated in the drawing, wherein: Figure 1 schematically shows a remote sensing technique which is suitable for the purpose of the invention; Figure 2 is a flow diagram showing the steps according to the invention; Figure 3 is a block diagram showing the main components of a machining device according to the invention; Figure 4 is a schematic side view of a topographic miniature obtained using the method according to the invention. Figure 1 schematically shows the principle of remote sensing, in particular "3D-aerial laser scanning", whereby an area 1 is scanned from the air by an aeroplane 2. The aeroplane 2 flies above the area 1 in the direction of arrow 3. The area 1 is scanned point by point, as indicated by dots 5, by means of a laser beam 4. The laser beam 4 thereby moves crosswise, in direction B, whilst the aeroplane moves in longitudinal direction L of the area 1. A laser scanner (not shown) mounted in the aeroplane 2 registers the time difference between the emission of a laser beam 4 and the receipt of the laser signal which is reflected back to the aeroplane 2 by objects in the area 1. The time difference is a measure for the relative height of the objects in the area 1. For an accurate positioning of the dots 5 use is made of the well-known GPS (Global Positioning System), by means of a GPS ground station 6 and GPS satellites 7, 8 and 9. The position information as well as the height information of the dots 5 forms a scan data collection which comprises a three-dimensional representation of the scanned area 1. With this type of "3D-aerial laser scanning", also called "Airborne Laser Scanning", a height accuracy of 10 - 15 cm can be achieved, whereby the aeroplane 2 flies at an altitude of about 900 m above the area 1. The scanned data are delivered in the form of a "cloud" or collection of digital points, whereby an area having a length L and a width B of 1 by 1 km can be represented by 40,000 scanned spots or even more, which corresponds with one measurement per 20 - 25 . For more detailed information about this type of remote sensing reference is made to a publication "Airborne Laser Scanning for Elevation Mapping", by Chung Han San in GIM, November 1995, Vol. 9, pp. 24-26. Instead of using the above-described laser scan, for the purpose of the invention, it is also possible to use the so-called "3D- aerial radar scanning", wherein a radar beam rather than a laser beam 4 is used for scanning, and the so-called "3D-satellite scanning", wherein the area 1 is scanned from a satellite rather than from an aeroplane. The invention is not limited to these types of remote sensing. In fact it is possible to use any similar technique wherein scan data are produced in, for example, the form of a cloud of digital points, whereby each point includes three-dimensional information with regard to the position 5 in the area 1 and the (relative) height of the respective location, for example in the form of an x, y, z coordinate system. Figure 2 is a flow diagram, which illustrates the successive steps of the method according to the invention. Block 10, "remote sensing", represents the step of scanning an intended area or an intended object in an area, and the provision of a scan data collection comprising a three-dimensional representation of the scanned area or object, for example in the form of a cloud of digital points as described with reference to Figure 1. The obtained scan data as a whole or in part, may be processed into control data as indicated in block 11, for controlling a processor-controlled machining device for the purpose of producing a three- dimensional physical shape or model. The processed scan data and/or control data can be selectively subjected to one or more data processing operations, such as filtering, (partial) scaling and/or the addition of data, as illustrated in block 12. By processing scan and/or control data in this manner, it is possible to produce physical reproductions which deviate from the real situation, for example in order to show specific objects in a more pronounced manner or in order to obtain a reproduction wherein objects have been omitted or replaced by new objects. The obtained control data or the processed control data are then fed to a machining device, as illustrated in block 13, for the purpose of producing three-dimensional physical reproductions. Machining devices which are suitable for this purpose are known in practice, for example a machining device of the type Benchman (TM), VMC 5000 Machining Centers, or a machining device of the type hyperMILL (TM) . Suitable software for the processing of scan data into control data is likewise known in practice, for example under the name of hyperDIGIT (TM) . Suitable analog and/or digital processing techniques for data processing operations such as filtering, scaling and the removal and/or substitution of data are known in practice and need not be explained to those skilled in the art. Of course it is also possible to use other machines and/or devices besides the aforesaid machining devices and software for producing three-dimensional physical reproductions on the basis of control data. Figure 3 is a block diagram of an embodiment of a device for producing three-dimensional physical reproductions in accordance with the present invention. The device 15 comprises a processor 16, such as a microprocessor, and memory means coupled thereto, such as a ROM (Read Only Memory) programme memory and a RAM (Random Access Memory) working memory 18. The microprocessor 16 controls process tooling means 19, which may have the form of mechanical machining means, such as milling cutters, saws, drills and the like, or means for applying material or causing material to grow on a starting material for the purpose of producing the three-dimensional physical reproduction, for example a stereo lithography machine. In accordance with the invention, means 20 are added for processing the scan data collection obtained by remote sensing, which scan data collection is fed to means 20 via an interface I 21. The means - 5 20 for processing the scan data may comprise a processor, such as a microprocessor. In a preferred embodiment of the device according to the invention the processing means 20 are integrated in the processor means 16 in the form of suitable software which is stored in the programme memory 17. 10 Those skilled in the art will appreciate that Figure 3 only shows those components that are essential for a correct understanding of the invention. The device 15 may comprise further components, such as monitoring means and further control means (not shown). Figure 4 is a side view of a three-dimensional physical 15 reproduction provided in accordance with the invention, which may be made in one piece of a starting material such as plastic, wood, ceramics, glass, stone and metal , including brass, stainless steel, copper, bronze, aluminium or any other suitable material. The particular physical reproduction is provided in 20 the form of a miniature 22, whereby the areas and/or objects 24 obtained from the scan data are present on a pedestal 23. Figure 4 shows a so-called "positive" reproduction, wherein the area and/or the objects 4 are depicted in conformity with the real situation. It is also possible, however, to produce a "negative" 25 reproduction of the area and/or the objects 24 in question, for example in the form of a mould for forming mouldings. As already described in the introduction, the method according to the invention may be used for a wide variety of applications, both for professional purposes such as town and country planning, property 30 development and the like, but also for the commercial production of physical reproductions of, for example, tourist attractions and the like. A physical reproduction thus produced in accordance with the invention can be selectively subjected to further processing operations, such as painting, etching, immersion in a paint bath and the like.

Claims: CLAIMS 1. A method for producing three-dimensional physical reproductions, characterized by the steps of: - providing a scan data collection comprising a three- dimensional representation of a scanned area or object using a remote sensing technique; - processing scan data of the scan data collection into control data suitable for controlling a processor-controlled machining device for the purpose of producing a three-dimensional reproduction associated with the scanned area or object; and - providing the reproduction in a three-dimensional physical shape by means of the machining device. 2. A method according to claim 1, characterized in that said scan data collection is obtained as a "cloud" of digital points using a remote sensing technique such as "3D-aerial laser scanning", "3D-aerial radar scanning", "3D-satellite scanning" or another technique which is used for remote aerial sensing purposes, wherein points in the points cloud comprise three-dimensional information. 3. A method according to one or more of the preceding claims, characterized in that the scan data of the scan data collection are subjected to one or more data processing operations, such as filtering, scaling and/or the addition of data for the purpose of providing processed scan data, which processed scan data are processed into control data for controlling the machining device. 4. A method according to one or more of the preceding claims, characterized in that control data are subjected to one or more data processing operations, such as filtering, scaling and/or the addition of data for the purpose of providing processed control data, which processed control data are used for controlling the machining device. 5. A method according to one or more of the preceding claims, characterized in that said three-dimensional physical reproduction is obtained by subjecting a starting material to a material-removing operation. 6. A method according to one or more of the claims 1 - 4, characterized in that said three-dimensional physical reproduction is obtained by applying further material to a starting material. 7. A method according to one or more of the preceding claims, characterized in that a positive physical reproduction is provided. 8. A method according to one or more of the claims 1 - 6, characterized in that a negative physical reproduction is provided. 9. A method according to one or more of the preceding claims, characterized in that said physical reproduction is made of a material or of a combination of materials such as plastic, wood, ceramics, glass, stone and metal, including brass, stainless steel, copper, bronze, aluminium. 10. A three-dimensional physical reproduction made in accordance with the method of one or more of the preceding claims. 11. A three-dimensional physical reproduction according to claim 10, characterized by a base or pedestal which supports said reproduction. 12. A three-dimensional physical reproduction according to claim 11, characterized in that said base or pedestal and said reproduction are made in one piece. 13. A three-dimensional physical reproduction according to one or more of the preceding claims, characterized in that said reproduction is made in the shape of a mould. 14. A three-dimensional physical reproduction according to one or more of the preceding claims, characterized in that said reproduction is provided in the shape of a topographic and/or geographic miniature. 15. A device for producing three-dimensional physical reproductions, comprising processor means and mechanical machining means controlled by said processor means, characterized by processing means for processing scan data obtained by remote sensing into control data for said processor means for the purpose of producing a three-dimensional physical reproduction of a scanned area or object being represented by said scan data. 16. A device according to claim 15, characterized in that said processing means are arranged for filtering, scaling and/or the addition of data for the purpose of providing processed scan data and/or processed control data. 17. A device according to claim 15 or 16, characterized in that said processing means comprise suitably programmed processor means.

Inventors: DE LANGE ANTHONIE ARIE, DE LANGE, ANTHONIE, ARIE
Applicants: LANGE ANTHONIE ARIE DE, DE LANGE, ANTHONIE, ARIE
Application year: 1998
Main classification: G09B25
IPC codes: G05B19, G09B25