GB2517713A

GB2517713A - Three dimensional scanners

Info

Publication number: GB2517713A
Application number: GB201315323A
Authority: GB
Inventors: Mark Waterman
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-08-28
Filing date: 2013-08-28
Publication date: 2015-03-04
Also published as: GB201315323D0

Abstract

A three dimensional scanner comprising a pair of supports which may be mounted on a base, with three concentric rings comprising an outer ring, a middle ring and an inner ring, and three rotational sensors. The outer ring is free to rotate about diametrically opposed points by which it is attached to the supports; the middle ring is free to rotate about diametrically opposed points by which it is attached to the inner surface of the outer ring and that are at right angles to the axis of rotation of the outer ring.he inner ring is free to rotate about diametrically opposed points by which it is attach it to the inner surface of the middle ring and that are at right angles to the axis of rotation of the middle ring. At least one imaging device, in one embodiment this is a laser and laser detector form an image of an object mounted the within the inner ring.

Description

Three dimensional scanners [0001] This invention relates to a device to enable objects to be scanned in three dimensions.

[0002] The primary application of the invention is to produce a three dimensional computer model of a real object which can then be replicated as it is or after modification of the model, by means of a three dimensional printer or other suitable manufacturing equipment such as a milling machine.

[0003] Existing method of scanning small objectives have difficulty profiling all surfaces and are generally expensive.

[0004] Positional information for each of the gyroscopic rings during rotation combined with the distance from a fixed laser is used to generate surface points that can be connected with suitable software to form a three dimensional computer model of the object.

[0005] According to the present invention a device for scanning an object in three dimensions comprises a pair of supports, three concentric rings, the three concentric rings comprising an outer ring, a middle ring and an inner ring.

The outer ring is free to rotate about diametrically opposed points by which it is attached to the supports. The middle ring is free to rotate about diametrically opposed points by which it is attached to the inner surface of the outer ring and that are at right angles to the axis of rotation of the outer ring. The inner ring is free to rotate about diametrically opposed points by which it is attach it to the inner surface of the middle ring and that are at right angles to the axis of rotation of the middle ring.

[0006] Normally the supports are attached to a base, but this would not preclude other means of mounting the supports, such a vice or in clamps, for

example.

[0007] It can be thus appreciated that the invention is based around a gyroscopic frame that is used to rotate the object to be scanned relative to a fixed laser and detector.

[0008] Rotational positional data for the inner ring relative to the middle ring is provided by suitable resolver or rotary encoder [0009] Rotational positional data for the middle ring relative to the outer ring is provided by suitable resolver or rotary encoder [0010] Rotational positional data for the outer ring relative to a fixed mounting point and the position of the laser is provided by suitable resolver or rotary encoder [0011] The three rings may be rotated via motor or by hand, each different position of the rings providing data to build up a computer model of the surface of the object being scanned [0012] The object to be scanned is fixed to the inner ring via a support structure that can be removed from the model with suitable software before manufacture or physically afterwards.

[0013] One embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing which shows the basic configuration of a three dimensional scanner according to the invention; [0014] In figure 1 a three dimensional scanner 1 comprises a pair of supports 5 fixed to a base 14, three concentric rings 2, 3, 4, the three concentric rings comprising an outer ring 2, a middle ring 3 and an inner ring 4. The outer ring 2 is free to rotate about diametrically opposed points by which it is attached to the supports 5. The middle ring 3 is free to rotate about diametrically opposed points by which it is attached to the inner surface of the outer ring 2 and that are at right angles to the axis of rotation of the outer ring. The inner ring 4 is free to rotate about diametrically opposed points by which it is attach it to the inner surface of the middle ring 3 and that are at right angles to the axis of rotation of the middle ring 3.

[0015] The object to be scanned 10 is attached to the inner ring 3 via a suitable holding device 9, in this case the holding device comprises three adjustable needles mounted equally spaced within the inner ring 4. The points of the needles being adjustable inwards or outward to grip object to be scanned.

[0016] The angular position of the outer ring 2 relative to the laser detector 11 is measured by means an angular resolver 15 with power and signals via cable 19 that is connected to suitable power supply and signal decoding equipment.

[0017] The angular position of the middle ring 3 relative to the outer ring 2 is measured by means an angular resolver 16 with signal and power cables run within the outer ring 2 and connected to one side of a slip ring 6 mounted between the outer ring 2 and one of the supports 5. The other side of the slip ring 6 is connected to signal and power cable 18 that is connected to suitable power supply and signal decoding equipment.

[0018] The angular position of the inner ring 4 and thus the object to be scanned relative to the middle ring 3 is measured by means an angular resolver 17 with signal and power cables run within the middle ring 3 and connected to one side of a slip ring 7 mounted between the outer ring 2 and the middle ring 3. The other side of the slip ring 7 are power and signal cables that run within the outer ring 2 and connect to the slip ring 6.

The other side of the slip ring 6 is connected to signal and power cable 18 that is connected to suitable power supply and signal decoding equipment.

[0019] A laser detector 11 is mounted in a fixed position relative to the base 6 and supports 5 with power and signals via cable 12 that is connected to suitable power supply and signal decoding equipment.

[0020] In the configuration shown the rings are rotated manually, with the angular resolvers 15, 16 and 17 comprising rotational sensors. In an alternative configuration (not shown) one or more of the rings can be rotated by an electric motor, which if it were a step motor can replace the angular sensor for detecting the relevant position of the ring concerned. If three step motor(s) were used, all the angular positions of the rings could be determined from the positions of the step motors, which would comprise the rotational sensors, and the angular resolvers 15, 16 and 17 omitted.

[0021] As an alternative to the laser 11, two or more digital cameras can be directed towards the object, and a three dimensional picture of the object built up, for example, as described in Lin, H. Y., & Chang, W Z. (2009, November) "High dynamic range imaging for stereoscopic scene representation" published in Image Processing (ICIP), 2009 16th IEEE International Conference on (pp. 4305-4308). IEEE.

[0022] As a further alternative sound waves can be used. Ultrasound can be directed from at least two sources positioned in a similar way to the digital cameras described in the previous paragraph with the reflected sound being captured and analysed in a manner similar to that used for ultrasound scanning in medical equipment.

[0023] Digitisation and coding of the information captured using the scanner is conventional and not part of the invention.

Claims

Claims 1. A three dimensional scanner comprises a pair of supports, three concentric rings comprising an outer ring, a middle ring and an inner ring and three rotational sensors, the outer ring being free to rotate about diametrically opposed points by which it is attached to the supports, the middle ring being free to rotate about diametrically opposed points by which it is attached to the inner surface of the outer ring and that are at right angles to the axis of rotation of the outer ring, and the inner ring being free to rotate about diametrically opposed points by which it is attached to the inner surface of the middle ring and that are at right angles to the axis of rotation of the middle ring and at least one imaging device to form an image of an object mounted within the inner ring as it is rotated about the three axis.
2. A three dimensional scanner according to claim 1 wherein the supports are mounted on a base.
3. A three dimensional scanner according to claim 1 or 2 wherein the imaging device comprises a laser and laser detector, said laser being directed towards the position of the object mounted in the inner ring.
4. A three dimensional scanner according to claim 1 or 2 having a least two imaging devices comprising digital cameras.
5. A three dimensional scanner according to claim 1 or 2 having a least two imaging devices utlising sound waves.
6. A three dimensional scanner according to any preceding claim in which the inner ring supports an object holding clamp, said clamp comprising three adjustable inwardly pointing needles to grip an object between their points.
7. A three dimensional scanner according to claims 1 to 5 in which the inner ring supports an object to be scanned by means of a fine mesh stretched over the surface of the object and attached to the inner ring.
8. A three dimensional scanner according to any preceding claim in which one or more of the rotational sensors is an angular resolver.
9. A three dimensional scanner according to any preceding claim in which one or more of the rotational sensors is a rotary encoder.
10. A three dimensional scanner according to any one of preceding claims in which one or more of the rings is rotated by a motor.
11. A three dimensional scanner according to claim 10 in which one or more of the motors is a step motor which also acts a rotational sensor.
12. A three dimensional scanner substantially as hereinbefore described with reference to the accompanying drawing.