GB2372809A

GB2372809A - 3-dimensional co-ordinate determination

Info

Publication number: GB2372809A
Application number: GB0104952A
Authority: GB
Inventors: Barbara Lynn Jones
Original assignee: Snap On Equipment Ltd; Snap On Technologies Inc
Current assignee: Snap On Equipment Ltd; Snap On Inc
Priority date: 2001-02-28
Filing date: 2001-02-28
Publication date: 2002-09-04
Also published as: GB0104952D0; WO2002068902A3; WO2002068902A2

Abstract

In 3-dimensional mapping for automotive crash repair and diagnostics, the mapping of separate zones or one zone and a close-up region thereof is achieved without the use of a separate mechanical frame serving as a mounting for emitters, by mounting three or more optical emitters (28) on a vehicle to serve as a reference frame (26) during each of two mapping operations using respective camera positions with different fields of view (D1, D2), and adopting the same co-ordinate system for both mapping operations. Alternatively the direction of energy transmission may be reversed or other forms of energy signal including acoustic frequencies may be used. Four emitters may be mounted on a cross shaped support, other emitters or transmitter members (30, 32, 34) may mounted on the vehicle at chosen locations, or a hand-held wand with a mapping tip may be used.

Description

METHOD AND APPARATUS FOR THREE-DIMENSIONAL MAPPING

This invention relates to a method and apparatus for three-dimensional mapping and in particular, but not exclusively, to such a method and apparatus applicable to automotive diagnostic and repair work mapping operations.

An aspect of automotive three-dimensional mapping operations concerns the frequently-arising requirements to be able to carry out mapping tasks in relation to more than one area of a vehicle. For example, there may be a need to map both the underside and certain portions of the superstructure of the vehicle. Or indeed it may be necessary to map opposite sides of the vehicle due to the particularities of a specific vehicle impact which has occurred. The variety of these leads to enormous variation in the mapping requirements.

Conventionally, the approach to the mapping of vehicle portions requiring more than one camera position (so far as optical systems are concerned) has been to provide as an ancillary item of equipment for use in such situations a reference frame comprising optical emitters additional to those provided in relation to the mapping of the vehicle itself. The reference frame is positioned by the user so as to be within the field of view of the camera not only during the mapping operation for the first zone to be mapped, but also in the mapping of the other zone so that when the time comes to move the camera between its positions for the two mapping operations, there can be maintained an unchanged three-dimensional coordinate reference system for both regions of the vehicle whereby the mapping data for validation against the vehicle manufacturers's original equipment mapping data can be carried out in a minimum number of steps and without the establishment of two coordinate systems.

Such an approach is of course technically straightforward and raises no particular difficulties in the sense that the use of a coordinate reference frame for linking such operations has a relatively clear and straightforward mathematical basis which is well suited to implementation by a computer system of the kind employed routinely in such mapping operations.

However, the provision of a mechanically constructed reference frame for mounting in relation to a vehicle does represent a significant complication in relation to such mapping operations in that this additional item of equipment has to be purchased and accommodated and protected from damage (otherwise its memorised dimensional constants will be inaccurate). Moreover, the reference frame represents additional cost in terms of original equipment and it would be a significant step forward if some means could be found for enabling its function to be achieved in some more convenient and/or cost-effective manner.

An object of the present invention is to provide a method and apparatus offering improvements in relation to one or more of the matters discussed above, or improvements generally.

According to the invention there is provided a method and apparatus as defined in the accompanying claims.

In embodiments of the invention described below there is provided a three-dimensional mapping system in which mapping operations in relation to two locations on a vehicle or other object to be mapped and which require two or more corresponding camera positions are coordinated by means of a reference frame provided, not by means of any structure carrying emitters or the like, but by the use of emitters which are mounted in relation to the article to be mapped in any convenient way. For example, in one embodiment of the invention the reference frame (so-called) is provided by as

few as three standard mapping emitters (of the kind which are intended to be used as plug-in devices receivable in sockets provided at suitable mapping locations on the vehicle), and the positioning of these emitters is chosen by the user to enable a first mapping operation to be conducted with reference to them in relation to a first desired location on the vehicle, and so as also to enable a subsequent mapping operation to be carried out in a similar way in relation to another region or zone of the vehicle displaced from the first zone and yet within the field of view of the camera for that second mapping operation. In this latter regard, the field of view for the second mapping operation is likely to be completely different from the field of view for the first mapping operation because the camera will have been moved for that purposes, though of course (these so-called) reference frame emitters will not have been moved.

Thus, it can now be seen that the method of the present invention offers a significant simplification in relation to the mapping of a vehicle or other article where it is necessary to carry out mapping operations at distinctly separated or widely separated locations which would otherwise demand the use of a mechanical reference frame carrying emitters or else would demand quite separate mapping operations with the inherent difficulties and inaccuracies which are attendant upon the coordination of two such mapping operations.

In accordance with the embodiments of the present invention, the two mapping operations can be carried out in sequence by merely choosing an appropriate intermediate location for the emitters which are to be used (without being moved between the two mapping operations) intermediate the two zones to be mapped. Of course, if the two zones are very widely separated then it may be difficult to choose a

location for the nominal reference frame which is convenient for both. However, as mentioned above, this problem is assisted by the fact that the camera position itself is changed between the two mapping operations and this gives considerable flexibility which will often, as a practical matter eliminate the difficulty. In other words, by choosing the nominal reference frame emitter positions judiciously, the user can ensure that these will be readily within the field of view of the camera for both camera positions so that the successive mapping operations can be carried out accordingly.

It needs to be pointed out that the method of the present invention is by no means limited in its utility to the optical techniques described below with reference to the accompanying drawings, and is applicable to other related mapping systems employing emitters and receivers of energy signals of a wide variety of frequencies, including acoustic frequencies. Likewise, the mapping systems employing such energy signals do not depend upon the (forward or reverse) direction of transmission of the energy signal and such could in fact be inverted with respect to the transmission direction employed in the optical system disclosed below.

Summarising therefore the technical features of the embodiments described below, it can now be seen that these offer the user a system in which the mechanical reference frame of the past is replaced by the use of the conventional emitter (or receiver) devices which are suitably placed at the discretion of the user in locations adapted for cooperation with two selected camera positions and corresponding fields of view so as to enable mapping of two zones of the vehicle or other article. The data processing system which carries out the computational steps in the mapping operation is instructed that the initiallyestablished coordinate reference frame defined by the three

or more initial emitter (or receiver) positions is to be maintained for the subsequent mapping operation employing the second camera position, and the computations proceed accordingly.

As a practical matter, it is strongly preferred that all three (or more) of the emitters (or receivers) providing the nominal reference frame should be in camera view for both mapping operations since omission of one of three of these would permit significant and substantial errors.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which : Fig 1 shows a general perspective view of a mechanical reference frame with four associated emitters and corresponding coordinate reference axes indicated; Fig 2 shows a simplified reference frame in use in association with three corresponding emitters, with indication of the coordinate axes X, Y, Z and the two camera viewing directions D1 and D2; and Fig 3 shows an embodiment of the invention in which four emitters are mounted at suitable locations with respect to an article to be mapped and are employed to define a reference frame of which coordinates are likewise indicated in Fig 2 together with the corresponding viewing directions D1 and D2 for the camera positions adopted in relation to the reference frame.

As shown in Fig 1, a mechanical reference frame 10 is intended for use in relation to a method of threedimensional coordinate determination employing emitters and receivers, for example LED emitters and an optical camera assembly, adapted for use in an optical three-dimensional mapping system. Such mapping systems are relatively well known and it is believed that no further description of such is needed.

The mechanical reference frame 10 shown in Fig 1 comprises a generally cross-shaped frame member 12 providing arms 14,16, 18,20 each carrying its respective emitter 22 providing for oppositely facing LEDs 24 for energy emission purposes and having a corresponding power supply and control means (not shown).

Reference frame 10 is described here for the purposes of identifying and clarifying the benefits provided by the embodiments of the invention in terms of eliminating the need for such structures.

In use, the reference frame 10 is used in a threedimensional mapping system in the situation of carrying out two series of coordinate data evaluation steps with the apparatus. Typically, in an optical system of this kind, the emitters or LEDs are applied to the vehicle and the camera is used in two successive positions to map the vehicle accordingly, depending on the particular requirements.

Reference frame 10 is positioned, with its emitters 22, so as to be well within the field of view of the camera in both mapping operations. The user selects such a position accordingly. It is important that the position is fixed and that no disturbance of the reference frame occurs during the mapping operations.

A modified arrangement is illustrated in Fig 2 in which an emitter support 26 is shown, having a simple triangular structure shown at 26 with LED emitters 28.

Also shown in Fig 2 are three emitter or transmitter members 30,32, 34 each having a pair of LEDs 36. The emitters 30,32, 34 are adapted to be mounted on the vehicle at chosen mapping locations. Alternatively, a hand-held wand device could be employed in place of the emitters 30,32, 34 with the user identifying the required mapping locations by means of a defined mapping tip on the wand.

Fig 2 shows the two viewing directions for the camera,

namely D1 and D2. For these two viewing directions, support 26 remains fixed in its single position and the separate emitters 30,32, 34 are relocated for the separate mapping operations.

In Fig 1 and Fig 2, the coordinate axes X, Y and Z have been indicated which define respective axes for mapping purposes and the data-processing system sets up a corresponding theoretical mapping coordinate system having a suitably-located origin or Xo Yo Zo at a suitable location, for example symmetrically or centrally on the reference frame or support as shown at 38 in Figs 1 and 2.

Turning now to the embodiment of the invention shown in Fig 3, it will be noted that this differs from the apparatus described with reference to Fig 2 mainly in the absence of the mechanical reference frame 26. Four separate emitters are provided at 40,42, 44 and 46, each having a pair or LEDs 48, these emitters and LEDs being substantially as described and shown in relation to Fig 2, and adapted to plug into sockets in the vehicle.

The camera viewing directions D1 and D2 are shown together with the coordinate axes X, Y and Z.

Turning to the mode of use of the apparatus of Fig 3, the coordinate data evaluation apparatus comprising transmitter means and receiver means and data processing means is, as mentioned above, provided in the form of, for example, known optical mapping apparatus in which the transmitter means comprise the LEDs and the receiver means comprises camera means. Such apparatus may for example be as described in co-pending application GB 0102420.7 filed 31 January 2001.

The data processing means is adapted to process data derived from the transmission of an optical signal between the LEDs and the camera to determine information with respect to the three-dimensional coordinates of the

transmitter means with respect to the camera means, and indeed with respect to the vehicle or other article on which the transmitter means are mounted. In a typical embodiment, the transmitter or emitter means 40 are plugged into mounting holes on the vehicle underside. Alternatively, there may be employed an optical wand-type manually-held transmitter which the user employs to point (by contact with the tip) at locations to be mapped. Such a wand comprises at least two LED emitters in the same way as the emitters or transmitters 40.

Thus, a first series of coordinate data evaluation steps are carried out with the apparatus in which the transmitter means 40 are plugged into a first series of locations on the vehicle and mapping proceeds in relation to the coordinates X, Y and Z as shown on the basis of the positions of the emitters 40 as shown. The data processing means sets up the coordinate axes accordingly.

Then, having carried out the first series of coordinate data evaluation steps on the basis of the camera viewing direction Dl, a second series of mapping steps is carried out with a changed camera viewing direction as shown at D2 in Fig 3 in order to map a different portion of the vehicle or else to map a portion of it in more close-up detail. For this purpose, the emitters 40 to 46 are allowed to remain in their established positions in which the axes X, Y, Z are defined and remain constant for both of the two sets of mapping operations. Thus, the further series of coordinate data evaluation steps proceeds on the basis of the same coordinate axes as the first series and then the data processing means or computer carries out the mapping steps on the basis of the same coordinate axes for both sets of data and thus the two mapping operations are themselves coordinated geometrically. As a result, the data can be much more simply and readily compared for example with data

obtained from the vehicle manufacturer for the determination of the extent of non-compliance.

The above-described embodiment of the invention provides a cost effective and more customised way of achieving a reference frame than the mechanical versions shown in Figs 1 and 2. The nominal reference frame of the embodiment of Fig 3 can be positioned on any part of the object to be mapped using any suitable attachment means, such as (if considered beneficial) a mounting frame for example as described in GB 2349953 P54351GBA). In the embodiment above, once the coordinate-defining emitters have been positioned and observed by the camera, the centroid or origin and axes of the frame system can be readily determined by the data processing means. The technique of using Euclidean transformations (ones which preserve length and angle) to transfer co-ordinate systems between references is an established procedure.

The chosen coordinate-defining axes can lie along LED lines or otherwise, depending on the choice of the emitter locations and geometry. One simple approach is to use one target with three LEDs, one as origin and the other two making orthogonal lines to each other and thus determining the origin and the axes. The procedure allows the coordinate system to be moved several times to effect mapping of very large volumes, although such could lead to cumulative errors.

In a modification of the Fig 3 embodiment, the Fig 2 apparatus is employed in the Fig 3 manner using the support 26 and its LEDS as one of four"fixed"co-ordinate defining emitters.

Claims

CLAIMS 1 A method of three-dimensional coordinate determination adapted for automotive crash repair and diagnostics and the like, the method comprising : a) the step of providing coordinate data evaluation apparatus comprising transmitter means and receiver means and data processing means adapted to process data derived from the transmission of an energy signal between said transmitter and receiver means to determine information with respect to the three-dimensional coordinates of one of said transmitter means and said receiver means with respect to the other thereof; and b) the step of carrying out a series of coordinate data evaluation steps with said apparatus in which said one of said transmitter and receiver means is applied to one or more identifiable or predetermined locations on a vehicle or the like while said energy signal is transmitted and said other of said transmitter or receiver means is located at one or more fixed or known locations with respect to said vehicle or the like throughout said data evaluation steps; c) the step of carrying out a further series of coordinate data evaluation steps with said apparatus in which said one of said transmitter and receiver means is applied to one or more identifiable or predetermined further locations on a vehicle or the like whilst said energy signal is transmitted and said other of said transmitter and receiver means is located at one or more fixed or known locations relative to said vehicle or the like throughout said further data evaluation steps;

d) and said steps of carrying out said two series of coordinate data evaluation steps being carried out employing two corresponding respective positions of one of said transmitter and receiver means, and one corresponding position for coordinate reference means comprising at least three of the other of said transmitter and receiver means and support means to support same at defined positions within direct energy transmission range of said one of said transmitter and receiver means for both of its said two corresponding positions, to establish a coordinate reference basis for said two corresponding positions of said one thereof; characterised by e) providing said support means for said coordinate reference means comprising said at least three of said other of said transmitter and receiver means being adapted to be mounted on said vehicle or the like to be mapped, and said vehicle or the like to be mapped itself serving to support same during said coordinate determination, and the method including the step of causing said data processing means to adopt said coordinate reference means as such reference means for both of said two positions of said one of said transmitter and receiver means.
2 A method of three-dimensional coordinate determination adapted for automotive crash repair and diagnostics and the like, characterised by providing support means for coordinate reference means comprising at least three of one of transmitter means and receiver means by said one thereof being adapted to be mounted on a vehicle or the like to be mapped which serves to support same during coordinate determination, and the method including the step of causing data processing means to adopt said coordinate reference means as such for both of two positions of one of

said transmitter and receiver means.
3 A method according to claim 1 or claim 2 characterised by said one of said transmitter and receiver means which is employed in said two corresponding positions comprising receiver means, and said three of the other of said transmitter and receiver means comprising emitter means.
4 Apparatus for three-dimensional coordinate determination adapted for automotive crash repair and diagnostics and the like, the apparatus comprising : a) coordinate data evaluation apparatus comprising transmitter means and receiver means and data processing means adapted to process data derived from the transmission of an energy signal between said transmitter and receiver means to determine information with respect to the threedimensional coordinate of one of said transmitter means and said receiver means with respect to the other thereof; and b) said apparatus being adapted to carry out a series of coordinate data evaluation steps in which said one of said transmitter and receiver means is applied to one or more identifiable or predetermined locations on a vehicle or the like while said energy signal is transmitted and said other of said transmitter or receiver means is located at one or more fixed or known locations with respect to said vehicle or the like throughout said data evaluation steps; c) said apparatus being adapted to carry out a further series of coordinate data evaluation steps in which said one of said transmitter and receiver means is applied to one or more identifiable or predetermined further locations on a vehicle or the like whilst said energy signal is transmitted and said other of said transmitter and receiver means is located at one or more fixed or known locations relative to

said vehicle or the like throughout said further data evaluation steps ; d) and said apparatus being adapted to carry out said two series of coordinate data evaluation steps employing two corresponding respective positions of one of said transmitter and receiver means, and one corresponding position for coordinate reference means comprising at least three of the other of said transmitter or receiver means and support means to support same at defined positions within direct energy transmission range of said one of said transmitter and receiver means for both of its said two corresponding positions, to establish a coordinate reference basis for said two corresponding positions of said one thereof; characterised by e) said support means for said coordinate reference means comprising said at least three of said other of said transmitter and receiver means being adapted to be mounted on said vehicle or the like to be mapped, and said vehicle or the like to be mapped itself serving to support same during said coordinate determination, and said data processing means being adapted to adopt said coordinate reference means as such reference means for both of said two positions of said one of said transmitter and receiver means.
5 Apparatus for three-dimensional coordinate determination adapted for automotive crash repair and diagnostics and the like, characterised by support means for coordinate reference means comprising at least three of one of transmitter means and receiver means comprising said one thereof being adapted to be mounted on a vehicle or the like to be mapped which serves to support same during coordinate

determination, and the apparatus comprising data processing means adapted to adopt said coordinate reference means as such for both of two positions of one of said transmitter and receiver means.
6 Apparatus according to claim 4 or claim 5 characterised by said one of said transmitter and receiver means which is employed in said two corresponding positions comprising receiver means, and said three of the other of said transmitter and receiver means comprising emitter means.
7 A method of three dimensional coordinate determination substantially as described herein with reference to the accompanying drawings.
8 Apparatus for three-dimensional coordinate determination substantially as described herein with reference to the accompanying drawings.