WO1995026011A1

WO1995026011A1 - Apparatus and method for three-dimensional control

Info

Publication number: WO1995026011A1
Application number: PCT/SE1995/000293
Authority: WO
Inventors: Björn Andersson; Joakim KVARNLÖF
Original assignee: Nabla Hb
Priority date: 1994-03-22
Filing date: 1995-03-22
Publication date: 1995-09-28
Also published as: SE502186C2; SE9400947L; AU2153195A; SE9400947D0

Abstract

A method and a device are adapted for three-dimensional control, especially of a display. The ranges of application include three-dimensional 'mice' and touch screens controllable in three dimensions. A free control space (S) is located between a radiant means and a detecting means, of which at least one is two-dimensional. An object, such as a human finger, is moved freely within the control space (S) in three directions (x, y, z), thus throwing two or more shadows (S1, S2) on the detecting means (10). The current position of the object (12) in the control space (S) is established on the basis of the absolute and relative positions of the shadows (S1, S2) detected. If the distance between the object (12) and the detecting means (10) is altered, the spacing of the shadows (S1, S2) is likewise altered. Generated control information indicates the current position of the object in three dimensions.

Description

APPARATUS AND METHOD FOR THREE-DIMENSIONAL CONTROL

This invention relates to a method and a device for three-dimensional control, especially but not exclusively of a display.

The expression "for three-dimensional control of a display" is meant to encompass at least the case where the inventive device is designed as a separate input unit, such as a mouse or a control ball, for three-dimen¬ sional control of a cursor- or a pointer on a display, as well ay the case where the inventive device is applied directly to a display in order to produce a touch screen controllable in three dimensions. Other conceivable ranges of application for the invention include all sorts of three-dimensional control of apparatus, such as indus¬ trial robots. In today's computer technologies, various posi¬ tioners and pointing devices are widely used for supply¬ ing the coordinates for a pointer, a cursor or the like on a display. Examples of prior-art devices used for this purpose are the mouse, the control ball and the joy stick. Such devices, for instance a mouse, usually have one or more manually-operated function keys enabling the user to select different computer functions.

The prior-art mouse has the limitation of permitting only two-dimensional control. In recent years, one has, however, developed various computer applications requir¬ ing three-dimensional control, i.e. control not only in the plane of the display but also in a third dimension virtually extending into the display. Thus, these appli¬ cations cannot be controlled by conventional positioners and pointing devices.

EP-A1-0 526 015 discloses a mouse for three-dimen¬ sional control. Here, the user holds the mouse in his hand in front of and at a distance from the display and moves the mouse freely in the air in front of the dis- play. In this way, the user is able to create three- dimensional pictures on the display by moving his hand in the air. The mouse carries a transmitter directed towards the display, and three spaced-apart receivers directed towards the transmitter of the mouse are arranged at the edges of the display. A microprocessor processes informa¬ tion from the transmitter and the receivers so as to determine the position of the mouse in the air. Even though this prior-art mouse might work in theory, it is really impracticable, since the user cannot, for ergono- mic reasons, hold a mouse in the air for any longer periods of time. In addition, this known mouse no doubt results in poor accuracy.

As an instance of the prior art, EP-A1-0 526 015 mentions a pointing device operating with a control ball and being adapted for three-dimensional control. A con¬ trol ball projecting upwards through a cover enables two- dimensional control, and a movable ring encircling the control ball enables control in the third dimension with¬ out the user having to remove his hand from the ball. However, this known solution is disadvantageous in that a linear movement of the pointing device in the third dimension corresponds to a circular movement of the ring, rendering work more difficult.

The prior art further encompasses transmitter- receiver devices for two-dimensional control arranged in the immediate vicinity of the frame of a display, a human finger, a pen or the like being held against the display, thus blocking one or more light beams emitted in parallel with the display. The xy-coordinates of the finger on the display are determined with the aid of receivers arranged in suitable fashion. An instance of this prior art is disclosed by EP-A3-0 121 840, which describes a device for determining the position of an object in the visual field of a display. This device comprises two pointlike radiation sources, each disposed in a bottom corner of the frame of the display, a retroreflecting strip extending along the two side edges and the top of the display, as well as two one-dimensional detectors, each disposed behind one of the radiation sources. The radiation emanating from the two radiation sources covers the entire visual field, and if a finger is applied against the display in this field, a shadow will be thrown on each of the one-dimensional detectors. As a result, the xy-coordinates of the finger on the display can be determined trigonometrically. However, this known solution cannot be applied to a mouse, neither is it suitable for three-dimensional control, even though the EP specification suggests how the device can be adapted to three-dimensional control by giving the retroreflecting strip an undulated shape.

One object of the invention is to provide a method and a device for three-dimensional control-, especially but not exclusively of a display, which do not suffer from the drawbacks of the prior art described above.

Thus, the inventive solution should not require that the user holds an object in the air. Furthermore, the solution should be applicable to the remote control of a cursor or a pointer, i.e. to such fields of application as pointing devices and positioners, as well as to direct control on a display, i.e. to the field of application of touch screens. Another object of the invention is that the solution provided should be of simple and inexpensive design and be insensitive to disturbances from the surroundings.

Yet another object of the invention is that the solution provided should be such that the user is able to carry out linear control commands or movements in three directions directly linked to the corresponding control directions on the display.

According to the invention, these and other objects are achieved by a method and a device having the features recited in the appended claims.

According to the invention, a general condition is that the object whose position is to be determined should be freely movable in three dimensions within a control space located between a radiant means and a detecting means, this arrangement being such that ^*che object throws two shadows on the detecting means. Furthermore, the device comprises means for determining the position of the object in three dimensions with the aid of these shadows.

In a first aspect of the invention, the device is characterised in that the radiant means comprises at least two spaced-apart radiant points, in the following referred to as radiants, and that the detecting means comprises a detecting surface, which is position-sensi¬ tive in two dimensions and which is located at a distance from and is irradiated by the radiants. The object at issue, which thus is freely movable in the control space located between the radiants and the detecting surface, will then throw two shadows on the detecting surface, each shadow being associated with one of the radiants, said means determining the position of the object on the basis of the absolute and relative positions of the sha¬ dows on the detecting surface, as well as emitting con¬ trol information corresponding to the current position of the object.

This aspect of the invention is distinguished by the fact that one and the same detecting surface is used for the control in all three directions, which is in contra¬ distinction to the solution according to EP-A3-0 121 840 mentioned above. According to the invention, the position of the one shadow on the detecting surface in one posi- tion of the object may thus coincide with the position of the other shadow on the detecting surface in another position of the object.

In a second aspect of the invention, the device is characterised in that the radiant means comprises a radiant surface having a two-dimensional matrix of a plurality of separate radiant points, in the following referred to as radiants, and that the detecting means comprises at least two spaced-apart detecting elements, which are located at a distance from and are irradiated by the radiants. The object whose position is to be determined is freely movable in a control space located between the radiant surface and the detecting elements and thus throws two shadows on the detecting elements, the position of the object being determined on the basis of the absolute and relative positions of the shadows and on the basis of information indicating with which radiants on the radiant surface the shadows are asso¬ ciated.

Thus, these two aspects of the invention are based on the same main principle, namely that the control space, into which one introduces the object whose posi- tion is to be determined in three dimensions, has, at least on the one side, a surface which is two-dimensional in function. In the first aspect of the invention, this surface consists of a detecting surface that is position- sensitive in two dimensions, whereas in the second aspect of the invention, this surface consists of a two-dimen¬ sional matrix of radiants. The other side need not neces¬ sarily be two-dimensional in function. With a two-dimen¬ sional detecting surface, the position of the object at issue can thus be determined with the aid of only two radiants located on the opposite side of the control space. With a two-dimensional matrix of radiants, the position of the object may thus, in similar fashion, be determined with the aid of only two detecting elements located on the opposite side of the control space. In the first as well as the second aspect of the invention, the position of the object in a first direc¬ tion (x) and in a second direction (y) in a plane (xy- plane) parallel to the two-dimensional surface can be determined on the basis of the positions of the two shadows. Alternatively, the xy-coordinates of the object can be determined as the centre between the two shadows. According to the invention, the position of the object in the third direction (z), i.e. the distance between the object and the detecting surface, is determined on the basis of the relative positions of the shadows. In, for instance, the first aspect of the invention, the two shadows will be spaced apart by a comparatively large distance when the object is located relatively close to the radiants and relatively distant from the detecting surface. As the object is moved closer to the detecting surface, the two shadows will approach each other. In relation to one another, the shadows will thus move in a predictable fashion if the object is moved towards or axay from the detecting surface. The alteration of the distance between the shadows corresponding to a specific alteration of the distance between the object and the detecting surface may, however, be dependent on the abso¬ lute positions of the shadows on the detecting surface. This also goes for the second aspect of the invention.

It will be appreciated that the first and the second aspect of the invention may well be combined, in which case the control space is located between a detecting surface that is position-sensitive in two dimensions and a two-dimensional matrix of radiants. Such an arrangement will be described below with reference to Figs 6-8.

The invention may be implemented as a three-dimen- sional "mouse", which in suitable fashion is connected to the display but which, unlike a conventional mouse, nor¬ mally is intended to be stationary on the surface of a table or the like. In, for instance, the first aspect of the invention, the detecting surface may rest directly on the subjacent surface, and the radiants may be connected to the detecting surface while being disposed at a cer¬ tain height above the latter. The user may perform the three-dimensional control by moving a finger, a pen or some other object in three directions within the free control space above the detecting surface.

In both its aspects, the invention may also be implemented in the immediate vicinity of a display so as to produce a touch screen controllable in three dimen¬ sions. If so, a control space of a certain thickness is obtained immediately in front of and parallel to the dis¬ play. Thus, the radiant means and the detecting means are arranged at two opposing edges of the display. When the invention is implemented in this fashion, the user may, by using a finger, a pointing device or the like, carry out three-dimensional control in the control space, and the movements he makes correspond directly to the same control directions on the display.

The two applications of the invention described above do not require any movable parts in order to achieve the three-dimensional control.

The actual determination of the control information can be performed in many ways, for instance by means cf a preprogrammed microprocessor, and is dependent on the geometry of the device. Generally, electric output sig¬ nals from the detecting side are used as input parameters for processing control information or control signals for the three-dimensional control. The manner of determining this information in each individual case depends solely on the current application of the invention. In most cases, the control information may, however, be deter¬ mined by using simple trigonometric relationships. The detecting means may comprise elements of CCD type. If a detecting surface is employed, this may con¬ sist of a flat, coherent surface, several part surfaces located in the same plane, several part surfaces located in different planes, or a curved surface. In the first aspect of the invention, the number of radiants and the number of shadows may exceed two. To enable determination of the distance between the object and the detecting surface, it must, however, always be clear with which radiant a certain shadow is associated. In the simplest possible case (with two radiation sources distributed over the space transversely of the direction in which the object is introduced), the shadows will always be located on the same side of each other. How¬ ever, other embodiments of the invention comprise means enabling a distinction to be made between the different shadows. This can be achieved in many ways. For instance, the radiants can emit different types of radiation, e.g. involving different power, frequencies or modulations, the detecting surface being adapted to distinguish between the radiation from the different radiants. Also, the different shadows can be distinguished by the radiants emitting radiation in different, successive time windows, in which case the detection is synchronised with these windows. In this case, some sort of memory function may be required. Moreover, a radiation-refracting slit or the like can be provided in front of each radiant, in which case the distinction between the different shadows will be based on the interference pattern on the detect¬ ing surface.

It may be necessary to distinguish between the dif¬ ferent shadows if the object in a first position throws shadows associated with a first and a second radiant, while the object in a second position, in which the shadow from the first radiant falls outside the detect¬ ing surface, throws shadows associated with the second radiant and a third radiant. According to the invention, the radiation emitted by the radiant means may be generated by one and the same radiation source, whence the radiation is conducted to the different radiants in suitable fashion. Alternative¬ ly, such a common radiation source may be movable (rotary and/or linearly reciprocating) so as to emit radiation from different radiants in different time windows. The radiation may consist of just about any electromagnetic radiation, preferably invisible radiation, such as infra¬ red radiation, in order to prevent disturbances due to background light.

These and other distinctive features, advantages and ranges of application of the invention will appear from the following description of embodiments. In the accompa¬ nying drawings,

Fig. 1 is a schematic perspective view illustrating one mode of implementation of the invention; Fig. 2 is a schematic view of an arrangement in which the invention is implemented as a stationary mouse; Fig. 3 is a schematic plan view intended to explain the presence of "blind zones" in a control space;

Figs 4A and 4B are schematic plan views of an embo- diment comprising four radiants;

Fig. 5 is a schematic view of an arrangement in which the invention is implemented in the immediate vici¬ nity of a display in order to produce a touch screen con¬ trollable in three dimensions; Fig. 6 is a schematic view .of an alternative embodi¬ ment of the invention;

Fig. 7 is a schematic view illustrating one mode of determining the position of an object in the embodiment of Fig. 6; and Fig. 8 is a block diagram illustrating one embodi¬ ment of electronic circuits for performing the position determination in Fig. 7.

Reference is now made to Fig. 1, which shows a flat, rectangular and two-dimensional detecting surface 10 extending in the xy-plane of the orthogonal xyz-coordi¬ nate system indicated in the Figure. The detecting sur¬ face 10 is composed of a number of separate detecting elements 11 distributed over the entire surface in the form of an xy-matrix. For the sake of simplicity, only a few elements 11 are schematically shown. The number of detecting elements 11 and the size of the active surface of each of these elements depend, among other things, on the desired resolution and accuracy of the device. The detecting surface 10 may, for instance, be implemented in the form of one or more CCD units. For the sake of sim¬ plicity, Fig. 1 does not show the electric connections to the detecting surface 10, nor the signal-processing elec- tronics required for evaluating the results of detection and for processing control information, since these com¬ ponents are easily devised by those skilled in the art. Two separate radiant points Pi and P2, in the fol- lowing referred to as radiants, are arranged at a dis¬ tance from the detecting surface 10 in the z-direction and are spaced apart in the x-direction. Each radiant PI, P2 irradiates the entire detecting surface 10. The radia¬ tion employed may consist of just about any electromagne- tic radiation that can be detected by the detecting ele¬ ments 11. However, use is preferably made of infrared radiation in order to eliminate any disturbances due to visible background light.

The space between the radiants PI, P2 and the detecting surface 10 is absolutely free and is referred to as the control space, generally designated S. The con¬ trol space is adapted to receive an object 12, preferably a rather thin, elongate object, such as a finger, a pen or a suitable pointing device. In the example, it is assumed that the object 12 is elongate and is introduced in its longitudinal direction into the control space S essentially in positive y-direction. The dimensions of the object 12 in relation to the rest of the arrangement are such that the object 12 throws two elongate shadows SI and S2 on the detecting surface 10, which are asso¬ ciated with the radiants PI and P2, respectively. The extensions of the shadows SI and S2 in the y-direction are designated yl and y2, respectively, and their spacing in the x-direction is designated Δx. On the basis of the absolute and relative positions of the shadows SI, S2 on the detecting surface 10, the position of the object 12 in the control space S can be determined in three dimensions (x,y,z). The position in the x-direction can be determined on the basis of the positions of the shadows SI, S2 in the x-direction. If a shadow covers more than one detecting element 11, the shadow edge with the highest x-value may, for instance, be regarded as representing the x-coordinate of the shadow. The position of the object 12 in the y-direction can be determined on the basis of the shadow extensions yl and y2. The position of the object 12 in the z-direction, i.e: the perpendicular distance from the detecting sur¬ face 10, is established by determining the spacing of the shadows SI, S2 in the x-direction.

As regards the arrangement schematically illustrat- ed in Fig. 1, it is understood that the left-hand shadow S2 will at all times be associate with the right-hand radiant P2, and vice versa, regardless of the position of the object 12 in the control space. In this case, no special means for distinguishing between the shadows SI and S2 are required.

It should be observed that the area of the detecting surface 10 covered by the shadow S2 is irradiated by the radiant Pl_t and that the area of the detecting surface 10 covered by the shadow SI is irradiated by the radiant P2. Thus, the shadows SI and S2 are "half-shadows" , but they nevertheless involve a clearly and unambiguously detect¬ able change of radiation level on the detecting surface 10.

If the position of the object 12 is to be determin- ed, the object 12 thus has to throw at least two shadows on the detecting surface 10. In the arrangement illu¬ strated in Fig. 1, there are, however, certain "blind zones", in which the object 12 cannot throw two shadows on the detecting surface 10. This is illustrated in Fig. 3, which shows the arrangement of Fig. 1 in the xz-plane, dash-dot lines 15-18 having been drawn between the respective radiation sources PI, P2 and the boundary edges 19, 20 of the detecting surface in the x-direction. If the object 12 is located within the two triangles Tl and T2, it can only throw a single shadow on the detect¬ ing surface 10. If, on the other hand, the object 12 is located within the shadowed triangle T3, it will throw on the detecting surface 10 the two shadows SI and S2 required for determining its position. As indicated by dashed lines 21, 22 and 23 in Fig. 3, provision can be made of suitable means in the form of walls or the like for restricting the movements of the object 12 to an area in which two shadows are always obtained.

Figs 4A and 4B illustrate an example of an arrange¬ ment comprising four radiants P1-P4. In Fig. 4A, the object 12 occupies a position A, in which It throws two shadows SI and S2 associated with the two left-hand radiants PI and P2, whereas the two right-hand radiants P3 and P4 do not give rise to any shadows owing to the limited extension of the detecting surface to the left in Fig. 4A. In Fig. 4B, the object 12 occupies a posi- tion B farther to the right and slightly higher up than the position A. In the position B, the object 12 throws two shadows S2 and S3 associated with the two radiation sources P2 and P3 in the middle, whereas the two outer radiation sources PI and P4 do not give rise to any shadows owing to the limited extension of the detecting surface to the right and to the left in Fig. 4B. The two positions A and B have been especially chosen to illu¬ strate the fact that the shadow S2 constitutes the left- hand shadow (the lowest x-coordinate) in the position A, while constituting the right-hand shadow (the highest x-coordinate) in the position B. Thus, this arrangement requires means enabling an identification of the radia¬ tion source of a specific shadow in each conceivable position of the object. As indicated above, this can be achieved in many ways. For instance, the radiants P1-P4 may be sequentially turned on and off, such that each radiant only emits radiation within a predetermined time window. It is understood that such time windows conve¬ niently are so brief that the object is essentially sta- tionary during an entire sequence. Alternatively, one and the same radiation source can be moved between the four radiants. Furthermore, the radiation from the radiants can be modulated in different ways, in which case the detecting surface has to be so designed that it is pos¬ sible to determine the type of radiation received on the basis of the detecting signals emitted by the detecting surface.

Fig. 2 shows an arrangement, in which the invention is implemented as a "mouse" 20, which comprises a base plate 21, whose upper side forms the detecting surface 10, and a number of light sources P1-P3, which are sup- ported by the base plate 21 via legs 22. The mouse 20 is intended to be placed stationarily on a subjacent surface and be connected, via a wire 23, to a personal computer

30 or the like for three-dimensional control of a poini er

31 on a display 32. The arrangement shown in Fig. 1 can be controlled with the aid of one of the user's fingers, which is moved in three dimensions within the free control space. Instead of a finger, use can be made of any other suitable object, such as a pen. In order to provide the same "clicking functions" as a conventional mouse, the object employed may be provided with one or more manually-operated function keys, which can be used once the object has been brought to the desired position in the control space.

Fig. 5 shows an arrangement in which the invention is implemented as a touch screen 40 controllable in three dimensions, a detecting surface 10 with separate detect¬ ing elements 11 being arranged essentially horizontally along the lower edge of the display 40, and a number of radiants P1-P7 being distributed along the upper edge of the display 40. Fig. 5 further shows a pointing device 50 replacing the finger of the previous examples and being provided with one or more function keys 51 that the user may press in order to "click" on different function fields on the display. Reference is now made to Figs 6-8, which illustrate a mode of implementation of the second aspect of the invention. The main components of the embodiment shown in Figs 6-8 are a radiant matrix RM of radiants, here in the form of 10 x 10 infrared-emitting diodes 60, and a detecting matrix DM of detecting elements, here in the form of 10 x 10 infrared receivers 62. The radiant and detecting matrices RM and DM are spaced apart by a suit¬ able distance H (Fig. 7), for instance 20 cm, so as to define a control space S therebetween, as shown in Fig. 1. Fig. 6 shows how dashed lines can be drawn between an individual infrared-emitting diode 60 and each of the infrared receivers 62. An object 12, such as a finger, introduced into the control space S will block some of the radiation emitted by an individual infrared- emitting diode 60. This means that, along some of the lines (LI and L2 in Fig. 6), no radiation will be able to reach the corresponding infrared receivers 62. By establishing such "shadow lines" between at least two different pairs of emitters and receivers 60/62, one is able to obtain all the information required for deter- mining the position of the object 12 in three dimensions within the control space S.

In the embodiment of Fig. 6, the position of the object can be determined as follows, reference being had to the designations used in Fig. 7. Thus, the posi- tion of the object in the vertical direction or z-direc- tion is calculated as Z = (H * ΔX2)/(ΔX1 + ΔX2) ; the position of the object in the x-direction is calculated as X = X2 + (XI - X2 *Z)/H; and the position of the object in the y-direction is calculated in a fashion analogous to that used for calculating the position in the x-direction.

Fig. 8 is a schematic block diagram illustrating electronic circuits that may be used to control the device in Fig. 6 and to perform the position determina- tion in Fig. 7. For instance, the electronic circuits may be incorporated into a mouse. A preprogrammed central unit CPU 70 serves to con¬ trol, via a data bus 72 and latches 74 and 76, which of the infrared-emitting diodes 60 of the radiant matrix SM is to be switched on at a given time. At the end of each cycle, the CPU 70 checks the status of the infrared receivers 62 via the data bus 72 and latches 78 and 80, i.e. checks which of these have received infrared radia¬ tion during the cycle at issue. In this embodiment, the CPU 70 begins by activating the infrared-emitting diode P0 (see Fig. 6) in the remote right-hand corner in

Fig. 6, and then sequentially switches on and off the following infrared-emitting diodes 60 in the same row in the x-direction. For each infrared-emitting diode 60 switched on, the CPU 70 checks the status of the receivers 62. This goes on until the CPU 70 finds that one infrared detector Dl is blocked (i.e. shadowed by the object 12 and thus not receiving any infrared radiation from the infrared-emitting diode PI switched on), i.e. goes on until a shadow line LI (Pl-Dl) has been found. When this happens, the CPU 70 is programmed to instead activate the infrared-emitting diode at the other end of the same row in the radiant matrix RM and to then work its way successively in the opposite direction towards the first end of the row by sequentially switching on and off the infrared-emitting diodes until an infrared receiver (D2) is blocked and another shadow line L2 (P2-D2) thus has been found. If no other shadow line is found in this row, the CPU proceeds to the next adjoining row to there look for two shadow lines. When the two shadow lines LI and L2 have been found, the CPU 70 has access to all the information required for performing the above determination. The position informa¬ tion can thus be transmitted via interface circuits 82 and 84 and the wire 23 to a computer 30, as shown in Fig. 1. Then, the process for determining new position information is started anew. Reference numeral 86 indicates manually-operated activating means, such as the buttons of a mouse, and reference numeral 88 indicates a latch for transmitting the corresponding signals to the CPU 120 via the data bus.

It will be appreciated that the circuit in Fig. 8 can be used also in the embodiment of Fig. 1, in which case it is, however, slightly modified as regards the control of the radiant means. In order to distinguish between the infrared radia¬ tion and background radiation, the infrared-emitting diodes can be modulated by a suitable frequency, as is well known in the field of conventional infrared remote controls. The embodiments of the invention described above can be modified in many ways within the scope of the appended claims, as exemplified in the following.

The detecting surface may be composed of several part surfaces, and it need not necessarily be flat. - The detecting surface may be designed as a surface that is continuously position-sensitive in two dimen¬ sions, instead of as a plurality of separate detect¬ ing elements as above.

The object displaced in the control space may have another shape than the elongate one shown in the Figures.

The object may be connected to the device via some sort of universal joint, so as to be available adja¬ cent to the device at all times. - The position of the object in the z-direction can be determined on the basis of the relative positions of more than two shadows, enabling higher accuracy. The distance between the radiants can be varied, resulting in different degrees of resolution. - The radiants may be distributed in other directions than the x-direction, for instance in the y-direction only. Although this alternative might result in some shadowed areas with "full shadow" (shadow associated with both radiants) and some shadowed areas with "half-shadow" (shadow associated with but one radiant) , it would still be perfectly feasible to distinguish between the shadows.

As to the extension of the radiants, this may, in actual practice, differ considerably from the "point¬ like" extension mentioned above. The only requirement is that the necessary shadows are obtained on the detecting surface.

The processing of control informarion on the basis of the output signals from the detecting surface may be varied according to the aimed-at properties of the three-dimensional control. Thus, one may choose sig- nal processing which, for a certain movement of the object, provides a movement of exactly the same length for the mouse pointer. Alternatively, use may be made of signal processing dependent on the current position of the object.

Claims

1. A device for three-dimensional control, especial- ly of a display, c h a r a c t e r i s e d by radiant means in the form of at least two spaced- apart radiant points (Pi, P2), in the following referred to as radiants, detecting means in the form of a detecting surface (10), which is position-sensitive in two dimensions and which is located at a distance from and is irradiated by the radiants (PI, P2) , and means for determining the position in three dimen-^" sions of an object (12), which is freely movable in a control space (S) located between the radiants (PI, P2)- and the detecting surface (10) and which thus throws two shadows (SI, S2) on the detecting surface (10), each shadow being associated with one of the radiants (PI, P2), said position being determined on the basis of the absolute and relative positions of the shadows (SI, S2) on the detecting surface (10), as well as for emitting control information corresponding to the current position (x,y,z) of said object (12).

2. A device as set forth in claim 1, c h a r a c - t e r i s e d in that the detecting surface (10) is com¬ posed of a plurality of separate detecting elements (11) distributed over the detecting surface (10) in two direc¬ tions (x,y).

3. A device as set forth in claim 1 or 2, c h a r - a c t e r i s e d in that the radiants (PI, P2) are spaced apart in at least one direction ( ) parallel to the detecting surface (10).

4. A device as set forth in claim 2, c h a r a c ¬ t e r i s e d in that the radiants (PI, P2) are spaced apart in at least one direction (x) parallel to the detecting surface (10) as well as to one of the two directions (x, y) in which the separate detecting ele¬ ments (11) of the detecting surface (10) are distributed.

5. A device as set forth in any one of claims 1-4, c h a r a c t e r i s e d in that, apart from said two radiants (PI, P2), it comprises one or more additional radiants (P3, P4 ...), all the radiants (PI, P2, P3, P4) being spaced apart and irradiating the detecting surface (10).

6. A device for three-dimensional control, especial- ly of a display, c h a r a c t e r i s e d by radiant means in the form of a radiant surface hav¬ ing a two-dimensional matrix (RM) of a plurality of sepa¬ rate radiant points, in the following referred to as radiants ( 60) , detecting means in the form of at least two spaced- apart detecting elements ( 62) , which are located at a distance from and are irradiated by the radiants (60), and means (70) for determining the position in three dimensions of an object (12), which is freely movable in a control space (S) located between the radiant surface and the detecting elements ( 62) and which thus throws two shadows (SI, S2) on the detecting elements (62), said position being determined on the basis of the absolute and relative positions of the shadows (SI, S2) and on the basis of information indicating with which radiants (PI, P2) the shadows (SI, S2) are associated, as well as for emitting control information corresponding to the current position (x,y,z) of said object (12).

7. A device as set forth in claim 6, c h a r a c ¬ t e r i s e d in that the detecting elements (62) form part of a two-dimensional matrix (DM) of a plurality of separate detecting elements ( 62) .

8. A device as set forth in any one of the preceding claims, c h a r a c t e r i s e d in that the detecting means are of CCD type.

9. A device as set forth in any one of the preceding claims, c h a r a c t e r i s e d in that the movements of the object (12) in the control space (S) are so restricted that the object (12) can throw at least two shadows on the detecting means in each conceivable posi¬ tion.

10. A device as set forth in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that the radia¬ tion employed is infrared radiation.

11. A device as set forth in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that the radiant •means comprise radiants emitting different types of radiation, and that at least one of the detecting means and the position-determining means is adapted to distin- guish between radiation from the different radiants.

12. A device as set forth in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that the radiants emit radiation in different, successive time windows.

13. A device as set forth in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that the radiant means comprise a radiation source common to all the radiants.

14. A device as set forth in any one of the preced- ing claims, c h a r a c t e r i s e d in that it consti¬ tutes a separate input unit (20), such as a mouse or a control ball, which is connectible to a computer (30) for three-dimensional control of a pointer or cursor (31) on a display (32).

15. A device as set forth in any one of the preced¬ ing claims, c h a r a c t e r i s e d in that, in order to produce a touch screen (40) controllable in three dimensions, the radiant means are arranged at a first edge of the display, and that the detecting means are arranged at an opposing edge of the display, such that the control space (S) in which said object (12) is freely movable is located immediately in front of the display (40).

16. A device as set forth in any one of the preced¬ ing claims, wherein said object (50) forms part of the device proper, c h a r a c t e r i s e d in that the object (50) is provided with a manually-operated activat¬ ing means (51) which, when activated, generates an acti¬ vating signal emitted together with said control informa¬ tion.

17. A method for three-dimensional control, espe¬ cially of a display, c h a r a c t e r i s e d by the steps of emitting radiation from at least two spaced-p.part points (PI, P2) , in the following referred to as radiants, moving an object (12) in three dimensions within a control space (S) located between the radiants (PI, P2) and a detecting surface ( 10), which is position-sensitive in two dimensions and which is located at a distance from and is irradiated by the radiants (PI, P2), such that the object (12) thus throws two shadows (SI, S2) on the detecting surface ( 10) , each shadow being associated with one of the radiants (PI, P2), and generating, on the basis of the absolute and rela- tive positions of the shadows (SI, S2) on the detecting surface (10), control information corresponding to the current position (x,y,z) of said object (12) in three dimensions within the control space (S) .

18. A method for three-dimensional control, espe- cially of a display, c h a r a c t e r i s e d by the steps of emitting radiation from a radiant surface having a two-dimensional matrix (RM) of a plurality of separate radiant points, in the following referred to as radiants (60), moving an object (12) in three dimensions within a control space (S) located between the radiant surface and a detecting means, which comprises at least two spaced-apart detecting elements (62) located at a dis¬ tance from and being irradiated by the radiants ( 60), such that the object (12) thus throws two shadows (SI, S2) on the detecting means, and generating, on the basis of the absolute and rela¬ tive positions of the shadows (SI, S2) as well as infor¬ mation indicating with which radiants (Pi, P2) the shadows (SI, S2) are associated, control information corresponding to the current position (x,y,z) of said object (12) in three dimensions within the control space (S).

19. A method as set forth in claim 18, c h a r ¬ a c t e r i s e d by activating the radiants (60) sequen- tially until a first shadow has been detected, and then activating the radiants (60) sequentially until a second shadow has been detected.

20. A method as set forth in any one of claims 17-19, c h a r a c t e r i s e d by using an elongate object (12, 50), such as a human finger, as said object (12).

21. A method as set forth in any one of claims 17-20, c h a r a c t e r i s e d by using the control information for three-dimensional control of a cursor (31) or a pointer of a display (32).

22. A method as set forth in any one of claims 17-21, c h a r a c t e r i s e d by using the control information for producing a three-dimensional touch screen (40) .