DE3342721A1 - PHOTODETECTOR SYSTEM FOR DETECTING OR MEASURING THE POSITION OF ONE OR MULTIPLE LIGHT SOURCES - Google Patents

Abstract

The position of one or a plurality of light sources is determined by means of a photo-sensitive detection unit comprised of at least one detector body (1) having a plurality of insulated detector elements (for example 5) arranged on top of each other or next to each other and of which the detection surfaces are offset with respect to each other. The light coming from the light sources is reproduced on the detection surfaces by means of an optical reproduction unit comprised of elongated lens elements (2, 3, 4) belonging to the detector elements which are insulated and offset with respect to each other according to the relative shifting of the detection surfaces.

Description

Photo detector system for detection or measurement

the position of one or more light sources The invention relates relies on a photodetector system to determine or measure the position of a or several light sources by means of a photosensitive detector arrangement the light emitted by the respective light source through an optical imaging arrangement is directed.

A system of the type described above is already known (EP application 81106262.9). The photosensitive detector arrangement and the optical Imaging arrangement constructed rotationally symmetrical with respect to the same axis. With the help of this known system it is possible to display the position-sensitive Photodetector arrangement of the surface shape of the object being examined, on the size of the spot of light thrown on its surface and different strong reflections or scattering of the surface of the object being examined to make largely independent. However, it has been found that the detection area d. H. the angle of view of the photosensitive detector arrangement is sometimes not includes sufficient area.

One could now use a system of the known type considered above provide in a plurality and to be arranged side by side in order to i.e.

to widen the angle of view. This is also possible in principle, shows however, the disadvantage that a linear constitution of the position of one or more Light sources is practically only possible along the axis, along which the relevant Systems are arranged side by side.

Meanwhile, the position of the light source or the light sources changes also in the other direction, so act in the area between adjacent ones Systems existing pincushion distortions negatively affect the evaluation of each obtained signals.

The invention is accordingly based on the object of showing a way as in a system of the type mentioned above, avoiding the above the disadvantages shown, an extended detection area for the detection or Measuring the position of one or more light sources can be achieved.

The object indicated above is achieved in a system of initially mentioned type according to the invention in that the detector arrangement by at least one detector body with a plurality of one above the other or next to one another arranged individual detector elements is formed with their detector surfaces are offset relative to one another, and that the optical imaging arrangement through Elongated lens elements associated with the individual detector elements are formed which is offset from one another in accordance with the relative displacement of the detector surfaces are arranged.

The invention has the advantage that on relatively simple Way, the position of one or more light sources can be determined or measured can whose position is in a relative wide detection area can change, holme that problem learning in the determination or measurement in question of the kind shown above. This means that in an advantageous manner between there are no undefined areas for the individual detector elements, see above that the light source to be detected is practically in any direction with respect to the detector body can change and yet in their respective position is clearly detectable.

It is also advantageous that according to the invention with smaller dimensions of the measuring space is managed as before and that the distance between the respective Light source and the detector elements can be smaller than previously possible was. This brings a better resolution and accuracy in the evaluation of the measurement signals with himself.

The detector elements are preferably on with their detector surfaces in a common line lying one above the other or next to one another. this has the advantage of a relatively simple structural design.

However, at least two detector elements are expediently in one Plane provided with their detector surfaces offset from one another, and in at least a plane immediately adjacent to the plane in question is at least one detector element provided, the detector area of which is based on the detector areas in the first-mentioned Level existing detector elements is offset. This has the advantage of that the respective detector body has a relatively wide detection range.

Preferably the two are immediately adjacent levels associated lens elements with their lens surfaces in an overlapping relationship arranged to each other. This has the advantage that a relatively further Detection range of a detector body with lens elements of relatively simple design is achieved.

It is also advantageous if several detector bodies are provided and with their longitudinal axes in one of two mutually perpendicular planes are arranged. This advantageously enables spatial determination the position of one or more light sources.

To the above-mentioned position determination with simple circuit means to be able to make, are the detector elements of the detector body with their signal outputs preferably connected to a computing circuit which contains a microprocessor can.

But it is also possible to provide several detector bodies and with to arrange their longitudinal axes lying next to each other. This has the advantage that in a relatively simple way motion sequences in a given direction can easily be recognized and thus evaluated.

The light sources whose light is to be determined or measured arrive preferably in time division mode to light up. This enables in particular easy way to distinguish the individual light sources from each other.

But it is also easily possible as light sources, their light to determine or measure is to use modulated light sources. These too measure advantageously allows the individual light sources to be easily separated from one another to be able to distinguish. The modulation of the light sources in question can be the frequency of the light emitted in each case.

To operate the individual light sources in a particularly simple way being able to do without annoying cable connections are preferred provide the individual light sources with their own power supply.

A control device associated with the light sources is preferred provided which the intensity of the light emitted by the light sources holds a predetermined value. From this measure is then in an advantageous manner Made use of when the distance between the light sources and the detector elements is different or varies.

Semiconductor elements are preferably used as light sources and as detector elements. In particular, light-emitting diodes (LED) are used as light sources, and as detector elements conventional detector elements are used, as described in connection with the above considered known system are already described. It should be noted here that charge coupled devices (CCD) can also be used as detector elements can.

The invention is exemplified below with reference to drawings explained in more detail.

Fig. 1 shows in a perspective view a detector body such as it is used in the Fo + adetektor system according to the invention.

FIG. 2 shows a plan view of the detector body shown in FIG. 1.

3 shows the use of three detector bodies in a perspective view according to the invention for spatial determination or measurement of the position at least a light source.

4 shows detector bodies arranged next to one another in one plane.

Fig. 5 shows in a schematic representation relationships that results from the use of two detector bodies of the three shown in FIG Detector body result.

Fig. 6 shows a block diagram of a computing circuit which is shown in Connection with the device according to FIG. 3 can be used.

7 shows, in a time diagram, pulses with the aid of which light sources can be controlled to emit light.

Fig. 8 shows in a block diagram a control device with whose help the intensity of the light emitted by light sources on a given Value can be kept.

9 shows a measuring arrangement for three-dimensional determination or measuring the position of one or more light sources. FIG. 10 shows a known one uniaxial photodetector system Figure 10 shows a known uniaxial Detector system.

The light emanating from a light source 71 is passed through a lens 72 bundled to form a point of light that hits the surface of a position-sensitive Photodetector element falls. The position sensitive photodetector element is made from a semiconducting substrate 73, at both ends of which electrodes 74 and 75 are upset. Furthermore, an electrode 76 is attached in the middle on the underside. One pole of a voltage source 77 is connected to the electrode 76. The other Pole of the voltage source leads to the plus input of each operational amplifier 78, 79. The minus input of the two operational amplifiers 78, 79 is connected to the corresponding one Electrode 74, 75 connected. Furthermore, the minus input of every operational amplifier is 78, 79 with the corresponding output through a corresponding negative feedback resistor tied together. The voltages u1 and u2 at the outputs of the operational amplifiers 78, 79 depend on where the light spot strikes the substrate 73. When the light spot hits exactly in the middle, both voltages are equal. When the light spot for example, when the light source 71 is changed to 71 'closer to the electrode 74 occurs than at the electrode 75, the voltage u1 is greater than the voltage u2. Any change in the angle of the light source 71 accordingly leads to a change of the voltages at the outputs of the operational amplifiers 78, 79 The photodetector system shown corresponds to the photodetector system in Figure 4 of the European Applicant's patent application 81106262.9. Such a photodetector system is called "uniaxial" referred to. This is because with such a system only changes of location can be determined in the direction of connection between the two electrodes 74, 75 take place.

If you look at right angles to the strip-shaped electrodes 74, 75 the two sides of the substrate 73 applies further electrodes and their output signals evaluates in the same way as shown in Figure 10, one obtains a '2-axis' photodetector system.

Such is, for example, in the IEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. SC-13, NO. 3, June 19-78.

In the present case, only "uniaxial" light detector systems are of interest.

Figure 1 shows a generally designated 1 detector body, the in the photodetector system according to the invention for detecting or measuring the Position of one or more light sources can be used. The detector body 1 has a circular cylinder on the outside of which three elongated lens elements 2, 3 and 4 are provided. These lens elements are cylindrical lens elements, which in the present case lie on two different levels. On one level is the lens element 2, and in the other plane are the lens elements 3 and 4. As can be seen from Fig. 1, the lens elements 3 and 4 are arranged so that their lens surfaces are in an overlapping relationship with the lens surface of the lens element 2, which lies in the other plane.

The lens elements 2, 3, 4 are individual flat detector elements associated, of which in FIG. 1 only the detector element associated with the lens element 2 5 and which are position-sensitive only in the direction of the lens curvature of the lens elements are and an exactly linear sensitivity curve in the axial direction of the lens elements demonstrate. In Fig. 2 it is shows that the lens elements 3 and 4 the detector elements 6 and 7 are associated. From Fig. 1 and 2 it can be seen that that the detector elements 5, 6 and 7 with their detector surfaces relative to one another are offset and that the individual detector elements 5, 6 and 7 associated elongated lens elements 2, 3 and 4 corresponding to the relative offset der'Detektorflächen the detector elements 5, 6 and 7 arranged offset to one another are.

At this point it should be noted that in deviation from the in Fig. 1 and 2 shown relationships of each detector body basically more Detector elements and lens elements may have, as previously indicated. Furthermore it should be noted here that it is shown in connection with FIGS. 1 and 2, that the detector elements and these associated lens elements are arranged one above the other are, but that by appropriate rotation, the relevant elements then next to each other are arranged. It should also be noted that the detector elements differ of the conditions previously considered with their detector surfaces on a common Line can be arranged lying one above the other or side by side. In this In this case, the line in question would be the center line of the circular cylinder body respectively.

Detector body 1.

Fig. 3 shows the application of three detector bodies in Figs. 1 and 2 type shown. According to Fig. 3 are the relevant detector body labeled 11, 12 and 13. The detector bodies 11 and 12 are with their longitudinal axes aligned in the vertical direction, and the detector body 13 is with its longitudinal axis arranged in the horizontal direction.

With the aid of the two detector bodies 11 and 12, the one indicated in FIG. 3 is indicated Space in a plane with respect to the position of at least one (not shown) Light source monitored or detected. The use of two detector bodies 11 and 12 brings an expansion of the detection area compared to the use only one detector body with it. With the help of the detector body 13, the mentioned Monitored space in the vertical direction.

The detector elements of the individual detector bodies 11, 12 and 13 are connected with their signal outputs to a common computing circuit 14, of the one at outputs X, Y and * for the individual spatial coordinates of a light source, which is located in the space indicated in FIG. 3, characterizing position signals can be submitted. This will be discussed in connection with FIGS. 5 and 6 will.

FIG. 4 shows a deviation from the relationships shown in FIG a case according to which a plurality of detector bodies, denoted by 16, 17, 18 and 19 are provided and are arranged lying next to one another with their longitudinal axes. By such an arrangement the detector body 16 to 19 becomes a relatively wide detection range achieved for light sources to determine their position or is to be measured. Such light sources can be worn by athletes, for example in order to be able to determine and evaluate their movements.

With regard to the relationships shown in Fig. 4, it should be noted that that in the hatched areas 20 a double evaluation of each one Light source emitted light rays takes place. In these cases, however, a Corresponding correction of the output signals of the affected detector body 16 to 19 take place.

Fig. 5 illustrates mathematical relationships that exist between the Detector bodies 11 and 12 shown in Fig. 3 are present. According to Fig. 5 are the two detector bodies 11 and 12 in a coordinate field with an x-axis and placed with a y-axis. A light source is labeled Py to indicate that their x and y coordinate values are to be determined.

A straight line running from the detector body 11 to the point Px, y forms an angle one with the y-axis between the detector body 12 and the Point Px, y running straight line forms an angle β with the y-axis. The distance between the two detector bodies 11 and 12 is 2d. With this in mind Values result in the following relationships: 2d = y (tan + tan), (1) from which for y the Relationship follows 2d y = tan + + tanj3) (2) and the value x results in x = -d + ytan c & (3) For Gie determination of the coordinate values given above y and x, only the large tan and tan ß are required. These sizes are but proportional to the output signals which the detector bodies 11 and 12 or their detector elements deliver.

In other words, this means that the output signals of the detector elements of the detector body 11 and 12 after multiplication by certain given proportionality constants for the quantities tana and tan / 3 are used can be.

Fig. 6 shows a block diagram of a computing circuit which the aforementioned quantities tan and tan ß for performing calculations exploits. According to FIG. 6, the quantity tan d is fed to an input terminal 21, and an input terminal 22, the variable tan ß is supplied. At this point be noted that actually the relevant quantities tan d and tan indicating binary numbers respectively.

Binary words are fed. At the two inputs 21 and 22 is a first computing circuit 23 connected to its inputs. This computing circuit 23 outputs to an output terminal 25 an output signal which is represented by the above equation (2) is sufficient. This means that an output signal occurs at the output terminal 25, which relates to the y-coordinate value of a light source that has just been detected.

At the output of the computing circuit 23 and at the input terminal 21 is a further computing circuit 24 connected, which at an output terminal 26 a Output signal according to the above relation (3) emits. This means that at the output terminal 26 a for the x-coordinate value of a light source just detected characterizing output signal is available.

In addition to the above, it should be noted that a computing circuit corresponding to the computing circuits indicated in FIG. 6 can be provided in order to determine the position of the detector body 13 according to FIG for a light source in a further coordinate axis z. The one in question Coordinate value z satisfies the relationship z = ytanf) (4) where t means the angle, a straight line between the detector body 13 according to FIG. 3 and a light source with respect to a reference plane (that is, the x-y plane).

To find the position of each light source using the previously described Detector body to be able to determine and at the same time a distinction between the To be able to meet different light sources, provision is made for the relevant light sources either to light up or get there one after the other in time division multiplex mode to let, or to modulate the frequency of the individual light sources, like this that they emit different colored light. But it is also possible to take both measures to be used in conjunction with each other.

Fig. 7 shows in a timing diagram different pulses for the Time division multiplexing a variety of light sources can be used. With 30 trigger pulses are designated in Fig. 7, which can be used to to emit light upon the supply of a further pulse 31, 32 or 3n, and although for the duration of the relevant pulse 31, 32 or 3n.

As plotted on the time axis in FIG. 7, the repeats relevant processes in a specified cycle. The individual light sources preferably with its own power supply, i.e.

be provided with its own battery.

The aforementioned time division multiplexing of the.

individual light sources may differ from those related with Fig. 7 specially explained conditions also take place so that the individual Light sources contain separate timers, which, for example, in the from Fig.7 come into effect in an apparent staggered manner. The relevant timer can do this for example from one of the triggers.

pulses 30 according to FIG. 7 are controlled.

Fig. 8 shows in a block diagram a circuit arrangement with whose help the useful-noise-signal ratio in the evaluation of the position signals indicating light sources can be kept relatively high. The person in question Circuit arrangement has two input connections 40 and 42- to which signals are supplied, which for different coordinate values of a light source in one and the same coordinate direction, e.g. in the x-coordinate direction are. At the input connection 40 there is an amplifier 41 with an adjustable gain factor connected. On the output side, the amplifier 41 is at the input + of a differential amplifier 44 and connected to the + input of a buzzer 47. The differential amplifier 44 is with its input - together with another input + of the adder 47 connected to the output of an amplifier 43, the gain factor of which is adjustable and which is connected on the input side to the input connection 42.

At the output of the differential amplifier 44 is a detector circuit 45 connected to a Output terminal 46 has an x value gives away.

A detector circuit 48 is connected to the output of the summer 47, which emits a control signal at an output terminal 49, which for the intensity or strength of the respective signal is characteristic.

This signal is also transmitted via an analog-to-digital converter (-ADC) 50 used to control a memory 51, in which the last Query result, i.e. the previously determined intensity signal is saved is. This signal is now emitted by the analog-to-digital converter 50 along with the Signal in a logic circuit 52 compared to a setting signal for setting of the gain factors of the amplifiers 41 and 43. By this measure there is a decrease in intensity or an excessive increase in the intensity of the input signals balanced. By taking advantage of those occurring at output ports 46 and 49 Signals can thus indicate the intensity of the light emitted by the light sources be held at a predetermined value.

The above is a system for determining or measuring the position one or more light sources by means of a photosensitive detector arrangement has been explained. With the help of such light sources, in particular by semiconductor elements, as light-emitting diodes (LED) can be formed, it is possible to add motion sequences record, for example by athletes or people with Parkinson's disease. But it is also easily possible, the invention for the detection of any movement sequences, for example also in industrial areas. As detector elements CCD detectors can also be used. In general, they can used detector elements somehow shaped surfaces, so z. B. also curved Have surfaces.

In Fig. 9 is a measuring arrangement for three-dimensional detection bwz. Measuring the position of one or more light sources shown. This system can be used, for example, for bio-mechanical measurements, in sports medicine and for checking be used by motion sequences in sports training. Furthermore, this measuring arrangement for measurements in car collisions or the like.

be used.

The measuring arrangement shown in Fig. 9 consists of a tubular vertical support 60, on which three uniaxial at approximately the same distance from each other Photodetector systems 61, 62, 63 are provided. The angular range of the top one Detector system 61 is delimited by a straight line 64 and an incline 65. The angular range of the lowermost detector system is represented by a straight line 67 and a Slope 66 limited. The two angular ranges of the two photodetector systems 61, 63 merge into one another at a certain distance from the carrier 60.

The angular range of the central photodetector system 62 is through the dashed line 68, 69 indicated.

This angular range extends perpendicular to the angular ranges of the outer photodetector systems 61, 63. The angular range of the middle photodetector system However, 62 is not limited to the level delimited by lines 68, 69, rather, it also has an opening angle (not shown here) in the vertical direction. However, the middle photodetector system 62 only registers changes in light sources, which are perpendicular to the plane of the drawing. In contrast, the two register external photodetector systems 61, 63 changes of light sources between ceiling and the floor of the measuring room.

In the measuring room in FIG. 9, a test person 70 carries a light source 71, for example in the form of a light emitting diode. With the three photodetector systems 61, 62, 63 three angular coordinates can be determined, which by means of a Computer can be converted into Cartesian space coordinates.

It is also possible for the test subject 70 to have several light sources 71 carries. These can then be modulated differently, for example, whereby a separation of the response signals associated with each light source at the photodetector systems 61, 62, 63 is possible.

Such a use of multiple light sources and a corresponding one Separation of the signals is described in DE-OS 23 39 390, for example.

The three photodetector systems 61, 62, 63 can be of the narrow angle type 10 or of the wide-angle type according to FIGS. 1 and 2.

- blank page -

Claims (18)

PATENT CLAIMS 9 Photo detector system for detecting or measuring the position of one or more light sources by means of a photosensitive detector arrangement, to which the light emitted by the respective light source through an optical imaging arrangement is guided, characterized in that the detector arrangement by at least a detector body (1) with a plurality of one above the other or next to one another arranged individual detector elements (5,6,7) is formed with their detector surfaces are offset relative to one another, and that'die optical imaging arrangement through elongated lens elements associated with the individual detector elements (5, 6, 7) (2, 3, 4) is formed, which corresponds to the relative displacement of the detector surfaces are arranged offset to one another. 2. photodetector system according to claim 1, characterized in that the detector elements (5, 6, 7) with their Detector surfaces on one common line are arranged lying one above the other or side by side. 3. photodetector system according to claim 1, characterized in that at least two detector elements (6, 7) in one plane with their detector surfaces are provided offset from one another and that in. At least one of the relevant At least one detector element (5) is provided on the plane immediately adjacent to the plane is, whose detector area is based on the detector area in the first-mentioned. Level existing detector elements (6, 7) is offset. 4. photodetector system according to claim 3, characterized in that the lens elements (2, 3, 4) associated with two immediately adjacent planes their lens surfaces are arranged in an overlapping relationship with one another. 5. photodetector system according to one of claims 1 to 4, characterized in that that several detector bodies (11, 12, 13) are provided and their longitudinal axes respectively are arranged in one of two mutually perpendicular planes. 6. photodetector system according to claim 5, characterized in that the detector elements of the detector body (11, 12, 13) with their signal outputs a computing circuit (14) are connected. 7. photodetector system according to one of claims 1 to 4, characterized in that that several detector bodies (16, 17, 13, 19) are provided and with their longitudinal axes are arranged side by side. 8. photodetector system according to one of claims 1 to 7, through this characterized in that the detector elements (5, 6, 7) are flat. 9. photodetector system according to one of claims 1 to 7, characterized in that that the detector elements (5, 6, 7) are curved. 10. Photodetector system according to one of claims 1 to 9, characterized characterized in that the light sources whose light is to be determined or measured, come on in time division multiplex mode. 11. Photodetector system according to one of claims 1 to 10, characterized characterized in that the light sources whose light is to be determined or measured, are modulated light sources. 12. Photodetector system according to one of claims 1 to 11, characterized characterized in that the individual light sources each have a power supply are provided. 13. Photodetector system according to one of claims 1 to 12, characterized characterized in that a control device (Fig. 8) is associated with the light sources, which the intensity of the light emitted by the light sources on a given Value holds. 14. Photodetector system according to one of claims 1 to 13, characterized characterized in that semiconductor elements serve as light sources and detector elements. 15. Arrangement for determining or. Measure the position of an or multiple light sources using a uniaxial in an angular range effective photodetector system, in particular according to one of claims 1 to 4, characterized in that to determine the three spatial coordinates of the light source (s) (71) two further uniaxial photodetector systems are used each of which is effective in a range of angles, and that at least two of the three photodetector systems (61, 62, 63) are offset from one another so that cross their angular ranges. 16. The arrangement according to claim 15, characterized in that the three Photodetector systems (61, 62, 63) are arranged on a straight line. 17. The arrangement according to claim 16, characterized in that the angular ranges the two outer photodetector systems (61, 63) run parallel to one another, and that the angular range of the central photodetector system (62) is perpendicular to the Angular ranges of the two outer photodetector systems (61, 63) runs. 18. Arrangement according to claim 16 or 17, characterized in that the three photodetector systems (61, 62, 63) are arranged on a carrier (60) in such a way that that the straight line runs vertically, that the angular ranges of the two outer photodetector systems (61, 63) each bounded by a horizontal line (64, 67) and an incline (65, 66) are such that the two angular ranges are at a certain distance from the carrier (60) merge into one another.