DE102006052921A1 - Method and device for measuring a body - Google Patents

Abstract

Method for measuring a body (9), comprising the steps of providing a plurality of light sources (4 <SUB> 1 </ SUB>) and light detectors (5 <SUB> 1 </ SUB>), which light sources and light detectors, in particular linear and arranged opposite each other and each connected to a control device, placing the body (9) between the light sources (4 <SUB> 1 </ SUB>) and light detectors (5 <SUB> 1 </ SUB>), so that the body (9) is located in the optical path between light sources and light detectors, assigning a light detector to a light source for forming a light source light detector pairing, repeating step iii) for all remaining light detectors and light sources such that the optical paths of the pairings formed are parallel to one another run, sequentially turning on the light sources from the steps iii) and iv), and measuring the light intensity with the corresponding assigned light detectors from step iii), wherein at Ein switching of a respective next light source the previous light source is switched off again, determining the two light source light detector pairings at the boundaries of the body, between which a light beam still passes, and calculating the distance between the two light sources or the two light detectors of the light source Lichtdetektor- Pairings of step vi).

Description

The The invention relates to a method and a device for non-contact Measuring a length a body, especially of feet.

at a conventional one Measurement of feet comes a caliper or the like used, the displaceable attached to a tray. To determine the shoe size or the sole length the foot gets up put the tray and then the caliper to the Foot introduced. Of the Foot becomes mostly placed with the heel in a fixed stop of the tray, making it an exact reference point for sufficient measurement accuracy results. On a scale can then read the foot length and possibly also the foot width become. Since this method does not work without contact, can at measuring the foot to be squeezed which determines too small a foot length becomes. Is in contrast the foot is not directly to the fixed stop, so too large a foot length is determined. Another disadvantage of such a measuring tray is that it's a natural, upright state of the customer requires, so a care by an operator needed is.

In a more modern embodiment of the above-mentioned measuring tablet is the movable caliper and / or a stop for the foot motor driven, so that an automatic measurement of the foot is possible. Disadvantage here is, however, that because of a low drive speed of Caliper or stop this measurement not very fast is, and a pressing force due to the motor drive not on matched a custom foot is. From this you can undesirable Measurement errors result.

in the The prior art is also known to include feet with flat board scanners measured. Such flat-panel scanners are under the name ParoScan or GP Foot scan known. The person to be measured stands with his foot on the Scanner, after which the foot of Scanned in below. With a corresponding image processing software can the picture of the foot be edited and measured. The scanning process usually takes several seconds, with the person to be measured calm or immobile must stand on the scanner. Another disadvantage is that a manual post-processing of the images is necessary because the different colors of the socks and the ambient light one automatic evaluation of the foot length difficult.

Corresponding the invention has the object, a method and a Device to create, with which a non-contact and fast measurement a body, especially one foot possible with low fault tolerance is.

These The object is achieved by a Method with the features of claim 1, and by a device solved with the features of claim 40. Advantageous developments of the invention are in the dependent claims Are defined.

• i) Bereitstellen einer Mehrzahl von Lichtquellen und Lichtdetektoren, welche Lichtquellen und Lichtdetektoren insbesondere linear und einander gegenüberliegend angeordnet und jeweils mit einer Steuereinrichtung verbunden sind,
• ii) Platzieren des Körpers zwischen den Lichtquellen und Lichtdetektoren, so dass sich der Körper in dem Strahlengang zwischen Lichtquellen und Lichtdetektoren befindet,
• iii) Zuweisen eines Lichtdetektors zu einer Lichtquelle zur Bildung einer Lichtquelle-Lichtdetektor-Paarung,
• iv) Wiederholen des Schritts iii) für alle übrigen Lichtdetektoren und Lichtquellen derart, dass die Strahlengänge der jeweils gebildeten Paarungen zueinander parallel verlaufen,
• v) sequentielles Einschalten der Lichtquellen aus den Schritten iii) und iv), und Messen der Lichtintensität mit den entsprechend zugewiesenen Lichtdetektoren aus Schritt iii), wobei beim Einschalten einer jeweils nächsten Lichtquelle die vorhergehende Lichtquelle wieder ausgeschaltet ist,
• vi) Bestimmen der beiden Lichtquelle-Lichtdetektor-Paarungen an den Grenzen des Körpers, zwischen denen ein Lichtstrahl noch passiert, und
• vii) Berechnen des Abstands der beiden Lichtquellen bzw. der beiden Lichtdetektoren der Lichtquelle-Lichtdetektor-Paarungen von Schritt vi).

The method according to the invention for the contactless measurement of a body comprises the steps:

• i) provision of a plurality of light sources and light detectors, which light sources and light detectors are arranged in particular linearly and opposite to each other and in each case connected to a control device,
• ii) placing the body between the light sources and light detectors so that the body is in the optical path between light sources and light detectors,
• iii) assigning a light detector to a light source to form a light source-light detector pairing,
• iv) repeating step iii) for all other light detectors and light sources in such a way that the beam paths of the pairs formed in each case run parallel to one another,
• v) sequentially switching on the light sources from steps iii) and iv), and measuring the light intensity with the correspondingly assigned light detectors from step iii), wherein when switching on a respective next light source, the preceding light source is switched off again,
• vi) determining the two light source light detector pairings at the boundaries of the body, between which a light beam still passes, and
• vii) calculating the distance of the two light sources or the two light detectors of the light source light detector pairings of step vi).

The inventive method is particularly suitable for measuring the feet of a person. however Alternatively, a measurement of any other bodies is possible, the be positioned between the light sources and the light detectors can, or around it the plurality of light sources and light detectors can be positioned. An important aspect regarding A sufficiently high measurement accuracy is that the body has no angular edges. Preferably, the body should have rounded edges or round or oval with respect to the plane of the light sources and the light detectors are formed.

In particular, the plurality of light sources and the plurality of light detectors may be linear be arranged in a row, wherein the light sources and the light detectors are arranged opposite to each other and are each connected to the control device. Advantageously, the light sources can be spaced apart equidistant from each other, so that in each case the same equidistant distance exists between the individual light sources. The same applies to the light detectors. Conveniently, the equidistant distances between the light sources and the light detectors are chosen to be equal.

As defined in step v), the light sources can be switched on individually, wherein the light intensity incident on the light detectors for each detector can be measured individually. The light sources are designed so that the light a larger opening angle and meets at least a plurality of opposed light detectors. Thus, as defined in step iii), several possible light source light detector pairings can be formed. The control of the light sources and the reading of the light detectors as well as the processing of this data is handled by a suitable control device, a microcontroller or the like, taken over. These are the individual light sources and the individual light detectors with the Control device connected.

The inventive method is particularly suitable for non-contact Measuring a foot of a human to determine a desired shoe size. Here, the body or the foot between the light sources and the light detectors positioned so that he in the beam path between the light sources and the light detectors located. The length of the foot will be first for the Case determines that a respective light source and a corresponding directly opposite the assigned light detector. The light source light detector pairings from step vi) between which a light beam still passes those in which the light beam is not blocked or interrupted by the foot becomes. Instead occurs in these light source light detector pairings the respective light beam at the boundaries of the body, i. at a front and rear end of the foot, unhindered over and falls to a respective light detector. Here, the length of the Feet overestimated, maximum twice the distance between the light sources or the light detectors, minimal by zero. The mean error is a simple one Distance between the light sources or the light detectors. through the light source light detector pairings from step vi) becomes the Length of the body or of the foot on average overestimated by the distance of the light sources. By the distance of the light sources the maximum error can be determined.

One Advantage of the method according to the invention is that no moving parts are used, the get in touch with the foot to be measured. The light sources can be switched on or off very quickly, if in step v) the light sources are switched on sequentially one after the other, so that several thousand light source light detector pairings per Second can be measured. An entire foot can thus be measured several times per second, what the measurement accuracy elevated. This also means that the customer only has his foot for a short time between the light sources and light detectors must, without to stand still for a long time. If the foot is still stands, then the error in the length determination remains the same. Because the survey of the foot done quickly, the must Only walk for a short time Stop time. In a short time the foot of different Pages are measured, whereby the measurement accuracy is further increased.

in the In view of said rapid switching on and off of the light sources come expediently Light emitting diodes are used as light sources, which are characterized by a low power consumption and a long service life. In an advantageous embodiment, the light intensity of the LEDs adapted by means of a control of the electric current, to exclude measurement errors or reduce. Preferably, an opening angle of the light sources or the light emitting diodes so that the emitted light on more than one opposite Light detector drops. Thus, in step iii) optionally different light source light detector pairings can be formed, to override the said overriding of Foot or a misalignment of the foot between the light sources and the light detectors.

In Advantageous development of the invention, the individual light sources and the individual light detectors from step i) are each an integer Index of i = 1 to m be assigned. Preferably, in this case the opposite ones Light sources and light detectors the same index. When a peripheral light source has index i = 1, and the other at the edge lying light source has the highest index m can the measuring process can be speeded up by the fact that when switching on the light sources in step iii) each with the light sources with the smallest index i = 1 or started with the highest index i = m becomes, and thus takes place in a direction toward the body. Here are the light sources from a respective edge of the row of light sources switched on sequentially, so that an evaluation of the light source-light detector pairings, whose Beam path through the body is interrupted, can be omitted.

In Advantageous development of the invention, the rows of Light sources and the rows of light detectors to each other equal distance and are substantially parallel to each other. In conjunction with the above-mentioned equidistant distance between the light sources or the light detectors results from this much less computational effort in the evaluation of the light measurement.

• viii) Bestimmen der beiden Lichtquellen der Paarungen aus Schritt vi),
• ix) Auswählen jeweils eines Lichtdetektors (5₁ ), dessen Index bezüglich des Index der Lichtquellen (4₁ ) aus Schritt viii) um einen Versatz V = ± N verschoben ist, mit

  V:

  Versatz

  N:

  natürliche Zahl ≥ 1

  und Zuweisen dieser Lichtdetektoren (5₁ ) zu den entsprechenden Lichtquellen (4₁ ) aus Schritt viii) zur Bildung einer neuen Lichtquelle-Lichtdetektor-Paarung,
• x) Einschalten der jeweiligen Lichtquelle (4₁ ) aus Schritt viii) und Messen der Lichtintensität mit dem entsprechenden Lichtdetektor (5₁ ) aus Schritt ix),
• xi) falls zwischen einer jeweiligen Lichtquelle-Lichtdetektor-Paarung aus Schritt ix) Licht passiert: weiter mit Schritt xii), sonst weiter mit Schritt xvi),
• xii) Auswählen einer Lichtquelle (4₁ ) in einer Richtung hin zu dem Körper (9),
• xiii) Auswählen eines Lichtdetektors (5₁ ), dessen Index bezüglich des Indexes der Lichtquelle (4₁ ) aus Schritt xii) um den gleichen Versatz (V) wie in Schritt ix) verschoben ist, und Zuweisen dieses Lichtdetektors (5₁ ) zu der Lichtquelle (4₁ ) aus Schritt xii) zur Bildung einer neuen Lichtquelle-Lichtdetektor-Paarung,
• xiv) Einschalten der Lichtquelle (4₁ ) aus Schritt xii) und Messen der Lichtintensität mit dem Lichtdetektor (5₁ ) aus Schritt xiii),
• xv) falls zwischen einer Lichtquelle-Lichtdetektor-Paarung aus Schritt xiii) Licht passiert: weiter mit Schritt xii), sonst weiter mit Schritt xvi),
• xvi) Auswählen einer jeweiligen Lichtquelle in einer Richtung weg von dem Körper (9), die zu der entsprechenden Lichtquelle (4₁ ) aus Schritt xii) benachbart ist,
• xvii) Auswählen eines Lichtdetektors (5₁ ), dessen Index bezüglich des Indexes der Lichtquelle (4₁ ) aus Schritt xvi) um den gleichen Versatz (V) wie in Schritt ix) verschoben ist, und Zuweisen dieses Lichtdetektors (5₁ ) zu der Lichtquelle (4₁ ) aus Schritt xvi) zur Bildung einer neuen Lichtquelle-Lichtdetektor-Paarung,
• xviii) Einschalten der Lichtquelle (4₁ ) aus Schritt xvi) und Messen der Lichtintensität mit dem Lichtdetektor (5₁ ) aus Schritt xvii),
• ixx) falls zwischen der Lichtquelle-Lichtdetektor-Paarung aus Schritt xvii) Licht passiert: weiter mit Schritt xx), sonst weiter mit Schritt xvi),
• xx) Bestimmen der beiden Lichtquelle-Lichtdetektor-Paarungen aus Schritt xviii) an den Grenzen des Körpers (9), zwischen denen ein Lichtstrahl noch passiert,
• xxi) mehrfaches Wiederholen der Schritte ix) bis xx) mit einem jeweils unterschiedlichen Versatz (V), wobei die Anzahl der Versätze (V) mit positivem und negativem Vorzeichen vorzugsweise gleich ist,
• xxii) Bestimmen einer positiven Index-Differenz (L₁) der beiden Lichtquellen (4₁ ) aus Schritt i) der jeweiligen Lichtquelle-Lichtdetektor-Paarungen aus Schritt xxi),
• xxiii) Berechnen einer korrigierten Länge (L_korr,1) für die einzelnen Index-Differenzen aus Schritt xxii), mit Lkorr,1 = L1·cos(arctan(V/B1))worin:

  L₁:

  jeweilige positive Index-Differenz aus Schritt xxii) für die Lichtquellen (4₁ ) aus Schritt i)

  V:

  jeweiliger Versatz aus Schritt ix)

  B₁:

  rechtwinkliger Abstand zwischen den Lichtquellen (4₁ ) und den Lichtdetektoren (5₁ ),

• xxiv) Durchführen einer Regression für die korrigierten Längen (L_korr,1) aus Schritt xxiii),
• xxv) Berechnen einer ersten modifizierten Länge (L_reg,1) auf Grundlage der Regression von Schritt xxiv), mit Ireg,1 = a1V + a2V2 ... + akVk + a0 worin:

  V:

  jeweiliger Versatz aus Schritt ix), und

• xxvi) Berechnen einer ersten tatsächlichen Länge (L_tat,1) des Körpers (9), mit Ltat,1 = (Lreg,1 – 1)·s1 worin:

  L_reg,1:

  erste modifizierte Länge aus Schritt xxv)

  s₁:

  Abstand zwischen den Lichtquellen (4₁ ) bzw. Lichtdetektoren (5₁ ) aus Schritt i),

  und
• xxvii) Anzeigen der ersten tatsächlichen Länge (L_tat,1) anstelle des Abstands aus Schritt vii).

In an advantageous embodiment of the invention, the method may further comprise the following steps:

• viii) determining the two light sources of the pairings from step vi),
• ix) each selecting a light detector ( 5 ₁ ) whose index relative to the index of light sources ( 4 ₁ ) from step viii) by an offset V = ± N, with

  V:

  offset

  N:

  natural number ≥ 1

  and assigning these light detectors ( 5 ₁ ) to the corresponding light sources ( 4 ₁ from step viii) to form a new light source light detector pairing,
• x) switching on the respective light source ( 4 ₁ ) from step viii) and measuring the light intensity with the corresponding light detector ( 5 ₁ from step ix),
• xi) if light passes between a respective light source light detector pairing from step ix): continue with step xii), otherwise continue with step xvi),
• xii) Selecting a light source ( 4 ₁ ) in a direction towards the body ( 9 )
• xiii) selecting a light detector ( 5 ₁ ) whose index relative to the index of the light source ( 4 ₁ ) from step xii) is shifted by the same offset (V) as in step ix), and assigning this light detector ( 5 ₁ ) to the light source ( 4 ₁ ) from step xii) to form a new light source light detector pairing,
• xiv) switching on the light source ( 4 ₁ ) from step xii) and measuring the light intensity with the light detector ( 5 ₁ from step xiii),
• xv) if light passes between a light source light detector pairing from step xiii): continue with step xii), otherwise continue with step xvi),
• xvi) selecting a respective light source in a direction away from the body ( 9 ) leading to the corresponding light source ( 4 ₁ ) from step xii) is adjacent,
• xvii) Selecting a light detector ( 5 ₁ ) whose index relative to the index of the light source ( 4 ₁ ) from step xvi) is shifted by the same offset (V) as in step ix), and assigning this light detector ( 5 ₁ ) to the light source ( 4 ₁ ) from step xvi) to form a new light source light detector pairing,
• xviii) switching on the light source ( 4 ₁ ) from step xvi) and measuring the light intensity with the light detector ( 5 ₁ ) from step xvii),
• ixx) if light passes between the light source light detector pairing of step xvii): continue with step xx), otherwise continue with step xvi),
• xx) determining the two light source light detector pairings from step xviii) at the boundaries of the body ( 9 ) between which a ray of light still passes,
• xxi) repeatedly repeating steps ix) to xx) with a respectively different offset (V), wherein the number of offsets (V) with positive and negative signs is preferably the same,
• xxii) determining a positive index difference (L ₁ ) of the two light sources ( 4 ₁ from step i) of the respective light source light detector pairings from step xxi),
• xxiii) calculating a corrected length (L _{korr, 1} ) for the individual index differences from step xxii), with L corr, 1 = L 1 * Cos (arctan (V / B 1 )) wherein:

  L ₁ :

  respective positive index difference from step xxii) for the light sources ( 4 ₁ ) from step i)

  V:

  respective offset from step ix)

  B ₁ :

  right-angled distance between the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ )

• xxiv) performing a regression on the corrected lengths (L _{corr, 1} ) of step xxiii),
• xxv) calculating a first modified length (L _{reg, 1} ) based on the regression of step xxiv), with I reg 1 = a 1 V + a 2 V 2 ... + a k V k + a 0 wherein:

  V:

  respective offset from step ix), and

• xxvi) calculating a first actual length (L _{tat, 1} ) of the body ( 9 ), With L tat, 1 = (L reg 1 - 1) · s 1 wherein:

  L _{reg, 1} :

  first modified length from step xxv)

  s ₁ :

  Distance between the light sources ( 4 ₁ ) or light detectors ( 5 ₁ ) from step i),

  and
• xxvii) display the first actual length (L _{tat, 1} ) instead of the distance from step vii).

In an advantageous development of the invention, the first modified length L _{reg, 1} defined in step xxv) is determined to a ₀ when the body is aligned with its longitudinal axis substantially parallel to the light sources or light detectors from step i). In other words, in the case where the body is "just" positioned between the light sources and the light detectors, greater measurement accuracy can be achieved by defining the first modified length L _{reg, 1} defined in step xxv) for an offset of V = 0, from which follows L _{reg, 1} = a _0. The regression parameter a ₀ is then inserted into the equation from step xxvi) to calculate the actual length L _{tat, 1.} Such a calculation of the first actual length of the body is in each case more accurate than the distance between the two light source light detector pairings from step vi) at an offset V = 0, since at this distance there is a comparatively large overestimation of the length of the body.

In Advantageous development, the method further comprises a step aa) in which further light sources and light detectors are provided are each linear in a row and opposite each other arranged and each connected to a control device, these rows of light sources and light detectors are preferably perpendicular to the rows of light sources and light detectors from step i) are arranged. In practice, the foot may be not exactly parallel to the rows of light sources and light detectors from step i) aligned. Instead, the foot can go wrong be placed, with its longitudinal axis with a longitudinal extension the light sources or light detectors forms an angle α. Out this misalignment of the foot can inaccurate, i. too big, Measured values result. Therefore, the inventive method a step bb), in which the steps iii) to vii) for the light sources and light detectors from step aa).

In Advantageous development of the invention are the rows of light sources and light detectors from step aa) to each other in a same Distance spaced so that these rows are substantially parallel to each other. this leads to advantageous to a reduced effort in the evaluation of the measurement results.

In the same way as the light sources from step i), the Light sources from step aa) be created so that the of Light source emitted light on more than one opposite light detector falls. Thus, in step iii), if performed according to step bb), a Make up a plurality of different light source light detector pairings. Furthermore, you can the light sources or the light detectors from step aa) to each other an equidistant Have distance, which the computational effort in the evaluation of Measurement results also reduced.

• cc) Bestimmen der beiden Lichtquellen aus Schritt aa) der Paarungen gemäß Schritt vi), soweit durchgeführt in Schritt bb),
• dd) ausgehend von den beiden Lichtquellen aus Schritt cc): Durchführen der Schritte ix) bis xxi),
• ee) Bestimmen einer positiven Index-Differenz (L₂) der Lichtquellen aus Schritt aa) der jeweiligen Lichtquelle-Lichtdetektor-Paarungen aus Schritt xxi),
• ff) Berechnen einer korrigierten Länge (L_korr,2) für die einzelnen Index-Differenzen aus Schritt ee), mit Lkorr,2 = L2·cos(arctan(V/B2))worin:

  L₂:

  jeweilige positive Index-Differenz aus Schritt ee) für die Lichtquellen aus Schritt aa)

  V:

  jeweiliger Versatz aus Schritt ix), bezogen auf die Lichtquellen und Lichtdetektoren aus Schritt aa),

  B₂:

  rechtwinkliger Abstand zwischen den Reihen von Lichtquellen und Lichtdetektoren aus Schritt aa),

• gg) Durchführen einer Regression für die korrigierten Längen (L_korr,2) aus Schritt ff),
• hh) Berechnen einer zweiten modifizierten Länge (L_reg,2) auf Grundlage der Regression von Schritt gg), mit Lreg,2 = b1V + b2V2 ... + bkVk + b0 worin:

  V

  = jeweiliger Versatz aus Schritt ix), soweit bezogen auf die Lichtquellen und Lichtdetektoren aus Schritt aa),

• jj) Bestimmen eines lokalen Extremums der Regressionsgleichung aus Schritt hh),
• kk) Berechnen eines Extremum-Versatzes (V_g), der aus dem lokalen Extremum von Schritt jj) resultiert,
• ll) Berechnen eines Winkels (α), mit α = arctan(Vg/B2),worin:

  V_g:

  Extremum-Versatz aus Schritt kk)

  B₂:

  Abstand zwischen den Reihen von Lichtquellen und Lichtdetektoren aus Schritt aa),

• mm) Berechnen eines angepassten Versatzes (V₁), mit V1 = tan(α)·B1 worin:

  V₁:

  angepasster Versatz

  α:

  Winkel aus Schritt ll)

  B₁:

  rechtwinkliger Abstand zwischen den Lichtquellen und den Lichtdetektoren aus Schritt i),

• nn) Berechnen der modifizierten Länge (L_reg,1) in Schritt xxv) mit V = V₁,
• oo) Berechnen der tatsächlichen Länge (L_tat,1) des Körpers in Schritt xxvi) mit der modifizierten Länge (L_reg,1) aus Schritt nn), und
• pp) Anzeigen der tatsächlichen Länge (L_tat,1) aus Schritt oo) anstelle der zunächst in Schritt xxvi) berechneten Länge, wobei die Schritte xxvii) und vii) ausgelassen werden.

To compensate for the possible misalignment of the foot, the method may further comprise the following steps:

• cc) determining the two light sources from step aa) of the pairings according to step vi), if carried out in step bb),
• dd) starting from the two light sources from step cc): performing steps ix) to xxi),
• ee) determining a positive index difference (L ₂ ) of the light sources from step aa) of the respective light source light detector pairings from step xxi),
• ff) calculating a corrected length (L _{korr, 2} ) for the individual index differences from step ee), with L corr, 2 = L 2 * Cos (arctan (V / B 2 )) wherein:

  L ₂ :

  respective positive index difference from step ee) for the light sources from step aa)

  V:

  respective offset from step ix) with respect to the light sources and light detectors from step aa),

  B ₂ :

  right-angled distance between the rows of light sources and light detectors from step aa),

• gg) performing a regression for the corrected lengths (L _{korr, 2} ) from step ff),
• hh) calculating a second modified length (L _{reg, 2} ) based on the regression of step gg), with L reg 2 = b 1 V + b 2 V 2 ... + b k V k + b 0 wherein:

  V

  = respective offset from step ix), with respect to the light sources and light detectors from step aa),

• jj) determining a local extremum of the regression equation from step hh),
• kk) calculating an extremum offset (V _g ) resulting from the local extremum of step jj),
• ll) calculating an angle (α), with α = arctane (V G / B 2 ) wherein:

  _Vg :

  Extremum offset from step kk)

  B ₂ :

  Distance between the rows of light sources and light detectors from step aa),

• mm) calculating a fitted offset (V ₁ ), with V 1 = tan (α) · B 1 wherein:

  V ₁ :

  adjusted offset

  α:

  Angle from step ll)

  B ₁ :

  right-angled distance between the light sources and the light detectors from step i),

• nn) calculating the modified length (L _{reg, 1} ) in step xxv) with V = V ₁ ,
• oo) calculating the actual length (L _{tat, 1} ) of the body in step xxvi) with the modified length (L _{reg, 1} ) from step nn), and
• pp) displaying the actual length (L _{tat, 1} ) from step oo) instead of the length initially calculated in step xxvi), omitting steps xxvii) and vii).

The aforementioned steps cc) to pp) are based on the approach that by means of the measurement with the light sources and light detectors from step aa) a number of positive index differences L ₂ and from this by an angle correction a point set of corrected lengths L _{corr, 2} is generated, for which then a regression is performed. By determining a local extremum of the regression equation, an extremum offset V _g between a respective light source and a correspondingly assigned light detector is computationally determined, in which the beam path between such light source light detector pairings best approximates a longitudinal axis of the body. Based on this extremum offset, the angle α of the misalignment of the foot relative to the light sources and light detectors from step i) can be determined via the relationship α = arctan (V _g / B ₂ ). B ₂ corresponds to the distance of the light sources from step aa). With this angle α, the adjusted offset V ₁ is then calculated, as defined in step nn), and then inserted into the equation for the modified length L _{reg, 1} defined in step xxv). With the modified length L _{reg, 1} thus calculated _, the actual length L _{tat of} the body is finally calculated as defined in step xxvi). Through this approach, the "misalignment" of the body is taken into account and essentially compensated.

• – Berechnen der zweiten modifizierten Länge (L_reg,2) aus Schritt hh) mit: V = (Vg)aus Schritt kk), und
• – Berechnen einer zweiten tatsächlichen Länge (L_tat,2) des Körpers (9), mit: (Ltat,2) = (Lreg,2 – 1)·s2,worin:

  s₂:

  jeweiliger Abstand zwischen den Lichtquellen (4₂ ) bzw. Lichtdetektoren (5₂ ) aus Schritt aa),

  und
• – Anzeigen der zweiten tatsächlichen Länge (L_tat,2).

In an advantageous development of the invention, the method after step kk) instead of steps ll) to pp) may comprise the following steps:

• Calculating the second modified length (L _{reg, 2} ) from step hh) with: V = (V G ) from step kk), and
• Calculating a second actual length (L _{tat, 2} ) of the body ( 9 ), With: (L tat, 2 ) = (L reg 2 - 1) · s 2 . wherein:

  s ₂ :

  respective distance between the light sources ( 4 ₂ ) or light detectors ( 5 ₂ ) from step aa),

  and
• - Display the second actual length (L _{tat, 2} ).

The lead the above steps to the advantage that by means of the second actual length, the width of the foot for the Case is determined that he "crooked" between the light sources and light detectors, i. with its longitudinal axis essentially not parallel to a series of light sources or Light detectors is positioned.

In Advantageous development of the invention is in step xxiv) or gg) regression defined a quadratic regression. A such quadratic regression ensures sufficient measurement accuracy at a reasonable computing cost.

In an advantageous development, light can be used in the form of light-emitting diodes in the infrared wavelength range. Accordingly, photodiodes with a daylight filter can be used as light detectors that allows infrared light to pass. Thus, the measurement is largely independent of the ambient light.

A further elimination of the ambient light influence can be achieved be that just before step v), x), xiv) or xviii) the Ambient light intensity measured on the light detectors with light sources switched off becomes when the body positioned between the light source-light detector pairings. Subsequently becomes the total intensity on a respective light detector with the light source switched on measured. From the difference of the total intensity to the ambient light intensity results a caused by a respective light source light intensity, the Measuring the light intensity in step v), x), xiv) or xviii) is taken into account. Thus, will measured the incident on each light detector daylight and for Determination of pairings according to step vi) and xxii).

In Advantageous development of the invention is before the actual Measuring the body one Basic calibration of all light sources and light detectors performed. in this connection are all without a body before step ii) or before step bb) Light sources from step i) or from step aa) turned on in succession and the light intensity for all possible Combination of light detectors that measured these light sources are opposite. The thereby measured light intensity on the respective light detectors is in a memory unit stored and in determining the pairings of step vi) and xxii) are considered accordingly. The Light intensity on the light detectors in step v), x), xiv) and xviii) compared with the previously measured light intensity according to the basic calibration. If a light intensity significantly smaller than that of the basic calibration is so located the body is between the corresponding light source light detector pairing.

If the foot is positioned with its longitudinal axis substantially parallel to the light sources and light detectors of step i), the actual length calculated in step xxvi) corresponds to the foot length. In an advantageous embodiment of the invention, not only the misalignment of the foot can be computationally compensated by the light sources from step aa), but also the width of the foot can be determined. For this, after step hh), the second modified length L _{reg, 2 is} calculated as: L _{reg, 2} = b ₀ , and then a second actual length of the foot corresponding to the foot width is calculated as: L _{tat, 2} = ( b ₀ - 1) · s ₂ . The value s ₂ here corresponds to the equidistant distance between the individual light detectors from step aa). In this approach for measuring the foot width by means of the light sources and light detectors of step aa), it is assumed that the foot is positioned substantially "straight", ie without skewing relative to the light sources and light detectors of step i) can also be determined during a "misalignment". For this purpose, L _{reg, 2 is determined} at point V _g as determined in step kk).

A inventive device for contactless Measuring a body comprises a plurality of light sources, in particular linear are arranged in a row, a plurality of light detectors, which are opposite to the light sources and in particular arranged linearly in a row, wherein the Light sources and the light detectors are directed towards each other, so that the body in the beam path between the light sources and the light detectors is positionable, a control device with which the light sources and the light detectors are respectively connected so that the light detectors and the light sources optionally with each other to different pairings combinable and hereafter the light sources sequentially switched one after the other are, wherein by means of the control means light source light detector pairings at the boundaries of the body are determinable between which a ray of light still happens when the body between This pairings is positioned, with a distance between the two Light sources or the two light detectors of these light source light detector pairings a measure of a length of Body is.

In the same way as the inventive method is the inventive device especially for non-contact Measuring feet of one People. However, a measurement of any other bodies or Objects possible, as long as these are between the light sources and the light detectors can be positioned.

In Advantageous development of the invention, the light sources and the Light detectors are each arranged linearly in a row, these Rows to each other have the same distance and substantially are parallel to each other. A particularly simple and inexpensive Embodiment of the device is given by a frame device, which encloses a bottom plate. The light sources and light detectors are at opposite Sides of the frame device are attached and are from the bottom plate each spaced at the same distance. The body or the Foot lets itself put on the bottom plate without further ado, passing between the light sources and the light detectors is positioned.

In Advantageous development of the invention, the light sources and the Be provided light detectors on all four sides of the frame device, being at the opposite Side of the frame device in each case a plurality of the light sources or a plurality of the light detectors are mounted. Thus let itself both a length as well as a width of the body or of the foot, and / or a misalignment of the body with respect to a longitudinal axis Compensate the frame means computationally to a greater accuracy to achieve.

In Advantageous development of the invention, the frame device be formed at least partially from a frame profile, wherein the light sources or the light detectors within the frame profile are included. The frame profile is adjacent to the light sources or light detectors each have an opening through which a light beam can pass through. The accommodation of the light sources or the Light detectors within the frame profile provides good protection against environmental influences or prevents possible damage of these components. Appropriately, can in the opening the frame profile to be bordered by a cover that the frame profile outward closes. The cover can only be used for the frequency of the measuring light permeable be, and / or consist of a transparent disc. Conveniently, The cover can also serve as a daylight filter.

In Advantageous development of the invention, the device can Have distance sensor attached to the frame device and pivotable about at least one axis above the bottom plate is. By means of such a distance sensor can not only the length or the width of a body, but also its height be measured.

In Advantageous development of the invention, the distance sensor be pivotable about two axes above the bottom plate. This improves the Measurement accuracy with respect the height measurement of the body. Conveniently, the measurement is carried out by means of the altimeter on the principle of triangulation.

Further Advantages and embodiments of the invention will become apparent from the Description and attached drawing.

It it is understood that the above and the following yet to be explained features not only in the specified combination, but also in other combinations or alone, without to leave the scope of the present invention.

The Invention is based on an embodiment schematically shown in the drawing and is below under Referring to the drawings described in detail.

It demonstrate:

1 a perspective view of a device according to the invention,

2 a side cross-sectional view of the device along the line AA of 1 .

3 a plan view of the device of 1 when measuring with light sources and light detectors along the longitudinal side of the device,

3a a schematic plan view of the device of 1 in which geometric relationships for a correction of the length are explained,

4 a table of measurement of 3 .

5 a graph for the corrected length according to 4 as a function of the offset V,

6 a plan view of the device of 1 when measuring with light sources and light detectors along a broad side of the frame means,

7 a table of measured values of the measurement of 6 .

8th a diagram of the corrected width according to the table of 7 as a function of the offset V,

9 a top view of a further embodiment of the device according to the invention, when a measurement is performed with light sources and light detectors on opposite edge sides of the frame device,

10 a table of measured values of the measurement of 9 .

11 a diagram of the corrected length according to the table of 10 as a function of the offset V,

12 a plan view of the device of 9 wherein a measurement is performed with light sources and light detectors on the other pair of edges of the frame means,

13 a table of measurement results for the measurements according to 12 .

14 a diagram of the corrected width according to the table of 13 as a function of the offset V, and

15 a perspective view of another embodiment of the device according to the invention, in which a distance sensor is provided for height measurement of the body.

In the 1 to 8th is a first embodiment of a device according to the invention 1 and explains the underlying measuring principle for measuring a body.

The device 1 includes a rectangular bottom plate 2 on which a circumferential frame 3 from four frame segments 3a to 3d is mounted. The bottom plate 2 or the circulating frame device 3 are dimensioned so that a foot can be positioned within the frame means. The frame means is sized large enough for a foot when the longitudinal frame segments 3a and 3c For example, 40 cm long, and the wide frame segments 3b and 3d 20 cm long. However, any other size of the frame segments or the frame device is possible to measure larger bodies or objects than that of a human foot can. Furthermore, the frame means may also have a shape deviating from a rectangle.

On the longitudinal frame segment 3a are a plurality of light sources 4 ₁ attached in the direction of the opposite frame segment 3c refer and have an equidistant distance to each other. At the opposite frame segment 3c are a plurality of light detectors 5 ₁ attached to the respective light sources 4 ₁ are aligned and each other also have an equidistant distance. The light sources 4 ₁ and the light detectors 5 ₁ are each arranged in the same equidistant distance from each other. In this case, the distance between the light sources or the light detectors is determined by the desired measurement accuracy. In other words, the distance between the light sources or the light detectors determines the maximum or mean error without regression. Performing a regression will minimize this error. Since shoe sizes are usually graded at a distance of about 5 mm, offers for the equidistant distance between the light sources or light detectors at a distance of 5 mm. However, this distance can be changed or tuned to measure other bodies in any way.

In the same way as on the frame segments 3a . 3c are also on the frame segments 3b . 3d light sources 4 ₂ and light detectors 5 ₂ arranged. The light sources 4 ₂ are on the frame segment 3b also attached in an equidistant distance from each other. The same applies to the light detectors 5 ₂ on the frame segment 3d , Whose equidistant distance from one another corresponds to the distance between the individual light sources 4 ₂ equivalent.

All light sources 4 ₁ . 4 ₂ and all light detectors 5 ₁ . 5 ₂ are from the bottom plate 2 slightly spaced, for example by 10 to 15 mm. The light detectors may be formed as a strip element. The distance of the light sources 4 ₁ . 4 ₂ and light detectors 5 ₁ . 5 ₂ from the bottom plate is chosen so large that it is just below the height of the toe or the heel of one on the bottom plate 2 positioned human foot. Also, other distances of the light sources or light detectors to the bottom plate are readily possible if bodies other than a human foot are to be measured.

All light sources 4 ₁ . 4 ₂ and all light detectors 5 ₁ . 5 ₂ are connected to a control device or to a microcontroller or the like. The microcontroller (not shown) controls switching on and off of the light sources and readout of the light intensity on the individual light detectors.

The light sources 4 ₁ attached to the frame segment 3a are attached, are of the on the frame segment 3c mounted light detectors 5 ₁ removed by a distance B ₁ . The on the frame segment 3b mounted light sources 4 ₂ are from the on the frame segment 3d mounted light detectors 5 ₂ spaced by a distance B ₂ .

In 2 is the device 1 in a side cross-sectional view along the line AA of 1 shown. It can be seen that the frame segments are formed in the form of a rectangular profile. The frame segments 3a . 3c have on their respective inner wall surface an opening 6 on, which is formed in the longitudinal direction of the frame segments as a continuous slot. Into the respective opening 6 is a transparent pane 7 or the like enclosed, so that the interior of the frame segments is closed to the outside. The light sources 4 ₁ and the light detectors 5 ₁ are within the frame segments via suitable brackets 8th so fastened that they are adjacent to the opening 6 or the transparent pane 7 are positioned. A light beam can thus be from a light source 4 through the two discs 7 through to a corresponding light detector 5 ₁ meet if there is no body or measurement object in the beam path. It is understood that the frame segments 3b and 3d analogous to the representation of 2 are formed, wherein herein the light sources 4 ₂ and the light detectors 5 ₂ in the same Wei se are appropriate.

In 2 is also a measurement object 9 shown on the bottom plate 2 is placed. Without being limited to this, the measurement object becomes 9 hereinafter always referred to as foot. Already from the presentation of 2 it can be seen that the beam path at least between some light sources 4 ₁ respectively. 4 ₂ and some light detectors 5 ₁ respectively. 5 ₂ is interrupted when the foot 9 on the bottom plate 2 is attached.

The device 1 serves for non-contact measuring of the foot 9 by means of the light sources 4 ₁ . 4 ₂ or the light detectors 5 ₁ . 5 ₂ , The measuring principle is explained in detail below.

The individual light detectors may optionally be assigned to a particular light source to form a light source light detector pairing. Such assignment of a light detector 5 ₁ . 5 ₂ to a light source 4 ₁ . 4 ₂ is not constant, but variable for different measuring runs. The light sources 4 ₁ . 4 ₂ can be switched on sequentially by means of the microcontroller, so that the light intensity of a specific light source can be read out on the light detector of the corresponding light source light detector pairing. With a sufficiently large light intensity on the light detector, the beam path between this light source light detector pairing is not interrupted, or a light beam passes between this pairing. This is the case when the beam path through the foot 9 is not blocked. Otherwise, if the foot is in the beam path of a light source-light detector pairing, the light intensity read out on the light detector of this pairing is only very small. By a previously performed basic calibration of all possible combinations of light sources and light detectors can be exactly determine the light intensity that occurs when passing the light beam.

The evaluation of the light intensity on the light detectors of the respective light source light detector pairings can be simplified mathematically by assigning the individual light sources and light detectors respectively an integer index of i = 1 to m. In the top view of 3 this is shown. All light sources 4 ₁ attached to the frame segment 3a are attached, are provided with an index of i = 1 to 20. The same applies to the light detectors 5 ₁ on the opposite frame segment 3c , The light sources 4 ₂ on the frame segment 3b are also provided with an integer index, namely i = 1 to 10. This also applies to the light detectors 5 ₂ to that on the frame segment 3d are attached. From the 3 It can be seen that the respectively opposite light sources and light detectors each have the same index. In this case, a respective light source lying on the edge has the index i = 1. The same applies to the peripheral light detectors.

It is understood that the number of twenty light sources or light detectors on the frame segments 3a respectively. 3c and the number of ten light sources or light detectors on the frame segments 3b respectively. 3d only to be understood as an example in order to explain the measuring principle. Depending on the actual length of the frame segments and the selected distances between the light sources and the light detectors, the respective number of light sources or light detectors may be chosen differently.

As explained above, individual light detectors can be used 5 ₁ . 5 ₂ a particular light source 4 ₁ . 4 ₂ optionally allocate to form a light source light detector pairing. Depending on a respective measurement run, these light source light detector pairings can be changed by assigning a different light detector to a particular light source. The different measurement runs are now referring to 3 explained.

After the foot 9 on the bottom plate 2 is set up, starting from the edges of the frame segment 3a the light sources with the index 1 . 20 . 2 . 19 etc sequentially turned on sequentially. In a first measurement run, these light sources are assigned light detectors with an even-numbered index. The light beam between such light source light detector pairings each having an equal index is in 3 For example, marked with a solid full line. If a light detector with the index i = 5 is assigned to a light source with also the index i = 5, according to the invention there is an offset V = 0.

As by the solid solid lines for the offset V = 0 in 3 As shown, the light source light detector pairings with index i = 5 and l = 14, respectively, are those pairings at the boundaries of the foot 9 between which a ray of light still passes. In other words, the light beam between pairings with index i = 6 or i = 13 is already through the foot 9 blocked. Accordingly, only a small value is measured for the light intensity on the light detectors with the index i = 6 or i = 13. From the distance of the two light sources with the index i = 5 and i = 14 can be approximated a length of the foot 9 be determined. As in 3 to recognize, is thereby by the distance of the light sources with the index 5 and 14 the length of the foot 9 overestimated. The overestiming takes a maximum of twice the distance between the light sources or light detectors, minimally the value zero. The mean error of overestimation is included a simple distance between the light sources 4 ₁ or the light detectors 5 ₁ ,

In order to reduce the level of overestimation and to obtain more accurate measurement results, new light source light detector pairings are subsequently formed. Here, starting from the light sources of the two light source-light detector pairings at the boundaries of the foot 9 between which a light beam is still passing, new light detectors are selected whose index is shifted by an offset V = +/- N with respect to the index of the light sources just mentioned, where N is a natural number ≥ 1. These newly selected light detectors are then the two light sources of the pairings at the boundaries of the foot 9 assigned. The example of the representation of 3 this means the following:
In a first measurement run, the light sources are at the index 5 and 14 at the borders or edges of the foot 9 , wherein at a selected offset of V = 0 nor a light beam to the light detectors with the index 5 respectively. 14 falls. To perform a new sweep, now the light source with the index 5 respectively. 14 assigned new light detectors, for example, with an offset of 1. This means that the light detectors with the index i = 6 or i = 15 of the light source with the index 5 respectively. 14 be assigned to. In other words, the index of these two light detectors is larger by 1 than the index of the correspondingly assigned light sources.

The second measurement run works as follows:
After the new pairing with the light source with the index 5 and the light detector with the index 6 is formed, the light source with the index 5 switched on. As in 3 To detect the light beam between this light source light detector pairing is not through the foot 9 blocked, wherein the distance between the beam path and the edge of the foot is less than in the first measurement between the light source and the light detector respectively with the index 5 is. If necessary, to further increase the measurement accuracy and reduce the overshoot, then the light source with the index 6 and in turn a light detector with the offset V = 1, namely the light detector with the index 7 , assigned. The offset between light source and light detector remains in comparison to the previous combination light source with index 5 and light detector with index 6 equal if now the light source with index 6 is selected. Subsequently, the light source with index 6 Turned on and checked that the emitted light beam to the light detector with the index 7 falls. 3 shows that this is not the case, since the foot 9 located in the corresponding beam path. After that, the measurement cycle jumps to the light source with index 5 and its assigned light detector with index 6 back and realize that for this combination the light beam still passes.

The same procedure is used for the light source with index 14 carried out. After for the combination light source with index 14 and light detector with index 15 , ie for the offset of V = 1, it is found that the beam path is not through the foot 9 is interrupted, then the light source with index 13 selected and her the light detector with index 14 assigned. After switching on the light source with index 13 is by means of the light detector with index 14 found that the beam path also happens in this mating and not by the foot 9 is interrupted. In a next step, a next light source is selected in a direction towards the foot, in the present case the indexed light source 12 , Accordingly, this light source becomes a light detector with index 12 assigned. Since it is recognized for the last-mentioned light source light-detector pairing that no more light is passing, the method selects a light source in a direction away from the foot adjacent to the light source from the previous step. In the example of 3 this is the light source with index 13 , Again, the light source is indexed 13 assigned a light detector with V = 1, so the light detector with index 14 , So this is the light source-light detector pairing, between which light is still passing at one edge of the foot and the light is not interrupted.

Important for this further measurement run is that for an offset of V = 1, the light sources of the two light source-light detector pairings at the edges of the foot 9 be determined between which a beam of light still passes. In the example just mentioned, these are the light sources with the index 5 and 13 , The same offset in these two pairings means that the beam path of these pairings is parallel. Based on the index of the two light sources of this pairing, a positive index difference is subsequently formed. In the present case, the positive index difference L ₁ = 13-5 = 8.

Following this, starting from the two light sources with the index 5 respectively. 14 new light source light detector pairings formed, now for example with an offset of V = 2. This means that a light detector with the index 7 the light source with the index 5 is assigned. Then the light source with the index 5 turned on and the light intensity on the light detector with the index 7 measured. As in the example of 3 shown, the light beam of this mating of the foot 9 blocked. Accordingly, a light source is selected in a direction away from the body which is the indexed light source 5 is adjacent. In the present case this is the light source the index 4 , This light source is in turn assigned a light detector with an offset of V = 2, ie the light detector with the index 6 , When turning on the light source with the index 4 is then evaluated by evaluating the light intensity on the light detector with the index 6 found that the light beam passes through this mating and not through the foot 9 is blocked.

At the other end of the foot is the light source with index 14 also assigned a light detector with an offset of V = 2, ie the light detector with the index 16 , When turning on the light source with the index 14 is by reading the light intensity on the light detector with the index 16 found that the beam of light passes between this mating. Accordingly, subsequently, a light source is selected in a direction toward the body corresponding to the light source with the index 14 is adjacent, ie the light source with the index 13 , This light source is in turn assigned a light detector with an offset of V = 2, ie the light detector with the index 15 , Then turn on the light source with the index 13 is by reading the light detector with the index 15 found that the beam of light passes between this mating. Therefore, the method selects another light source in a direction toward the foot, in the present case the indexed light source 12 , and assigns to this light source an indexed light detector 14 (ie offset V = 2). However, since no more light passes between this latter pairing, the method selects a light source in a direction away from the foot, that is, the indexed light source 13 off, with appropriate assignment of the light detector with index 15 , As explained above, the light is indexed between the pairing of the light source 13 and the light detector with index 15 not interrupted by the foot. Accordingly, for this measurement run, the two light source light detector pairings are at the edges of the foot 9 between which a light beam still passes, those with the light sources with the index 4 and 13 are. The corresponding positive index difference L ₁ between these two light sources is 13 - 4 = 9.

Following this, starting from the light sources with the index 5 respectively. 14 each further pairings formed with a different offset. In the example of 3 Further pairings with an offset of 3 and 4, and also pairings with an offset of -1 to -4 are formed. A negative offset means that the index of a selected light detector is smaller than that of a corresponding light source. For example, with an offset of -3, the light source is indexed 7 the light detector with index 4 assigned. Analogously, this applies, for example, to the light source with index 15 which at an offset of -3 the light detector with index 12 is assigned.

The formation of each new light source light detector pairings with a different offset in each case now takes place in the same manner as explained above with respect to an offset of +1 or +2. At the edges of the foot 9 By suitable displacement of the light sources, the pairings are always determined with the same offset, between which a light beam still passes at the edges of the foot. These pairings are in 3 marked by appropriate lines, as from the legend of 3 evident. As explained, a positive index difference L ₁ is then formed for the two light sources of all the respective pairings.

In the example of 3 A total of nine measurement runs are performed, each for an offset of 0, +1 to +4, and -1 to -4. It is recommended to do the same number of passes for a positive and negative offset. In 3 this is the case since four measurement runs are performed with a positive offset and four measurement runs with a negative offset.

The respective values for the positive index difference resulting from the respective light source light detector pairings at the edges of the foot 9 result, between which a light beam still passes, are then subjected to an angle correction according to the equation: L _{corr, 1} = L ₁ * cos (arctan (V / B ₁ )). The geometric relationships underlying the equation for the angle correction are shown in FIG 3a entered. With reference to the light source with the index 14 and the light detector with the index 10 It can be seen that the distance indicated by L _{corr, 1} and perpendicular to the connecting line between the light source with index 14 and the light detector with index 10 is less than the distance between the light source and the index 5 and the light source with index 14 , It can be seen from the geometrical relationships that the larger the offset V is, the smaller is this corrected length L _{corr, 1} . This results from the fact that the correction factor cos (arctan (V / B ₁ )) becomes smaller as the V increases. In the table according to 4 are the measurement results of the measurement of 3 summarized.

In the diagram of 5 are the calculated values for the corrected length of the table from 4 plotted as a function of the respective offset V. Corresponding to the nine carried out measuring runs are in the diagram of 5 registered nine measuring points. For the measuring points of the diagram of 5 then a regression is performed, for example a quadratic regression. Based on this regression, a modified length is calculated, which is, for example, in the case of quadratic regression Commission is determined L reg 1 = a 2 · V 2 + a 1 · V + a 0 ,

In the diagram of 5 is the actual length of the foot with a dashed line 9 entered. It can be seen that at an offset V = 0, ie with the light source light detector pairings with the index 5 and 14 the foot's length is overestimated since the associated measurement point is above the regression curve. Suppose that the foot is essentially "straight" within the frame 3 is placed, ie with its longitudinal axis parallel to the frame segments 3a respectively. 3c is positioned, the mentioned overestimation of the foot length can be calculated by calculating the modified length with L _reg = a ₀ . Here, a _{0 is} a regression parameter that was previously determined when performing the regression. A more accurate length of the foot can then be calculated using the following equation: L tat, 1 = (a 0 - 1) · s 1

In other words, the value of 1 is subtracted from the regression parameter a ₀ , and then with the distance s ₁ between the respective light sources or light detectors connected to the frame segments 3a respectively. 3c are attached, multiplied. This result corresponds to the actual foot length with greater accuracy. The subtraction of 1 from the regression parameter a ₀ is performed because the mean error in over-estimating the foot is the simple distance between two light sources or light detectors.

At certain positions of the foot 9 within the framework 3 It may be that the foot with its longitudinal axis 10 at an angle parallel to the frame segments 3a respectively. 3c stands. This is for example also in the foot position according to 3 the case, hereby includes the longitudinal axis 10 of the foot 9 with a straight line parallel to the frame segments 3a respectively. 3c is, an angle 6 one. Such "skewing" of the foot will misdetermine its actual length as a result of overestimation 6 to 8th explains how such a misalignment computationally compensated and thus a more accurate Fußvermessung is achieved.

For this purpose, following the measurement runs according to 3 the foot 9 also by means of the light sources 4 ₂ and light detectors 5 ₂ measured on the frame segments 3b respectively. 3d are attached. Measurement by means of light sources 4 ₂ and light detectors 5 ₂ takes place analogously to the measurement according to 3 in a total of nine measurement runs, each with a different offset between the individual light sources 4 ₂ and the correspondingly assigned light detectors 5 ₂ is selected. The legend according to 6 , in which an offset of -4 over the value zero to +4 is marked with different lines, this is clear.

First, therefore, a measurement is made with an offset of V = 0. Here, each individual light source 4 ₂ a light detector 5 ₂ assigned with the same index. In this measurement run, as the light source-light detector pairings at the edges of the foot, between which a light beam still passes, are those with the index 3 and 8th certainly. The light beams of the pairings with the index 4 to 7 be through the foot 9 blocked.

If the light sources 4 ₂ from the respective edges of the frame segment 3b If necessary, you can measure the pairings with the index 5 and 6 superfluous, since already for the pairings with the index 4 respectively. 7 blocking the beam of light through the foot 9 is detected. Thus, the pairings with the index 5 and 6 be left out. With an increased number of light sources or light detectors along the frame segments 3b respectively. 3d This leads to a reduced measuring time.

Starting from the light source light detector pairing with the offset V = 0 then becomes a positive index difference 12 formed between the two light sources of this pairing. In the present case, for V = 0, the index difference L ₂ = 8 - 3 = 5.

Following the measurement with V = 0, eight sequential measurements are now performed in which the offset between the light sources and the assigned light detectors is +1 to +4 and -1 to -4. For the formation of the new light source-light detector pairings, each of the light sources with the index 3 respectively. 8th gone out, so the two light sources for which at V = 0 still a passing of the light beam was detected. Following a respective measurement run with a certain offset then becomes a positive index difference 12 formed between the two light sources of the pairings, between which a light beam still passes. Since the measuring principle for selecting the respective light sources and selecting or assigning the corresponding light detectors completely analogous to the measurement according to 3 is referenced to avoid repetition.

As a result of the measurement runs for the light sources 4 ₂ and the light detectors 5 ₂ are in the representation of 6 represented by the dashed lines, the pairings as a function of a different offset, between which at the edges of the foot still passes a beam of light.

L₂:

jeweilige positive Index-Differenz als Funktion eines gewählten Versatzes V,

V:

jeweils gewählter Versatz zwischen den Lichtquellen 4₂ und den Lichtdetektoren 5₂ , und

B₂:

Abstand zwischen den Lichtquellen 4₂ und den Lichtdetektoren 5₂ .

Analogous to the geometric contexts of 3a Then, for the nine values of the index differences L _2, a corrected length is calculated using the equation: L corr, 2 = L 2 * Cos (arctan (V / B 2 )) in which:

L ₂ :

respective positive index difference as a function of a selected offset V,

V:

each selected offset between the light sources 4 ₂ and the light detectors 5 ₂ , and

B ₂ :

Distance between the light sources 4 ₂ and the light detectors 5 ₂ ,

The value of the respective angle correction factor cos (arctan (V / B ₂ ) and the values for the correspondingly corrected length together with the offset and the positive index difference L ₂ in the table of 7 summarized.

In the diagram according to 8th the corrected length L _{2 is} plotted as a function of the offset. In accordance with the nine measurement runs according to 6 can be found in the table of 7 nine line entries and in the chart of 8th nine measuring points. For this set of points, a regression is then carried out, in particular a quadratic regression. Based on the quadratic regression, a second modified length L _{reg, 2 is determined} to: L reg 2 = b 2 · V 2 + b 1 · V + b 0

Based on the curve for the quadratic regression is then a local extremum, or in the case of the curve according to 8th a local minimum, and calculated for this minimum computational offset V _g . The diagram of 8th makes it clear that for the minimum of the curve, the computational offset is about -1.8. This result correlates well with the measurement result 6 : There it can be seen that at an offset of V = -2 the beam path between the light source and light detector pairings with the light source index 3 respectively. 6 and light detector index 5 respectively. 8th the smallest distance to the long sides of the foot 9 and best fits the foot 9 snugly.

Starting from the calculated computational offset V _g can be determined via the relationship α = arctane (V G / B 2 ) The angle α can be determined by the body with its longitudinal axis 10 in terms of parallels to the frame segments 3a respectively. 3c This angle α is equal to the angle 6 from 3 ,

In a next step, an adjusted offset V _{1 is} calculated with: V 1 = tan (α) · B 1

The adjusted offset V ₁ is a computationally determined offset, which is the aforementioned misalignment of the foot 9 within the framework 3 considered. With this adjusted offset, the first modified length L _{reg, 1 is again} calculated using L reg 1 = a 1 · V 1 + a 2 · V 1 2 + a 0

From this result the modified length becomes the value 1 subtracted, and then with the equidistant distance s ₁ between the light sources 4 ₁ and the light detectors 5 ₁ multiplied, which is expressed in the following equation: L tat, 1 = (L reg 1 - 1) · s 1

The thus calculated first actual length L _{tat, 1} now has a lower measurement error, since the misalignment of the foot 9 within the framework 3 by means of the measurement with the light sources 4 ₂ and light detectors 5 ₂ at least partially excluded.

In addition to a length of the foot, which expresses in the size "first actual length, can also determine a width of the foot. For this purpose, the second modified length L _{reg, 2 is} calculated with V = V _g , the width of the foot then being determined as the second actual length L _{tat, 2 being} determined from: (L tat, 2 ) = (L reg 2 - 1) · s 2 . wherein s _{2 is} a respective distance between the light sources 4 ₂ or light detectors 5 ₂ is. In the same way as the actual length L _did, the width of the foot can be displayed as the second actual length L _{tat, 2} by means of a display unit.

In the 9 to 13 is another embodiment of a device according to the invention 1 and shown the underlying principle of measurement. In contrast to the embodiment according to the 1 to 8th In this embodiment, the frame device 3 and accordingly also the bottom plate 2 square shaped. Accordingly, the frame segments 3a to 3d the same length, wherein the distances B ₁ and B ₂ between the respective light sources and light detectors are the same size.

The measuring principle in the device 1 with a square frame device 3 otherwise identical to the measuring principle as in the 3 to 8th explained. First, a Mes with an offset of V = 0 for the light sources 4 ₁ and light detectors 5 ₁ performed as in 9 shown. Subsequently, eight further measurement runs are made for light source / light detector pairings in which the offset V is selected from +4 to -4.

The results of these nine measurement runs are in the table of 10 including the respective index differences L ₁ , the angle correction factors and the correspondingly corrected lengths L _{corr, 1} . The corrected lengths are a function of the offset in the diagram of FIG 11 a regression, preferably a quadratic regression, is performed for this set of points. The possible misalignment of the foot within the frame device 3 is then about the measurement by means of the light sources 4 ₂ and light detectors 5 ₂ compensated, as determined by the measurement process according to 12 shown. The measurement results according to the measurement of 13 are in the diagram of 14 applied. The determination of a local extremum enables the calculation of a computational offset V _g at which the ray paths of the two pairings at the edges of the foot are best of the longitudinal axis 10 of the foot 9 nestle. At this computational offset V _g is thus the slightest overestimation of the foot width, whereby the misalignment of the foot 9 is detected. Because of the square shape of the frame device 3 is the computationally determined extremum offset V _g equal to the adjusted offset V ₁ , so that the modified length L _{reg, 1} newly determined to L reg 1 = a 1 · V 1 + a 2 · V 1 2 + a 0

This corresponds to the determination of the actual length in the embodiment according to FIGS 1 to 8th ,

In the perspective view of 15 is another embodiment of the device 1 shown at the on the frame device 3 via a suitable holder 11 a distance sensor 12 is appropriate. By means of the distance sensor can be a height of the foot 9 be determined. The measuring principle of the distance sensor is based, for example, on triangulation.

By means of the method according to the invention and the device according to the invention 1 is a non-contact measurement of the foot 9 in a very short time and with sufficiently high accuracy possible. By the compensation measurements by means of the light sources 4 ₂ and the light detectors 5 ₂ A possible misalignment of the foot within the frame means can be compensated or calculated out, so that an overestimation of the foot length is minimal and the calculated length of the foot corresponds approximately exactly with the actual foot length. It is understood that it is also possible to measure any other bodies or objects, and that the specified length dimensions for the frame device and the number for the light sources and light detectors are only to be understood as examples.

Claims (65)

Method for contactless measuring of at least one length of a body ( 9 ), comprising the steps of: i) providing a plurality of light sources ( 4 ₁ ) and light detectors ( 5 ₁ ), which light sources and light detectors are arranged in particular linearly and opposite to each other and in each case connected to a control device, ii) placing the body ( 9 ) between the light sources ( 4 ₁ ) and light detectors ( 5 ₁ ), so that the body ( 9 ) is located in the beam path between light sources and light detectors, iii) assigning a light detector ( 5 ₁ ) to a light source ( 4 ₁ iv) for repeating step iii) for all remaining light detectors ( 5 ₁ ) and light sources ( 4 ₁ ) such that the beam paths of the pairs formed in each case run parallel to one another, v) sequential switching on of the light sources ( 4 ₁ ) from steps iii) and iv), and measuring the light intensity with the correspondingly assigned light detectors ( 5 ₁ ) from step iii), wherein when switching on a respective next light source the previous light source is switched off again, vi) determining the two light source light detector pairings at the boundaries of the body ( 9 ), between which a light beam still passes, and vii) calculating the distance between the two light sources ( 4 ₁ ) or the two light detectors ( 5 ₁ ) of the light source light detector pairings of step vi). Method according to Claim 1, in which an opening angle of a light source ( 4 ₁ ) of step i) is such that the light emitted by the light source is transmitted to more than one opposite light detector ( 5 ₁ ) falls. Method according to Claim 1 or 2, in which the individual light sources and the individual light detectors from step i) are each assigned an integer index of i = 1 to m, the light sources ( 4 ₁ ) and light detectors ( 5 ₁ ) have the same index. Method according to Claim 3, in which a peripheral light source ( 4 ₁ ) has the index i = 1, the other light source ( 4 ₁ ) has the highest index m. Method according to Claim 3 or 4, in which the switching on of the light sources ( 4 ₁ ) in step iii) starts in each case with the light sources with the smallest index i = 1 or with the highest index i = m, and thus in one direction on the body ( 9 ) takes place. Method according to one of Claims 1 to 5, in which the light sources ( 4 ₁ ) or the light detectors ( 5 ₁ ) from step i) to each other in each case an equidistant distance (s ₁ ). Method according to one of Claims 1 to 6, in which the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ ) of step i) are each arranged linearly in a row, wherein the rows of light sources and light detectors to each other at the same distance (B ₁ ) and are substantially parallel to each other. Method according to one of claims 1 to 7, wherein the distance determined in step vii) is in a length of the body ( 9 ) and displayed on a display unit. Method according to one of Claims 3 to 8, comprising the further steps of: viii) determining the two light sources of the pairings from step vi), ix) selecting a respective light detector ( 5 ₁ ) whose index relative to the index of light sources ( 4 ₁ ) from step viii) is offset by an offset V = ± N, with V: offset N: natural number ≥ 1 and assignment of these light detectors ( 5 ₁ ) to the corresponding light sources ( 4 ₁ ) from step viii) to form a new light source light detector pairing, x) turning on the respective light source ( 4 ₁ ) from step viii) and measuring the light intensity with the corresponding light detector ( 5 ₁ ) from step ix), xi) if light passes between a respective light source light detector pairing from step ix): go to step xii), else go to step xvi), xii) select a light source ( 4 ₁ ) in a direction towards the body ( 9 ), xiii) Selecting a light detector ( 5 ₁ ) whose index relative to the index of the light source ( 4 ₁ ) from step xii) is shifted by the same offset (V) as in step ix), and assigning this light detector ( 5 ₁ ) to the light source ( 4 ₁ ) from step xii) to form a new light source light detector pairing, xiv) switching on the light source ( 4 ₁ ) from step xii) and measuring the light intensity with the light detector ( 5 ₁ ) from step xiii), xv) if light passes between a light source light detector pairing from step xiii): go to step xii), else go to step xvi), xvi) select a respective light source in a direction away from the body ( 9 ) leading to the corresponding light source ( 4 ₁ ) from step xii), xvii) selecting a light detector ( 5 ₁ ) whose index relative to the index of the light source ( 4 ₁ ) from step xvi) is shifted by the same offset (V) as in step ix), and assigning this light detector ( 5 ₁ ) to the light source ( 4 ₁ ) from step xvi) to form a new light source light detector pairing, xviii) switching on the light source ( 4 ₁ ) from step xvi) and measuring the light intensity with the light detector ( 5 ₁ ) from step xvii), ixx) if light passes between the light source light detector pairing from step xvii): go to step xx), else go to step xvi), xx) determine the two light source light detector pairings from step xviii) on the borders of the body ( 9 ), between which a light beam still passes, xxi) repeating steps ix) to xx) several times with a different offset (V), wherein the number of offsets (V) with positive and negative signs is preferably the same, xxii) determining a positive index difference (L ₁ ) of the two light sources ( 4 ₁ ) from step i) of the respective light source light detector pairings from step xx) and / or xxi), xxiii) calculating a corrected length (L _{korr, 1} ) for the individual index differences from step xxii) L corr, 1 = L 1 * Cos (arctan (V / B 1 )) wherein: L ₁ : respective positive index difference from step xxii) for the light sources ( 4 ₁ ) from step i) V: respective offset from step ix) B ₁ : right-angled distance between the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ xxiv) performing a regression on the corrected lengths (L _{korr, 1} ) of step xxiii), xxv) calculating a first modified length (L _{reg, 1} ) based on the regression of step xxiv), with L reg 1 = a 1 V + a 2 V 2 ... + a k V k + a 0 where: V: respective offset from step ix), and xxvi) calculating a first actual length (L _{tat, 1} ) of the body ( 9 ), With L tat, 1 = (L reg 1 - 1) · s 1 where: L _{reg, 1} : first modified length from step xxv) s ₁ : distance between the light sources ( 4 ₁ ) or light detectors ( 5 ₁ ) from step i), and xxvii) indicate the first actual length (L _{tat, 1} ) instead of the distance from step vii). The method of claim 9, wherein the first modified length (L _{reg, 1} ) of the body ( 9 ) in step xxv) with L _{reg, 1} = a ₀ , when the body ( 9 ) with its longitudinal axis substantially parallel to the light sources ( 4 ₁ ) or the light detectors ( 5 ₁ ) is aligned from step i). Method according to one of claims 1 to 10, comprising the further steps: aa) providing further light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) each arranged linearly in a row and opposite each other and each connected to a control device, these rows of light sources and light detectors being preferably arranged perpendicular to the rows of light sources and light detectors of step i), bb) performing steps iii) to vii) for the light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa). Method according to Claim 11, in which the rows of light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa) to each other at the same distance (B ₂ ) and are substantially parallel to each other. Method according to claim 11 or 12, in which an opening angle of a respective light source ( 4 ₂ ) according to step aa) is such that the light emitted by the light source is transmitted to more than one opposite light detector ( 5 ₂ ) falls. Method according to one of Claims 11 to 13, in which the individual light sources ( 4 ₂ ) and the individual light detectors ( 5 ₂ ) from step aa) is in each case assigned an integer index of i = 1 to m, the opposing light sources and light detectors having the same index. Method according to Claim 14, in which a peripheral light source ( 4 ₂ ) from step aa) has the index i = 1, wherein the other peripheral light source from step aa) has the highest index m. Method according to Claim 14 or 15, in which the switching on of the light sources ( 4 ₂ ) in step bb) starts in each case with the light sources with the smallest index i = 1 or with the highest index i = m, and thus in one direction on the body ( 9 ) takes place. Method according to one of Claims 11 to 16, in which the light sources ( 4 ₂ ) or the light detectors ( 5 ₂ ) from step aa) to each other in each case an equidistant distance (s ₂ ). Method according to one of claims 14 to 17, comprising the further steps: cc) determining the two light sources ( 4 ₂ from step aa) of the pairings according to step vi), if carried out in step bb), dd) starting from the two light sources from step cc): performing steps ix) to xxi), ee) determining a positive index difference (L ₂ ) the light sources ( 4 ₂ ) from step aa) of the respective light source light detector pairings from step xxi), ff) calculating a corrected length (L _{korr, 2} ) for the individual index differences from step ee) L corr, 2 = L 2 * Cos (arctan (V / B 2 )) wherein: L ₂ : respective positive index difference from step ee) for the light sources ( 4 ₂ ) from step aa) V: respective offset from step ix), relative to the light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa), B ₂ : right-angled distance between the rows of light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa), gg) performing a regression for the corrected lengths (L _{korr, 2} ) from step ff), hh) calculating a second modified length (L _{reg, 2} ) on the basis of the regression from step gg) L reg 2 = b 1 V + b 2 V 2 ... + b k V k + b 0 where: V = respective offset from step ix), as far as the light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa), jj) determining a local extremum of the regression equation from step hh), kk) calculating an extremum offset (V _g ) resulting from the local extremum from step jj), ll) calculating an angle (α) , With α = arctane (V G / B 2 ) wherein: V _g : extremum offset from step kk) B ₂ : distance between the rows of light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa), mm) calculating a fitted offset (V ₁ ), with V 1 = tan (α) · B 1 where: V ₁ : adjusted offset α: angle from step ll) B ₁ : rectangular distance between the light sources ( 4 ₂ ) and the light detectors ( 5 ₂ ) from step i), nn) calculating the first modified length (L _{reg, 1} ) in step xxv) with V = V ₁ , oo) calculating the first actual length (L _{tat, 1} ) of the body ( 9 in step xxvi) having the first modified length (L _{reg, 1} ) from step nn), and pp) indicating the first actual length (L _{tat, 1} ) from step oo) instead of the length initially calculated in step xxvi), steps xxvii) and vii) being omitted. Method according to Claim 18, in which, after step kk), the following steps are carried out instead of steps ll) to pp): - calculating the second modified length (L _{reg, 2} ) from step hh) with: V = (V G ) from step kk), and - calculating a second actual length (L _{tat, 2} ) of the body ( 9 ), With: (L tat, 2 ) = (L reg 2 - 1) · s 2 . wherein: s ₂ : respective distance between the light sources ( 4 ₂ ) or light detectors ( 5 ₂ ) from step aa), and - displaying the second actual length (L _{tat, 2} ). The method of claim 18, comprising the further steps of: qq) after step hh): calculating the second modified length (L _{reg, 2} ) with: L reg 2 = b 0 wherein: b ₀ : regression factor from step hh), rr) calculating a second actual length (L _{tat, 2} ) of the body ( 9 ), With: L tat, 2 = (b 0 - 1) · s 2 wherein: b ₀ : regression factor from step hh) s ₂ : respective distance between the light sources ( 4 ₂ ) or light detectors ( 5 ₂ ) from step aa), and ss) indicate the second actual length (L _{tat, 2} ). Method according to one of claims 1 to 20, wherein the regression in step xxiv) or xxv) is a quadratic regression. Method according to one of Claims 1 to 21, in which the respective light sources ( 4 ₂ ) and the light detectors ( 5 ₂ ) from step i) and from step aa) are attached to a measuring device. Method according to one of claims 12 to 22, wherein the distance (B ₁ ) between the light sources ( 4 ₁ ) and light detectors ( 5 ₁ ) from step i) and the distance (B ₂ ) between the light sources ( 4 ₂ ) and light detectors ( 5 ₂ ) from step aa) are the same. Method according to one of Claims 1 to 23, in which, immediately before the steps v), x), xiv) or xviii), the ambient light intensity on the light detectors ( 5 ₁ . 5 ₂ ) with light sources switched off ( 4 ₁ . 4 ₂ ) is measured, and then the total intensity is measured on a respective light detector with the light source switched on, wherein from the difference of the total intensity to the ambient light intensity one by a respective light source ( 4 ₂ ) ( 4 ₂ ), which is taken into account when measuring the light intensity in step v), x), xiv) or xviii). Method according to one of Claims 1 to 24, in which the light detectors ( 5 ₁ . 5 ₂ ) have a daylight filter that transmits light in the infrared wavelength range. Method according to one of Claims 1 to 25, in which a basic calibration of all light sources ( 4 ₁ . 4 ₂ ) and light detectors ( 5 ₁ . 5 ₂ ) is carried out at the before step ii) or before step bb) without a body ( 9 ) all the light sources from step i) or from step aa) are switched on one after the other and the light intensity for all possible combinations of light detectors ( 5 ₁ . 5 ₂ ), which are used by these light sources ( 4 ₁ . 4 ₂ ), wherein the measured light intensity is stored in a memory unit. Method according to one of claims 1 to 26, in which a body ( 9 ) is located between a respective pairing light source light sensor when the intensity of the corresponding light detector ( 5 ₁ . 5 ₂ ) is less than that of the basic calibration. Method according to one of Claims 1 to 27, in which the control device is a microcontroller, by means of which the light sources ( 4 ₁ . 4 ₂ ) and / or the light detectors ( 5 ₁ . 5 ₂ ) and / or by which the data of the light detectors ( 5 ₁ . 5 ₂ ) are processable. Method according to one of claims 1 to 28, wherein the control device connected to a storage unit in which readings for the various Light source light detector pairings are stored. Method according to one of claims 1 to 29, wherein the light intensity of the plurality of light sources ( 4 ₁ . 4 ₂ ) is adapted to each other. Method according to one of Claims 1 to 30, in which at least one light source ( 4 ₁ . 4 ₂ ) is a light emitting diode having an infrared wavelength range. The method of claim 31, wherein a plurality of light-emitting diodes is provided, wherein whose light intensity is adjusted by means of a control of the electric current to each other. Method according to one of Claims 1 to 32, in which at least one light detector ( 5 ₁ . 5 ₂ ) is a photodiode. The method of claim 33, wherein the photodiode includes a daylight filter. Method according to one of claims 1 to 34, wherein a height of the body ( 9 ) is measured. Method according to Claim 35, in which a distance sensor which can be pivoted in two axes ( 12 ) is provided, by means of which the height of the body ( 9 ) is measurable. Method according to Claim 36, in which the measurement with the distance sensor ( 12 ) is done by triangulation. Method according to one of claims 1 to 37, wherein a body ( 9 ) is measured, which has no angular edges. Method according to one of Claims 1 to 38, in which the body ( 9 ) in the plane of the light sources ( 4 ₁ . 4 ₂ ) or light detectors ( 5 ₁ . 5 ₂ ) is round, oval, rectangular or square, each with rounded edges. Contraption ( 1 ) for non-contact measurement of at least one length of a body ( 9 ) comprising a plurality of light sources ( 4 ₁ ), which are arranged in particular linearly in a row, a plurality of light detectors ( 5 ₁ ), the light sources ( 4 ₁ ) and in particular are arranged linearly in a row, wherein the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ ) are directed towards each other so that the body ( 9 ) in the beam path between the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ ) is positionable, a control device with which the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ ) are connected so that the light detectors ( 5 ₁ ) and the light sources ( 4 ₁ ) can be combined with each other to different pairings and thereafter the light sources ( 4 ₁ ) are sequentially switched on, wherein means of the control device light source-light detector pairings at the boundaries of the body ( 9 ) between which a light beam still passes when the body ( 9 ) is positioned between these pairings, wherein a distance between the two light sources or the two light detectors of these light source light detector pairings is a measure of a length of the body ( 9 ). Contraption ( 1 ) according to claim 40, wherein the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ ) are each arranged linearly in a row, the rows of light sources ( 4 ₁ ) and light detectors ( 5 ₁ ) (To each other the same distance B _1), and are substantially parallel to each other. Contraption ( 1 ) according to claim 40 or 41, wherein the light sources ( 4 ₁ ) and the light detectors ( 5 ₁ ) on opposite sides of a base plate ( 2 ) bordering, in particular rectangular, frame device ( 3 ) and from the bottom plate ( 2 ) are each spaced at the same distance, the body ( 9 ) on the bottom plate ( 2 ) can be placed. Contraption ( 1 ) according to claim 42, wherein the light sources ( 4 ₁ . 4 ₂ ) and the light detectors ( 5 ₁ . 5 ₂ ) on all four sides of the framework ( 3 ) are provided, wherein on the opposite sides of the frame device ( 3 ) Are mounted in each case a plurality of the light sources or a plurality of the light detectors. Contraption ( 1 ) according to claim 43, wherein on two adjoining sides of said frame means ( 3 ) a plurality of the light sources ( 4 ₁ . 4 ₂ ), and at the other two adjacent sides of the framework ( 3 ) a plurality of the light detectors ( 5 ₁ . 5 ₂ ) are mounted. Contraption ( 1 ) according to one of claims 42 to 44, in which the frame device ( 3 ) is formed at least partially from a frame profile, wherein the light sources ( 4 ₁ . 4 ₂ ) or the light detectors ( 5 ₁ . 5 ₂ ) are received within the frame profile and the frame profile adjacent to the light sources ( 4 ₁ . 4 ₂ ) or the light detectors ( 5 ₁ . 5 ₂ ) one opening each ( 6 ) having. Contraption ( 1 ) according to claim 45, wherein in the opening ( 6 ) of the frame profile, a cover is bordered, which is permeable to the frequency of the measuring light. Contraption ( 1 ) according to claim 45 or 46, wherein in the opening ( 6 ) of the frame profile a transparent cover, preferably a transparent pane ( 7 ) is enclosed. Contraption ( 1 ) according to claim 46 or 47, wherein the cover serves as a daylight filter. Contraption ( 1 ) according to one of claims 43 to 48, with which two different lengths of the body ( 9 ) can be measured, which are substantially perpendicular to each other and lie in a same plane. Contraption ( 1 ) according to one of claims 40 to 49, wherein the individual light sources ( 4 ₁ . 4 ₂ ) and the individual light detectors ( 5 ₁ . 5 ₂ ) is assigned in each case an integer index of i = 1 to m, wherein the directly opposing light sources ( 4 ₁ . 4 ₂ ) and light detectors ( 5 ₁ . 5 ₂ ) have the same index. Contraption ( 1 ) according to claim 50, wherein one at an edge of the frame means ( 3 ) has the index i = 1, one at the opposite edge of the frame device ( 3 ) lying light source has the highest index m. Contraption ( 1 ) according to claim 51, wherein the light sources ( 4 ₁ . 4 ₂ ) sequentially from each edge of the frame device ( 3 ), wherein the switching on of the light sources in each case starts with the light sources with the smallest index i = 1 or with the highest index i = m, and thus in one direction onto the body ( 9 ) takes place. Contraption ( 1 ) according to one of claims 40 to 52, in which the light sources ( 4 ₁ . 4 ₂ ) or the light detectors ( 5 ₁ . 5 ₂ ) Each have an equidistant distance (s ₁ , s ₂ ) to each other. Contraption ( 1 ) according to one of claims 40 to 53, comprising a display unit on which a length of the body determined by means of the light-source light detector pairings ( 9 ) can be displayed. Contraption ( 1 ) according to one of claims 40 to 54, wherein at least one light source is a light-emitting diode with an infrared wavelength range. Contraption ( 1 ) according to one of claims 40 to 55, wherein a plurality of light emitting diodes is provided as the light source, wherein the light intensity is adapted to each other by means of a control of the electric current. Contraption ( 1 ) according to one of claims 40 to 56, wherein at least one light detector is a photodiode. Contraption ( 1 ) according to claim 57, wherein the photodiode comprises a daylight filter. Contraption ( 1 ) according to one of claims 40 to 58, with which a height of the body ( 9 ) with respect to the bottom plate ( 2 ) is measurable. Contraption ( 1 ) according to claim 59, comprising a distance sensor ( 12 ) provided on the frame means ( 3 ) and is pivotable about at least one axis to the height of the body ( 9 ) to measure. Contraption ( 1 ) according to claim 60, wherein the distance sensor ( 12 ) above the bottom plate ( 2 ) is pivotable about two axes. Contraption ( 1 ) according to claim 61, wherein the measurement with the distance sensor ( 12 ) is done by triangulation. Contraption ( 1 ) according to one of claims 40 to 62, in which the light detectors ( 5 ₁ . 5 ₂ ) in each case an equal distance from the light sources ( 4 ₁ . 4 ₂ ) exhibit. Use of the device ( 1 ) according to one of claims 40 to 63 for measuring a body ( 9 ), which has no rounded edges, and in particular in its shape parallel to the bottom plate ( 2 ) is round, oval, rectangular or square, each with rounded edges. Use of the device ( 1 ) according to one of claims 40 to 64 for carrying out the steps of a method according to one of claims 1 to 39.