WO2009112260A1 - Dispositif et procédé de détection de déplacements relatifs d'un objet par rapport à une surface de référence - Google Patents

Dispositif et procédé de détection de déplacements relatifs d'un objet par rapport à une surface de référence Download PDF

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Publication number
WO2009112260A1
WO2009112260A1 PCT/EP2009/001783 EP2009001783W WO2009112260A1 WO 2009112260 A1 WO2009112260 A1 WO 2009112260A1 EP 2009001783 W EP2009001783 W EP 2009001783W WO 2009112260 A1 WO2009112260 A1 WO 2009112260A1
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WO
WIPO (PCT)
Prior art keywords
photosensors
groups
determined
vector field
reference surface
Prior art date
Application number
PCT/EP2009/001783
Other languages
German (de)
English (en)
Inventor
Ubbo Ricklefs
Stefan Charisse
Original Assignee
Fachhochschule Giessen-Friedberg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fachhochschule Giessen-Friedberg filed Critical Fachhochschule Giessen-Friedberg
Publication of WO2009112260A1 publication Critical patent/WO2009112260A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/36—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/64—Devices characterised by the determination of the time taken to traverse a fixed distance
    • G01P3/68—Devices characterised by the determination of the time taken to traverse a fixed distance using optical means, i.e. using infrared, visible, or ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/64—Devices characterised by the determination of the time taken to traverse a fixed distance
    • G01P3/80—Devices characterised by the determination of the time taken to traverse a fixed distance using auto-correlation or cross-correlation detection means
    • G01P3/806—Devices characterised by the determination of the time taken to traverse a fixed distance using auto-correlation or cross-correlation detection means in devices of the type to be classified in G01P3/68
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/50—Systems of measurement based on relative movement of target
    • G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems

Definitions

  • the invention relates to a device for detecting relative movements of an object to a reference surface according to the preamble of claim 1 and a method for detecting relative movements of an object to a reference surface according to the preamble of claim 8.
  • a reference surface having a random structure is imaged onto an optical receiver, such as a camera.
  • the image content changes from the content of the previous image.
  • EP 1 067 388 A1 describes a very complex correlation method of this type in which the correlation between the images of two cameras is calculated taking into account the triangulation.
  • Such a correlation method is known to be associated with a relatively large amount of computation and therefore also with a relatively large computation time. Since the complete calculation of a correlation is time-consuming, approximations of the correlation are usually calculated.
  • a reference surface with a random structure is imaged onto a photosensor and superimposed with a lattice-shaped periodic structure which is relative to a moving object relative to a reference surface is stationary and acts as spatial frequency filter which serves to mask the scattered light in the measurement volume.
  • Moving the photosensor relative to the reference surface produces a narrow-band, velocity-dependent signal which, in addition to low-frequency changes, also has a modulation whose frequency f 0 (maximum frequency of the temporal frequency spectrum) is a measure of the velocity of the object relative to the reference surface and has a clear relationship with the velocity along the orientation of the lattice structure, a lattice constant of the lattice structure and the magnification of an imaging optic and is proportional to the speed.
  • f 0 maximum frequency of the temporal frequency spectrum
  • the invention has for its object to provide an apparatus for performing the method according to the invention.
  • Main features of the invention are specified in the characterizing part of claim 1 and claim 8.
  • Embodiments are the subject of claims 2 to 7 and 9 to 23.
  • the invention provides that the n photosensors of the Line in groups m, are subdivided with each m photosensors, which define a distance s, where each two consecutive groups (m "m, +1 ) m-1 photo sensors belong.
  • the device according to the invention therefore comprises n photosensors arranged in a line which, arranged on an object, detect the brightness values of a reference surface irradiated with a light of a specific wavelength via an objective.
  • the n photo sensors of the line are interconnected or subdivided in such a way that they form groups m, with in each case m photosensors, which define distances s. Two consecutive groups m "m, +1 belong to m-1 photo sensors together.
  • Suitable photosensors include all known and suitable prior art receivers for optical radiation measurement, such as photodiodes or so-called CCDs (Charge Coupled Devices) and the like.
  • CCDs Charge Coupled Devices
  • the geometric design of the individual photosensors can be arbitrary.
  • sensor arrays are also suitable with which spatially resolved information about the surface can be obtained.
  • These include in particular magnetoresistive or capacitive sensor arrays for detecting local magnetic or electrical field distributions.
  • the sensors may be arranged at a distance successively in the row. However, such a successive arrangement of the photosensors is not necessarily required due to the random structure of the reference surface. Rather, the photosensors within the line may have any arrangement.
  • a plurality of lines each having n photo sensors are combined to form at least one matrix.
  • Such an arrangement of the lines not only allows the detection of the relative movement of the object to the reference surface in the longitudinal direction of the lines, but also the detection of a rotational movement of the object.
  • different movements are detected in staggered lines, wherein in the individual lines in each case the evaluation according to the invention takes place. If the sensors are arranged in a matrix, the evaluation described here for rows can also be done column by column.
  • ASIC Application Specific Integrated Circuit
  • the method according to the invention for detecting relative movements of an object relative to a reference surface in which the brightness values of the reference surface irradiated with a light are detected by means of n photo sensors arranged on the object in a row, is provided,
  • ⁇ that after the detection in the individual groups rrij for a selected frequency f a modulation function is determined which describes the brightness values along the distance Sj, wherein with the adaptation of the modulation function to the
  • Brightness values a parameter pair Ij, ⁇ is determined so that a maximum of n-m + 1 parameter pairs I 1 , ⁇ , which define a vector field V 1 for the first position of the line (20), are determined for the line (20),
  • a vector field V 1 + 1 with a maximum of n-m + 1 parameter pairs Ij, ⁇ , for the second position is determined, and ⁇ that the relative movement of the object (4) to the reference surface (7) is determined from the comparison of the vector field V, the first position with the vector field V J + 1 of the second position.
  • the brightness values of the reference surface along the line are consecutively detected by means of the individual groups m ", starting with a group defining a starting point.
  • the reference surface should be based on a random structure.
  • a modulation function with a frequency f is then selected and used in order to determine a function l (m,) which approximately describes the brightness values along the distance s.
  • x is a point of the distance S 1 .
  • the modulation is therefore preferably carried out with the periodic function
  • a vector field V J + 1 having a maximum of n-m + 1 parameter pairs (I 1 , ⁇ ,) defining the second position of the line is determined in an analogous manner.
  • the relative movement of the object to the reference surface is then determined from the correlation of the two vector fields V Jf V J + 1 .
  • vectors to be correlated come here the vectors (l " ⁇ ,), their amounts I 1 , and / or their directions ⁇ , in question.
  • the method according to the invention provides that the vectors I jj , cp ⁇ of the first vector field V j are vectorially subtracted from the vectors I j + u, (Pj + u of the second vector field V i + 1 generated subsequently, wherein the Amounts D j j of the difference vectors or the difference vectors themselves are added to a total error D 0 , and that at the same time for differentiation at least two further differences between the first vector field V j and the second vector field V j + 1 are performed, the differences D j j in an analogous manner between the vector pairs (IJJ, ⁇ jj) and (IJ + U + A, ⁇ PJ + I, J + A) and on the other between the vector pairs (I j j, ⁇ ji) and (lj + i, i + A2.
  • ⁇ Pj + i, i + A2) are formed in order to determine further total errors D A and D A2 ZU analogously to the total error D 0
  • the invention further provides that an average relative movement of the object to the reference surface is determined from at least three total errors D 0 , D A , D A2 .
  • Shift describes a parabola and that the position of the vertex corresponds to the parabola of the displacement.
  • the total direction ⁇ which belongs to the relative movement and is proportional to this can be determined.
  • the time between two detections of two successive groups is preferably dimensioned such that the overall direction ⁇ changes on average during the transition from the vector field Vj to the vector field V j + 1 by less than +/- ⁇ .
  • the method according to the invention represents a combination of the two measuring methods mentioned at the outset (correlation and spatial frequency filter methods). However, in contrast to these two methods, the method according to the invention requires significantly less computational effort, which leads to a significantly lower computing time. Furthermore, in contrast to the spatial frequency filter method, the method according to the invention is also suitable for detecting low relative speeds of the object relative to the reference surface.
  • the method according to the invention can be implemented in a metrologically simple manner. This circumstance predestines the method according to the invention for various technical applications, especially as its metrological implementation can be implemented cost-effectively.
  • At least m 3 photosensors are used according to the invention in the individual groups m.sub. ⁇ resulting from the consideration of the aforementioned sine function, with which the brightness values of the individual groups n.sub.rii along the path S.sub.j are described.
  • the distribution of the brightness values along the distance S 1 can be understood as an oscillation of the brightness values with the amplitude Ij around the mean value I 0 according to the sine function, but as such for the method according to the invention because of the difference method which will be described below. underlying difference formation is ignored or is irrelevant.
  • These Sinusoidal oscillation also has a phase shift ⁇ ( compared to a zero point, which can be evaluated by the phase method.
  • the displacements are determined separately from the rows of the matrix. This makes it possible to determine a rotational movement from the difference of the measured displacements.
  • a plurality of modulation functions can be determined which describe the brightness values along the distance Sj, wherein a parameter pair Ij, ⁇ i is determined for each of the modulation functions by the adaptation to the brightness values.
  • FIG. 2 shows a schematic illustration of a multiplicity of photosensors arranged in a row and corresponding to the sensor shown schematically in FIG. 1, and FIG.
  • Fig. 3 is a schematic representation of a plurality of arrayed in a matrix photosensors, wherein the individual rows and / or columns of the matrix correspond to the line shown in FIG.
  • Fig. 1 illustrates the implementation of a measuring device 16 according to the invention in a vehicle 4, which moves relative to a lane 6 in one direction at a speed v (t).
  • the device 16 comprises a light source, not shown here for the sake of simplicity, which irradiates an area 9 of the road surface 7 at an angle.
  • a converging lens 12 images the radiation reflected by the region 9 via a mirror 10 onto a photosensor 14.
  • the sensor 14 comprises n optical receivers arranged in a row, which are designed as photodiodes 18 and are arranged successively at a defined spacing.
  • Two consecutive groups rrii, m i + 1 belong to m-1 in each case, ie 5 photodiodes 18 together. This corresponds to a shift from group nrii to group m i + 1 along line 20 around a photodiode 18.
  • the senor 14 comprises n rows 20 combined into a matrix 22.
  • the two embodiments have in common that the photodiodes 18 are integrated on a user-specific IC or analog and / or digital component, a so-called ASIC (Application Specific Integrated Circuit), which contains a circuit designed according to customer requirements.
  • the sensor 14 comprises a plurality of rows combined into a matrix.
  • a first embodiment of the invention which is based on the difference method, are in a first position of the line 20 relative to the road surface 7 by means of the individual groups m, (In 1 , m 2 , m 3 , ...) starting with the group ITi 1 at the leftmost end of the line 20, which as such defines a starting point, sequentially detecting the brightness values of the reference surface 7 along the line 20. Subsequently, for the electrical signals generated in the individual groups m 1 , which represent the brightness values of the reference surface, by optimizing the parameters I 1 and ⁇ , a modulation with the periodic function
  • the parameter pair I 1 and ⁇ can be understood as the amplitude and direction or phase of a vector.
  • the parameter I 0 is not further investigated.
  • V 1 + 1 V 2 with again maximally n-m + 1 vectors (I 1 , ⁇ ,) ((I 1 , Cp 1 ), (I 2 , ⁇ 2 ), (I 3 , ⁇ 3 ), ... (I n -m + i,
  • the notation ( 1 jj j j) is used in the following:
  • the magnitudes I j j of the first vector field V j are determined by the amounts l j + 1 j of the second vector field V j + 1 is subtracted. then the amounts are added j1 D of the differences to an overall error D 0 and the
  • the D j i can also be formed by vectorially subtracting the vectors (I j j, ⁇ j j) from the vectors (l j + 1
  • D j i is the higher computational effort.
  • the distance A is determined as a function of the size of the relative movement performed between the two detection times and corresponds to a shift of the groups r ⁇ ii of the first vector field V j with respect to the vector field V j + 1 by A photo sensors 18.
  • the relative movement determined in this way corresponds to the movement of the sensor 14 in the longitudinal direction of the line 20. If several lines are used, then from this movement after the vector calculation movements at an angle to the line length direction can be determined.
  • the change of the phases ⁇ j j is evaluated, which results from a shift.
  • the magnitude of the vector l j , j changes only slightly, since both groups m-1 photodiodes belong together.
  • Its direction ⁇ jti changes on average during the transition from the group r ⁇ ii to the group m i + 1 by the angle 2 ⁇ / m. Due to the 2 ⁇ r periodicity of the sinusoidal function phase jumps can also occur in the determination of the direction cpj.j, which can lead to ambiguities.
  • the time between two detections of two successive vector fields V j and V j + 1 should be such that the directions ⁇ ui and ⁇ j + i, i at the transition from the vector field V j to the vector field V j + 1 on average to change significantly less like +/- ⁇ .
  • Total phase ⁇ is proportional to the relative motion can from the overall phase ⁇ the
  • Relative movement are determined, if the belonging to a relative movement phase change is known.
  • the difference method and the phase method are combined with each other.
  • the invention is not limited to one of the above-described embodiments, but can be modified in many ways. It can be seen, however, that the invention relates to a device and a method for detecting a relative movement of an object 4 relative to a reference surface 7.
  • the relative movement is detected by means of n photosensors 18 arranged on the object 4 in a row 20, which detect the brightness values of the reference surface 7.
  • the n photosensors 18 of the line 20 are subdivided into groups r ⁇ ii with in each case m photosensors 18 which define a route S 1 . In each case, two consecutive groups nrii, m i + 1 m-1 belong to photo sensors 18.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne un dispositif et un procédé de détection d'un déplacement relatif d'un objet (4) par rapport à une surface de référence (7). Le déplacement relatif est détecté au moyen de n photodétecteurs (18) disposés sur l'objet (4) en une ligne (20), lesquels détectent les valeurs de luminosité de la surface de référence (7). Les n photodétecteurs (18) de la ligne (20) sont subdivisés en groupes mi ayant chacun m photodétecteurs (18), qui définissent une parcours si. A chaque deux groupes successifs mi, mi+1 appartiennent m - 1 photodétecteurs (18).
PCT/EP2009/001783 2008-03-12 2009-03-12 Dispositif et procédé de détection de déplacements relatifs d'un objet par rapport à une surface de référence WO2009112260A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008013947.5A DE102008013947B4 (de) 2008-03-12 2008-03-12 Verfahren zur Erfassung von Relativbewegungen eines Objektes zu einer Bezugsfläche
DE102008013947.5 2008-03-12

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Publication Number Publication Date
WO2009112260A1 true WO2009112260A1 (fr) 2009-09-17

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6288966A (ja) * 1985-10-16 1987-04-23 Murata Mfg Co Ltd 焦電形センサアレイ
US6020953A (en) * 1998-08-27 2000-02-01 The United States Of America As Represented By The Secretary Of The Navy Feature tracking linear optic flow sensor
US20060091301A1 (en) * 2004-10-29 2006-05-04 Silicon Light Machines Corporation Two-dimensional motion sensor
WO2007051699A1 (fr) * 2005-11-04 2007-05-10 E2V Semiconductors Capteur de vitesse au sol d'un vehicule

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2848874C2 (de) * 1977-11-12 1983-02-17 Nippon Kogaku K.K., Tokyo Vorrichtung zum Bestimmen der Größe der Verschiebung eines durch ein optisches Abbildungssystem erzeugten Bildes
DE19530287C1 (de) * 1995-08-17 1996-11-14 Klaus Dr Christofori Verfahren und Vorrichtung zur Geschwindigkeitsmessung
US6675121B1 (en) 1999-07-06 2004-01-06 Larry C. Hardin Velocity measuring system
DE10248416B4 (de) * 2002-10-17 2006-01-26 Audi Ag Vorrichtung und Verfahren zur Bestimmung einer Relativbewegung eines Fahrzeugs
AU2003240778A1 (en) * 2003-05-02 2004-11-23 Universite De Neuchatel Image processing method and system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6288966A (ja) * 1985-10-16 1987-04-23 Murata Mfg Co Ltd 焦電形センサアレイ
US6020953A (en) * 1998-08-27 2000-02-01 The United States Of America As Represented By The Secretary Of The Navy Feature tracking linear optic flow sensor
US20060091301A1 (en) * 2004-10-29 2006-05-04 Silicon Light Machines Corporation Two-dimensional motion sensor
WO2007051699A1 (fr) * 2005-11-04 2007-05-10 E2V Semiconductors Capteur de vitesse au sol d'un vehicule

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DE102008013947B4 (de) 2016-03-10
DE102008013947A1 (de) 2009-09-24

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