EP4256509A1 - Procédé de mesure de l'influence d'une vitre transparente - Google Patents

Procédé de mesure de l'influence d'une vitre transparente

Info

Publication number
EP4256509A1
EP4256509A1 EP21798313.9A EP21798313A EP4256509A1 EP 4256509 A1 EP4256509 A1 EP 4256509A1 EP 21798313 A EP21798313 A EP 21798313A EP 4256509 A1 EP4256509 A1 EP 4256509A1
Authority
EP
European Patent Office
Prior art keywords
camera
windshield
textured surface
transparent pane
displacement field
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
EP21798313.9A
Other languages
German (de)
English (en)
Inventor
Henning Von Zitzewitz
Oliver Lange
Moritz Michael Knorr
Andre Wagner
Stephan Simon
Beke Junge
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP4256509A1 publication Critical patent/EP4256509A1/fr
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/0002—Inspection of images, e.g. flaw detection
    • G06T7/0004—Industrial image inspection
    • G06T7/001—Industrial image inspection using an image reference approach
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/20—Analysis of motion
    • G06T7/269—Analysis of motion using gradient-based methods
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/40—Analysis of texture
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10016—Video; Image sequence
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/30—Subject of image; Context of image processing
    • G06T2207/30248—Vehicle exterior or interior
    • G06T2207/30252—Vehicle exterior; Vicinity of vehicle

Definitions

  • the invention relates to a method for measuring the influence of a transparent pane, for example a windshield, and an arrangement for carrying out the method.
  • the windshield also known as the windscreen, is a pane, usually made of glass, for example laminated glass, which allows the driver of a vehicle to see ahead. At the same time, the windshield offers the driver protection from wind, weather and particles in the airflow.
  • the method described below is not limited to windscreens, but can also be used for camera systems behind rear windows or other vehicle windows. In the following, the case of a windscreen is considered as a typical application.
  • the disk induces, through refraction, a shift of sight rays and a change in angle.
  • the offset is typically small and does not change over distance. However, at greater distances, the angular misalignment leads to greater errors, depending on the angle.
  • the second effect, the induced change in angle should therefore be determined in particular with the displacement field.
  • the method presented is used for the particularly high-precision measurement of a transparent pane, for example for camera systems, with the influence of this pane being measured or measured.
  • the pane such as a windshield, is typically to be mounted or is in front of the camera assembled.
  • the method provides that a displacement field induced by the transparent pane is determined.
  • a first step a first image of a textured surface is recorded without the pane and a second image of the textured surface with the pane is recorded in a second step.
  • the displacement field is determined by analyzing the two images using an optical flow method.
  • the method described is not limited to windshields or windscreens, but can also be used for camera systems behind rear windows or other vehicle windows.
  • a windscreen is considered as a typical application.
  • Taking a picture with a disc means that the disc is between the camera and the textured surface and is therefore in the beam path between the camera and the textured surface. Similarly, in the no-disc recording, no disc is placed in place.
  • a texture or a textured surface is to be understood as meaning that this surface has a specific pattern.
  • Textures with random patterns for example noise patterns, which have a broad spectrum of spatial frequencies are particularly suitable for this method.
  • noise patterns which have a broad spectrum of spatial frequencies are particularly suitable for this method.
  • Such a pattern can be generated, for example, by superimposing noise patterns of different frequencies, with Perlin noise being used, for example.
  • the displacement field refers to the geometric displacement of objects in the image space, for example due to stretching, stretching, displacement, etc., which results from the changed beam path.
  • FIG. 1 shows a windshield and a camera in a schematic representation.
  • FIG. 2 shows the procedure for a high-precision calibration.
  • FIG. 3 shows an experimental setup for determining a displacement field.
  • FIG. 4 shows an experimental setup with an illuminated random pattern.
  • FIG. 5 shows an example of a displacement field determined using the method described.
  • Figure 6 shows a displacement field projected onto a curtain.
  • Figure 1 shows a schematic representation of the geometric deflection of the visual beams 12 emanating from a camera 10, which define a beam path 16, by a windshield 14.
  • This deflection and thus the influence of the windshield 14 on the beam path 16 is in the area of the windshield 14, here starting from the camera 10, clearly visible.
  • the changed beam path 16 leads both to an offset in terms of position and to a change in direction of the visual beams 12. Especially the latter is crucial for larger distances between the camera 10 and objects.
  • the displacement field is thus a vector field that represents a mathematical description of this change. This can be used to describe where each structure visible in the image has been moved to.
  • the method proposed here now allows this displacement field to be measured with high precision and densely, i. H. for each pixel of the target camera system.
  • a picture is taken with the target camera system of a textured surface with and without a windshield.
  • a method for determining dense displacement fields with respect to an optical flow in the image is then used to determine this. This is shown schematically in FIG.
  • FIG. 2 clarifies the procedure for a high-precision calibration.
  • the illustration shows a recording without a windscreen at the top 50 and a recording with a windscreen at the bottom 52 .
  • the illustration shows a camera 54 at the top 50 and bottom 52, a textured surface 56 and a windshield 58 at the bottom 52.
  • a first image 60 of the textured surface 56 without the windshield is taken.
  • a second image 62 with windshield 58 is then taken.
  • the displacement field is determined by analyzing the images 60, 62 using an optical flow method.
  • the corresponding point in the second image is determined for each point in the first image, whereby it is assumed that the appearance, e.g.
  • sampled texture should have some specific properties that are easy to generate. In some cases, suitable textured surfaces can also be found in the natural environment.
  • the method can be used to determine the characteristics of a series of windshields or even during ongoing production.
  • the assessment or approval of a windshield can depend directly on the result of the measurement.
  • FIG. 3 shows a possible experimental setup for determining the displacement field induced by a pane in front of a camera using a known and highly accurate calibration body 80.
  • This calibration body 80 can, for example, be a field with a checkerboard pattern.
  • the aim of the proposed method is now to determine the displacement field induced by a windshield and which results in the image space of a camera.
  • the displacement field designates the geometric displacement of objects in the image space, such as expansion, stretching, displacement, which results from the changed beam path.
  • FIG. 4 shows an experimental setup with an illuminated random pattern 100 and a camera 104 placed behind a windshield 102.
  • the camera 104 is set up on a tripod 106 in front of a wall 108.
  • the wall 108 either has a special texture itself or this is projected onto the wall 108 via a projector.
  • a support 110 for the windshield 102 is placed between the camera 104 and the wall 108 such that the camera 104 is in its typical mounting position, i. H. Position and orientation relative to the windshield 102 occupies.
  • the camera 104 takes at least one image with and without the windshield 102 in place.
  • the displacement field in the image is determined.
  • the imaging properties of the camera 104 without a windshield 102 are known or can be easily determined, namely more easily than with the windshield 102 mounted.
  • a measuring stand is used to calibrate the camera 104, in which the camera 104 is clamped in a special holder and a precisely known one Calibration body is used.
  • Such a procedure is not possible with one or more built-in camera(s). This means that the relationship between the angle of the line of sight and the pixels for the camera without a windshield is known. With the help of displacement field, a corrected pixel-line-of-sight relationship (with windshield) can now be calculated.
  • an optical element such as the windshield 102
  • the introduction of an optical element always has two effects, on the one hand the changed angular relationship and on the other hand, as shown in FIG. 1, an offset of the visual beam.
  • the latter is often not relevant in practice, since objects of interest are in many cases far away, e.g. several meters, and the influence of the offset is therefore negligible.
  • this offset can be determined by several recordings with different distances to the wall 108, as described above. This can be of interest for other applications.
  • FIG. 5 shows a displacement field 150 determined using the method. At every pixel there is a measurement by the dense optical flow method. Only the horizontal shift is shown here. Strength can be color coded.
  • Textures that have strong local contrasts and are as random as possible are particularly suitable for optical flow methods, e.g. B. a random noise pattern. So that the texture can also be used for different distances to the camera and cameras with different resolutions, i. H. pixels per degree works, ideally the pattern should have different local spatial frequencies. The pattern does not have to be known in advance.
  • the random texture makes it possible to determine the displacement field at each pixel when using a dense optical flow method.
  • this is typically not possible at all points. In the arrangement from FIG. 3, this is only possible at the crossing points.
  • Dense optical flow methods are known.
  • suitable optical flow methods can achieve a very high level of accuracy, namely well below the size of a pixel. The accuracy of the method is therefore directly related to the accuracy of the underlying optical flow method, but not to the accuracy of a calibration body.
  • the pattern can also be used with very different distances or camera image resolutions. In many cases, this is not easily possible with typical calibration bodies.
  • a textured foil can be applied to a wall or a pattern can simply be projected with one or more projectors.
  • the textured surface is at a similar distance from the camera and windshield as objects in a real situation, i. H. several meters. This is because the offset induced by the windshield has a similar impact. For cameras with larger opening angles, this requires very large surfaces. With a horizontal opening angle of 90 degrees and a distance of 5 meters, a flat surface should be at least 10 meters wide. Something like this can hardly be realized with typical calibration bodies. With the help of projectors z. B. just use big walls. Room corners or similar can also be used. In principle, the surface is not important, just that there should be no shading.
  • An example is a curtain 200 shown in Figure 6.
  • the only requirement is that the camera, surface and texture setup does not move during the recording. Note that instead of a flat wall, a random pattern is projected onto the curtain 200 here.
  • These recordings were used to measure the disc and are intended to illustrate the independence of the process from highly precise calibration bodies. If, when using projectors, several images are taken with and without a windscreen with different patterns, the accuracy of the optical flow methods can often be increased by combining the results.
  • a highly textured surface was created by imprinting it with a random texture at different spatial frequencies.
  • An alternative to this is to use projectors or beamers to generate random textures with different spatial frequencies on non-textured surfaces.
  • projectors can also be combined. This can be very useful to create the necessary coverage for cameras with a large opening angle.
  • monitors or screens can also be used.
  • Many naturally occurring textures are also suitable for the process, e.g. B. an asphalt surface, mottled carpets, painter's fleece or some house facades.
  • a flat surface does not necessarily have to be used. Curved surfaces or room corners can be ideal, especially for cameras with a large opening angle.
  • mirrors are used to extend the optical path. In principle, this method can also be used to determine the influence of imperfections in the mirror.
  • the method presented can be used in companies, particularly for the internal measurement of windshields.
  • the aim can be to build up statistics about windshields and feed this information back into the development process. In this way, a large number or all windshields produced can be measured and classified or approved according to the result.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Multimedia (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Image Analysis (AREA)

Abstract

L'invention concerne un procédé de mesure de l'influence d'une vitre transparente (14), dans lequel un champ de déplacement induit par la vitre (14) est déterminé ; dans une première étape, une première image d'une surface texturée sans la vitre transparente (14) est acquise ; dans une deuxième étape, une deuxième image de la surface texturée avec la vitre transparente (14) est acquise ; et dans une troisième étape, le champ de déplacement est déterminé par analyse des deux images à l'aide d'un procédé de flux optique.
EP21798313.9A 2020-12-07 2021-10-18 Procédé de mesure de l'influence d'une vitre transparente Pending EP4256509A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020215417.1A DE102020215417A1 (de) 2020-12-07 2020-12-07 Verfahren zum Vermessen des Einflusses einer transparenten Scheibe
PCT/EP2021/078805 WO2022122230A1 (fr) 2020-12-07 2021-10-18 Procédé de mesure de l'influence d'une vitre transparente

Publications (1)

Publication Number Publication Date
EP4256509A1 true EP4256509A1 (fr) 2023-10-11

Family

ID=78372006

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21798313.9A Pending EP4256509A1 (fr) 2020-12-07 2021-10-18 Procédé de mesure de l'influence d'une vitre transparente

Country Status (7)

Country Link
US (1) US20230410288A1 (fr)
EP (1) EP4256509A1 (fr)
JP (1) JP2023553885A (fr)
KR (1) KR20230118133A (fr)
CN (1) CN116601669A (fr)
DE (1) DE102020215417A1 (fr)
WO (1) WO2022122230A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2026013780A1 (fr) * 2024-07-10 2026-01-15 Ａｓｔｅｍｏ株式会社 Dispositif d'étalonnage de caméra et procédé d'étalonnage de caméra

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ATE415644T1 (de) * 2000-05-04 2008-12-15 Schott Donnelly Llc Verfahren zur herstellung einer electrochromen tafel
US7899236B2 (en) * 2006-11-09 2011-03-01 The Boeing Company Evaluation of optical distortion in a transparency
CN102507446A (zh) * 2011-10-24 2012-06-20 北京航空航天大学 一种透光玻璃光学角偏差的检测方法
JP6427900B2 (ja) * 2014-03-07 2018-11-28 株式会社リコー 校正方法、校正システム、プログラム及び移動体
US9470641B1 (en) * 2015-06-26 2016-10-18 Glasstech, Inc. System and method for measuring reflected optical distortion in contoured glass sheets
CN107238484B (zh) * 2016-03-28 2020-05-26 京东方科技集团股份有限公司 透明显示屏清晰度的检测方法和检测装置
US20180017799A1 (en) * 2016-07-13 2018-01-18 Ford Global Technologies, Llc Heads Up Display For Observing Vehicle Perception Activity
EP3293701B1 (fr) * 2016-09-07 2019-11-06 Conti Temic microelectronic GmbH Procédé et appareil pour la compensation de distorsions d'images statiques introduites par un parebrise sur une caméra d'aide à la conduite automobile
EP3844556B1 (fr) * 2018-08-29 2026-03-11 Saint-Gobain Sekurit France Dispositif de vérification pour un affichage tête haute (hud)

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Also Published As

Publication number Publication date
DE102020215417A1 (de) 2022-06-09
WO2022122230A1 (fr) 2022-06-16
CN116601669A (zh) 2023-08-15
US20230410288A1 (en) 2023-12-21
KR20230118133A (ko) 2023-08-10
JP2023553885A (ja) 2023-12-26

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