Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/20—Image signal generators
  • H04N13/296—Synchronisation thereof; Control thereof
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/20—Image signal generators
  • H04N13/204—Image signal generators using stereoscopic image cameras
  • H04N13/239—Image signal generators using stereoscopic image cameras using two 2D image sensors having a relative position equal to or related to the interocular distance
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/20—Image signal generators
  • H04N13/204—Image signal generators using stereoscopic image cameras
  • H04N13/25—Image signal generators using stereoscopic image cameras using two or more image sensors with different characteristics other than in their location or field of view, e.g. having different resolutions or colour pickup characteristics; using image signals from one sensor to control the characteristics of another sensor
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/70—Circuitry for compensating brightness variation in the scene
  • H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R11/00—Arrangements for holding or mounting articles, not otherwise provided for
  • B60R11/04—Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R11/00—Arrangements for holding or mounting articles, not otherwise provided for
  • B60R2011/0001—Arrangements for holding or mounting articles, not otherwise provided for characterised by position
  • B60R2011/0003—Arrangements for holding or mounting articles, not otherwise provided for characterised by position inside the vehicle
  • B60R2011/0026—Windows, e.g. windscreen

Definitions

• the invention relates to a stereo camera for a vehicle with a first camera having a first image sensor and a second image sensor having a second camera according to the preamble of claim 1. Furthermore, the invention relates to a method for exposure control of such a stereo camera.
• a traffic sign recognition or a lane departure warning camera systems especially stereo cameras for Improvement ⁇ th depth resolution can be used.
• stereo cameras are two cameras, each with a lens optics and a
• Image sensor understood offset from one another at a predetermined distance, for example, are mounted on a windshield of the vehicle.
• Stereo cameras have the advantage that they can be used to measure distances.
• camera systems require a horizontal opening angle of approximately 50 ° and a vertical opening angle of approximately 30 °.
• ⁇ to future camera systems require a significantly higher opening angle for new features such as cross-traffic detection or traffic light recognition.
• High-resolution, high-aperture camera systems require high pixel count multi-megapixel image sensors similar to those used for digital imaging
• a similar system of a stereo camera also describes the DE 10 2004 061998 AI, a black and white camera with an opening angle of 40 ° and a color camera with a
• the black and white camera has a grayscale image sensor with a high photosensitivity and a pixel size of 8 ym with a horizontal geometric resolution of 800 pixels.
• the color camera is equipped with a high-resolution color image sensor with a pixel size of 4 ym and a horizontal geometric resolution of 1600 pixels.
• the use of such a high-resolution color image sensor contradicts a cost-effective implementation of driver assistance functions.
• FIG. 8 shows a camera viewing window with an aperture angle of +/- 90 ° about an optical axis O with a high-resolution central region Z corresponding to an aperture angle of +/- 30 ° and peripheral zones ⁇ ⁇ and Z "with a lower resolution
• Figure 9 shows the graph of the resolution as a function of the opening angle, wherein the central area ⁇ Z having twice the resolution as the located outside the central region dimension Z ".
• These figures 8 and 9 also show a transition region Z ⁇ between the central region Z and the region Z ", which extends over an angular range of 10 °.
• the author of the above article further discusses the use of an image sensor with a panomorphic lens to provide the necessary image information for a driver assistance system.
• Such a stereo camera for a vehicle with a first camera having a first image sensor having a first opening angle, and a ei ⁇ NEN second image sensor having second camera whose camera field of view has a second opening angle, wherein the second opening angle is greater than that first opening ⁇ angle, is characterized in that
• a first lens optics and the second Ka ⁇ ra has a second lens optical system, wherein both the first and second lens optics with a lying in the angular range around the optical axis central portion of the camera view ⁇ field is formed higher angular resolution than outside the central region, and
• the first and second camera are arranged to each other such that overlap their camera fields of view.
• This stereo camera according to the invention is characterized in that a lens optic is used for both cameras, which in each case has a higher resolution in the central area than outside this central area.
• Such a stereo camera is inexpensive to implement, since the corresponding lens systems are available as commercially available products, for example from the company ImmerVision.
• the first and the second image sensor are formed with identical pixel densities, the two image sensors each having a size adapted to the aperture angle. Ent ⁇ speaking the larger opening angle also has the zugehö ⁇ membered image sensor relative to the image sensor of the camera with the smaller camera field of view on a larger area.
• the second-mentioned object is achieved by a method having the features of claims 4, 5 and 6.
• the first and second cameras are arranged in such a way that their camera field of view overlaps symmetrically with respect to the optical axis
• the exposure and readout of the image sensor pixels of ers ⁇ th and second image sensor is performed column by column, the exposure of the smaller image sensor begins after an exposure start of the larger image sensor when the first column of the smaller image sensor is reached in the larger image sensor.
• the camera field of view of the single ⁇ Lich extends a camera relative to the other in the horizontal direction, wherein the exposure control, the two image sensors are column-wise exposed and read out.
• the second-mentioned solution of the invention is characterized as ⁇ through out that
• a first lens optic is provided for the first camera and a second lens optic is provided for the second camera, wherein both the first and the second lens optics are formed with a higher angular resolution with a central region of the camera field of view lying at an angle to the optical axis than outside the central region , and
• the first and second cameras are arranged in such a way that their camera field of view overlaps symmetrically with respect to the optical axis, -
• the exposure and readout of the image sensor pixels of the ers ⁇ th and second image sensor is performed line by line, the exposure of the smaller image sensor begins after an exposure start of the larger image sensor when the first line of the smaller image sensor is achieved in the larger image sensor.
• a first lens optic is provided for the first camera and a second lens optic is provided for the second camera, wherein both the first and the second lens optics are formed with a higher angular resolution in the angular range around the optical axis of the camera field of view than outside the central region , and
• the first and second cameras are arranged in such a way that their camera field of view overlaps symmetrically with respect to the optical axis
• the camera field of view of one camera is widened in the horizontal as well as in the vertical direction, wherein the two image sensors are exposed and read out for the exposure control and virtual columns are created for adaptation in the horizontal direction for the smaller image sensor and inserted.
• the stereo camera according to the invention can be used for driver assistance systems in vehicles.
• Figure 1 is a schematic representation of a erfindungsge ⁇ MAESSEN stereo camera in the area of a windshield of a vehicle
• Figure 2 is a schematic representation of the constructive
• FIG. 4 shows a diagram with the resolution profile of the two
• Figure 5 is a schematic illustration of the exposure ⁇ scheme of the image sensors of the first and second camera of a stereo camera of the invention in a horizontal extension of the camera's aperture kels the second relative to the first camera,
• Figure 6 is a schematic illustration of the exposure ⁇ scheme of the image sensors of the first and second camera of a stereo camera of the invention in a vertical extension of the opening angle of the second camera relative to the first camera,
• Figure 7 is a schematic representation of the exposure scheme of the image sensors of the first and second
• FIG. 8 shows a camera field of view of a panomorphic lens having a central area of increased resolution with respect to the peripheral area, and a diagram with the resolution profile of the panomorphic lens of FIG. 8 as a function of the horizontal opening angle.
• the vehicle 10 illustrated in FIG. 1 comprises a driver assistance system with a stereo camera 1 arranged behind a windshield of the vehicle 10 and a control and evaluation unit 2, the stereo camera 1 having a first camera 1.1 and a second camera 1.2 and being mounted in a driving position. seen direction, the first camera 1.1 a left camera and the second camera 1.2 represents a right camera.
• the image data ⁇ the stereo camera 1 are evaluated by the control and evaluation. 2 Depending on the evaluation results, the execution of a driver assistance function of the driver assistance system takes place.
• the left camera 1.1 has a camera field of view Sl having a horizontal opening angle l, for example of 50 °, while the right camera 1.2 has a camera field of view S2 with a larger horizontal opening angle 2, for example of 90 °.
• FIG. 2 shows the structural design of the stereo camera 1 with the left and right camera 1.1 and 1.2.
• the left camera 1.1 comprises a first lens optics 1.12 and a first image sensor 1.11 assigned to this lens optics 1.12, which is controlled by an image evaluation unit 1.13.
• the right camera 1.2 has the identical structure and consists of a second lens optics 1.22 with a second image sensor 1.21, which is controlled by an image evaluation unit 1.23.
• the lens according to Figure 8 has an optical axis 0 surrounding the central region Z, in which this lens a higher on ⁇ solution as the two least the central region annularly surrounding regions ⁇ ⁇ and Z ", which lie outside this central ⁇ region Z.
• This Areas Z, ⁇ ⁇ and Z " have an elliptical shape, wherein the central area Z has a horizontal opening angle of 60 ° and the entire opening angle of this lens, which corresponds to the camera field of view, has a value of 180 °.
• the course of the resolution starting from the optical axis 0 to the edge area is shown in FIG. 9, according to which the resolution in the central area Z, ie up to the angle of 30 °, is twice as large as the area larger than an angle of 40 °
• the angle range of 30 ° to 40 ° represents a transition region between the central region Z and the outermost region Z "in which the resolution steadily changes from the higher value to the lower value.
• the first and second lens optics 1.12 and 1.22 of the left and right camera 1.1 and 1 2 have a corresponding property, which is shown in Figures 3 and 4.
• the first lens optics 1.12 The left camera 1.1 of the stereo camera 1, a central region ZI with egg ⁇ nem opening angle of all, while the second Linsenop ⁇ tik 22.1 of the right camera 1.2 of the stereo camera 1, a central zone Z2 with a larger opening angle a21 having.
• These two central areas ZI and Z2 8 may be elliptic or rotationally symmetrical, ie circular entspre ⁇ accordingly of FIG. Correspondingly, which run around these central areas ZI and Z2 subsequent preparation ⁇ che.
• FIG. 3 The course of the horizontal resolution via the camera view window Sl of the left camera 1.1 is shown in FIG. 3; the profile of the horizontal resolution via the camera view window S2 of the right camera 1.2 is shown in FIG.
• the opening angle is all the Monbe ⁇ rich ZI of the first lens optics 1.12
• the first camera 20 1.1 °, in which the resolution constant 40 pix / °.
• This central region ZI is followed by an angle range of 5 ° as transition region, in which the resolution drops from 40 pix / ° to 20 pix / ° and remains constant up to the edge at an angle value of 25 °, corresponding to an aperture angle of 50 °.
• this central area ZI with a relatively narrow opening angle of 20 ° there is a high resolution, which is required for object recognition in the long-range.
• the opening angle ⁇ 2 of the central region Z2 of the second lens optics 1.22 of the second camera 1.2 corresponding to the first lens optics 1.12 is also 20 °, in which the resolution is also constant at 40 pix / °.
• an angle range of 5 ° the resolution of 40 pix / ° to 20 pix / ° connects to as a transition region in which drops and constant up to the edge at a value of 45 °, corresponding to an opening angle of 90 ° remains.
• the stereo effect can be used up to an opening angle of 50 °.
• the image sensors 1.11 and 1.21 of the left and right camera 1.1 and 1.2 have different sizes, which are respectively adapted to the camera field of view Sl and S2, but each ⁇ have the same pixel density. Due to the size ⁇ ren field of view S2 of the right camera 1.2 in comparison to the field Sl of the left camera 1.1 of the second image sensor 21.1 of the right camera 1.2 is larger than the first image sensor 11.1 of the left camera 1.1 in its horizontal extension. In this case, the two cameras 1.1 and 1.2 are aligned with each other such that the camera field of view Sl and S2 overlap symmetrically, as shown in Figure 5.
• the larger image sensor 1.21 would only have to grow by about 50% in terms of the number of pixels in a merely horizontal extension of the opening angle 2 of the right camera 1.2 to 90 ° compared to an opening angle of 50 ° of the left camera 1.1, although the opening angle is almost doubled.
• transition region from the high-resolution central region ZI or Z2 into the low-resolution region leads to a situation in which rectification of the images for calculating a stereo-depth image is made more difficult. To this difficulty vice ⁇ hen, it is possible to move the transition area so far to the right, ie towards higher angular values that this transition region comes into play only in the right camera 1.2 with the larger opening angle. 2
• the synchronicity during exposure and readout of the image sensor pixels of the two image sensors 1.11 and 1.21 must be ensured. This poses no problem when using the "Global-Shutter-Principle" working image sensors, since all the image sensor pixels are exposed and read simultaneously, but it is possible to use the so-called rolling-shutter principle by synchronizing is achieved in the two image sensors 1.11 and 1.21 in that they are read out column by column.
• a stereo camera 1 with a left and right camera 1.1 and 1.2 is described with the figures 1 to 4, in which the opening angle 2 of the right camera 1.2 with respect to the opening angle l of the left camera 1.1 is extended in the horizontal direction. Accordingly, it is also possible to widen the opening angle of the right camera 1.2 relative to the opening angle of the left camera 1.1 in the vertical direction. Also in this case, the two lens optics 1.12 and 1.21 of the left and right camera 1.1 and 1.2, the properties described in connection with Figures 3 and 4. In this case, the two cameras 1.1 and 1.2 are aligned with one another in such a way that the camera field of view Sl and S2 overlap symmetrically, as shown in FIG.
• the exposure of the two image sensors 11.1 and 21.1 such a stereo camera 1 is performed according to this Figure 6 lines ⁇ example, by first exposure and the reading of the first line ZE21 of the larger image sensor 21.1 starts, and then the exposure and the readout of the smaller image sensor 1:11 only then begins when the exposure process of the larger image sensor 1.21 has reached the first line ZEH of the smaller image sensor 1.11.
• An extension of the opening angle of the right camera 1.2 relative to the opening angle of the left camera 1.1 can also be done both in the horizontal and in the vertical direction.
• the second image sensor 1.21 is larger in both the horizontal and in the vertical direction than the first image sensor 1.11.
• the two lens optics 1.12 and 1.21 of the left and right camera 1.1 and 1.2 on the properties described in connection with Figures 3 and 4.
• the two cameras 1.1 and 1.2 are aligned with each other such that the camera field of view Sl and S2 overlap symmetrically, as shown in Figure 7.
• the exposure and read-out process begins with the first line ZE21 of the larger image sensor 1.21, the first line ZEH of the smaller image sensor 1.11 is reached.
• one interval corresponding to the number of read-out clocks of the excess pixels have to be inserted in one line of the image sensor size ⁇ ren 1.21 for each line of clothing ⁇ Neren image sensor. 1.11 This is he ⁇ sufficient that a corresponding de number of virtual columns are added to the smaller image sensor 01.11 for which the pixel clock can continue without the smaller image sensor 11.1 the pixels of these virtual columns would have to be processed. Thereby, it is possible to wait for the exposure start of the subsequent line and to ensure the simultaneous start of the line-by-line exposure.

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Studio Devices (AREA)
• Cameras In General (AREA)
• Measurement Of Optical Distance (AREA)
• Stereoscopic And Panoramic Photography (AREA)
• Closed-Circuit Television Systems (AREA)

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• 2014
  • 2014-10-10 DE DE102014220585.9A patent/DE102014220585A1/de not_active Withdrawn
• 2015
  • 2015-09-15 DE DE112015003116.2T patent/DE112015003116A5/de active Pending
  • 2015-09-15 JP JP2017514649A patent/JP6588970B2/ja active Active
  • 2015-09-15 WO PCT/DE2015/200457 patent/WO2016055060A1/de not_active Ceased
  • 2015-09-15 CN CN201580054499.7A patent/CN106797461B/zh active Active
  • 2015-09-15 EP EP15794065.1A patent/EP3205090B1/de active Active
  • 2015-09-15 US US15/517,057 patent/US10334234B2/en active Active

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