WIDE ANGLE IMAGING SYSTEM FOR PROVIDING AN IMAGE OF THE SURROUNDINGS OF A VEHICLE, IN PARTICULAR A MOTOR VEHICLE

Abstract

An imaging system includes a digital camera having a sensor (such as a charge coupled device), a first lens directing a first image onto a first region of the sensor, a second lens directing a second image onto a second region of the sensor, and a third lens directing a third image onto a third region of the sensor. A display screen displays to a driver of the vehicle the first image, and a processing unit performs stereoscopic image analysis on data originating from the second and third regions. A fourth lens may be used to direct a fourth image onto a fourth region of the sensor, and the processing unit performs calculations on data from the fourth region for the detection of movement of the vehicle.

Claims

1. An imaging system comprising: an electro-optical sensor; a first lens directing an image onto the sensor; a display screen displaying the image; second and third inter-axially spaced lenses directing respective second and third images onto the sensor on opposite sides of the image, the second and third lenses producing purposeful width distortion of the respective images adapted for stereoscopic analysis; and a processing unit performing stereoscopic analysis on the second and third images.

2. The imaging system of claim 1, further comprising a fourth lens inter-axially spaced from the first, the second, and the third lenses to direct a fourth image onto a fourth region of the sensor located adjacent a third edge of the sensor, the fourth image exhibiting purposeful height distortion.

3. The imaging system of claim 2, wherein the processing unit performs calculations on data from the fourth region to detect lateral movement of a host vehicle.

4. The imaging system of claim 3, wherein the processing unit detects lateral movement of the vehicle by analyzing lane markings appearing in the fourth image.

5. The imaging system of claim 1, wherein at least one of the lenses comprises at least two mirrors optically aligned with one another.

6. The imaging system of claim 1, further comprising a data buffer associated with the processing unit.

7. An imaging system for a motor vehicle comprising: an electro-optical sensor; a first lens directing a first image onto a central region of the sensor; a display screen for displaying the first image to a driver of the vehicle; a second lens inter-axially spaced from the first lens to direct a second image onto a second region of the sensor located adjacent a first lateral edge of the sensor; a third lens inter-axially spaced from the first lens and the second lens to direct a third image onto a third region of the sensor located adjacent a second lateral edge of the sensor, the second lateral edge positioned opposite from the first lateral edge, the second and third images having substantially equal amounts of purposeful width distortion adapted for stereoscopic image analysis; and a processing unit performing stereoscopic image analysis on data originating from the second and third regions.

8. The imaging system of claim 7, further comprising a fourth lens inter-axially spaced from the lens, the second lens, and the third lens to direct a fourth image onto the sensor, the fourth image exhibiting height distortion.

9. The imaging system of claim 8, wherein the processing unit performs analysis on the fourth image to detect lateral movement of a host vehicle.

10. The imaging system of claim 9, wherein the processing unit detects lateral movement of the vehicle by analyzing lane markings appearing in the fourth image.

11. The imaging system of claim 7, further comprising a data buffer associated with the processing unit.

12. Apparatus comprising: a first lens directing a first image onto a first region of an electro-optical sensor; and second and third lenses spaced inter-axially from one another and located on opposite sides of the first lens and directing respective second and third images having substantially equal amounts of purposeful width distortion adapted for stereoscopic evaluation onto respective second and third regions of the sensor.

13. The apparatus of claim 12, further comprising a processing unit performing stereoscopic analysis on the second and third images.

14. The apparatus of claim 13, further comprising a data buffer associated with the processing unit.

15. The apparatus of claim 12, further comprising a display screen for displaying the first image to a driver of a host vehicle.

16. The apparatus of claim 12, wherein at least one of the lenses comprises at least two mirrors optically aligned with one another.

17. The apparatus of claim 12, further comprising a fourth lens inter-axially spaced from the first lens, the second lens, and the third lens to direct a fourth image onto the sensor, the fourth image exhibiting purposeful height distortion.

18. The apparatus of claim 17, further comprising a processing unit performing analysis on the fourth image to detect lateral movement of a host vehicle.

19. The apparatus of claim 18, wherein the processing unit detects lateral movement of the vehicle by analyzing lane markings appearing in the fourth image.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further details, features and advantages of the invention emerge from the following description of exemplary embodiments with the aid of the single drawing, in which:

[0018] FIG. 1 is an overview schematic of a vehicle with an embodiment of a wide angle imaging system;

[0019] FIG. 2 is a schematic of the division of an imaging sensor;

[0020] FIG. 3 is a schematic of the design of an embodiment of a lens system; and

[0021] FIG. 4 is a schematic of the design of an alternative embodiment of a lens system.

DETAILED DESCRIPTION

[0022] FIG. 1 is a schematic of a vehicle 1 having an imaging system 2 for providing an image of the vehicle surroundings U. The imaging system is able to display this image to the driver on a screen and to simultaneously digitally process the image for further evaluations.

[0023] The imaging system 2 comprises a camera 3 for imaging the surroundings U, here in particular the road S in front of or behind the vehicle 1. The camera 3 comprises a lens system 4 and a sensor 5, the lens system 4 directing multiple images of the surroundings onto the sensor 5. Sensor 5 is preferably an electronic optical sensor and may be a charge coupled device (CCD) or a complimentary metal-oxide semiconductor (CMOS) image sensor, as is well known in the field of artificial vision.

[0024] The imaging system 2 further comprises a visual display screen 6 for displaying to the driver of the vehicle the surroundings, as imaged by the camera 3 and directed onto the sensor 5 by the lens system 4. The driver is thereby enabled when driving backward to search the surroundings for objects, etc., visible on the display screen in a known way.

[0025] The imaging system 2 additionally comprises a data processing unit 7 for processing the electronic data originating from the sensor 5 for the purpose of further evaluations. The data processing unit 7 is switched logically between the sensor 5 and display 6, and can be embodied, with appropriate suitability, by a microprocessor, which is present in any case in the onboard electronics.

[0026] As seen in FIG. 3, the lens system 4 is configured with four lenses 4a, 4b, 4c, 4d in order to direct images of the surroundings onto the imaging sensor 5 as four optically different regions 5a, 5b, 5c, 5d (compare FIG. 2). The first region 5a is associated with the visual display screen 6. The other regions 5b, 5c, 5d are, by contrast, associated with the data processing unit 7 for digital image evaluation purposes.

[0027] Thus, the lenses 4a, 4b, 4c, 4d can be optimized independently of one another depending on the respective use of each particular region. Characteristics that may be optimized may, for example, relate to their distortion, resolution, etc. Thus, the region for the driver's visual display can be a large middle region allowing for an image of the surroundings in high resolution. The driver can thereby be provided with a central, more effectively resolved image, and it is possible for the other regions to be optimized for detection of direction and movement and/or for stereoscopic evaluation by image processing.

[0028] As seen in FIG. 2, a vehicle 11 located behind the driver's own vehicle is shown with little or no distortion in region 5a. The roadway directly behind the driver's own vehicle is illustrated in region 5b with height distortion for the purpose of detecting obstacles by processing unit 7. The region behind the driver's own vehicle is illustrated in regions 5c and 5d with width distortion, with in each case the same resolution for the purpose of stereoscopic evaluation performed by processing unit 7.

[0029] A quasi-stereoscopic evaluation is being carried out here, by means of a single camera with the aid of different camera positions (on the basis of the movement of the vehicle). The greater this inter-axis spacing between the respective central axes of the lenses, the more effective or accurate is the subsequent evaluation. The differences between the respective images on the two regions of the sensor can be used to determine angular differences between the observed objects, and to calculate a pixel displacement from them. The mutual inter-axis spacing between the two regions is known per se, and is used for the further evaluation by the processing unit.

[0030] It is also possible to combine two of more of the lenses so as, as illustrated here in the exemplary embodiment, to combine the two central lenses 4a and 4b into a combined central lens 8a/b that consists of an upper lens portion 4a and a lower lens portion 4b. The two lens portions 4a, 4b have different optical characteristics to produce the two different images in regions 5a and 5b respectively.

[0031] The first region 5a is located in this embodiment in the middle region of the sensor 5 which is usually of most interest for the driver, and so is associated with the driver's visual display on the display screen 6. The display of this image on display screen 6 can be overlaid with information of interest to the driver such as, for example, vehicle path and distance data, etc. This region 5a can also be used for the image calibration, and even for detection of collision with objects, without the main function of the driver display being influenced. The data of region 5a can also be processed, analyzed, and/or conditioned by the data processing unit 7.

[0032] The second region 5b lies at the middle lower edge, below the first region 5a. This region may, if appropriate, also already be used for the driver display together with the first region 5a.

[0033] The region 5b of may include the road directly in front of or behind the vehicle, and so the structures present there (compare above) may be used to evaluate movement, that is to say to detect the path of the vehicle, by image processing. The lower section of the image of the surroundings, which is preferably used for this purpose, on the sensor 5a permits this in a favorable way, since the observed region comprises the surface of the road which, in turn, includes structure (lane markings, lines, curbs, etc.) that allow a determination of the desired vehicle path or a deviation therefrom, and/or the determination of the longitudinal and transverse speeds.

[0034] The third and fourth regions 5c, 5d lie respectively at the left and right lateral edge outboard of the middle regions 5a and 5b. As already described above, the regions 5c, 5d may be used for stereoscopic evaluation, performed by processing unit 7. Furthermore, they are also suitable for monitoring a blind spot as well as for determining a rotation (angle and angular velocity) of the vehicle by means of image processing methods.

[0035] As best seen in FIGS. 3 and 4, the lens system is configured with independent lenses 4a, 4b, 4c, 4d in order to direct multiple images of the surroundings onto the three or four optically different regions 5a, 5b, 5c, 5d of the imaging sensor 5.

[0036] The inter-axis spacing A between the respective central axes of lenses 4c and 4d and between the respective regions 5c and 5d is significant for the stereoscopic evaluation with the aid of sequentially stored images of the surroundings, or their data from the sensor. A quasi-stereoscopic evaluation may be carried out here by means of a single camera with the aid of different camera points-of-view (on the basis of the movement of the vehicle). The greater this inter-axis spacing A, the more effective or more accurate is the subsequent evaluation. The spacing between the two regions 5c, 5d of the image of the surroundings U is used in this case to determine angular differences between the objects observed in the regions, and to calculate a pixel displacement from them. The spacing A between the two regions is known per se and is used for the further evaluation by processing unit 7.

[0037] Referring now to FIG. 4, each lens 4c, 4d comprises a pair of mirrors 9c, 10c and 9d, 10d respectively. The mirror pairs 9c, 10c and 9d, 10d are optically aligned to direct and focus the images onto regions 5c and 5d respectively. Other focusing lenses and/or prisms (not shown) may also be employed along with the mirrors to provide the desired optical characteristics. The outboard placement of mirrors 9c, 9d results in an increase in the effective spacing A between the optical regions for the purpose of stereoscopic evaluation. An increase in the resolution of the stereoscopy may be achieved thereby.