Camera Device and Method for Detecting a Surrounding Area of a Driver's Own Vehicle

Abstract

The invention relates to a camera device (2) for detecting a surrounding area of a driver's own vehicle (1), with optoelectronics comprising a high-resolution image capturing sensor and a wide-angle optical system, wherein the optoelectronics are designed to output an image sequence (8) of the surrounding area with a periodic exchange of high-resolution and resolution-reduced images (3, 4).

Claims

1. A camera device (2) for detecting a surrounding area of a subject vehicle (1), comprising optoelectronics including a high-resolution image capturing sensor and a wide-angle optical system, wherein the optoelectronics are configured to output an image sequence (8) periodically changing between high-resolution images and resolution-reduced images (3, 4) of the surrounding area.

2. The camera device (2) according to claim 1, wherein the optoelectronics are configured to output the image sequence (8) having the high-resolution images and the resolution-reduced images (3, 4) alternating with one another.

3. The camera device (2) according to claim 1, wherein the image capturing sensor is configured to capture the image sequence periodically changing between the high-resolution images and the resolution-reduced images (3, 4), and to output, without resolution modification, the high-resolution images (3, 4) that have been captured in a high resolution and the resolution-reduced images that have been captured in a lower resolution.

4. The camera device (2) according to claim 1, wherein the image capturing sensor is configured to capture an initial image sequence (7) with high-resolution images (3), wherein the optoelectronics further include an image processing apparatus configured to generate in a periodically changing manner, the resolution-reduced images (4) from some of the high-resolution images (3) captured in a high resolution in the initial image sequence, and to output the resolution-reduced images included in the image sequence (8) periodically changing between the high-resolution images and the resolution-reduced images (3, 4).

5. The camera device (2) according to claim 4, wherein a resolution reduction is performed by pixel binning and/or pixel skipping in order to generate the resolution-reduced images from some of the high-resolution images.

6. The camera device (2) according to claim 1, wherein the high-resolution images and the resolution-reduced images (3, 4) all have at least approximately a same number of pixels for each of the images.

7. The camera device (2) according to claim 1, wherein the optoelectronics are configured to output a plurality of the high-resolution images and one of the resolution-reduced images per processing cycle (6) in the image sequence, wherein the plurality of the high-resolution images jointly have at B least approximately a same number of pixels as the one resolution-reduced image (4) in the respective processing cycle.

8. The camera device (2) according to claim 1, wherein the high-resolution images (3) each respectively have a smaller image size than the resolution-reduced images (4).

9. The camera device (2) according to claim 1, configured to specify an image size and/or a location of a respective one of the high-resolution images within a total available capturing surface region of the image capturing sensor, dependent on a traffic area lying ahead of the subject vehicle (1), a category of a road on which the subject vehicle (1) is currently located, a current established vehicle speed of the subject vehicle and/or a current steering angle of the subject vehicle (1).

10. The camera device (2) according to claim 1, wherein the high-resolution images (3) each respectively have at least one image area of interest which has been established in a previously captured one of the images.

11. The camera device (2) according to claim 1, wherein the high-resolution image capturing sensor has a resolution of at least five megapixels, and wherein the wide-angle optical system has a horizontal viewing angle and/or a vertical viewing angle (, ) of at least +/50 degrees to an optical axis of the optical system.

12. The camera device (2) according to claim 1, wherein each one of the images, at least in a part of a central image portion (9) thereof, has a higher resolution, in particular at least double the resolution, than in a peripheral image portion (10) thereof adjoining the central image portion, wherein the central image portion (9) has a horizontal viewing angle (5) of at most +/25 degrees and/or the peripheral image portion (10) has a horizontal viewing angle (6) of at least +/50 degrees.

13. The camera device (2) according to claim 12, wherein the wide-angle optical system has a non-uniform distortion which is configured to realize the higher resolution in the central image portion (9).

14. The camera device (2) according to claim 1, further comprising an image evaluation apparatus that is configured to evaluate at least one target object in each one of the high-resolution images and the resolution-reduced images of the image sequence, and wherein the camera device (2) further comprises a driver assistance device that is configured to carry out at least one driver assistance function dependent on the evaluated at least one target object.

15. A combination comprising a vehicle (1) and the camera device (2) according to claim 1.

16. A method of using the camera device according to claim 1, to detect a surrounding area of a subject vehicle (1), comprising outputting, with the optoelectronics, the image sequence periodically changing between the high-resolution images and the resolution-reduced images (3, 4).

Description

[0039] Further features, advantages and effects of the invention are set out by the following description of preferred embodiment examples of the invention, wherein:

[0040] FIG. 1 shows a schematic top view of a vehicle comprising a camera device;

[0041] FIG. 2 shows a captured image sequence with high-resolution images as well as the image sequence output to an image evaluation apparatus with a periodic exchange of high-resolution and resolution-reduced images;

[0042] FIG. 3 shows a captured image sequence which is output in a non-modified form in terms of resolution with periodically alternating high-resolution and resolution-reduced images;

[0043] FIG. 4 shows an image output in a resolution-reduced manner and an image output in high resolution within one processing cycle as a first embodiment example;

[0044] FIG. 5 shows one image output in a resolution-reduced manner and two images output in high resolution within one processing cycle as a second embodiment example;

[0045] FIG. 6 shows a diagram of the resolution curve of a captured image, which has been captured with a camera device with an anamorphic optical system.

[0046] Parts corresponding to one another are provided with the same reference numeral in all of the figures.

[0047] FIG. 1 shows a schematic representation of a vehicle 1 with a camera device 2 for detecting a surrounding area lying ahead. In this embodiment example, the camera device 2 is a camera arranged in the interior of the driver's own vehicle 1 behind the windshield and aimed in the direction of travel of the driver's own vehicle 1. In particular, the camera device 2 is designed as a mono camera device 2 with precisely one optoelectronic system.

[0048] As represented by way of example in FIGS. 2 and 3, the optoelectronics of the camera device 2 are designed to capture an image sequence 7 of the surrounding area and to output the captured image sequence 7 as an image sequence 8 with a periodic exchange of high-resolution and resolution-reduced images 3, 4. An alternating exchange is illustrated, purely byway of example, in FIGS. 2 and 3. The utilization of an image evaluation apparatus of the following image processing can be advantageously kept approximately the same by means of the periodic exchange of high-resolution and resolution-reduced images 3, 4. In addition, the regular sequence of high-resolution and resolution-reduced images 3, 4, averaged, attains a data quantity which can be processed by the image evaluation apparatus in order to evaluate the target objects within a temporally specified processing cycle. At the same time, the evaluation of target objects in the resolution-reduced images 4 at least at close range and the evaluation of target objects in the high-resolution images 3 in the far range can be ensured.

[0049] According to the first embodiment example shown in FIG. 2, the optoelectronics of the camera device 2 are designed to capture an image sequence 7 with high-resolution images 3 of the surrounding area lying ahead. The image sequence 7 comprises, purely by way of example in FIG. 2, six images 3 which are successively captured in high resolution in a specified time interval.

[0050] In order to capture the high-resolution images 3, the optoelectronics comprise a wide-angle optical system and a high-resolution image capturing sensor. The wide-angle optical system has e.g. a horizontal and/or vertical viewing angle , of +/50 degrees to the optical axis A. An early evaluation of target objects such as crossing road users is made possible by means of the wide-angle optical system. The image capturing sensor has, for example, a resolution of at least five megapixels. This resolution also produces the evaluation of far-range target objects. In this way, it is possible to dispense with e.g. cost-intensive multiple optoelectronics which are, in particular, provided to evaluate either the marginal image portion or the central image portion.

[0051] Consequently, the camera device 2 is, on the one hand, designed with a wide-angle detection range which can be notably required for the early recognition of crossing road users in the crossroads area or for traffic light recognition, for example. On the other hand, the at least one initial image is realized in high resolution, so that both close-range target objects, for example in the distance range between one and 50 meters, and far-range objects, for example in the distance range between 50 and 500 meters, can be evaluated. As a consequence, the conflicting goals of the wide-angle and tele range is achieved using individual optoelectronics.

[0052] According to the embodiment example of FIG. 2, the optoelectronics comprise an image processing apparatus which is, in particular, designed to generate the images 3 captured in high resolution by the image capturing sensor as resolution-reduced images 4 in the periodic exchange. In other words, the captured images 3 are preferably reduced in terms of their resolution, according to the pre-determined periodic exchange; an alternating exchange is represented by way of example in FIG. 2. In particular, the image sequence 8 is subsequently output with the periodic exchange of high-resolution and resolution-reduced images 3, 4 which are non-modified in terms of their resolution, to the image evaluation apparatus.

[0053] According to the second embodiment example shown in FIG. 3, the image capturing sensor is designed to capture the image sequence 8 with the periodic exchange of high-resolution and resolution-reduced images 3, 4 and, in particular, to output them, in a non-modified form in terms of their resolution, to the image evaluation apparatus. Since, in other words, the images 3, captured alternately in high resolution and in a resolution-reduced manner by the image capturing sensor in the periodic image sequence are at least output in a non-modified form in terms of their resolution, no subsequent resolution reduction is advantageously required.

[0054] For example, the image capturing sensor or respectively the image processing apparatus is designed to carry out the resolution reduction by means of pixel binning. The term pixel binning denotes, in particular, combining multiple, for example four, physical pixels into one pixel. In the event of the four pixels being combined into one pixel, only of the physical number of pixels is to be processed as pixels.

[0055] The camera device 2, in particular the image capturing sensor, comprises e.g. the image evaluation apparatus that is designed to evaluate at least one target object, in each case, from the output images 3, 4. Moreover, the camera device 2 comprises e.g. at least one driver assistance device or is connectable to said driver assistance device of the driver's own vehicle 1. The driver assistance device is, in particular, designed to execute at least one driver assistance function on the basis of the target objects evaluated by the image evaluation apparatus.

[0056] The images 3, 4 output in high resolution and in a resolution-reduced manner have at least approximately the same number of pixels of e.g. two megapixels. At the same time, the images 3 output in high resolution have in particular a smaller image size than the images 4 output in a resolution-reduced manner, as shown by way of example in FIGS. 4 and 5.

[0057] Due to the output image sequence with the different image size of the high-resolution and resolution-reduced images 3, 4 and the at least approximately similar number of pixels, virtually the same working capacity is advantageously required at any rate and, consequently, the exceeding of the temporally specified processing cycle 6 is avoided.

[0058] FIG. 4 represents, byway of example, an embodiment example of a high-resolution and a resolution-reduced image 4 which have been captured e.g. within one processing cycle 6. The number and size of the pixels P in the resolution-reduced image 4, compared to the high-resolution image 3, are indicated purely schematically, in order to illustrate the different resolution based on the differences in image size despite the same number of pixels.

[0059] In particular, during an alternating exchange of high-resolution and resolution-reduced images 3, 4, as shown in FIG. 4, the high-resolution images 3 preferably have at least approximately the same number of pixels, in order to achieve an, on average, constant utilization of the image evaluation apparatus.

[0060] For example, the image size and/or location of the respective image 3 to be output in high resolution is specified within the total available capturing surface region of the image capturing sensor as a function of at least one image area of interest 5.

[0061] For example, the image area of interest 5 is a pre-defined search image region, consequently in particular a statically specified search image region. However, according to a preferred embodiment example, the image processing apparatus or the image capturing sensor is designed to specify the at least one image area of interest 5, in particular in the resolution-reduced images 4 in a variable manner, e.g. as a function of the traffic area lying ahead, the current category of road and/or the current vehicle speed. The image processing apparatus or the image capturing sensor is particularly preferably designed to track the at least one image area of interest 5 in the event of a target object evaluated herein in at least the subsequent image in order to keep track of the target object, so that object tracking of the target object to be kept track of is realized.

[0062] According to a preferred embodiment example, the image 3 output in high resolution has e.g. an image area of interest 5, which was established in a previously output image, according to FIG. 4 in an image 4 previously output in a resolution-reduced manner. The image area of interest 5 comprises, in particular, a target object which is, by way of example, a traffic sign.

[0063] Furthermore, it is possible for the image size and/or location of the respective image 3 to be output in high resolution within the total available image sensor capturing surface to be specified as a function of the vehicle speed, the steer angle, the transport area lying ahead and/or the category of road on which the driver's own vehicle 1 is currently located.

[0064] Due to the fact that, as the vehicle speed increases, an increasing resolution is likewise required in the central image portion, e.g. for the early evaluation of the traffic signs and/or of the course of the lane, the image area of interest 5 is preferably placed on a central image portion 9, for example in the event of a speed limit of e.g. 100 km/h being exceeded. Due to the fact that, at lower speeds, at least a sufficient resolution is to be ensured in the peripheral image portion 10 for early cross traffic and/or traffic light recognition, the image area of interest 5 is placed on a peripheral image portion 10, for example in the event of a speed limit of e.g. 30 km/h being fallen short of, specifically if the vehicle is stationary.

[0065] FIG. 5 schematically shows an image 4 output in a resolution-reduced manner and two images 3 successively output in high resolution, which have been captured e.g. within one processing cycle 6. In this embodiment example, two regions of interest of the image 5 have been established in the resolution-reduced image 4, each of which comprises a target object, here by way of example a traffic sign and a pedestrian. The two images 3 subsequently output in high resolution each comprise one of the two regions of interest of the image 5. In this way, a reliable evaluation of the target objects is achieved. In FIG. 5, the image areas of interest 5 are represented free of overlapping. However, it can e.g. likewise be provided that the image areas of interest 5 are arranged in an overlapping manner and, consequently, the two successive images, at least two images 3, output in high resolution has an overlapping range.

[0066] The duration of the image evaluation should not exceed the specified time interval of the processing cycle 6, in order to ensure an early execution of the at least one driver assistance function. Against this background, the images 3 output in high resolution within the processing cycle 6 preferably jointly have at least approximately the same number of pixels as the image 4 output in a resolution-reduced manner. Thus, e.g. one of the images 3 output in high resolution comprises 0.5 megapixels and the second of the images output in high resolution comprises 1.5 megapixels, consequently making a total of 2 megapixels and, as a consequence, these correspond to the number of pixels indicated by way of example of the resolution-reduced image 4 of 2 megapixels. In this way, a constant utilization of the image evaluation apparatus is ensured.

[0067] In FIG. 6, the resolution curve is plotted, by way of example, by means of the horizontal viewing angle of an image captured by the camera device 2 according to the invention. In this embodiment example, the optoelectronics comprise a high-resolution image capturing sensor having 7.23 megapixels in 16:9 format and an anamorphic wide-angle optical system with a horizontal viewing angle of +/50 degrees. The resolution in the central image portion 9 is raised, compared to a linear wide-angle optical system, at least in sections, by means of the anamorphic wide-angle optical system, so that an even more extensive capturing of far-range target objects is made possible. The central image portion 9 in this example has a higher resolution than in the peripheral image portion 10.

LIST OF REFERENCE NUMERALS

[0068] 1 Vehicle [0069] 2 Camera device [0070] 3 High-resolution image [0071] 4 Resolution-reduced image [0072] 5 Image area of interest [0073] 6 Processing cycle [0074] 7 Captured image sequence [0075] 8 Output image sequence [0076] 9 Central image portion [0077] 10 Peripheral image portion [0078] Horizontal viewing angle