Onboard environment recognition device
An onboard environment recognition device is obtained with which it is possible to improve recognition performance within the headlight illumination range and outside the headlight illumination range of a vehicle with an onboard camera. This onboard environment recognition device has: an imaging unit 100 for imaging, using a camera installed in the vehicle, at a wider-angle range than the headlight illumination range; an in-illumination/out-of-illumination exposure adjustment unit for setting appropriate exposure conditions separately within the headlight illumination range and outside the headlight illumination range; and a recognition unit 500 for recognizing images on the basis of the acquired images. Therefore, it is possible to maintain high recognition performance in the boundary regions of the headlight illumination range, and outside the range, and the present invention can also be used for wide-angle sensing at night.
1. An onboard environment recognition device comprising:
an onboard camera that captures an image in front of a subject vehicle, the onboard camera including a first imaging range based on a headlight illumination range of the subject vehicle and a second imaging range wider in a horizontal direction than the headlight illumination range of the subject vehicle, and the captured image being imaged by adjusting brightness between a first image of an in-illumination region obtained by imaging the first imaging range and a second image of an out-of-illumination region obtained by imaging the second imaging range;
software code stored on a non-transitory computer readable medium, the software code;
selects exposure conditions and sets the selected exposure conditions at successive shutter timings of the onboard camera to acquire the first image of the in-illumination region,
wherein the exposure conditions include at least shutter speed and gain,
uses an image within a headlight light distribution pattern as the first image of the in-illumination region and the image within the headlight light distribution pattern is selected so that when the selected exposure conditions are applied the first image is observed,
changes exposure conditions of the image within the headlight light distribution pattern to match the selected exposure conditions so a luminance average in the in-illumination region is within a specific range to obtain the first image,
selects different exposure conditions and sets the selected different exposure conditions at successive shutter timings of one camera to acquire the second image of the out-of-illumination region,
wherein the different exposure conditions include at least shutter speed and gain,
uses an image outside the headlight light distribution pattern as the second image of the out-of-illumination region and the image outside the headlight light distribution pattern is selected so that when the selected different exposure conditions are applied the second image is observed, and
changes exposure conditions of the image outside the headlight light distribution pattern to match the selected different exposure conditions so a luminance average in the out-of-illumination region is within an other specific range to obtain the second image, and
determines an ambient environment using the captured image from the onboard camera.
2. The onboard environment recognition device according to claim 1 , wherein
the software code sets exposure frames in the in-illumination region and the out-of-illumination region of the captured image, respectively, acquires luminance information in the set exposure frames, and sets the selected exposure conditions which include the adjusted brightness of the in-illumination region and the out-of-illumination region.
3. The onboard environment recognition device according to claim 1 , wherein
the onboard camera is a stereo camera,
the software code sets the in-illumination region and the out-of-illumination region using an image of a first camera included in the stereo camera, and
when stereo matching by horizontal search is performed while calculating a correlation with a local rectangular region of an image of a second camera using a local rectangular region of the image of the first camera as a reference image, it is guaranteed that the local rectangular region of the first camera and the horizontally-searched local rectangular region of the second camera are under a same exposure condition,
wherein the first camera and the second camera are any one of a left camera and a right camera included in the stereo camera as a base.
4. The onboard environment recognition device according to claim 3 , wherein
a plurality of images with two or more exposure conditions are acquired in each of the in-illumination region and the out-of-illumination region by the left camera and right camera,
a disparity image is generated using images with a same exposure condition,
disparity information is acquired from images with different exposure conditions at a same location of the captured image are held, and
the disparity information is prioritized based on at least one of a headlight light distribution pattern and the headlight illumination range.
5. The onboard environment recognition device according to claim 1 , wherein
a plurality of images with two or more exposure conditions in the in-illumination region and the out-of-illumination region are separately imaged at different shutter timings within a certain fixed period.
6. The onboard environment recognition device according to claim 1 , wherein
two or more exposure conditions are applied to each of the in-illumination region and the out-of-illumination region to perform imaging.
7. The onboard environment recognition device according to claim 1 , wherein
the first image and the second image are acquired with respect to the captured image using a gain table.
8. The onboard environment recognition device according to claim 1 , wherein
a group of images captured consecutively are used to integrate a plurality of images and reduce noise in the out-of-illumination region.