Estimating apparatus

Patent metadata

Field	Value
Publication number	US-10691959-B2
Application number	US-201815871712-A
Country	US
Kind code	B2
Filing date	Jan 15, 2018
Priority date	Jan 16, 2017
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

In a travelling road estimating apparatus, an estimator estimates, based on the coordinates of at least one of edge points included in a selected candidate, a road parameter using a previously prepared filter having an adjustable response level. The road parameter is associated with a condition of the travelling road relative to the vehicle and a shape of the travelling road. A determiner determines whether there is an unstable situation that causes an accuracy of estimating the edge points by an edge extractor to be reduced. A response level adjuster adjusts the response level of the filter in accordance with determination of whether there is an unstable situation that causes an accuracy of estimating the edge points by the edge extractor to be reduced.

First claim

What is claimed is:

1. A travelling road estimating apparatus comprising:
an edge extractor configured to:
extract edge points from an image of a travelling road ahead of a vehicle captured by an image capturing unit of the vehicle; and
calculate coordinates of each of the edge points, each of the edge points representing an extracted pixel of the image, the extracted pixel having a luminance level higher by at least a predetermined threshold level than a luminance level of at least one of pixels of the image adjacent to the extracted pixel;

a candidate extractor configured to extract, based on the coordinates of each of the edge points, at least one line candidate that is a candidate of a lane marking line of the travelling road;
a selector configured to select the at least one line candidate as a selected candidate;
an estimator configured to estimate, based on the coordinates of at least one of the edge points included in the selected candidate, a road parameter using a previously prepared filter having an adjustable response level, the road parameter being associated with a condition of the travelling road relative to the vehicle and a shape of the travelling road;
a determiner configured to determine whether there is an unstable situation that causes an accuracy of estimating the edge points by the edge extractor to be reduced;
a response level adjuster configured to adjust the response level of the filter in accordance with determination of whether there is an unstable situation that causes an accuracy of estimating the edge points by the edge extractor to be reduced; and
a reliability calculator configured to calculate a reliability of the at least one line candidate selected as the selected candidate, the reliability of the selected candidate taking a value being higher as the selected candidate is more similar to the lane marking line,
wherein the determiner is configured to:
determine whether the calculated reliability is lower than a predetermined reliability threshold; and
determine that there is the unstable situation upon determination that the calculated reliability is lower than the predetermined reliability threshold.

2. The travelling road estimating apparatus according to claim 1 , wherein:
the reliability calculator is configured to:
set the reliability of the selected candidate to be higher with an increase of at least one of a first contrast and a second contrast,

the first contrast being a contrast ratio of a luminance level of a line identified from the selected candidate to an averaged luminance level of a road-surface portion of the image,
the second contrast being a contrast ratio of a color of the line identified from the selected candidate to an averaged color of the road-surface portion of the image.

3. The travelling road estimating apparatus according to claim 1 , wherein:
the reliability calculator is configured to:
set the reliability of the selected candidate to be higher with a decrease of at least one of a first contrast and a second contrast,

the first contrast being a contrast ratio of a luminance level of a road-surface portion of the image at a boundary of a line identified from the selected candidate to an averaged luminance level of the road-surface portion of the image,
the second contrast being a contrast ratio of a color of the road-surface portion of the image at the boundary of the line identified from the selected candidate to an averaged color of the road-surface portion of the image.

4. The travelling road estimating apparatus according to claim 1 , wherein:
the at least one line candidate extracted by the candidate extractor comprises a plurality of line candidates;
the reliability calculator is configured to calculate the reliability of each of the line candidates, at least one of the line candidates being selected as the selected candidate; and
the determiner is configured to:
determine whether there is at least one low-reliability line candidate in the line candidates within an allowable range defined around the selected candidate, the reliability of the at least one low-reliability line candidate being lower than a predetermined threshold; and
determine that there is the unstable situation upon determination that there is at least low-reliability candidate in the line candidates within the allowable range defined around the selected candidate.

5. The travelling road estimating apparatus according to claim 1 , further comprising:
a feature generator configured to generate an item of feature information indicative of a feature of a line identified from the selected candidate,
wherein the determiner is configured to:
determine whether the generated item of the feature information is outside a predetermined acceptable range; and
determine that there is the unstable situation upon determination that the generated item of the feature information is outside a predetermined acceptable range.

6. The travelling road estimating apparatus according to claim 5 , wherein:
the feature generator is configured to, if the line identified from the selected candidate is comprised of a plurality of line segments, generate, as the item of the feature information, an item of the feature information for each of the line segments, the feature generator being configured to calculate an average and a variation of the generated line segments; and
the determiner is configured to:
determine whether at least one of the calculated average and the variation is equal to or more than a corresponding at least one feature threshold; and
determine that there is the unstable situation upon determination that the at least one of the calculated average and the variation is equal to or more than the corresponding at least one feature threshold.

7. The travelling road estimating apparatus according to claim 6 , wherein:
the line identified from the selected candidate is a dashed line comprised of the plurality of line segments; and
the feature generator is configured to generate, as the item of the feature information for each of the line segments, at least one of:
a longitudinal length of the corresponding one of the line segments; and
a length of each of intervals between the respective plurality of line segments.

8. The travelling road estimating apparatus according to claim 5 , wherein:
the image is captured by the camera every predetermined processing cycle;
the feature generator is configured to:
generate the item of the feature information every predetermined processing cycle, the item of the feature information generated for a first processing cycle in the processing cycles being referred to as a first item, the item of the feature information generated for a second processing cycle in the processing cycles being referred to as a second item, the second processing cycle being next to the first processing cycle; and
calculate an absolute value of a deviation of the second item of the feature information from the first item of the feature information; and

the determiner is configured to:
determine whether the absolute value of the deviation of the second item of the feature information from the first item of the feature information is equal to or more than a predetermined sudden-change threshold; and
determine that there is the unstable situation upon determination that the absolute value of the deviation of the second item of the feature information from the first item of the feature information is equal to or more than the predetermined sudden-change threshold.

9. The travelling road estimating apparatus according to claim 8 , wherein:
the feature generator is configured to generate, as the item of the feature information every predetermined pro

Assignees

• Soken Inc
• Denso Corp

Inventors

• Kumano Shunya
• Suzuki Shunsuke
• Hoki Kenta

Classifications

• G06V20/588

  Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road · CPC title

• G08G1/167 Primary

  Driving aids for lane monitoring, lane changing, e.g. blind spot detection · CPC title

• G06V10/44

  Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components · CPC title

• G06T2207/10024

  Color image · CPC title

• G06T2207/10016

  Video; Image sequence · CPC title