Three-dimensional object detection device

Patent metadata

Field	Value
Publication number	US-9349057-B2
Application number	US-201214235132-A
Country	US
Kind code	B2
Filing date	Jul 27, 2012
Priority date	Sep 12, 2011
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A three-dimensional object detection device basically includes a three-dimensional object detection unit, a natural object assessment unit and a control unit. The three-dimensional object detection unit detects three-dimensional objects based on image information of a rear of a vehicle from a camera. The natural object assessment unit assesses that a detected three-dimensional object is a natural object, such as a plant or snow, based on an irregularity evaluation value calculated based on a first pixel number of first pixels representing a first predetermined differential in the differential image containing the detected three-dimensional object and a second pixel number of second pixels corresponding to the three-dimensional object and representing a second predetermined differential greater than the first predetermined differential.

First claim

The invention claimed is:

1. A three-dimensional object detection device comprising:
an imaging unit configured to be installed on a vehicle to capture images of a region at a rear of the vehicle;
an image conversion unit configured to convert a viewpoint of the images obtained by the imaging unit to bird's-eye view images;
a differential waveform information creating unit configured to create differential waveform information by positionally aligning the bird's-eye view images of different times obtained by the image conversion unit within a bird's-eye view, the differential waveform information creating unit being further configured to create a frequency distribution of a number of pixels by counting the number of pixels representing a predetermined differential in a differential image of the bird's-eye view images that were positionally aligned;
a three-dimensional object detection unit configured to detect three-dimensional objects which are included in the differential waveform information and which are present in detection areas set in left and right rear sides of the vehicle, based on the frequency distribution of the number of pixels representing the predetermined differential in the differential image along a direction in which the three-dimensional object falls when the bird's-eye view images are viewpoint-converted; and
a natural object assessment unit programmed to calculate an irregularity evaluation value for evaluating an irregularity of the differential waveform information based on a first pixel number of first pixels representing a first predetermined differential in the differential image containing the detected three-dimensional object that was detected, and a second pixel number of second pixels that have been extracted along the direction in which the three-dimensional object falls when the bird's-eye view images are viewpoint-converted and that represent a second predetermined differential greater than the first predetermined differential in the differential image, and the natural object assessment unit configured to assess that the three-dimensional object detected by the three-dimensional object detection unit is a natural object including plants or snow present along a lane traveled by the vehicle when the calculated irregularity evaluation value is equal to or greater than a predetermined irregularity evaluation threshold set in advance.

2. A three-dimensional object detection device comprising:
an imaging unit configured to be installed on a vehicle to capture images of a region at a of the vehicle;
an image conversion unit configured to convert a viewpoint of the images obtained by the imaging unit to bird's-eye view images;
an edge information creating unit configured to create edge information by extracting pixels in which a luminance difference of adjacent image areas is equal to or greater than a predetermined threshold in the bird's-eye view images obtained by the image conversion unit;
a three-dimensional object detection unit configured to detect three-dimensional objects which are included in the edge information and which are present in detection areas set in left and right rear sides of the vehicle, based on the edge information including the pixels that are extracted along the direction in which the three-dimensional object falls when the bird's-eye view image is viewpoint-converted and that have a luminance difference of adjacent image areas equal to or greater than the predetermined threshold; and
a natural object assessment unit programmed to calculate an irregularity evaluation value for evaluating an irregularity of the edge information based on a first pixel number of first pixels in which the luminance difference of the adjacent image areas in the bird's-eye images containing the three-dimensional object that was detected is equal to or greater than a first predetermined threshold, and a second pixel number of second pixels that have been extracted along the direction in which the three-dimensional object falls when the bird's-eye view images are viewpoint-converted and in which the luminance difference of adjacent image areas in the bird's-eye images is equal to or greater than a second predetermined threshold greater than the first predetermined threshold, and the natural object assessment unit configured to assess that the three-dimensional object detected by the three-dimensional object detection unit is a natural object including plants or snow present along a lane traveled by the vehicle when the calculated irregularity evaluation value is equal to or greater than a predetermined irregularity evaluation threshold set in advance.

3. The three-dimensional object detection device according to claim 1 , wherein
the natural object assessment unit is further programmed to:
calculate a third pixel number by subtracting the second pixel number from the first pixel number; and
assess that the irregularity evaluation value is equal to or greater than the predetermined irregularity evaluation threshold when the second pixel number is less than a first predetermined value and the third pixel number is equal to or greater than a second predetermined value.

4. The three-dimensional object detection device according to claim 1 , wherein
the natural object assessment unit is further programmed to:
calculate a third pixel number by subtracting the second pixel number from the first pixel number; and
assess that the irregularity evaluation value is equal to or greater than the predetermined irregularity evaluation threshold when the value of subtracting the second pixel number from the third pixel number is equal to or greater than a third predetermined value.

5. The three-dimensional object detection device according to claim 1 , wherein
the natural object assessment unit is further programmed to:
calculate a third pixel number by subtracting the second pixel number from the first pixel number;
calculate an abundance rate of the third pixel number relative to the first pixel number or the second pixel number; and
assess that the irregularity evaluation value is equal to or greater than the predetermined irregularity evaluation threshold when the abundance rate of the third pixel number relative to either the first pixel number or the second pixel number is equal to or greater than a predetermined rate.

6. The three-dimensional object detection device according to claim 1 , wherein
the natural object assessment unit is further programmed to:
designate, as second pixels, pixels that are extracted along the direction in which the three-dimensional object falls when the bird's-eye view images are viewpoint-converted, and that, among pixels representing the second predetermined differential, constitute a pixel group aligned in at least a predetermined density, and
find the number of these second pixels as the second pixel number.

7. The three-dimensional object detection device according to claim 2 , wherein
the natural object assessment unit is further programmed to:
designate, as second pixels, pixels that are extracted along the direction in which the three-dimensional object falls when the bird's-eye view image is viewpoint-converted, and that, among pixels in which the luminance difference of adjacent image areas in the bird's-eye images are equal to or greater than a second predetermined threshold, constitute a pixel group aligned in at least a predetermined density, and
find the number of these second pixels as the second pixel number.

8. The three-dimensional object detection device according to claim 1 , further comprising:
a three-dimensional object assessment unit programmed to assess whether or not the three-dimensional object detected by the three-dimensional object detection unit is anoth

Assignees

• Tsuchiya Chikao
• Hayakawa Yasuhisa
• Tanaka Shinya
• Fukata Osamu
• Nissan Motor

Inventors

• Tsuchiya Chikao
• Hayakawa Yasuhisa
• Tanaka Shinya
• Fukata Osamu

Classifications

• G08G1/167

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

• B60R2300/8066

  for monitoring rearward traffic · CPC title

• B60R2300/8093

  for obstacle warning · CPC title

• B60R1/00

  Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles · CPC title

• G08G1/166

  for active traffic, e.g. moving vehicles, pedestrians, bikes · CPC title