Apparatus for measuring distance

• US 10,338,211 B2
• Filed: 11/22/2017
• Issued: 07/02/2019
• Est. Priority Date: 11/24/2016
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shirai, Noriaki
• Primary Examiner(s): Lee, Jonathan S
• Application Number:
  US15/821,145
• Publication Number:
  US 20180143315A1
• Time in Patent Office: 587 Days
• Field of Search: 382106
• CPC Class Codes: G01S 13/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9323 Alternative operation using light waves
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/30261 Obstacle
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes
• CPC Class Codes: H04N 13/128 Adjusting depth or disparity
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

The distance measuring device detects parallax between right and left captured images where a front object is present ahead of the own vehicle, and calculate a parallax distance between the front object and the own vehicle. The radar device detects a radar detected distance therebetween. The distance measuring device calculates a parallax error based on the difference between the parallax calculated distance and the radar detected distance. A correction region is set in the right captured image and divided into correction divided regions. The distance measuring device sets an individual correction parallax for every correction divided regions, based on the parallax error and the identified correction divided regions.

Claims

1. A distance measuring device comprising:

an image acquiring unit installed in a vehicle cabin of a vehicle, acquiring a plurality of images which are simultaneously captured from mutually different view points via a windshield of the vehicle, to include a common imaging region ahead of the vehicle which are shared by the plurality of images;

a parallax detection unit that detects a parallax between the plurality of images as a detected parallax, in response to a front object, as an object present ahead of the vehicle, being captured in the plurality of images, based on positions where the front object is captured in respective images;

a distance calculation unit that calculates distance between the front object and the vehicle as a parallax calculated distance based on the detected parallax;

a distance detection unit mounted on the vehicle, transmitting/receiving electromagnetic waves to detect distance between the front object and the vehicle as electromagnetic waves detected distance;

an error calculation unit that calculates a parallax error which is an error of the parallax detected by the parallax detection unit, the parallax error being calculated based on a difference between the parallax calculated distance calculated by the distance calculation unit and the electromagnetic waves detected distance detected by the distance detection unit;

a first region identifying unit that identifies a correction divided region where the front object corresponding to the parallax error calculated by the error calculation unit is captured, the correction divided region being divided from a correction region which is set in the imaging region of at least one of the plurality of images, the correction region being constituted of a plurality of pixels to correct a parallax;

an individual correction setting unit that sets an individual correction parallax for each of the correction divided regions, based on the parallax error calculated by the error calculation unit and the correction divided region identified by the first region identifying unit, the individual correction parallax being used for correcting the parallax calculated distance which is calculated based on the detected parallax;

a second region identifying unit that identifies the correction divided region where the front object corresponding to the detected parallax is captured;

a corrected distance calculation unit that calculates a distance between the front object and the vehicle as a corrected distance, based on the detected parallax and the individual correction parallax identified by the second region identifying unit.

2. The distance measuring device according to claim 1, wherein

the distance measuring device includes an overall correction setting unit that sets an overall correction parallax used for correcting the parallax calculated distance calculated based on the detected parallax in an overall area of the correction region, in accordance with the parallax error calculated by the error calculation unit and the correction divided region identified by the first region identifying unit.

3. The distance measuring device according to claim 1, wherein

the distance measuring device includes an interpolation unit that performs an interpolation for a correction divided region where no individual correction parallax is set by the individual correction setting unit, based on the individual correction parallax which is set in the correction divided region by the individual correction setting unit, thereby setting the individual correction parallax in the correction divided region where no individual correction parallax is set.

4. The distance measuring device according to claim 1, wherein the error calculation unit inhibits calculation of the parallax error in response to a predetermined calculation inhibit condition being satisfied, the predetermined calculation condition indicating a large parallax error which is calculated by the error calculation unit based on a difference between the parallax calculated distance and the electromagnetic waves detected distance.