Distance Calculator and Distance Calculation Method

• US 20150036886A1
• Filed: 02/06/2013
• Published: 02/05/2015
• Est. Priority Date: 03/09/2012
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Matono, Haruki, Mitoma, Hiroto
• Granted Patent: US 9,530,210 B2
• Time in Patent Office: Days
• US Class Current: 382/106
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01C 3/14 with binocular observation at a single point, e.g. stereoscopic type G01C3/20 takes precedence
• CPC Class Codes: G06T 7/529 from texture
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

In order to be able to measure a distance with disparity resolution of a stereo camera or less and precisely measure a relative distance to a target even in the event of degradation of the imaging condition, a distance calculator includes a monocular distance calculation section 203, a stereo distance calculation section 204, a blurriness level calculation section 201, a distance estimation section 202, and an output distance calculation section 206. The monocular distance calculation section 203 calculates the distance to a target based on image information captured by a camera 101 or 102. The stereo distance calculation section 204 calculates the distance to the target based on image information captured by the two cameras 101 and 102. The blurriness level calculation section 201 calculates the blurriness level of the image information captured by the image information captured by the cameras 101 and 102. The distance estimation section 202 estimates the distance to the target at the time of capturing of images by the cameras 101 and 102. The output distance calculation section 206 calculates the distance to the target to be output. The output distance calculation section 206 selects, as the distance to be output, the distance calculated by the monocular distance calculation section 203 or the distance calculated by the stereo distance calculation section 204 based on the blurriness level and the estimated distance.

Claims

1-5. -5. (canceled)

6. A distance calculator for an imaging system having a plurality of imaging devices, the distance calculator comprising:

a first distance calculation section adapted to calculate distance to a target based on image information captured by one of the plurality of imaging devices;

a second distance calculation section adapted to calculate distance to the target based on image information captured by at least two of the plurality of imaging devices;

a blurriness level calculation section adapted to calculate the blurriness level of the image information captured by the single imaging device and that of the image information captured by the at least two imaging devices;

a distance estimation section adapted to estimate distance to the target at the time of capturing of images by the single imaging device and the at least two imaging devices; and

an output distance calculation section adapted to calculate distance to the target to be output, wherein

the output distance calculation section selects either a first distance calculated by the first distance calculation section or a second distance calculated by the second distance calculation section as the distance to be output, the selection being based on the blurriness level calculated by the blurriness level calculation section and the estimated distance estimated by the distance estimation section.

7. The distance calculator of claim 6, wherein

the first distance calculation section calculates distance to the target based on the image information having the smallest blurriness level of the image information captured by the single imaging device and the image information captured by the at least two imaging devices.

8. The distance calculator of claim 6, wherein

the second distance calculation section has a plurality of distance calculation means adapted to calculate the distance to the target based on the image information captured by the at least two imaging devices.

9. The distance calculator of claim 8 further comprising:

a distance calculation selection section adapted to select one of the plurality of distance calculation means based on the blurriness level calculated by the blurriness level calculation section and the estimated distance estimated by the distance estimation section.

10. A distance calculation method of an imaging system having a plurality of imaging devices, the distance calculation method comprising:

calculating distance to a target based on image information captured by one of the plurality of imaging devices;

calculating distance to the target based on image information captured by at least two of the plurality of imaging devices;

calculating blurriness level of the image information captured by the single imaging device and that of the image information captured by the at least two imaging devices;

estimating distance to the target at the time of capturing of images by the single imaging device and the at least two imaging devices; and

selecting, as distance to the target to be output, one of the two calculated distances based on the blurriness level and the estimated distance.