Distance measuring apparatus and distance measuring method

Patent metadata

Field	Value
Publication number	US-9451213-B2
Application number	US-201013498659-A
Country	US
Kind code	B2
Filing date	Jul 23, 2010
Priority date	Jul 23, 2010
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A distance measuring apparatus ( 11 ) optically detects a measuring target, thereby measuring an object distance, which is the distance to the measuring target. The orientation of an optical axis of a lens is set to be different from an advancing direction of light incident from the measuring target. The lens is configured to form an image from the incident light, thereby obtaining an image of the measuring target. The distance measuring apparatus includes an imaging relative quantity calculating means ( 31, 32 ) for obtaining an imaging position indicative of a position of the image with respect to the lens for each of a plurality of wavelengths possessed by the incident light, thereby calculating an imaging relative quantity, which is a quantity indicative of a relative relationship between the imaging positions; storage means ( 17 ) for storing correlation information ( 18 ), which is information determined by a chromatic aberration characteristic of the lens and the orientation of the optical axis in order to indicate a correlation between the imaging relative quantity and the object distance; and distance calculating means ( 33 ) for calculating the object distance by checking the imaging relative quantity against the correlation information ( 18 ).

First claim

The invention claimed is:

1. A distance measuring apparatus for measuring distance to a measuring target by optically detecting the measuring target, the apparatus comprising:
a lens, an optical axis of which has a different orientation from an advancing direction of light incident from the measuring target, the lens being configured to form an image from the incident light, thereby obtaining an image of the measuring target;
an imaging relative quantity calculator circuitry configured to calculate an imaging relative quantity by obtaining an imaging position indicative of the position of the image with respect to the lens for each of a plurality of wavelengths possessed by the incident light, the imaging relative quantity being a quantity indicative of a relative relationship between the imaging positions;
a storage configured to store correlation information, which is information determined by a chromatic aberration characteristic of the lens and the orientation of the optical axis in order to indicate a correlation between the imaging relative quantity and an object distance; and
a distance calculator circuitry configured to calculate the object distance by checking the imaging relative quantity against the correlation information,
the distance calculator circuitry is configured to measure the distance to the measuring target based on a relative relationship between the imaging positions for the respective wavelengths, wherein the light is refracted in a refractive index for each wavelength so that the imaging positions of the light are different from each other in a direction perpendicular to the advancing direction of the incident light for each wavelength, the object distance, which is the distance between the lens and the measuring target, is varied so that an incident angle of the light on the lens is made different, the object distance is varied so that an imaging position of light of a single wavelength is also changed,
the distance calculator circuitry is configured to obtain a difference between the imaging positions for the respective wavelengths based on the chromatic aberration by detecting the imaging positions for the respective wavelengths through a common lens by using light having a wavelength that is not subjected to the chromatic aberration correction for the measurement of the distance.

2. The distance measuring apparatus according to claim 1 , wherein
the light has two wavelengths, in which the imaging positions are different from each other, and
the correlation information constitutes map data, in which the imaging relative quantities are caused to correspond to the object distances, respectively.

3. The distance measuring apparatus according to claim 2 , wherein the imaging relative quantity is an imaging position difference, which is the difference between the imaging positions for the two wavelengths.

4. The distance measuring apparatus according to claim 2 , wherein the imaging relative quantity is an imaging position ratio, which is the ratio of the imaging positions for the two wavelengths.

5. The distance measuring apparatus according to claim 1 , wherein the optical axis of the lens is inclined with respect to the advancing direction of the incident light.

6. The distance measuring apparatus according to claim 1 , wherein a surface of the lens is non-rotationally symmetrical with respect to the optical axis of the lens.

7. The distance measuring apparatus according to claim 1 , wherein a refractive index of the lens is non-rotationally symmetrical with respect to the optical axis of the lens.

8. The distance measuring apparatus according to claim 1 , wherein the lens is a part of a spectrum sensor for detecting light transmitted from the measuring target.

9. A distance measuring method using a distance measuring apparatus for measuring distance to a measuring target by optically detecting the measuring target, the method comprising:
forming an image of the measuring target by means of a lens of the distance measuring apparatus having an optical axis in a different orientation from an advancing direction of light incident from the measuring target;
obtaining an imaging position indicative of the position of the image with respect to the lens for each of a plurality of wavelengths possessed by the incident light;
using an imaging relative quantity calculator circuitry of the distance measuring apparatus, calculating an imaging relative quantity, which is a quantity indicative of a relative relationship between the imaging positions;
using a distance calculator circuitry of the distance measuring apparatus, calculating an object distance by checking the imaging relative quantity against correlation information, which is information determined by the imaging relative quantity, a chromatic aberration characteristic of the lens, and the orientation of the optical axis in order to indicate a correlation between the imaging relative quantity and the object distance;
using the distance calculator circuitry, measuring the distance to the measuring target based on a relative relationship between the imaging positions for the respective wavelengths, wherein the light is refracted in a refractive index for each wavelength so that the imaging positions of the light are different from each other in a direction perpendicular to the advancing direction of the incident light for each wavelength, the object distance, which is the distance between the lens and the measuring target, is varied so that an incident angle of the light on the lens is made different, the object distance is varied so that an imaging position of light of a single wavelength is also changed; and
using the distance calculator circuitry, obtaining a difference between the imaging positions for the respective wavelengths based on the chromatic aberration by detecting the imaging positions for the respective wavelengths through a common lens by using light having a wavelength that is not subjected to the chromatic aberration correction for the measurement of the distance.

10. The distance measuring method according to claim 9 ,
wherein the incident light has two wavelengths,
the method further comprising:
by obtaining an imaging position, obtaining the imaging position for each of the two wavelengths; and
acquiring the correlation information from map data, which causes the imaging relative quantity to correspond to the object distance to calculate the object distance.

Assignees

• Kawamata Shinya
• Funayama Ryuji
• Satori Shin
• Aoyanagi Yoshihide
• Komatsuda Tadayoshi
• Toyota Motor Co Ltd

Inventors

• Kawamata Shinya
• Funayama Ryuji
• Satori Shin
• Aoyanagi Yoshihide
• Komatsuda Tadayoshi

Classifications

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• H04N7/18 Primary

  Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast · CPC title

• G01S11/12

  using electromagnetic waves other than radio waves · CPC title

• G01C3/08 Primary

  Use of electric radiation detectors · CPC title