Distance-measuring optical apparatus, distance-measuring method, distance-measuring system, in-vehicle imager, and in-vehicle driving support apparatus

• US 7,283,211 B2
• Filed: 07/29/2005
• Issued: 10/16/2007
• Est. Priority Date: 07/30/2004
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamamoto, Yoshiharu, Yoshikawa, Motonobu, Matsuki, Daizaburo
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): BRAINARD, TIMOTHY A
• Application Number:
  US11/192,406
• Publication Number:
  US 20060023200A1
• Time in Patent Office: 809 Days
• Field of Search: 356/4.03
• US Class Current: 356/4.03
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors

Abstract

A distance-measuring optical apparatus for measuring a distance to an object as a target comprises an imaging optical system; an image sensor; a driving section for moving at least the imaging optical system substantially perpendicular to an optical axis; an image sensor control section for outputting a periodical timing signal for designating a timing at which the image sensor takes an object image; and a driving control section for controlling the driving section to reciprocate the imaging optical system. The timing signal is periodically output when the imaging optical system is located near two positions away from each other in a direction substantially perpendicular to the optical axis. The distance-measuring optical apparatus further comprises an image processing operation section for finding, through an operation, a distance from the imaging optical system to the object using the image signal when the imaging optical system is at each of the two positions.

Claims

1. A distance-measuring optical apparatus for measuring a distance to an object as a target, comprising:

an imaging optical system for forming an image of the object;

an image sensor for taking the image of the object formed by the imaging optical system, converting the image into an image signal, and outputting the image signal;

a driving section for moving at least the imaging optical system substantially perpendicular to an optical axis;

an image sensor control section for outputting a periodical timing signal for designating a timing at which the image sensor takes the image of the object; and

a driving control section for controlling the driving section such that the imaging optical system reciprocates at a predetermined cycle between two positions which are away from each other in a direction substantially perpendicular to the optical axis;

wherein;

the periodical timing signal is periodically output when the imaging optical system driven by the driving section is located in the vicinity of the two positions which are away from each other in a direction substantially perpendicular to the optical axis; and

the distance-measuring optical apparatus further comprises an image processing operation section for receiving the image signal from the image sensor and performing an operation to obtain the distance from the imaging optical system to the object, using the image signal converted when the imaging optical system is at each of the two positions which are away from each other in a direction substantially perpendicular to the optical axis.

2. A distance-measuring optical apparatus according to claim 1, wherein the driving section moves the imaging optical system in one direction with respect to the optical axis.

3. A distance-measuring optical apparatus according to claim 2, wherein δ

1≧

P/|m−

m′

| where m is the image forming magnification of an object located at a shortest imaging distance of the imaging optical system, m′

the image forming magnification of an object which is away from the object at the shortest imaging distance by a distance-measuring resolvable distance, P is the pixel pitch of the image sensor, and δ

1 is the distance by which the imaging optical system is moved in one direction substantially perpendicular to the optical axis.

4. A distance-measuring optical apparatus according to claim 1, wherein the driving section moves the imaging optical system in two directions with respect to the optical axis.

5. A distance-measuring optical apparatus according to claim 4, wherein δ

2≧

P/(|2m−

m′

|) where m is the image forming magnification of an object located at a shortest imaging distance of the imaging optical system, m′

the image forming magnification of an object which is away from the object at the shortest imaging distance by a distance-measuring resolvable distance, P is the pixel pitch of the image sensor, and δ

2 is the distance by which the imaging optical system is moved in each of the two directions substantially perpendicular to the optical axis.

6. A distance-measuring optical apparatus according to claim 1, wherein the driving section moves the imaging optical system and the image sensor substantially perpendicular to the optical axis.

7. A distance-measuring optical apparatus according to claim 1, wherein the driving section moves only the imaging optical system substantially perpendicular to the optical axis.

17. An in-vehicle imager including a distance-measuring optical apparatus according to any one of claims 1 through 6.

8. A distance-measuring method for measuring a distance to an object as a target, wherein the distance-measuring method uses an imaging optical system for forming an image of the object;

an image sensor for taking the image of the object formed by the imaging optical system, converting the image into an image signal, and outputting the image signal; and

a driving section for moving at least the imaging optical system substantially perpendicular to an optical axis, the distance-measuring method comprising the steps of;

reciprocating the imaging optical system at a predetermined cycle between two positions which are away from each other in a direction substantially perpendicular to the optical axis; and

performing an operation to obtain a distance from the imaging optical system to the object, using the image signal converted by the image sensor when the imaging optical system is at each of the two positions which are away from each other in a direction substantially perpendicular to the optical axis.

9. A distance-measuring system for measuring a distance to an object as a target, generating information which is to be recognized by an operator in accordance with the measured distance and presenting the information to the operator, the distance-measuring system comprising:

a distance-measuring optical apparatus for measuring the distance to the object; and

a presentation section for generating information which is to be recognized by the operator in accordance with the distance measured by the distance-measuring optical apparatus and presenting the information to the operator;

wherein the distance-measuring optical apparatus includes;

an imaging optical system for forming an image of the object;

an image sensor for taking the image of the object formed by the imaging optical system, converting the image into an image signal, and outputting the image signal;

a driving section for moving at least the imaging optical system substantially perpendicular to an optical axis;

an image sensor control section for outputting a periodical timing signal for designating a timing at which the image sensor takes the image of the object; and

a driving control section for controlling the driving section such that the imaging optical system reciprocates at a predetermined cycle between two positions which are away from each other in a direction substantially perpendicular to the optical axis;

wherein;

the periodical timing signal is periodically output when the imaging optical system driven by the driving section is located in the vicinity of the two positions which are away from each other in a direction substantially perpendicular to the optical axis; and

the distance-measuring optical apparatus further comprises an image processing operation section for receiving the image signal from the image sensor and performing an operation to obtain the distance from the imaging optical system to the object, using the image signal converted when the imaging optical system is at each of the two positions which are away from each other in a direction substantially perpendicular to the optical axis.

10. A distance-measuring system according to claim 9, wherein the information to be recognized by the operator is information on a result of comparison of the distance measured by the distance-measuring optical apparatus and a predetermined distance value.

11. A distance-measuring system according to claim 9, wherein the presentation section includes one of a display device for displaying the information as an image signal;

a light emitting device for transmitting the information as an optical signal, an illumination device for transmitting the information as an optical signal;

a sound generator for transmitting the information as an audio signal; and

a vibration generation device for transmitting the information as sense-of-touch information by vibrating a component operated by the operator.

12. A distance-measuring system according to claim 9, wherein the presentation section includes a display device for displaying the information as an image signal, and the display device is capable of displaying the image signal obtained by the image sensor as a visible image.

13. A distance-measuring system according to claim 12, wherein the presentation section includes:

a display device for displaying the information as an image signal; and

an image processing device for replacing an image signal converted by the image sensor in a period in which the imaging optical system is moving substantially perpendicular to the optical axis with an image signal obtained by the image sensor before the imaging optical system is moved.

14. A distance-measuring system according to claim 12, wherein the presentation section includes:

a display device for displaying the information as an image signal; and

an image processing device for replacing an image signal converted by the image sensor in a period in which the imaging optical system is moving substantially perpendicular to the optical axis with an image signal generated by motion prediction based on an image signal obtained by the image sensor before the imaging optical system is moved.

15. A distance-measuring system according to claim 13 or 14, wherein the image processing device displays an image of an object with a short imaging distance in the state of being surrounded by a frame of a highly recognizable color.

16. A distance-measuring system according to claim 13 or 14, wherein the image processing device displays an image of an object with a short imaging distance in the state where the color thereof is converted into a highly recognizable color.

18. An in-vehicle driving support apparatus including a distance-measuring optical system according to any one of claims 9 through 14.