Three-dimensional structure estimation apparatus

• US 6,847,392 B1
• Filed: 10/31/1997
• Issued: 01/25/2005
• Est. Priority Date: 10/31/1996
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: House, Gregory
• Primary Examiner(s): An, Shawn S.
• Application Number:
  US08/962,315
• Time in Patent Office: 2,643 Days
• Field of Search: 348/36, 348/39, 348/42, 348/47, 348/61, 348/135, 348139-140, 356/3, 356/3.13, 356/3.14, 356/3.15, 356/3.16, 356/4.01, 356/4.03, 356/9, 356/12, 356/13, 382/104, 382/106, 382/154
• US Class Current: 348/36
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: H04N 13/25 using two or more image sensors with different characteristics other than in their location or field of view, e.g. having different resolutions or colour pickup characteristics; using image signals from one sensor to control the characteristics of another sensor

Abstract

A three-dimensional structure estimation apparatus by which an image of a wide visual field and another image which has a high resolution at part of the visual field are provided and a high resolution three-dimensional structure of an object in the visual field can be estimated is disclosed. A wide visual field image and a narrow visual field image outputted from cameras which have a wide visual field cone and a narrow visual field cone of different visual fields and produce images of different resolutions are converted into images whose pixel units are equal in magnitude by a conversion section. The conversion section includes a sampling section which samples pixels of the narrow visual field image to produce a coincident pixel unit image which has a pixel unit coincident with that of the wide visual field image, and a depth image production section which receives and compares the wide visual field image and the coincident pixel unit image with each other to produce a depth image. Preferably, the sampling section produces a plurality of images of coincident pixels by successively displacing sampling positions little by little so that the depth distance can be estimated with a higher degree of accuracy.

Claims

1. A method for measuring a distance to an object, comprising:

producing a first image of the object using a first camera;

producing a second image of the object using a second camera spaced apart from the first camera along a common baseline and having a different viewing angle than the first camera, the second camera having a resolution that is greater than the resolution of the first camera such that pixel units of the image produced by the first camera represent a greater amount of the object than pixel units of the image produced by the second camera;

producing a set of sampled images, each of the sampled images being produced by sampling pixels of the second image at given intervals beginning at respective different locations in the second image for each sampled image;

calculating a set of distances to the object corresponding to the set of sampled images, each distance being calculated based on the positions of the cameras on the common baseline, the directions of the first and second cameras with respect to the common baseline, and the locations of a common point on the object in the first image and the respective sampled image;

calculating a set of indexes, each respective index being representative of the degree of appropriateness of a distance corresponding to one of the sampled images; and

selecting one of the respective distances to the object based on the index associated with its corresponding sampled image.

2. The method claimed in claim 1, wherein the second image is interpolated prior to producing the set of sampled images.

3. The method claimed in claim 1, wherein the index corresponding to a sampled image represents the difference between a pixel value of the sampled image and a pixel value at a corresponding pixel of the first image.

4. A method for measuring a distance to an object, comprising:

producing a first image of the object using a first camera;

producing a second image of the object using a second camera spaced apart from the first camera along a common baseline and having a different viewing angle than the first camera, the second camera having a field of view that is less than the field of view of the first camera such that pixel units of the image produced by the first camera represent a greater amount of the object than pixel units of the image produced by the second camera;

producing a set of sampled images, each of the sampled images being produced by sampling pixels of the second image at given intervals beginning at respective different locations in the second image for each sampled image;

calculating a set of distances to the object corresponding to the set of sampled images, each distance being calculated based on the positions of the cameras on the common baseline, the directions of the first and second cameras with respect to the common baseline, and the locations of a common point on the object in the first image and the respective sampled image;

calculating a set of indexes, each respective index being representative of the degree of appropriateness of a distance corresponding to one of the sampled images; and

selecting one of the respective distances to the object based on the index associated with its corresponding sampled image.

5. The method claimed in claim 4, wherein the second image is interpolated prior to producing the set of sampled images.

6. The method claimed in claim 4, wherein the index corresponding to a sampled image represents the difference between a pixel value of the sampled image and a pixel value at a corresponding pixel of the first image.

7. An apparatus for measuring a distance to an object, comprising:

a first camera for producing a first image of the object;

a second camera for producing a second image of the object, the second camera being spaced apart from the first camera along a common baseline and having a different viewing angle than the first camera, the second camera having a resolution that is greater than the resolution of the first camera such that pixel units of the image produced by the first camera represent a greater amount of the object than pixel units of the image produced by the second camera; and

a data processing section performing processing comprising;

producing a set of sampled images, each of the sampled images being produced by sampling pixels of the second image at given intervals beginning at respective different locations in the second image for each sampled image;

calculating a set of distances to the object corresponding to the set of sampled images, each distance being calculated based on the positions of the cameras on the common baseline, the directions of the first and second cameras with respect to the common baseline, and the locations of a common point on the object in the first image and the respective sampled image;

calculating a set of indexes, each respective index being representative of the degree of appropriateness of a distance corresponding to one of the sampled images; and

selecting one of the respective distances to the object based on the index associated with its corresponding sampled image.

8. The apparatus claimed in claim 7, wherein the second image is interpolated prior to producing the set of sampled images.

9. The apparatus claimed in claim 7, wherein the index corresponding to a sampled image represents the difference between a pixel value of the sampled image and a pixel value at a corresponding pixel of the first image.

10. An apparatus for measuring a distance to an object, comprising:

a first camera producing a first image of the object;

a second camera producing a second image of the object, the second camera being spaced apart from the first camera along a common baseline and having a different viewing angle than the first camera, the second camera having a field of view that is less than the field of view of the first camera such that pixel units of the image produced by the first camera represent a greater amount of the object than pixel units of the image produced by the second camera; and

a data processing section performing processing comprising;

producing a set of sampled images, each of the sampled images being produced by sampling pixels of the second image at given intervals beginning at respective different locations in the second image for each sampled image;

calculating a set of distances to the object corresponding to the set of sampled images, each distance being calculated based on the positions of the cameras on the common baseline, the directions of the first and second cameras with respect to the common baseline, and the locations of a common point on the object in the first image and the respective sampled image;

calculating a set of indexes, each respective index being representative of the degree of appropriateness of a distance corresponding to one of the sampled images; and

selecting one of the respective distances to the object based on the index associated with its corresponding sampled image.

11. The apparatus claimed in claim 10, wherein the second image is interpolated prior to producing the set of sampled images.

12. The apparatus claimed in claim 10, wherein the index corresponding to a sampled image represents the difference between a pixel value of the sampled image and a pixel value at a corresponding pixel of the first image.