Method and device for detecting three-dimensional information

• US 7,016,519 B1
• Filed: 10/15/1999
• Issued: 03/21/2006
• Est. Priority Date: 10/15/1998
• Status: Expired due to Fees

• Current Assignee: Nippon Hoso Kyokai
• Original Assignee: Nippon Hoso Kyokai
• Inventors: Iizuka, Keigo, Aida, Tahito, Kawakita, Masahiro, Nakamura, Haruhito
• Primary Examiner(s): Werner, Brian P.
• Application Number:
  US09/418,441
• Time in Patent Office: 2,349 Days
• Field of Search: 382/106, 382/154, 350/5.03, 350/5.04, 350/602, 350/610, 250/559.22, 250/559.23, 250/559.31, 250/559.38, 250/201.6
• US Class Current: 382/106
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01S 17/89 for mapping or imaging

Abstract

An image of an object illuminated by illumination light having given intensity is formed as an optical image. The distance between respective points of the object is determined on the basis of a video which is obtained by acquiring the optical image with a given image pick-up gain. Here, either the intensity of the illumination light or the image pick-up gain is changed with time. The distribution of intensity of the image acquired by utilization of such intensity or image pick-up gain reflects a time lag between the time at which the illumination light is emitted from a light source and the time at which the light reflected from individual points of the object reaches an image pick-up device. The distribution of intensity includes information pertaining to the distance between the light source and the respective points of the object.

Claims

1. A method of detecting three-dimensional information, comprising:

illuminating an object sequentially with, a first illumination light which has a linearly varying intensity and a second illumination light which has a constant intensity;

acquiring an image of the object illuminated by said two illumination lights such that a rate of change of an image pickup gain is faster than a rate of change of intensity of the first illumination light, wherein the image of the object is acquired at least two times, once during each illumination, and with a same pick-up gain during each illumination by an image pick-up element having storage effect; and

detecting a distance between individual points of the object on the basis of the image obtained;

wherein

the distance between respective points of the object is detected at a speed at which three-dimensional image is output in real time, the three-dimensional image being output within a period of time corresponding to one normal image frame of a video signal being received by an image pickup device.

2. The method of detecting three-dimensional information as defined in claim 1, wherein

a first and a second optical images of the object illuminated by the first and the second illumination light are formed;

the first and the second optical images are obtained alternately by acquiring the first and the second optical images with a single image pick-up gain over a given period of time;

the first and the second images obtained are stored; and

the distance between respective points of the objects are detected by each of the first and second images and are detected sequentially for each frame of the video signal.

3. A method of detecting three-dimensional information, comprising:

illuminating an object sequentially with a first illumination light which has a linearly varying intensity and a second illumination light which has a constant intensity;

acquiring an image of the object illuminated by said two illumination lights by acquisition of the given level of a image pick-up gain such that a cycle of picking up images is shorter than a cycle of illumination changes, wherein the image of the object is acquired at least two times, once during each illumination, with a same pick-up gain during each illumination, by an image pick-up element having storage effect; and

detecting a distance between individual points of the object on the basis of the image obtained;

wherein

the distance between respective points of the object is detected at a speed at which three-dimensional image is output in real time, the three-dimensional image being output within a period of time corresponding to one normal image frame of a video signal being received by an image pickup device.

4. The method of detecting three-dimensional information as defined in claim 3, wherein

a first and a second optical images of the object illuminated by the first and the second illumination light are formed;

the first and the second optical images are obtained alternately by acquiring the first and the second optical images with a single image pick-up gain over a given period of time;

the first and the second images obtained are stored; and

the distance between respective points of the objects are detected by each of the first and second images and are detected sequentially for each frame of the video signal.

5. A method of detecting three-dimensional information, comprising:

illuminating an object sequentially with a first illumination light and a second illumination light, the second illumination light immediately following the first illumination light, both illumination lights having a linearly varying intensity;

acquiring an image of the object illuminated by at least two illumination lights by acquisition of a image pick-up gain having faster changing rate than a changing rate of the intensity of the illumination lights, wherein the image of the object is acquired a plurality of times by an image pick-up element having storage effect; and

detecting a distance between individual points of the object on the basis of the image obtained;

wherein

the distance between respective points is detected at a speed at which three-dimensional image is output in real time, the three-dimensional image being output within a period of time corresponding to one normal image frame of a video signal being received by an image pickup device.

6. The method of detecting three-dimensional information as defined in claim 5, wherein the intensity of the first illumination light is increased with time, and the second illumination light is decreased with time.

7. A method of detecting three-dimensional information, comprising:

illuminating an object sequentially with at least a first illumination light and a second illumination light, the second illumination light immediately following the first illumination light, both illumination lights having a linearly varying intensity;

acquiring an image of the object illuminated by said at least two illumination light by acquisition of the given level of a pick-up gain with shorter changing cycle than a changing cycle of the intensity of the illumination light, wherein the image of the object is acquired a plurality of times by an image pick-up element having storage effect; and

detecting a distance between individual points of the object on the basis of the image obtained;

wherein

the distance between respective points of the object is detected at a speed at which three-dimensional image is output in real time, the three-dimensional image being output within a period of time corresponding to one normal image frame of a video signal being received by an image pickup device.

8. The method of detecting three-dimensional information as defined in claim 7, wherein the intensity of the first illumination light is increased with time, and the second illumination light is decreased with time.