Picture detecting sensor unit

• US 5,528,354 A
• Filed: 07/09/1993
• Issued: 06/18/1996
• Est. Priority Date: 07/10/1992
• Status: Expired due to Fees

• Current Assignee: Bodenseewerk Gerätetechnik Gmbh
• Original Assignee: Bodenseewerk Gerätetechnik Gmbh
• Inventors: Uwira, Bernd
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US08/088,640
• Time in Patent Office: 1,075 Days
• Field of Search: 356/5, 356/141.1, 356/5.01, 348/164, 250/203.2, 250/206.2, 250/342, 250/334
• US Class Current: 356/5.01
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/89 for mapping or imaging

Abstract

A picture detecting sensor unit has a passive sensor resolving a field of view into picture elements having different brightness. Picture processing means receive data from the picture detecting sensor. An additional active LADAR sensor having a laser emitting a laser beam and a scanning system for scanning an area of the field of view by this laser beam provides distance signals from the radiation reflected by an object in the field of view. The scanning of the field of view by the LADAR sensor is controlled by the picture processing means associated with the passive sensor such that the scanning effected by the LADAR sensor is limited to objects detected by the passive sensor in the field of view. A common imaging optical system is provided for the LADAR sensor and the passive sensor. A beam splitter separates the beams detected by the passive sensor and the returning beams of the LADAR sensor.

Claims

1. A device for detecting and identifying an object in a field of view comprising:

laser means for generating a laser beam and means for directing said laser beam towards said object;

scanning beam deflecting means for deflecting said laser beam to scan two-dimensionally over all of the surface of said object;

LADAR sensor means exposed to laser light reflected by said object for providing relief information for each scanned spot of said object;

optical system means for forming an image of said field of view in an image plane;

passive image resolving sensor means in said image plane for providing picture output signals indicative of the two-dimensional image of said field of view;

beam splitter means between said optical system means and said image plane for directing said laser beam deflected by said scanning beam deflecting means through said optical system means towards said object and for directing said reflected laser light towards said LADAR sensor means;

image processing means to which said picture output signals from said passive image resolving sensor means are applied for segmenting and detecting individual objects within said field of view,

said image processing means being arranged to control said scanning beam deflecting means such that said laser beam scans substantially only the surface of objects detected by said image processing means within said field of view;

means for deriving, from said relief information, a three-dimensional relief representation of said object; and

means for identifying said object on the basis of said three-dimensional relief representation.

2. A device for detecting and identifying an object in a field of view comprising:

laser means for generating a laser beam and means for directing said laser beam towards said object;

scanning beam deflecting means for deflecting said laser beam to scan two-dimensionally over all of the surface of said object;

LADAR sensor means exposed to laser light reflected by said object for providing relief information for each scanned spot of said object;

optical system means for forming an image of said field of view in an image plane;

passive image resolving sensor means in said image plane for providing picture output signals indicative of the two-dimensional image of said field of view;

beam splitter means between said optical system means and said image plane for directing said laser beam deflected by said scanning beam deflecting means through said optical system means towards said object and for directing said reflected laser light towards said LADAR sensor means;

image processing means to which said picture output signals from said passive image resolving sensor means are applied for segmenting and detecting individual objects within said field of view,

said image processing means being arranged to control said scanning beam deflecting means such that said laser beam scans substantially only the surface of objects detected by said image processing means within said field of view;

wherein

said scanning beam deflecting means are controlled by said image processing means to scan, in a first scanning cycle, the objects detected by said passive image resolving sensor along a path sweeping over the objects only once, whereby first scanning cycle information is obtained,

said first scanning cycle information is applied to selecting means for selecting, out of the objects detected by said passive image resolving sensor those objects meeting predetermined criteria, and

said scanning beam deflecting means being controlled by said image processing means and said selecting means to scan, in a second scanning cycle, line-by-line, only limited areas of the field of view containing said selected objects;

means for deriving, from said relief information, a three-dimensional relief representation of said object; and

means for identifying said object on the basis of said three-dimensional relief representation.

3. A device as claimed in claim 2, wherein said beam splitter is a wavelength-selective beam splitter.

4. A device as claimed in claim 3, wherein said scanning beam deflecting means are arranged between said beam splitter and said LADAR sensor means.

5. A device as claimed in claim 4, wherein a quarter wave plate and a polarization beam splitter are provided between said beam deflecting means and said LADAR sensor means, said quarter wave plate and polarization beam splitter being arranged to reflect said outgoing laser light beam from said laser means towards said optical system means and to pass said reflected laser light to a detector of said LADAR sensor means.

6. A device for detecting and identifying an object in a field of view comprising:

optical system means for forming an image of said field of view in an image plane;

passive image resolving sensor means in said image plane for providing picture output signals indicative of the two-dimensional image of said field of view;

laser means for generating a laser beam;

scanning beam deflecting means for deflecting said laser beam, LADAR sensor means;

beam splitter means between said optical system means and said image plane for directing said laser beam deflected by said scanning beam deflecting means through said optical system means towards said object to scan over the whole surface of said object and for directing light reflected by said object and collected by said optical system means towards said LADAR sensor means for providing relief information for each scanned spot of said object;

image processing means to which said picture output signals from said passive image resolving sensor means are applied for segmenting and detecting individual objects within said field of view,

said image processing means being arranged to control said scanning beam deflecting means such that said laser beam scans substantially only the surface of objects detected by said image processing means within said field of view;

means for deriving, from said relief information, a three-dimensional relief representation of said object; and

means for identifying said object on the basis of said two-dimensional image and said three-dimensional relief representation.

7. A device for detecting and identifying an object in a field of view comprising:

optical system means for forming an image of said field of view in an image plane;

passive image resolving sensor means in said image plane for providing picture output signals indicative of the two-dimensional image of said field of view;

laser means for generating a laser beam;

scanning beam deflecting means for deflecting said laser beam;

LADAR sensor means;

beam splitter means between said optical system means and said image plane for directing said laser beam deflected by said scanning beam deflecting means through said optical system means towards said object to scan over the whole surface of said object and for directing light reflected by said object and collected by said optical system means towards said LADAR sensor means for providing relief information for each scanned spot of said object;

image processing means to which said picture output signals from said passive image resolving sensor means are applied for segmenting and detecting individual objects within said field of view,

said image processing means being arranged to control said scanning beam deflecting means such that said laser beam scans substantially only the surface of objects detected by said image processing means within said field of view;

wherein

said scanning beam deflecting means are controlled by said image processing means to scan, in a first scanning cycle, the objects detected by said passive image resolving sensor along a path sweeping over the objects only once, whereby first scanning cycle information is obtained,

said first scanning cycle information is applied to selecting means for selecting, out of the objects detected by said passive image resolving sensor those objects meeting predetermined criteria, and

said scanning beam deflecting means being controlled by said image processing means and said selecting means to scan, in a second scanning cycle, line-by-line, only limited areas of the field of view containing said selected objects;

means for deriving, from said relief information, a three-dimensional relief representation of said object; and

means for identifying said object on the basis of said two-dimensional image and said three-dimensional relief representation.