Method and system for recognizing behavior of object

• US 5,675,404 A
• Filed: 04/12/1995
• Issued: 10/07/1997
• Est. Priority Date: 06/15/1994
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakazawa, Fumihiko, Abe, Fumitaka
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US08/420,686
• Time in Patent Office: 909 Days
• Field of Search: 356/4.01, 356/5.01-5.15, 356/152.1, 356/141.1, 340/555, 180/169, 901/47, 250/206.2
• US Class Current: 356/4.01
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16

Abstract

A method includes steps of measuring a distance in a straight line to an object within a target area by means of a range finder; storing object data indicative of the measured distance in a memory; repeating the above steps a plurality of times; and comparing n-th object data with (n-1)-th object data to detect whether the object changes in distance to the range finder; whereby recognizing a behavior of the object, and a system includes; a range finder for measuring a distance in a straight line to an object within a target area to output distance data corresponding to the measured distance means for periodically sampling the output distance data; a memory for storing the sampled distance data as object data and means for comparing n-th object data with (n-1)-th object data to output a judging signal representing whether the object changes in distance to the range finder when a difference between both the object data exceeds a predetermined value.

Claims

1. A method comprising the steps of:

measuring distances in a plurality of straight lines radially extending from a range finder to an object within a target area;

calculating a gradient of the object with respect to one of the straight lines based on the measured distances;

storing object data indicative of the calculated gradient in a memory;

repeating the above steps a plurality of times;

comparing n-th object data with (n-1)-th object data to calculate a rotation angle of the object; and

recognizing a behavior of the object when the calculated rotation angle is larger than a predetermined value.

4. A method of claim 1 or 2, further comprising the step of displaying an image on a display device, the image corresponding to the recognized behavior.

2. A method comprising the steps of:

measuring distances in a plurality of straight lines radially extending from a range finder to an object within a target area;

extracting distances in two straight lines extending to opposite edges of the object from the measured distances to calculate a size of the object based on the extracted distances and an angle between the two straight lines;

calculating data indicative of a state of the object based on the measured distances;

storing object data indicative of the calculated data and the size in a memory;

repeating the above steps a plurality of times;

comparing n-th object data with (n-1)-th object data;

determining that both the n-th object data and the (n-1)-th object data are data obtained from the same object when a difference between the sizes included in both the n-th object data and the (n-1)-th object data is smaller than a predetermined value; and

recognizing a behavior of the object based on a difference between both the n-th object data and the (n-1)-th object data obtained from the same object.

3. A method of claim 2, in which the data indicative of a state of the object includes data representing at least one of a position of the object, an opposing angle of the object with respect to the range finder and a morphological attitude of the object.

5. A system comprising:

a range finder for measuring distances in a plurality of straight lines radially extending from the range finder to an object within a target area to output distance data corresponding to the measured distances;

means for periodically sampling the output distance data;

means for calculating a gradient of the object with respect to one of the straight lines based on the sampled distance data;

a memory for storing object data indicative of the calculated gradient;

means for comparing n-th object data with (n-1)-th object data to calculate a rotation angle of the object; and

means for recognizing a behavior of the object when the calculated rotation angle is larger than a predetermined value.

6. A system of claim 5, in which the range finder emits straight beams to an object and detects the beams reflected by the object to measure a distance to the object.

7. A system comprising:

a range finder for measuring distances in a plurality of straight lines radially extending from the range finder to an object within a target area to output distance data corresponding to the measured distances;

means for periodically sampling the output distance data;

means for extracting distances in two straight lines extending to opposite edges of the object from the measured distances to calculate a size of the object based on the extracted distances and an angle between the two straight lines;

means for calculating state data indicative of a state of the object based on the measured distances;

a memory for storing object data indicative of the state data and the size;

means for comparing n-th object data with (n-1)-th object data;

means for determining that both the n-th object data and the (n-1)-th object data are obtained from the same object when a difference between the sizes included in both the object data is smaller than a predetermined value;

means for outputting a judging signal representing a behavior of the object when a difference in the state data between the n-th object data and the (n-1)-th object data obtained from the same object exceeds a predetermined value.

8. A system of claim 7, in which the data indicative of a state of the object includes data representing at least one of a position of the object, an opposing angle of the object with respect to the range finder and a morphological attitude of the object.

9. A system of claim 7, in which the range finder includes a plurality of optical sensors, each of the sensors emitting a straight light beam to an object and detecting the beam reflected by the object to measure a distance to the object, the plurality of the optical sensors arranged so that beams of the optical sensors are radially emitted.

10. A system of claim 7, in which the range finder includes an optical sensor for emitting a straight beam to an object and detecting the beam reflected by the object to measure a distance to the object and scanning means for rotating the optical sensor so that the beam emitted from the optical sensor scans the target area.

11. A system of claim 7, in which the range finder includes a plurality of optical sensors, each of the sensors emitting a straight light beam to an object and detecting the beam reflected by the object to measure a distance to the object, the optical sensors arranged so that beams of the optical sensors are radially emitted on a vertical plane, scanning means for rotating the optical sensors so that the beams emitted from the optical sensors horizontally scan the target area.

12. A system of claim 7, further comprising a display device which displays an image corresponding to the judging signal.