Laser area sensor

• US 20090091447A1
• Filed: 10/03/2008
• Published: 04/09/2009
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Original Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Inventors: Iwasawa, Masashi
• Granted Patent: US 7,940,178 B2
• Time in Patent Office: Days
• US Class Current: 340/557
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G08B 13/187 by interference of a radiation field

Abstract

In an embodiment, a laser area sensor of the present invention comprises: a laser range finder; a scanning mechanism that changes a measurement direction of the laser range finder; a distance data acquiring portion that defines a detection area and acquires distance information in each direction in the detection area in a time-series manner, by periodically causing the laser range finder to perform measurement while causing the measurement direction to be changed; a human body judging portion that extracts a portion that is presumed to correspond to a human body, from among the distance information and judges whether or not the extracted portion matches a human body based on a time-series moving status of the extracted portion; an alert output control portion; a memory; and a DIP switch.

Claims

1. A laser area sensor, comprising:

a laser range finder that emits laser light, and measures a distance to an object that is present in a laser light emitting direction based on a period of time for light reflected by the object to return;

a scanning mechanism portion that changes a measurement direction of the laser range finder;

a distance information acquiring portion that defines a detection area and acquires distance information in each direction in the detection area in a time-series manner, by periodically causing the laser range finder to perform measurement while causing the scanning mechanism portion to change the measurement direction;

a human body judging portion that extracts a portion that is presumed to correspond to a human body, from among the distance information acquired by the distance information acquiring portion, and judges whether or not the extracted portion matches a human body based on a time-series moving status of the extracted portion; and

a human body detection signal output portion that outputs a human body detection signal when the human body judging portion judges that a human body is present.

2. The laser area sensor according to claim 1, further comprising:

an area storage portion in which, with respect to a direction in which a normal measurement distance is a constant distance shorter than the maximum detection distance of the laser range finder, the constant distance is recognized to correspond to a detection area boundary face and stored as detection area information,

wherein the human body judging portion has a first operation mode in which judgment is performed regarding a human body in a first region that is determined by the shorter distance of the maximum detection distance and the distance to the detection area boundary face in each direction, based on the detection area information stored in the area storage portion.

3. The laser area sensor according to claim 2, wherein the human body judging portion has a second operation mode in which judgment is performed regarding a human body in a second region obtained by excluding a first band-shaped area that extends along the detection area boundary face and has a first predetermined width, from the first region, based on the detection area information stored in the area storage portion.

4. The laser area sensor according to claim 3, further comprising:

a switching portion that switches the mode between the first operation mode and the second operation mode.

5. The laser area sensor according to claim 3, wherein the first operation mode and the second operation mode are automatically switched.

6. The laser area sensor according to claim 2, wherein the human body judging portion has a third operation mode in which judgment is performed regarding a human body in a first band-shaped area that extends along the detection area boundary face and has a first predetermined width, based on the detection area information stored in the area storage portion.

7. The laser area sensor according to claim 2, wherein the human body judging portion has a fourth operation mode in which judgment is performed regarding a human body in a second band-shaped area that is positioned farther than and next to a first band-shaped area and has a second predetermined width, based on the detection area information stored in the area storage portion, the first band-shaped area extending along the detection area boundary face and having a first predetermined width.

8. The laser area sensor according to claim 2, wherein the human body judging portion has a movement line storing operation mode in which judgment is performed regarding a human body in the first region and a movement line of an object judged to be a human body is stored as a locus, and a fifth operation mode in which judgment is performed regarding a human body in a third region that is determined by a distance to the movement line stored in the movement line storing operation mode in each direction.

9. The laser area sensor according to claim 8, wherein if there is a discontinuous portion in the movement line, the human body judging portion completes the discontinuous portion by interpolation processing, and stores the movement line.

10. The laser area sensor according to claim 8, wherein, if a plurality of movement lines are present in the same direction, the human body judging portion stores a movement line with a closer distance in priority to the others.