Device for detecting whether a vehicle seat is occupied by means of a stereoscopic image recording sensor

• US 6,704,114 B1
• Filed: 08/17/2001
• Issued: 03/09/2004
• Est. Priority Date: 11/16/1998
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Poechmuller, Werner
• Primary Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US09/856,019
• Time in Patent Office: 935 Days
• Field of Search: 356/601, 356/602, 356/612, 356/613, 356/623, 701/45, 250/559.22, 180/268, 280/735
• US Class Current: 356/601
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2210/22 Optical; Photoelectric; Lidar [Light Detection and Ranging]
• CPC Class Codes: B60R 21/01538 for image processing, e.g. cameras or sensor arrays
• CPC Class Codes: G06V 20/593 Recognising seat occupancy
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

The device includes a stereoscopic image recording device having at least one optical sensor which records the scene at the vehicle seat and derives from that a three-dimensional map, partitioned into a plurality of zones, giving for each zone its distance from a reference point. In order to make possible reliable recognition of the manner of the seat'"'"'s occupation, even during great fluctuations of light intensity, the at least one optical sensor has a nonlinear characteristic curve, describing the correlation between the incident light intensity and its electrical output signal, whose characteristic curve steepness decreases with increasing light intensity.

Claims

1. A device for detecting a manner in which a vehicle seat is occupied, comprising:

a stereoscopic image recording device including at least one optical sensor recording a scene at the vehicle seat, the image recording device deriving, from the scene, a three-dimensional map partitioned into a plurality of zones, indicating for each of the zones a distance from a reference point, the at least one optical sensor having a nonlinear transducer characteristic curve over an entire operating range, describing a correlation between an incident light intensity and an electrical output signal of the at least one optical sensor, a steepness of the characteristic curve decreasing with increasing light intensity; and

a light source arranged to illuminate the scene at the vehicle seat and to shine infrared light synchronously with an activation of the stereoscopic image recording device.

2. The device according to claim 1, wherein the characteristic curve has a logarithmic shape.

3. The device according to claim 1, wherein the at least one optical sensor includes two optical sensors situated at a predefined distance from each other, the at least two optical sensors simultaneously recording the scene at the vehicle seat.

4. The device according to claim 1, further comprising a stereo-optical instrument taking two images of the vehicle seat, offset by a defined distance from each other, on a single optical sensor.

5. The device according to claim 1, further comprising an infrared band-pass filter situated in front of the at least one optical sensor.

6. The device according to claim 1, further comprising an infrared band-pass filter situated in front of the at least one optical sensor.

7. The device according to claim 1, further comprising an image processor arranged to derive the three-dimensional map from recorded images and to communicate with one of a restraint device and a device to control the restraint device.

8. The device according to claim 1, wherein the light source includes a plurality of light diodes configured to emit infrared light.