Stereo imaging rain sensor

• US 6,596,978 B2
• Filed: 06/28/2001
• Issued: 07/22/2003
• Est. Priority Date: 06/28/2001
• Status: Expired due to Term

• Current Assignee: Valeo Electrical Systems Incorporated (Valeo SE)
• Original Assignee: Valeo Electrical Systems Incorporated (Valeo SE)
• Inventors: Hochstein, Peter A.
• Primary Examiner(s): PYO, KEVIN K
• Application Number:
  US09/894,340
• Publication Number:
  US 20010042822A1
• Time in Patent Office: 754 Days
• Field of Search: 250/208.1, 250/227.25, 250/573, 250/574, 318/483, 318/DIG.2, 340/602, 340/603, 340/604, 15D/IG.15, 361/286
• US Class Current: 250/208.1
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0837 with a particular arrangement of the optical elements
• CPC Class Codes: B60S 1/0844 including a camera
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: H04N 13/218 using spatial multiplexing
• 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

Two embodiments include a first image sensor (14, 114) for sensing a first image of the exterior surface of the glass (12) along a first optical axis A and a second image sensor (16, 116) for sensing a second image of the exterior surface of the glass (12) along a second optical axis B which intersects the first optical axis A at an intersection X disposed adjacent the exterior surface of the glass (12). Both embodiments include an image correlator (22) for correlating the first and second images and producing an activation signal (24) in response to coincidence of moisture (10) in the respective correlated first and second images. The rain sensor accurately interprets images of moisture that lie in a narrow measurement zone adjacent the exterior surface of the windshield while disregarding images of objects that lie outside that zone.

Claims

1. A method for sensing moisture (10) on the exterior surface of a sheet of glass (12) comprising the steps of;

viewing the exterior surface of the glass (12) along a first optical axis A to produce a first image,

viewing the exterior surface of the glass (12) along a second optical axis B which intersects the first optical axis A at an intersection X disposed adjacent the exterior surface of the glass (12) to produce a second image,

correlating the first and second images,

producing an activation signal (24) in response to coincidence of moisture (10) in the respective correlated first and second images, and

viewing along at least one of the optical axes through at least one mirror.

2. A method as set forth in claim 1 including focusing the intersection X of the optical axes onto first (14, 114) and second (16, 116) image sensors to produce the first and second images.

3. A method as set forth in claim 1 further defined as digitally correlating the first and second images, and analyzing the correlated images and establishing predetermined set points (42) of coincidences as a precondition for producing the activation signal (24).

4. A method as set forth in claim 1 including focusing the intersection X of the optical axes through a first lens (26) and unto a first image sensor (14, 114) and through a second lens (28) onto a second image sensor (16, 116) to produce the respective first and second images.

5. A method as set forth in claim 1 including focusing the intersection X of the optical axes through a first lens (26) and unto a first image sensor (14, 114) and through the first lens (26) onto a second image sensor (16, 116) to produce the respective first and second images.

6. A method as set forth in claim 5 further defined as viewing along the first optical axis A through a first mirror system and viewing along the second optical axis B through a second mirror system.

7. An assembly for sensing moisture (10) on the exterior surface of a sheet of glass (12) comprising;

a first image sensor (14, 114) for sensing a first image of the exterior surface of the glass (12) along a first optical axis A,

a second image sensor (16, 116) for sensing a second image of the exterior surface of the glass (12) along a second optical axis B which interests the first optical axis A at an intersection X disposed adjacent the exterior surface of the glass (12),

an image correlator (22) for correlating the first and second images and producing an activation signal (24) in response to coincidence of moisture (10) in the respective correlated first and second images, and

said lens system including a single lens (30) and a first mirror system for focusing the view along said first optical axis A onto said first image sensor (14, 114) and a second mirror system for focusing the view along said second optical axis B onto said second image sensor (16, 116).

8. An assembly as set forth in claim 7 including a lens system for focusing the intersection X of the optical axes onto said first (14, 114) and second (16, 116) image sensors to produce the first and second images.

9. An assembly as set forth in claim 8 wherein said lens system includes a first lens (26) for focusing the view along said first optical axis A onto said first image sensor (14, 114) and a second lens (28) for focusing the view along said second optical axis B onto said second image sensor (16, 116).

10. An assembly as set forth in claim 7 wherein said correlator (22) comprises a digital correlator (22) for digitally correlating the first and second images, and a processor (40) for analyzing the correlated images and establishing predetermined set points (42) of coincidences as a precondition for producing said activation signal (24).