Interleaved mosiac imaging rain sensor

• US 20030001121A1
• Filed: 06/28/2001
• Published: 01/02/2003
• Est. Priority Date: 06/28/2001
• Status: Active Grant

• Current Assignee: Valeo Electrical Systems Incorporated (Valeo SE)
• Original Assignee: Valeo Electrical Systems Incorporated (Valeo SE)
• Inventors: Hochstein, Peter A.
• Granted Patent: US 6,573,490 B2
• Time in Patent Office: Days
• US Class Current: 250/573
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• 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

Abstract

A plurality of the first L1 and second L2 image sensor elements are interleaved with one another. The first image sensor element L1 has a peak response at the first wavelength λ1 for capturing an illuminated image of the glass and objects on the glass containing a first wavelength λ1 from an infrared illuminator (12). The second image sensor element L2 has a peak response at a second wavelength λ2 for capturing an ambient image of light rays at the second wavelength λ2 passing through the glass (10) from the exterior to the interior surfaces simultaneously with the capture by the first image sensor element L1. Instead of storing two complete sequential images and differentially subtracting them, the present invention creates two simultaneous images from a specially interleaved, single imager (14). A processor includes a camera control and frame capture unit (20), an image detector (22), an image storage unit (24), and a differential comparator (26). The comparator (26) algebraically sums the first and second images and an analyzer (28) analyzes and sets preset setpoints for initiating a wiper activation signal (30).

Claims

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

illuminating the glass (10) and objects on the glass with light rays at a first wavelength λ

1,

capturing an illuminated image of the glass (10) containing the first wavelength λ

1,

simultaneously capturing an ambient image of light rays at a second wavelength λ

2 passing through the glass (10) from the exterior to the interior surfaces thereof, and

comparing the images to produce a moisture signal.

2. A method as set forth in claim 1 wherein the capturing is further defined as capturing the illuminated image at a first plurality of image sensor elements and capturing the ambient image at a second plurality of image sensor elements interleaved with the first plurality of image sensor elements.

3. A method as set forth in claim 1 wherein the first wavelength λ

1 is separated from the second wavelength λ

2 by one hundred nm.

4. A method as set forth in claim 1 wherein the first plurality of image sensor elements exhibit peak response at the first wavelength λ

1 and the second plurality of image sensor elements exhibit peak performance at the second wavelength λ

2.

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

an illuminator (12) for illuminating the glass (10) on objects on the glass with light rays at a first wavelength λ

1,

a first image sensor element L1 having a peak response at the first wavelength λ

1 for capturing an illuminated image of the glass (10) containing the first wavelength λ

1,

a second image sensor element L2 having a peak response at a second wavelength λ

2 for capturing an ambient image of light rays at the second wavelength λ

2 passing through the glass (10) from the exterior to the interior surfaces thereof simultaneously with the capture by said first image sensor element L1, and

a processor for comparing the simultaneously captured images to produce a moisture signal.

6. An assembly as set forth in claim 5 including a plurality of said first image sensor elements L1 and including a plurality of said second image sensor elements L2, said first plurality being interleaved with said second plurality of image sensor elements.

7. An assembly as set forth in claim 6. wherein said first and second plurality of image sensor elements are disposed in one of alternating rows and columns

8. An assembly as set forth in claim 6 wherein said first and second plurality of image sensor elements are disposed in a checkerboard array.

9. An assembly as set forth in claim 6 wherein each of said sensor elements comprises a pixel.

10. An assembly as set forth in claim 9 including a first filter disposed over each of one of said first and second image sensor element L2 for filtering light to one of said first and second wavelengths λ

2.

11. An assembly as set forth in claim 6 including a lens for focusing said images onto said sensor elements.

12. An assembly as set forth in claim 11 wherein said processsor includes a comparator for algebraically summing the first and second images and an analyzer for setting preset setpoints for initiating the moisture signal.