Two-dimensional and three-dimensional position sensing systems and sensors therefor

• US 8,969,822 B2
• Filed: 12/16/2011
• Issued: 03/03/2015
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: Baanto International Ltd.
• Original Assignee: Baanto International Ltd.
• Inventors: Utukuri, Avanindra, McFadyen, Stephen, Clarke, Jonathan
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Igyarto, Carolyn
• Application Number:
  US13/329,215
• Publication Number:
  US 20120267541A1
• Time in Patent Office: 1,173 Days
• Field of Search: 250/394
• US Class Current: 250/370.1
• CPC Class Codes: G01D 5/34 the beams of light being detected by photocells
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G01J 2001/4247 for testing lamps or other light sources
• CPC Class Codes: G01S 3/784 using a mosaic of detectors
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

Two and three dimensional position sensing systems and sensors for use in such systems are disclosed. The sensors incorporate linear array sensors and an aperture plate to block light or other radiation from reaching most elements of the sensors. A direction of a radiation source relative is determined based on illuminated sensor elements in each sensor. The sensors are combined in systems to allow the position of a radiation source to be estimated.

Claims

1. A method of estimating the direction of a radiation source positioned in a sensing region, the method comprising:

providing a two-dimensional radiation sensor, the radiation sensor comprising;

a first linear array sensor having a plurality of first sensor elements arranged linearly, the first sensor elements facing the sensing region;

a second linear array sensor having a plurality of second sensor elements arranged linearly, the second sensor elements facing the sensing region;

an aperture plate positioned between the first and second linear array sensors and the sensing region to block radiation from the sensing region from reaching the first and second linear array sensors;

a first aperture formed in the aperture plate to allow radiation from the sensing region to reach one or more of the first sensor elements; and

a second aperture formed in the aperture plate to allow radiation from the sensing region to reach one or more of the second sensor elements;

receiving a first intensity signal from the first linear array sensor, wherein the first intensity signal includes first intensity values corresponding to radiation incident on the first sensor elements through the first aperture;

receiving a second intensity signal from the second linear array sensor, wherein the second intensity signal includes second intensity values corresponding to radiation incident on the second sensor elements through the second aperture; and

determining the direction based on the first and second intensity signals, wherein;

the first radiation intensity signal includes a first range of high intensity values corresponding to a range of first sensor elements exceeding a first threshold value; and

the second radiation intensity signal includes a second range of high intensity values corresponding to a range of second sensor elements exceeding a second threshold value;

and wherein determining the direction includes;

selecting a first center sensor element based on the first range of high intensity values in the first radiation intensity signal;

selecting a second center sensor element based on the second range of high intensity values in the second radiation intensity signal; and

determining a direction based on the first and second center sensor element.

2. The method of claim 1 wherein the first and second radiation intensity signals are analog signals and wherein determining the direction includes:

converting the first radiation intensity signal into a corresponding first final radiation intensity signal;

converting the second radiation intensity signal into a corresponding second final radiation intensity signal; and

determining the direction based on the first and second final radiation intensity signals.

3. The method of claim 1 wherein the first and second radiation intensity signals are digital signals, and wherein the intensity values of the first and second radiation intensity signals correspond respectively to each of first sensor elements and to each of the second sensor elements, wherein each intensity value has either a high value or a low value.

4. The method of claim 1 including filtering the first and second radiation intensity signals to remove spurious values before determining the direction.

5. The method of claim 1 wherein determining the direction includes looking up a first angle corresponding to the first radiation intensity signal in a lookup table and looking up a second angle corresponding to the second radiation intensity signal in a lookup table.

6. The method of claim 1 wherein determining the direction includes calculating a first angle and calculating a second angle.

7. The method of claim 6 further including combining the first and second angles to determine the direction.