System and method for improving methods of manufacturing stereoscopic image sensors

• US 9,438,889 B2
• Filed: 09/18/2012
• Issued: 09/06/2016
• Est. Priority Date: 09/21/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Atanassov, Kalin Mitkov, Goma, Sergiu R, Ramachandra, Vikas, Aleksic, Milivoje
• Primary Examiner(s): Sun, Yulin
• Application Number:
  US13/622,318
• Publication Number:
  US 20130070055A1
• Time in Patent Office: 1,449 Days
• Field of Search: 348/46
• US Class Current: 1/1
• CPC Class Codes: H04N 13/246 Calibration of cameras

Abstract

Described herein are methods, systems and apparatus to improve imaging sensor production yields. In one method, a stereoscopic image sensor pair is provided from a manufacturing line. One or more images of a correction pattern are captured by the image sensor pair. Correction angles of the sensor pair are determined based on the images of the correction pattern. The correction angles of the sensor pair are represented graphically in a three dimensional space. Analysis of the graphical representation of the correction angles through statistical processing results in a set of production correction parameters that may be input into a manufacturing line to improve sensor pair yields.

Claims

1. A method to improve imaging sensor yields for a pair of image sensors configured to capture a stereoscopic image, comprising:

providing a stereoscopic image sensor pair taken from a manufacturing line;

capturing one or more images of a correction pattern with the sensor pair;

determining correction angles of the sensor pair based on the one or more images of the correction pattern;

representing the correction angles of the sensor pair in a three dimensional space;

analyzing the three dimensional space of correction angles by determining a mean and variance of the correction angles to determine a set of production correction parameters that satisfies one or both of a minimized variance of the correction angles or a zero-valued mean of the correction angles; and

inputting the production correction parameters to the manufacturing line to improve sensor pair yields.

2. The method of claim 1, wherein determining correction angles of the sensor pair comprises measuring a roll correction angle, measuring a yaw correction angle, and measuring a pitch correction angle of the image sensors in the sensor pair.

3. The method of claim 1, wherein the correction pattern is a checkerboard composed of alternating light and dark squares.

4. The method of claim 1, wherein the correction pattern further comprises colorations in addition to alternating light and dark squares such that the colorations provide an orientation point for the image sensors in the sensor pair.

5. The method of claim 1, wherein capturing one or more images of a correction pattern comprises capturing a first image of a correction pattern with a first imaging sensor and capturing a second image of a correction pattern with a second imaging sensor.

6. The method of claim 5, wherein determining correction angles of the sensor pair further comprises the steps of detecting a coordinate system origin for each of the first and second images;

detecting a set of key point coordinates within a boundary around the origin for each of the first and second images;

determining a set of real world coordinates from the set of key point coordinates for each of the first and second images; and

comparing the set of real world coordinates with the set of key point coordinates to determine correction angles for each sensor pair.

7. The method of claim 1, wherein representing the correction angles of the sensor pair in a three dimensional space comprises graphing a sensor pair correction requirement in a three dimensional space in which a first axis corresponds to a roll correction, a second axis corresponds to a yaw correction, and a third axis corresponds to a pitch correction.

8. The method of claim 2, wherein analyzing the three dimensional space of correction angles further comprises determining the mean and variance for the roll correction angle, the pitch correction angle, and the yaw correction angle.

9. The method of claim 2, wherein analyzing the three dimensional space of correction angles further comprises determining a set of possible combinations of two of the roll, pitch or yaw correction angles while holding fixed a mean of a third correction angle and determining the set of production correction parameters from the set of possible combinations.

10. The method of claim 2, wherein analyzing the three dimensional space of correction angles further comprises determining a maximum correction angle for each of roll, pitch and yaw and minimizing each correction angle sequentially.

11. The method of claim 7, further comprising building a projection matrix of the production correction parameters of the roll, pitch, and yaw correction angles and retaining only those correction angles which result in correction of the images captured by the sensor pair within a specified budget.

12. A system to improve imaging sensor yields for a pair of image sensors configured to capture a stereoscopic image, comprising:

a correction pattern comprised of two sheets of alternating light and dark squares joined at a ninety degree angle;

a support for holding a stereoscopic image sensor pair in front of the correction pattern;

a control module configured to;

capture one or more images of the correction pattern with a sensor pair;

determine correction angles of the sensor pair based on the one or more images of the correction pattern;

represent the correction angles of the sensor pair in a three dimensional space;

analyze the three dimensional space of correction angles by determining a mean and variance of the correction angles to determine a set of production correction parameters that satisfies one or both of a minimized variance of the correction angles or a zero-valued mean of the correction angles; and

input the production correction parameters to a manufacturing line to improve sensor pair yields.

13. The system of claim 12, wherein the control module is configured to determine correction angles of the sensor pair by measuring a roll correction angle, measuring a yaw correction angle, and measuring a pitch correction angle of the image sensors in the sensor pair.

14. The system of claim 12, wherein the correction pattern is a checkerboard composed of alternating light and dark squares.

15. The method of claim 14, wherein the correction pattern further comprises colorations in addition to alternating light and dark squares such that the colorations provide an orientation point for the image sensors in the sensor pair.

16. An apparatus for improving imaging sensor yields for a pair of image sensors configured to capture a stereoscopic image, comprising:

a support for holding a stereoscopic image sensor pair in front of a correction pattern;

a control module configured to;

measure correction angles of the image pair;

represent the correction angles in a three dimensional space;

analyze the three dimensional space of correction angles by determining a mean and variance of the correction angles to determine a set of production correction parameters that satisfies one or both of a minimized variance of the correction angles or a zero-valued mean of the correction angles;

compare the correction angles to a specified maximum correction parameter; and

input the production correction parameters to a manufacturing line to improve sensor pair yields.

17. An apparatus improving imaging sensor yields for a pair of image sensors configured to capture a stereoscopic image, comprising:

means for providing a first image and a second image of a stereoscopic image pair;

means for capturing one or more images of a correction pattern with the sensor pair;

means for determining correction angles of the sensor pair based on the one or more images of the correction pattern;

means for representing the correction angles of the sensor pair in a three dimensional space;

means for analyzing the three dimensional space of correction angles by determining a mean and variance of the correction angles to determine a set of production correction parameters that satisfies one or both of a minimized variance of the correction angles or a zero-valued mean of the correction angles; and

means for imputing the production correction parameters to a manufacturing line to improve sensor pair yields.

18. A non-transitory, computer readable medium, comprising instructions that when executed by a processor cause the processor to perform a method of improving imaging sensor yields for a pair of image sensors configured to capture a stereoscopic image, the method comprising:

providing a stereoscopic image sensor pair taken from a manufacturing line;

capturing one or more images of a correction pattern with the sensor pair;

determining roll, pitch and yaw correction angles of the sensor pair based on the one or more images of the correction pattern;

representing the correction angles of the sensor pair in a three dimensional space with each dimension corresponding to one of roll, pitch, and yaw;

analyzing the three dimensional space of correction angles by determining a mean and variance for the correction angles to determine a set of production correction parameters that satisfies one or both of a minimized variance of the correction angles or a zero-valued mean of the correction angles; and

inputting the production correction parameters to the manufacturing line to improve sensor pair yields.

19. The computer readable medium of claim 18, further containing processor executable instructions that when executed perform a method of building a projection matrix of the production correction parameters of the roll, pitch, and yaw correction angles and retaining only those correction angles which result in correction of the images captured by the sensor pair within a specified budget.

20. The computer readable medium of claim 18, wherein the correction pattern is a checkerboard composed of alternating light and dark squares.