Imaging system with built-in diagnostics

• US 6,726,103 B1
• Filed: 11/07/2001
• Issued: 04/27/2004
• Est. Priority Date: 11/07/2001
• Status: Expired due to Term

• Current Assignee: Pixim, Inc. (Sony Group Corp.)
• Original Assignee: Pixim, Inc. (Sony Group Corp.)
• Inventors: Motta, Ricardo J., Weinschenk, Robert
• Primary Examiner(s): Le, Thien M.
• Assistant Examiner(s): TRAIL, ALLYSON NEEL
• Application Number:
  US10/045,877
• Time in Patent Office: 902 Days
• Field of Search: 235/454, 235/487, 235/462.25, 250/214.1, 250/332, 250/557, 356/492
• US Class Current: 235/454
• CPC Class Codes: H04N 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 25/68 applied to defects
• CPC Class Codes: H04N 25/772 comprising A/D, V/T, V/F, I/T or I/F converters

Abstract

An imaging system with built-in diagnostics and preferably implemented as an integrated system-on-a-chip (SOC) imaging system. According to one implementation of the present invention, the imaging system can be operated in two operating modes: a normal operating mode and a special diagnostic mode. While running in the diagnostic mode, the imaging system can be configured to detect manufacturing defects. The imaging system can be further configured to compensate for certain types of manufacturing defects. While running in the diagnostic mode, the imaging system (1) identifies pixels that function incorrectly and (2) creates a record of such pixels. In the normal operating mode, the imaging system can use the record to compensate for the missing or incorrect data from these defective pixels during real-time image processing. The present invention simplifies testing of imaging systems and/or image sensors. It also increases manufacturing yield and, therefore, results in lower per-unit manufacturing cost.

Claims

1. An imaging system comprising an image sensor, a memory, and a processor, wherein:

the image sensor and the memory are implemented in a single integrated circuit;

the image sensor is a digital pixel sensor configured to generate digital image data corresponding to an image of a scene for storage in the memory;

the memory is configured to store the digital image data corresponding to the image; and

the processor is configured to control operations of the imaging system in a diagnostic mode and in a normal operating mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to determine if the image sensor is defective and, prior to operating the image sensor in the normal operating mode, no physical modifications are made to the image sensor in response to identifying one or more defective pixels in the image sensor during the diagnostic mode.

2. The invention of claim 1, wherein:

the image sensor, the memory, and the processor are implemented as a system-on-a-chip (SOC) in the single integrated circuit.

3. The invention of claim 1, wherein:

the image sensor, the memory, and the processor are implemented as a system-on-a-chip (SOC) in the single integrated circuit; and

the diagnostic mode enables the imaging system to be tested using a testing system, wherein;

a test controller different from the processor generates instructions for controlling test operations of the testing system;

the testing system provides a set of light stimuli for the image sensor in response to the instructions;

the processor generates test results based on the digital image data indicating whether the image sensor is defective;

the test results are stored in the imaging system for access by the processor during the normal operating mode;

the test results identify a set of one or more defective pixels in the image sensor;

the imaging system is configured to use the test results during the normal operating mode to compensate for the one or more defective pixels identified during the diagnostic mode; and

the testing system is configured to test a packaged image sensor.

4. The invention of claim 3, wherein:

no diagnostic testing is performed on the image sensor to identify the one or more defective pixels in the image sensor prior to assembling the image sensor into the packaged image sensor; and

the testing system is adapted to test multiple instances of the imaging system simultaneously.

5. An imaging system comprising an image sensor, a memory, and a processor, wherein:

the image sensor and the memory are implemented in a single integrated circuit;

the image sensor is a digital pixel sensor configured to generate digital image data corresponding to an image of a scene for storage in the memory;

the memory is configured to store the digital image data corresponding to the image;

the processor is configured to control operations of the imaging system in a diagnostic mode and in a normal operating mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to determine if the image sensor is defective; and

the diagnostic mode enables the imaging system to be tested using a testing system, wherein;

a test controller different from the processor generates instructions for controlling test operations of the testing system;

the testing system provides a set of light stimuli for the image sensor in response to the instructions; and

the processor generates test results based on the digital image data indicating whether the image sensor is defective.

6. The invention of claim 5, wherein the test results are stored in the imaging system for access by the processor during the normal operating mode.

7. The invention of claim 5, wherein the test results identify a set of one or more defective pixels in the image sensor.

8. The invention of claim 5, wherein the imaging system is configured to use the test results during the normal operating mode to compensate for one or more defective pixels identified during the diagnostic mode.

9. The invention of claim 5, wherein the testing system is configured to test a packaged image sensor.

10. The invention of claim 5, wherein the testing system is adapted to test multiple instances of the imaging system simultaneously.

11. A method for fabricating an imaging system comprising the steps of:

(a) forming an image sensor configured to generate digital image data corresponding to an image of a scene, wherein the image sensor is a digital pixel sensor;

(b) forming a memory configured to store the digital image data corresponding to the image, wherein the image sensor and the memory are implemented in a single integrated circuit; and

(c) forming a processor configured to control operations of the imaging system in a diagnostic mode and in a normal operating mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to determine if the image sensor is defective and, prior to operating the image sensor in the normal operating mode, no physical modifications are made to the image sensor in response to identifying one or more defective pixels in the image sensor during the diagnostic mode.

12. The invention of claim 11, wherein:

the image sensor, the memory, and the processor are implemented as a system-on-a-chip (SOC) in the single integrated circuit.

13. The invention of claim 11, wherein:

the image sensor, the memory, and the processor are implemented as a system-on-a-chip (SOC) in the single intergrated circuit; and

the diagnostic mode enables the imaging system to be tested using a testing system, wherein;

a test controller different from the processor generates instructions for controlling test operations of the testing system;

the testing system provides a set of light stimuli for the image sensor in response to the instructions;

the processor generates test results based on the digital image data indicating whether the image sensor is defective;

the test results are stored in the imaging system for access by the processor during the normal operating mode;

the test results identify a set of one or more defective pixels in the image sensor;

the imaging system is configured to use the test results during the normal operating mode to compensate for the one or more defective pixels identified during the diagnostic mode; and

the testing system is configured to test a packaged image sensor.

14. The invention of claim 13, wherein:

no diagnostic testing is performed on the image sensor to identify the one or more defective pixels in the image sensor prior to assembling the image sensor into the packaged image sensor; and

the testing system is adapted to test multiple instances of the imaging system simultaneously.

15. A method for fabricating an imaging system comprising the steps of:

(a) forming an image sensor configured to generate digital image data corresponding to an image of a scene, wherein the image sensor is a digital pixel sensor;

(b) forming a memory configured to store the digital image data corresponding to the image, wherein the image sensor and the memory are implemented in a single integrated circuit; and

(c) forming a processor configured to control operations of the imaging system in a diagnostic mode and in a normal operating mode, wherein during the diagnostic mode, the processor analyzes the digital image data to determine if the image sensor is defective and the diagnostic mode enables the imaging system to be tested using a testing system, wherein;

a test controller different from the processor generates instructions for controlling test operations of the testing system;

the testing system provides a set of light stimuli for the image sensor in response to the instructions; and

the processor generates test results based on the digital image data indicating whether the image sensor is defective.

16. The invention of claim 15, wherein the test results are stored in the imaging system for access by the processor during the normal operating mode.

17. The invention of claim 15, wherein the test results identify a set of one or more defective pixels in the image sensor.

18. The invention of claim 15, wherein the imaging system is configured to use the test results during the normal operating mode to compensate for one or more defective pixels identified during the diagnostic mode.

19. The invention of claim 15, wherein the testing system is configured to test a packaged image sensor.

20. The invention of claim 15, wherein the testing system is adapted to test multiple instances of the imaging system simultaneously.

21. An imaging system comprising an image sensor, a memory, and a processor, wherein:

the image sensor and the memory are implemented in a single integrated circuit;

the image sensor is a digital pixel sensor configured to generate digital image data corresponding to an image of a scene for storage in the memory;

the memory is configured to store the digital image data corresponding to the image;

the processor is configured to control operations of the imaging system in a normal operating mode, wherein, during the normal operating mode, the processor processes the digital image data to compensate for one or more defective pixels in the image sensor; and

the processor is further configured to control operations of the imaging system in a diagnostic mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to identify the one or more defective pixels in the image sensor and, prior to operating the image sensor in the normal operating mode, no physical modifications are made to the image sensor in response to identifying the one or more defective pixels in the image sensor during the diagnostic mode.

22. The invention of claim 21, wherein:

the image sensor, the memory, and the processor are implemented as a system-on-a-chip (SOC) in the single integrated circuit.

23. The invention of claim 21, wherein:

the image sensor, the memory, and the processor are implemented as a system-on-a-chip (SOC) in the single integrated circuit; and

the diagnostic mode enables the imaging system to be tested using a testing system, wherein;

a test controller different from the processor generates instructions for controlling test operations of the testing system;

the testing system provides a set of light stimuli for the image sensor in response to the instructions;

the processor generates test results based on the digital image data indicating whether the image sensor is defective;

the test results are stored in the imaging system for access by the processor during the normal operating mode; and

the testing system is configured to test a package image sensor.

24. The invention of claim 23, wherein:

no diagnostic testing is preformed on the image sensor to identify the one or more defective pixels in the image sensor prior to assembling the image sensor into the packaged image sensor; and

the testing system is adapted to test multiple instances of the imaging system simultaneously.

25. An imaging system comprising an image sensor, a memory, and a processor, wherein:

the image sensor and the memory are implemented in a single integrated circuit;

the image sensor is a digital pixel sensor configured to generate digital image data corresponding to an image of a scene for storage in the memory;

the memory is configured to store the digital image data corresponding to the image; and

the processor is configured to control operations of the imaging system in a normal operating mode, wherein, during the normal operating mode, the processor processes the digital image data to compensate for one or more defective pixels in the image sensor;

the processor is further configured to control operations of the imaging system in a diagnostic mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to identify the one or more defective pixels in the image sensor and the diagnostic mode enables the imaging system to be tested using a testing system, wherein;

a test controller different from the processor generates instructions for controlling test operations of the testing system;

the testing system provides a set of light stimuli for the image sensor in response to the instructions; and

the processor generates test results based on the digital image data indicating whether the image sensor is defective.

26. The invention of claim 25, wherein the test results are stored in the imaging system for access by the processor during the normal operating mode.

27. The invention of claim 25, wherein the testing system is configured to test a packaged image sensor.

28. The invention of claim 25, wherein the testing system is adapted to test multiple instances of the imaging system simultaneously.

29. An imaging system comprising an image sensor, a memory, and a processor, wherein:

the image sensor and the memory are implemented in a single integrated circuit;

the image sensor is a digital pixel sensor configured to generate digital image data corresponding to an image of a scene for storage in the memory;

the memory is configured to store the digital image data corresponding to the image;

the processor is configured to control operations of the imaging system in a diagnostic mode and in a normal operating mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to determine if the image sensor is defective; and

no diagnostic testing is performed on the image sensor to identify one or more defective pixels in the image sensor prior to assembling the image sensor into a packaged image sensor.

30. A method for fabricating an imaging system comprising the steps of:

(a) forming an image sensor configured to generate digital image data corresponding to an image of a scene, wherein the image sensor is a digital pixel sensor;

(b) forming a memory configured to store the digital image data corresponding to the image, wherein the image sensor and the memory are implemented in a single integrated circuit; and

(c) forming a processor configured to control operations of the imaging system in a diagnostic mode and in a normal operating mode, wherein, during the diagnostic mode, the processor analyzes the digital image data to determine if the image sensor is defective and no diagnostic testing is performed on the image sensor to identify one or more defective pixels in the image sensor prior to assembling the image sensor into a packaged image sensor.

31. An imaging system comprising an image sensor, a memory, and a processor, wherein:

the image sensor and the memory are implemented in a single integrated circuit;

the image sensor is a digital pixel sensor configured to generate digital image data corresponding to an image of a scene for storage in the memory;

the memory is configured to store the digital image data corresponding to the image; and

the processor is configured to control operations of the imaging system in a normal operating mode, wherein, during the normal operating mode, the processor processes the digital image data to compensate for one or more defective pixels in the image sensor and no diagnostic testing is performed on the image sensor to identify the one or more defective pixels in the image sensor prior to assembling the image, sensor into a packaged image sensor.