Method, apparatus and system providing adjustment of pixel defect map

• US 8,582,005 B2
• Filed: 03/21/2011
• Issued: 11/12/2013
• Est. Priority Date: 08/25/2006
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Subbotin, Igor
• Primary Examiner(s): Ye, Lin
• Assistant Examiner(s): Chon, Peter
• Application Number:
  US13/052,660
• Publication Number:
  US 20110193998A1
• Time in Patent Office: 967 Days
• Field of Search: 348/175, 348/176, 348/177, 348/178, 348/179, 348/180, 348/187, 348/189, 348/241, 348/243, 348/244, 348/246, 348/247, 348/250, 348/251
• US Class Current: 348/247
• CPC Class Codes: H04N 25/68 applied to defects
• CPC Class Codes: H04N 25/683 by defect estimation performed on the scene signal, e.g. real time or on the fly detection

Abstract

A method, apparatus and system that allows for the identification of defective pixels, for example, defective pixel clusters, in an imager device. The method, apparatus and system determine, during use of the imager device, that a pixel defect, e.g., cluster defect, exists and accurately maps the location of the defective pixel. By analyzing more than one frame of an image, the method increases the accuracy of the defect mapping, which is used to improve the quality of the resulting image data.

Claims

1. An imager device comprising:

an array of pixel image sensors for providing a plurality of pixel output signals;

a memory for storing a pixel defect map, the stored map having data on a plurality of locations, each location corresponding to a pixel image sensor in the array; and

a processor for determining if a pixel defect cluster is detected at a first location using said pixel output signals corresponding to the first location and at least one neighboring location in the array and, if a pixel defect cluster is detected at the first location based on analyzing more than one frame of an image, updating the stored pixel defect map based on a type of the pixel defect cluster,

wherein the processor removes the pixel defect cluster at the first location from the stored map if the type of the pixel defect cluster at the first location is different from the type of a defect cluster that was previously present at the first location in the stored map.

2. The imager device of claim 1, wherein the processor determines whether a pixel defect cluster exists at the first location based on comparing the data in the stored map associated with the first location and the at least one neighboring location to current data on the received pixel output signals.

3. The imager device of claim 1, wherein the processor updates the stored map based on the existence of the pixel defect cluster at the first location, and a comparison of the type of the pixel defect cluster at the first location to the type of defect cluster that was previously present at the first location in the stored map.

4. The imager device of claim 3, wherein the processor identifies the pixel defect cluster at the first location from the stored map as a true defect cluster if the type of the pixel defect cluster at the first location is the same as the type of defect cluster that was previously present at the first location in the stored map.

5. The imager device of claim 1, wherein the processor determines whether the pixel defect cluster is a “

BRIGHT”

pixel defect type or a “

DARK”

pixel defect type.

6. The imager device of claim 1, wherein if a pixel defect cluster is detected at the first location, the processor adds the pixel defect cluster to the first location in the stored map if no pixel defect cluster was previously detected at the first location in the stored map.

7. The imager device of claim 1, wherein the data corresponding to a location in the map includes data related to pixel location, pixel defect cluster information and the type of the pixel defect cluster.

8. The imager device of claim 1, wherein if a pixel defect cluster is not detected at the first location and a pixel defect cluster was previously present at the first location in the stored map, the processor removes the pixel defect cluster at the first location in the map when conditions for detecting a pixel defect cluster meet pre-determined criteria.

9. The imager device of claim 8, wherein the pre-determined criteria include comparing pixel output signals to a saturation threshold.

10. A camera system comprising the imager device of claim 1.

11. An imager device comprising:

an array of pixel image sensors for providing a plurality of pixel output signals;

a memory for storing a pixel defect map, the stored map having saved data on a plurality of locations, each location corresponding to a pixel image sensor in the array; and

a processor for updating the stored pixel defect map using the pixel output signals to locate current pixel defects in accordance with pixel defect criterias,

wherein for every current pixel defect, if the corresponding location in the stored map was previously marked as defective, the processor removes the defect mark for the corresponding location in the map when the saved data for the corresponding location in the map is different from current data of said respective current pixel defect.

12. The imager device of claim 11, wherein if the corresponding location in the stored map was previously marked as defective, the processor marks the corresponding location in the map as a true defect when the saved data for the corresponding location in the map is the same as the current data of said respective current pixel defect.

13. The imager device of claim 11, wherein if the corresponding location in the stored map was not previously marked as defective, the processor marks the corresponding location in the map as defective.

14. The imager device of claim 11, wherein for every pixel defect location in the map that does not correspond to a current pixel defect location, the processor removes the defect mark for the corresponding location in the map when conditions for detecting a pixel defect meet pre-determined criteria.

15. The imager device of claim 14, wherein the pre-determined criteria include comparing the pixel output signals to a saturation threshold.

16. The imager device of claim 11, wherein the processor uses the pixel output signals for the corresponding location and at least one neighboring location in the map to locate current cluster defects.

17. The imager device of claim 16, wherein the processor updates the stored map according to a defect type corresponding to a current cluster defect, the processor identifies the defect type by comparing the pixel output signals to threshold bright and dark values.

18. A camera system comprising the imager device of claim 11.