Systems and methods for processing infrared images

• US 8,208,026 B2
• Filed: 03/02/2009
• Issued: 06/26/2012
• Est. Priority Date: 03/02/2009
• Status: Expired due to Fees

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: Högasten, Nicholas, Ingerhed, Malin
• Primary Examiner(s): Donaghue, Larry
• Assistant Examiner(s): MCLEOD, MARSHALL M
• Application Number:
  US12/396,340
• Publication Number:
  US 20100220193A1
• Time in Patent Office: 1,212 Days
• Field of Search: 348/164
• US Class Current: 348/164
• CPC Class Codes: H04N 23/20 for generating image signals from infrared radiation only
• CPC Class Codes: H04N 25/677 for reducing the column or line fixed pattern noise
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

One or more embodiments of the invention provide a system and method for processing an infrared image to receive infrared image data of a non-uniform scene, apply column noise filter correction to the infrared image data, and/or apply row noise filter correction to the infrared image data, and provide corrected infrared image data based on the column and/or row noise filter correction as infrared output image data.

Claims

1. A method for processing infrared image data, comprising:

receiving infrared image data from a multi-pixel infrared detector based on a non-uniform scene;

determining column noise offset terms for corresponding columns, wherein the determining comprises;

calculating, for each pixel, a difference between a center pixel and a plurality of neighboring pixels to determine column neighbor differences, and

generating, for each column, a histogram of the column neighbor differences;

applying column noise filter correction to the infrared image data based on the column noise offset terms, wherein the column noise offset term is applied to at least a majority of the infrared image data in each corresponding column;

providing corrected infrared image data based on the column noise filter correction as infrared output image data; and

storing the infrared output image data.

2. The method of claim 1, further comprising:

determining row noise offset terms for corresponding rows; and

applying row noise filter correction to the infrared image data based on the row noise offset terms, wherein the row noise offset term is applied to at least a majority of the infrared image data in each corresponding row,

wherein the providing corrected infrared image data as infrared output image data is further based on the row noise filter correction.

3. The method of claim 2, wherein:

the determining the row noise offset terms comprises calculating, for each pixel, a difference between a center pixel and a plurality of neighboring pixels to determine row neighbor differences.

4. The method of claim 3, wherein the determining the row noise offset terms comprises generating, for each row, a histogram of the row neighbor differences.

5. The method of claim 4, comprising:

separately comparing the column and row neighbor differences to a predetermined threshold; and

adding the column and row neighbor differences to respective columns and rows, if the difference is below the predetermined threshold.

6. The method of claim 5, wherein the adding of the column and row neighbor differences to respective columns and rows comprises adding the column and row neighbor differences to the histogram for specific columns and rows, respectively.

7. The method of claim 6, comprising determining a median difference for respective columns and rows.

8. The method of claim 7, comprising:

adding the median difference to one or more previous column and row correction terms for respective columns and rows; and

applying the column and row correction terms to the infrared image data.

9. The method of claim 2, comprising high pass filtering the infrared image data prior to applying the column and row noise filter correction to the infrared image data.

10. The method of claim 9, wherein the high pass filtering of respective rows and columns comprises subtracting a result of a low pass filter operation.

11. The method of claim 2, comprising:

delaying the infrared image data by one frame prior to applying the column and row noise filter correction; and

displaying the infrared output image data.

25. A non-transitory computer readable medium on which are stored computer readable instructions for performing the method of claim 1.

26. A non-transitory computer readable medium on which are stored computer readable instructions for performing the method of claim 2.

12. An infrared imaging system, comprising:

an infrared detector;

a processor adapted to process infrared image data from the infrared detector of a non-uniform scene by;

receiving infrared image data based on a non-uniform scene from a multi-pixel infrared detector;

determining column noise offset terms for corresponding columns, wherein the determining comprises;

calculating, for each pixel, a difference between a center pixel and a plurality of neighboring pixels to determine column neighbor differences, and

generating, for each column, a histogram of the column neighbor differences;

applying column noise filter correction to the infrared image data based on the column noise offset terms, wherein the column noise offset term is applied to at least a majority of the infrared image data in each corresponding column; and

providing corrected infrared image data based on the column noise filter correction as infrared output image data; and

a memory component adapted to store the infrared output image data.

13. The infrared imaging system of claim 12, wherein the processor is further adapted to process infrared image data from the infrared detector of a non-uniform scene by:

determining row noise offset terms for corresponding rows; and

applying row noise filter correction to the infrared image data based on the row noise offset terms, wherein the row noise offset term is applied to at least a majority of the infrared image data in each corresponding row,

wherein the providing corrected infrared image data as infrared output image data is further based on the row noise filter correction.

14. The infrared imaging system of claim 13, wherein:

the determining the row noise offset terms comprises calculating, for each pixel, a difference between a center pixel and a plurality of neighboring pixels to determine row neighbor differences.

15. The infrared imaging system of claim 14, wherein the determining row noise offset terms comprises generating, for each row, a histogram of the row neighbor differences.

16. The infrared imaging system of claim 15, wherein the determining row and column noise offset terms comprises processing infrared image data by:

separately comparing the column and row neighbor differences to a predetermined threshold; and

adding the column and row neighbor differences to respective columns and rows, if the difference is below the predetermined threshold.

17. The infrared imaging system of claim 16, wherein the adding of the column and row neighbor differences to respective columns and rows comprises adding the column and row neighbor differences to the histogram for specific columns and rows, respectively.

18. The infrared imaging system of claim 17, wherein the determining row and column noise offset terms comprises processing infrared image data by determining a median difference for respective columns and rows.

19. The infrared imaging system of claim 18, wherein the determining row and column noise offset terms comprises processing infrared image data by:

adding the median difference to one or more previous column and row correction terms for respective columns and rows; and

applying the column and row correction terms to the infrared image data.

20. The infrared imaging system of claim 19, wherein the determining row and column noise offset terms comprises processing infrared image data by high pass filtering the infrared image data prior to applying column and row noise filter correction to the infrared image data.

21. The infrared imaging system of claim 13, wherein the processor is adapted to process infrared image data by:

delaying the infrared image data by one frame prior to applying the column and row noise filter correction; and

displaying the infrared output image data via a display component.

22. The infrared imaging system of claim 12, wherein the infrared imaging system comprises an infrared camera adapted to capture and process the infrared image data including infrared video image data of the non-uniform scene, and wherein the infrared detector is adapted to detect infrared radiation and provide representative infrared image data of the non-uniform scene.

23. The infrared imaging system of claim 12, wherein the infrared detector is remote from the processor, and wherein the infrared detector is adapted to remotely relay infrared image data to the processor, with the processor comprising a computer system.

24. The infrared imaging system of claim 12, wherein the infrared imaging system comprises an infrared camera, the infrared camera comprising:

a control component adapted to interface with a user and receive user input control signals to control various operations of the infrared imaging system; and

a display component adapted to display infrared image data,

wherein the processor is adapted to obtain infrared image data from the infrared detector and display the obtained infrared image data on the display component, and

wherein the processor is adapted to retrieve infrared image data from the memory component and display the retrieved infrared image data on the display component.