METHOD OF PROCESSING AN INFRARED IMAGE, INFRARED IMAGE CAPTURING SYSTEM AND COMPUTER READABLE MEDIUM

• US 20100238294A1
• Filed: 07/09/2007
• Published: 09/23/2010
• Est. Priority Date: 07/09/2007
• Status: Active Grant

• Current Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Original Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Inventors: Andersson, Fredrik, Högasten, Nicholas
• Granted Patent: US 9,215,384 B2
• Time in Patent Office: Days
• US Class Current: 348/164
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 5/40 using histogram techniques
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement
• CPC Class Codes: G06T 7/194 involving foreground-background segmentation
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 5/2226 Determination of depth image, e.g. for foreground/background separation determining depth by image analysis in general G06T7/50; segmentation by image analysis in general G06T7/10
• 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

A system and method for processing an infrared image. The infrared image is processed to provide a background portion of the infrared image and a detail portion of the infrared image. The background portion and/or the detail portion is scaled to provide a level of the detail portion relative to a level of the background portion. The background portion and the detail portion are merged after the scaling to provide a processed infrared image. The processed infrared image is stored.

Claims

1. A method of processing an infrared image, characterized in that the method comprises:

processing the infrared image to provide a background portion of the infrared image and a detail portion of the infrared image;

scaling the background portion and/or the detail portion to provide a level of the detail portion relative to a level of the background portion;

merging the background portion and the detail portion after the scaling to provide a processed infrared image; and

storing the processed infrared image.

2. The method of claim 1, characterized in that the method further comprises:

performing histogram equalization to the background portion prior to the merging of the background portion and the detail portion.

3. The method of claim 2, characterized in that the processing the infrared image comprises:

filtering the infrared image to provide the background portion; and

subtracting the background portion from the infrared image to provide the detail portion.

4. The method of claim 3, characterized in that the filtering applies a bilateral filter to the infrared image, and that the bilateral filter uses a filter parameter corresponding to a user input value.

5. The method of claim 4, characterized in that the method further comprises storing a table of values of radiometric weights as a function of radiometric distance for the filter parameter for use by the filtering.

6. The method of claim 1, characterized in that the scaling is applied only to the detail portion to provide a level of the detail portion relative to a level of the background portion.

7. The method of claim 6, characterized in that the scaling to provide a level of the detail portion relative to a level of the background portion is based on a gain ratio corresponding to a user input value.

8. The method of claim 1, characterized in that the method further comprises:

capturing the infrared image; and

displaying the processed infrared image

9. The method of claim 1, characterized in that the method further comprises receiving a control signal value from a user, wherein the processing and the scaling use filtering and gain values, respectively, corresponding to the control signal value.

10. The method as claimed in any of the preceding claims, characterized in that the merging of the background and the detail portion is controlled by two variables.

11. The method of claim 10, characterized that one variable represents a standard deviation of the radiometric Gaussian.

12. The method of claim 10 or 11, characterized in that the other variable represents the ratio between the dynamic range of the detailed portion and the dynamic range of the background portion.

13. An infrared image capturing system characterized in that the system comprises:

an image capture component adapted to capture an infrared image;

a processing component;

a memory component adapted to store information to control the processing component to perform infrared image processing comprising;

filtering the infrared image to provide a background portion of the infrared image and a detail portion of the infrared image;

scaling the background portion and/or the detail portion to provide a level of the detail portion relative to a level of the background portion;

merging the background portion and the detail portion after the scaling to provide a processed infrared image; and

storing the processed infrared image.

14. The infrared image capturing system of claim 13, characterized in that the system further comprises a display component adapted to display the processed infrared image.

15. The infrared image capturing system of claim 13, characterized in that the system further comprises a sensing component adapted to provide environmental information to the processing component.

16. The infrared image capturing system of claim 13, characterized in that the system further comprises a user control component adapted to allow a user to select a processing control value to control the filtering and the scaling.

17. The infrared image capturing system of claim 16, characterized in that the infrared image processing performed by the processing component further comprises performing histogram equalization to the background portion prior to the merging of the background portion and the detail portion.

18. The infrared image capturing system of claim 17, characterized in that the filtering the infrared image comprises:

applying a bilateral filter to the infrared image, wherein the bilateral filter uses a filter parameter corresponding to the processing control value; and

subtracting the background portion from the infrared image to provide the detail portion.

19. The infrared image capturing system of claim 18, characterized in that the scaling is applied only to the detail portion to provide a level of the detail portion relative to a level of the background portion, and wherein the scaling is based on a gain ratio corresponding to the processing control value.

20. A computer-readable medium, characterized in that on the medium is stored information for performing a method, the method comprising:

filtering an infrared image to provide a background portion of the infrared image and a detail portion of the infrared image;

scaling the background portion and/or the detail portion to provide a level of the detail portion relative to a level of the background portion;

performing histogram equalization to the background portion;

merging the background portion and the detail portion after the scaling to provide a processed infrared image; and

storing the processed infrared image.

21. The computer-readable medium of claim 20, characterized in that the information comprises an adaptive contrast (AC) filtering algorithm, and that the method further comprises receiving an AC value that corresponds to a filter value and a gain value for use by the filtering and the scaling, respectively.

22. The computer-readable medium of claim 21, characterized in that the filtering the infrared image comprises:

applying a bilateral filter to the infrared image, wherein the bilateral filter uses the filter value;

subtracting the background portion from the infrared image to provide the detail portion; and

wherein the scaling is applied only to the detail portion to provide a level of the detail portion relative to a level of the background portion, and wherein the scaling uses the gain value.

23. The computer-readable medium of claim 22, further comprising:

capturing the infrared image; and

displaying the processed infrared image.