Method of processing an infrared image, infrared image capturing system and computer readable medium

• US 9,215,384 B2
• Filed: 07/09/2007
• Issued: 12/15/2015
• 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, Hgasten, Nicolas
• Primary Examiner(s): Pe, Geepy
• Assistant Examiner(s): Adrovel, William
• Application Number:
  US12/668,557
• Publication Number:
  US 20100238294A1
• Time in Patent Office: 3,081 Days
• US Class Current: 1/1
• 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, the method comprising:

capturing the infrared image;

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;

receiving a user operated control signal value from a user controlling two variables with a single control, wherein the processing and the scaling use filtering and gain values, respectively, corresponding to the control signal value;

merging the background portion and the detail portion after the scaling to provide a processed infrared image, wherein the merging of the background and the detail portion is controlled by the two variables, wherein a first variable of the two variables represents a standard deviation of the radiometric Gaussian, and wherein a second variable of the two variables represents a ratio between a dynamic range of the detail portion and a dynamic range of the background portion; and

storing or displaying the processed infrared image.

2. The method according to claim 1, further comprising:

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

3. The method according to claim 2, wherein 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 according to claim 3, wherein the filtering applies a bilateral filter to the infrared image, and wherein the bilateral filter uses a filter parameter corresponding to the user operated control signal value.

5. The method according to claim 4, further comprising:

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 according to claim 1, 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.

7. The method according to claim 6, wherein 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 the user operated control value.

8. An infrared image capturing system, comprising:

an infrared detector configured to capture an infrared image;

a processor;

a display;

a single control configured to control both of two variables; and

a memory structure configured to store information to control the processor to perform infrared image processing comprising;

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;

receiving a user operated control signal value from a user controlling the two variables with the single control, wherein the processing and the scaling use filtering and gain values, respectively, corresponding to the control signal value;

merging the background portion and the detail portion after the scaling to provide a processed infrared image, wherein the merging of the background and the detail portion is controlled by the two variables, wherein a first variable of the two variables represents a standard deviation of the radiometric Gaussian, and wherein a second variable of the two variables represents a ratio between a dynamic range of the detail portion and a dynamic range of the background portion;

storing or displaying the processed infrared image; and

wherein the display is configured to display the processed infrared image.

9. The infrared image capturing system according to claim 8, further comprising:

a sensor configured to provide environmental information to the processing component.

10. The infrared image capturing system according to claim 8, wherein the infrared image processing performed by the processor further comprises performing histogram equalization to the background portion prior to the merging of the background portion and the detail portion.

11. The infrared image capturing system according to claim 10, wherein the processing of 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.

12. The infrared image capturing system according to claim 11, wherein the filtering of the infrared image comprises applying a bilateral filter to the infrared image, and wherein the bilateral filter uses a filter parameter corresponding to the user operated control signal value.

13. The infrared image capturing system according to claim 12, wherein the infrared image processing performed by the processor 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.

14. The infrared image capturing system according to claim 8, 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.

15. The infrared image capturing system according to claim 14, wherein the scaling is based on a gain ratio corresponding to the user operated control signal value.

16. A computer program product of processing an infrared image, comprising:

a non-transitory computer-readable medium,

computer program instructions recorded on the computer readable medium and executable by a processor for performing a method comprising;

capturing the infrared image;

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;

receiving a user operated control signal value from a user controlling two variables with a single control, wherein the processing and the scaling use filtering and gain values, respectively, corresponding to the control signal value;

merging the background portion and the detail portion after the scaling to provide a processed infrared image, wherein the merging of the background and the detail portion is controlled by the two variables, wherein a first variable represents a standard deviation of the radiometric Gaussian, and wherein a second variable represents the ratio between the dynamic range of the detailed portion and the dynamic range of the background portion; and

storing or displaying the processed infrared image.

17. The computer program product according to claim 16, wherein the processing of the infrared image comprises:

filtering infrared image to provide the background portion; and

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

18. The computer program product according to claim 16, wherein the method further comprises:

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

19. The computer program product according to claim 18, wherein the filtering of the infrared image comprises applying a bilateral filter to the infrared image, and wherein the bilateral filter uses a filter parameter corresponding to the user operated control signal value.

20. The computer program product according to claim 19, wherein 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.

21. The computer program product according to claim 16, 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.

22. The computer program product according to claim 21, wherein the scaling is based on a gain ratio corresponding to the user operated control signal value.