CONVERTING AN IMAGE FROM A DUAL-BAND SENSOR TO A VISIBLE COLOR IMAGE

• US 20150288941A1
• Filed: 10/17/2013
• Published: 10/08/2015
• Est. Priority Date: 10/17/2013
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: SCHACHTER, Bruce J., Vanmaasdam, Peter J., Riddle, Jack Gordon
• Granted Patent: US 9,544,562 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: H04N 23/20 for generating image signals from infrared radiation only
• 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
• CPC Class Codes: H04N 9/77 Circuits for processing the brightness signal and the chrominance signal relative to each other, e.g. adjusting the phase of the brightness signal relative to the colour signal, correcting differential gain or differential phase circuits for matrixing H04N9/67

Abstract

One embodiment describes a method for converting a dual-band image to a visible color image. The method includes converting the dual-band image to data in a placeholder image in a placeholder color space. The placeholder color space employs a wavelet-based image fusion technique while mimicking the oppositional color processing technique of the human visual system. The placeholder image is further mapped into visible color space, generating the visible color image.

Claims

1. An apparatus, comprising:

a non-transitory memory storing machine-readable instructions; and

a processor that facilitates the execution of the machine-readable instructions to at least;

convert an image from a dual-band image sensor to a placeholder image in a placeholder color space that is established based on a wavelet-based image fusion and an oppositional color processing technique; and

create a visible color image by mapping the placeholder image to a visible color space.

2. The apparatus of claim 1, wherein the dual-band image sensor is a dual-band forward looking infrared sensor or at least two of a long wave infrared sensor, a mid wave infrared sensor, a short wave infrared sensor, a monochrome visible sensor, a near infrared sensor, or an image intensified image sensor.

3. The apparatus of claim 1, wherein:

the image from the dual-band sensor comprises long-wave data and mid-wave data; and

data within the placeholder image exhibits a decreased redundancy relative to a pairing of the long-wave data and the mid-wave data.

4. The apparatus of claim 1, wherein:

the image from the dual-band sensor comprises long-wave data and mid-wave data;

the oppositional color processing technique creates a temporary red channel, a temporary green channel, and a temporary blue channel;

the temporary red channel comprises the long-wave data;

the temporary green channel comprises the mid-wave data; and

the temporary blue channel comprises data that represents a function of the long-wave data and the mid-wave data.

5. The apparatus of claim 4, wherein:

the placeholder image comprises a* data, and b* data;

the a* data comprises a function of data from the temporary red channel and data from the temporary green channel; and

the b* data comprises a function of data from the temporary blue channel, data from the temporary red channel, and data from the temporary green channel.

6. The apparatus of claim 4, wherein:

the placeholder image further comprises luminance (L*) data; and

the L* data comprises data representing a fused image based on a wavelet-based image fusion of the image from the dual-band sensor.

7. The apparatus of claim 1, wherein the processor further facilitates the execution of the machine-readable instructions to transform the visible color image to a different color space to emphasize a feature of the visible color image.

8. The apparatus of claim 1, wherein the processor further facilitates the execution of the machine-readable instructions to apply a mean filter, a median filter, a high-pass filter, a low-pass filter, or an unsharp-mask filter to at least one of the image from the dual-band sensor, the placeholder image, or the visible color image.

9. A non-transitory computer-readable storage medium storing instructions executable by an associated processor to perform a method for converting a dual-band image to a visible color image, the method comprising:

converting the dual-band image to a placeholder image in a placeholder color space established based on wavelet-based image fusion and an oppositional color processing technique used by the human visual system, wherein the converting comprises reducing a redundancy between a first channel of the dual-band image and a second channel of the dual-band image; and

mapping the placeholder image into a visible color space to create the visible color image.

10. The non-transitory computer-readable storage medium of claim 9, wherein:

the first channel of the dual-band image comprises long-wave data and the second channel of the dual-band image comprises mid-wave data;

the placeholder image comprises luminance (L*) data, a* data and b* data, and

the visible color space comprises red-band data, green-band data, and blue-band data.

11. The non-transitory computer-readable storage medium of claim 10, wherein the converting the dual-band image to the placeholder image comprises:

generating the L* data based on the wavelet-based image fusion of the long-wave data and the mid-wave data;

generating the a* data and the b* data based on the oppositional color processing technique, the a* data and the b* data comprising functions of the long-wave data and the mid-wave data.

12. The non-transitory computer-readable storage medium of claim 11, wherein the converting the dual-band image to the placeholder image further comprises:

reducing a redundancy in the placeholder image by expanding a dynamic range of the a* data and a dynamic range of the b* data.

13. The non-transitory computer-readable storage medium of claim 9, wherein the method further comprises:

applying a filtering algorithm to reduce noise in the dual-band image to facilitate the converting; and

standardizing a dynamic range of the first channel of the dual-band image and the second channel of the dual-band image to facilitate the converting.

14. A non-transitory computer-readable device storing executable instructions executable by an associated processor to perform operations that convert a dual-band infrared image to a visible color image, the operations comprising:

reducing noise in the dual-band infrared image;

standardizing a dynamic range of a first band of the dual-band infrared image and a dynamic range of a second band of the dual-band infrared image;

converting the dual-band infrared image with reduced noise and standardized dynamic range of the first band and the second band to a placeholder image in a placeholder color space established based on wavelet-based image fusion and an oppositional color processing technique used by the human visual system; and

transforming the placeholder image to a visible color space to create the visible color image.

15. The non-transitory computer-readable device of claim 14, wherein the operations further comprise displaying the visible color image on a display device.

16. The non-transitory computer-readable device of claim 14, wherein:

the first band comprises long-wave data;

the second band comprises mid-wave data;

the placeholder color space comprises luminance (L*) data, a* data, and b* data; and

the visible color space comprises red channel data, green channel data, and blue channel data.

17. The non-transitory computer-readable device of claim 16, wherein the oppositional color processing technique comprises:

forming a temporary red channel, a temporary green channel and a temporary blue channel, wherein;

the temporary red channel comprises the long-wave data;

the temporary green channel comprises the mid-wave data; and

the temporary blue channel comprises a function of the long-wave data and the mid-wave data; and

converting the placeholder image into the placeholder color space,

wherein;

the a* data comprises data from the red channel and data from the green channel, and

the b* data comprises data from the blue channel, data from the red channel and data from the green channel.

18. The non-transitory computer-readable device of claim 17, wherein the wavelet-based image fusion comprises creating the L* data based on fusing the long wave data and the short wave data according to a dual-tree complex wavelet transform process.

19. The non-transitory computer-readable device of claim 18, wherein the dual-tree complex wavelet transform process comprises:

converting the long-wave data and the mid-wave data to a transform domain according to a dual-tree complex wavelet transform process that increases a shift invariance and increases a directional sensitivity in the L* data; and

forming a transform image by selecting coefficients from the transformed long-wave band image and the transformed mid-wave band image.

20. The non-transitory computer-readable device of claim 19, wherein the dual-tree complex wavelet transform process further comprises producing the fused grayscale image by taking an inverse transform of the transform image.