System and method for image fusion

• US 20040141659A1
• Filed: 01/17/2003
• Published: 07/22/2004
• Est. Priority Date: 01/17/2003
• Status: Active Grant

• Current Assignee: University of New Brunswick
• Original Assignee: University of New Brunswick
• Inventors: Zhang, Yun
• Granted Patent: US 7,340,099 B2
• Time in Patent Office: Days
• US Class Current: 382/284
• CPC Class Codes: G06T 2207/10036 Multispectral image; Hyperspectral image
• CPC Class Codes: G06T 2207/10041 Panchromatic image
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 2207/30181 Earth observation
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction

Abstract

A method of fusing a low resolution multispectral image with a high resolution panchromatic image comprising the step of generating a new synthetic pan image using multispectral bands from the multispectral image.

Claims

1. A method of fusing a low resolution multispectral image with a high resolution panchromatic image comprising the step of generating a new synthetic pan image using multispectral bands from the multispectral image.

2. A method according to claim 1 wherein the new synthetic pan image is generated using the equation:

3. A method according to claim 2 wherein the coefficients φ

_k are calculated using the equation;

4. A method according to claim 1 including the step of performing a histogram standardization on all bands.

6. A claim according to claim 4, including the steps of determining the full grey value range and the common mean wherein the full grey value range is equal to the maximum grey value range of all the original image bands used in the fusion and the common mean is located at the centre of the full grey value range.

5. A method of histogram standardization of image bands comprising the steps of:

(a) calculating the means and standard deviations of all of the bands; and

(b) stretching the histograms of all the image bands to a common full grey value range with a common mean according to their individual means and standard deviations.

7. A claim according to claim 5, wherein the image bands in the stretching step lie within a standard deviation of ±

3σ and

±

7σ

.

8. A method of fusing a low resolution multispectral image with a high resolution panchromatic image comprising the steps of:

(a) selecting from the multispectral image, multispectral bands having spectral ranges which overlap the spectral range of panchromatic image;

(b) determining coefficient values using the selected multispectral bands and the panchromatic image;

(c) generating a synthetic panchromatic image using the coefficient values and the selected multispectral bands; and

(d) generating one or more fused image bands using the panchromatic image, one or more multispectral bands, and the synthetic panchromatic image.

9. A method according to claim 8 wherein the synthetic panchromatic image has a grey value variation similar to that of the panchromatic image.

10. A method according to claim 8, wherein the selected multispectral bands together cover a spectral range close or equal to that of the panchromatic image within the range from visible to infrared.

11. A method according to claim 8, wherein the images being fused are optical images such as images taken by IKONOS, QuickBird, Landsat 7 ETM+ and other sensors.

12. A method according to claim 11, wherein for IKONOS and QuickBird images, the selected multispectral bands are bands 1, 2, 3 and 4.

13. A method according to claim 11, wherein for Landsat 7 images, the selected multispectral bands are bands 2, 3 and 4.

14. A method according to claim 12, wherein the fused image bands are any three multispectral bands.

15. A method according to claim 12, wherein the fused image bands are one or more bands selected from the group comprising bands 1, 2, 3 and 4.

16. A method according to claim 13, wherein the fused image bands are one or more bands selected from the group comprising bands 1, 2, 3, 4, 5 and 7.

17. A method according to claim 15, including the step of fusing bands 1, 2, 3 and 4 at the same time.

18. A method according to claim 16, including the step of fusing bands 1, 2, 3, 4, 5 and 7 at the same time.

19. A method according to claim 8, wherein the coefficient values are generated using a computational method selected from the group comprising regression and least squares.

20. A method according to claim 8, including the step of performing histogram standardization on the bands being fused.

21. A method of histogram standardization of image bands comprising the steps of:

(a) calculating means, deviations, and a covariance matrix from all the image bands,

(b) calculating band weights for simulating the NewPan_Syn from the covariance matrix,

(c) standardizing all the bands using the means and deviations,

(d) generating a NewPanSyn using the band weights and the selected standardized multispectral bands, and

(e) performing the Product-Synthetic Ratio using the standardized panchromatic band, the standardized multispectral bands and the NewPanSyn.