NOISE REMOVAL DEVICE, NOISE REMOVAL METHOD, AND COMPUTER READABLE RECORDING MEDIUM

• US 20090060323A1
• Filed: 08/28/2008
• Published: 03/05/2009
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Kanazawa University, Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: KOMATSU, Takashi, SAITO, Takahiro, ARAGAKI, Hideya
• Granted Patent: US 8,391,635 B2
• Time in Patent Office: Days
• US Class Current: 382/164
• CPC Class Codes: G06T 2207/20064 Wavelet transform [DWT]
• CPC Class Codes: G06T 5/10 using non-spatial domain filtering
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06V 10/30 Noise filtering

Abstract

A noise removal device that removes noise from an image signal includes: a separation unit that separates the image signal into at least two subband signals; a parameter setting unit that sets a plurality of coring ranges in relation to at least one of the subband signals; and a coring unit that performs coring processing on the basis of the plurality of coring ranges.

Claims

1. A noise removal device that removes noise from an image signal, comprising:

a separation unit that separates the image signal into at least two subband signals;

a parameter setting unit that sets a plurality of coring ranges in relation to at least one of the subband signals; and

a coring unit that performs coring processing on the basis of the plurality of coring ranges.

2. The noise removal device as defined in claim 1, wherein the parameter setting unit sets fixed output values relative to the plurality of coring ranges, and

the coring unit transforms a signal value belonging to any one of the plurality of coring ranges within the subband signal into a corresponding output value, and corrects a signal value that does not belong to any one of the plurality of coring ranges.

3. The noise removal device as defined in claim 2, wherein the image signal is constituted by a plurality of color components, and

the separation unit, the parameter setting unit, and the coring unit are applied to each of the color components.

4. The noise removal device as defined in claim 3, wherein the parameter setting unit sets the plurality of coring ranges on the basis of a calculation value of a signal value of the plurality of color components.

5. The noise removal device as defined in claim 4, wherein the parameter setting unit calculates the calculation value on the basis of at least one of a color difference and a color sum calculated from the signal value of the color components.

6. The noise removal device as defined in claim 2, further comprising a noise estimation unit that estimates a noise amount in relation to the image signal or the subband signal,

wherein the parameter setting unit adjusts the plurality of coring ranges on the basis of the noise amount.

7. The noise removal device as defined in claim 1, wherein the separation unit employs a wavelet transform.

8. The noise removal device as defined in claim 1, further comprising a synthesis unit that synthesizes the plurality of subband signals following the coring processing.

9. A noise removal method for removing noise from an image signal, comprising:

a separation step for separating the image signal into at least two subband signals;

a parameter setting step for setting a plurality of coring ranges in relation to at least one of the subband signals; and

a coring step for performing coring processing on the basis of the plurality of coring ranges.

10. The noise removal method as defined in claim 9, wherein the parameter setting step sets fixed output values relative to the plurality of coring ranges, and

the coring step transforms a signal value belonging to any one of the plurality of coring ranges within the subband signal into a corresponding output value, and corrects a signal value that does not belong to any one of the plurality of coring ranges.

11. The noise removal method as defined in claim 10, wherein the image signal is constituted by a plurality of color components, and

the separation step, the parameter setting step, and the coring step are applied to each of the color components.

12. The noise removal method as defined in claim 11, wherein the parameter setting step sets the plurality of coring ranges on the basis of a calculation value of a signal value of the plurality of color components.

13. The noise removal method as defined in claim 12, wherein the parameter setting step calculates the calculation value on the basis of at least one of a color difference and a color sum calculated from the signal value of the color components.

14. The noise removal method as defined in claim 10, further comprising a noise estimation step for estimating a noise amount in relation to the image signal or the subband signal,

wherein the parameter setting step adjusts the plurality of coring ranges on the basis of the noise amount.

15. The noise removal method as defined in claim 9, wherein the separation step employs a wavelet transform.

16. The noise removal method as defined in claim 9, further comprising a synthesis step for synthesizing the plurality of subband signals following the coring processing.

17. A noise removal device that removes noise from an image signal, comprising:

separation means for separating the image signal into at least two subband signals;

parameter setting means for setting a plurality of coring ranges in relation to at least one of the subband signals; and

coring means for performing coring processing on the basis of the plurality of coring ranges.

18. A computer readable storage medium, comprising:

a program encoded and stored in a computer readable format to cause a computer to execute a method for removing noise from an image signal comprising steps of;

a separation step for separating the image signal into at least two subband signals;

a parameter setting step for setting a plurality of coring ranges in relation to at least one of the subband signals; and

a coring step for performing coring processing on the basis of the plurality of coring ranges.