Method and apparatus for enhancing digital images utilizing non-image data

1. A method of enhancing a digital image captured by a digital camera, comprising the steps of:

a) providing one or more data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and camera noise magnitude;

b) employing the one or more data to generate one or more noise processing parameters; and

c) employing the one or more noise processing parameters to enhance the spatial detail of the digital image;

further comprising the steps of providing photosensitivity data characterizing a digital camera image sensor, and also employing the photosensitivity data to generate the one or more noise processing parameters.

2. The method claimed in claim 1 , wherein the photosensitivity data is ISO speed setting.

3. The method claimed in claim 1 , further comprising the steps of providing the number of pixels in the image data and employing the number of pixels in the image data to generate the one or more noise processing parameters.

4. The method of claim 1 , wherein the step of enhancing the spatial detail of the image includes using the noise processing parameters to control a spatial filter, and applying the spatial filter to the digital image.

5. The method of claim 4 , wherein the spatial filter is a noise reduction filter that removes noise from a digital image.

6. The method of claim 4 , wherein the spatial filter is a sharpening filter that enhances the spatial detail of a digital image.

7. The method of claim 4 , wherein the spatial filter is a non-linear spatial filter.

8. The method of claim 1 , wherein the noise processing parameter relates to the standard deviation of the expected noise magnitude present in the digital image.

9. The method of claim 1 , wherein the digital image is a color digital image having color channels and further including the step of generating a noise processing parameter individually for each color channel.

10. The method of claim 1 , wherein the step of generating the one or more noise processing parameters includes generating a plurality of noise processing parameters as a function of pixel value.

11. The method of claim 1 , wherein the one or more data are recorded in an image file with the digital image.

12. The method of claim 11 , wherein the digital camera records the one or more data.

13. The method of claim 1 , wherein the one or more noise processing parameters are generated by using the one or more data to select from previously generated noise processing parameters.

14. The method of claim 1 , wherein the one or more noise processing parameters are embodied in a noise characteristic table.

15. The method of claim 14 , wherein the noise characteristic table is a table of noise standard deviation values.

16. The method of claim 1 , wherein the enhancing step employs a sigma noise filter.

17. A method of enhancing a digital image captured by a digital camera, comprising the steps of:

a) providing one or more data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and camera noise magnitude;

b) employing the one or more data to generate one or more noise processing parameters; and

c) employing the one or more noise processing parameters to enhance the spatial detail of the digital image;

wherein the step of enhancing the spatial detail of the image includes using the noise processing parameters to control a spatial filter, and applying the spatial filter to the digital image;

wherein the spatial filter is a noise reduction filter that removes noise from a digital image; and

wherein the digital image includes pixel values and the noise reduction filter comprises the steps of:

c1) calculating a pixel difference value as the absolute value difference between a pixel value to be enhanced and neighboring pixel values; and

c2) using the pixel difference values and the noise processing parameter(s) to selectively average neighboring pixel values to calculate a noise reduced pixel value for the pixel to be enhanced.

18. A method of enhancing a digital image captured by a digital camera, comprising the steps of:

a) providing one or more data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and camera noise magnitude;

b) employing the one or more data to generate one or more noise processing parameters; and

c) employing the one or more noise processing parameters to enhance the spatial detail of the digital image;

wherein the step of enhancing the spatial detail of the image includes using the noise processing parameters to control a spatial filter, and applying the spatial filter to the digital image;

wherein the spatial filter is a sharpening filter that enhances the spatial detail of a digital image; and

wherein the digital image includes pixel values and the sharpening filter comprises the steps of:

c1) calculating a variance value for a neighborhood of pixel values about a pixel value to be enhanced; and

c2) using the calculated variance value and the noise processing parameter(s) to enhance the spatial detail of the digital image.

19. Apparatus for enhancing a digital image captured by a digital camera, comprising:

a) a source of one or more data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and camera noise magnitude;

b) means employing the one or more data for generating one or more noise processing parameters; and

c) means employing the one or more noise processing parameters for enhancing the spatial detail of the digital image; and

further comprising a source of photosensitivity data characterizing a digital camera image sensor, and means employing the photosensitivity data for generating the one or more noise processing parameters.

20. The apparatus claimed in claim 19 , wherein the photosensitivity data is ISO speed setting.

21. The apparatus claimed in claim 19 , further comprising a source of the number of pixels in the image data and means employing the number of pixels in the image data for generating the one or more noise processing parameters.

22. The apparatus of claim 19 , wherein the means for enhancing the spatial detail of the image includes means using the noise processing parameters for controlling a spatial filter, and means for applying the spatial filter to the digital image.

23. The apparatus of claim 22 , wherein the spatial filter is a noise reduction filter that removes noise from a digital image.

24. The apparatus of claim 22 , wherein the spatial filter is a sharpening filter that enhances the spatial detail of a digital image.

25. The apparatus of claim 22 , wherein the spatial filter is a non-linear spatial filter.

26. The apparatus of claim 19 , wherein the noise processing parameter relates to the standard deviation of the expected noise magnitude present in the digital image.

27. The apparatus of claim 19 , wherein the digital image is a color digital image having color channels and further including means for generating a noise processing parameter individually for each color channel.

28. The apparatus of claim 19 , wherein means for generating the one or more noise processing parameters includes means for generating a plurality of noise processing parameters as a function of pixel value.

29. The apparatus of claim 19 , wherein the source of the one or more data is an image file containing the digital image.

30. The apparatus of claim 29 , wherein the digital camera includes means for recording the one or more data.

31. The apparatus of claim 19 , wherein the one or more noise processing parameters are generated by using the one or more data to select from previously generated noise processing parameters.

32. The apparatus of claim 19 , wherein the one or more noise processing parameters are embodied in a noise characteristic table.

33. The apparatus of claim 32 , wherein the noise characteristic table is a table of noise standard deviation values.

34. The apparatus of claim 19 , wherein the enhancing means employs a sigma noise filter.

35. Apparatus for enhancing a digital image captured by a digital camera, comprising:

a) a source of one or more data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and camera noise magnitude;

b) means employing the one or more data for generating one or more noise processing parameters; and

c) means employing the one or more noise processing parameters for enhancing the spatial detail of the digital image;

wherein the means for enhancing the spatial detail of the image includes means using the noise processing parameters for controlling a spatial filter, and means for applying the spatial filter to the digital image;

wherein the spatial filter is a noise reduction filter that removes noise from a digital image; and

wherein the digital image includes pixel values and the noise reduction filter comprises:

c1) means for calculating a pixel difference value as the absolute value difference between a pixel value to be enhanced and neighboring pixel values; and

c2) means for using the pixel difference values and the noise processing parameter(s) to selectively average neighboring pixel values to calculate a noise reduced pixel value for the pixel to be enhanced.

36. Apparatus for enhancing a digital image captured by a digital camera, comprising:

a) a source of one or more data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and camera noise magnitude;

b) means employing the one or more data for generating one or more noise processing parameters; and

c) means employing the one or more noise processing parameters for enhancing the spatial detail of the digital image;

wherein the means for enhancing the spatial detail of the image includes means using the noise processing parameters for controlling a spatial filter, and means for applying the spatial filter to the digital image;

wherein the spatial filter is a sharpening filter that enhances the spatial detail of a digital image; and

wherein the digital image includes pixel values and the sharpening filter comprises:

c1) means for calculating a variance value for a neighborhood of pixel values about a pixel value to be enhanced; and

c2) means for using the calculated variance value and the noise processing parameter(s) to enhance the spatial detail of the digital image.

37. A software program product embodied in a computer readable medium for performing the method of claim 1 .

38. A method of enhancing a digital image captured by a digital camera, comprising the steps of:

a) providing a plurality of data selected from the group consisting of camera model type, image sensor type, type of light source, type of image compression, previous noise reduction processing history, previous spatial sharpening processing history, and photosensitivity data characterizing a digital camera image sensor;

b) employing the plurality of data to generate for each data a relative noise magnitude scaling factor;

c) employing the plurality of relative noise magnitude scaling factors to enhance the spatial detail of the digital image.

39. The method claimed in claim 38 , wherein the step of enhancing the spatial detail further comprises the steps of:

c1) combining the plurality of relative noise magnitude scaling factors into a single noise scaling factor;

c2) using the single noise scaling factors to generate one or more noise processing parameters; and

c3) employing the one or more noise processing parameters to enhance the spatial detail of the digital image.