Image signal processing apparatus, imaging apparatus, image signal processing method and computer program

1. An image signal processing apparatus, comprising:

a noise reduction processing unit that:

establishes weights for first pixel values of a first demosaic image based on edge information extracted from a second demosaic image;

generates second pixel values for the first demosaic image based on an application of the established weights to corresponding ones of the first pixel values;

a speculum detecting unit that establishes an evaluation result based on differences in the second pixel values and differences in third pixel values of the second demosaic image;

a first blend execution unit that generates output image data based on the evaluation result and a product of the second pixel values and fourth pixel values generated through an application of a filter to the third pixel values; and

a second blend execution unit generating visible output image data based on the evaluation result and the generated output image data.

2. The image signal processing apparatus of claim 1 , wherein the second blend execution unit determines whether the evaluation result represents a first type of result.

3. The image signal processing apparatus of claim 2 , wherein:

the image processing apparatus further comprises a filter unit that generates fifth pixel values based on an application of a filter to the first pixel values; and

the second blend execution unit enlarges at least one of the fifth pixel values to generate at least a portion of the visible output image data, when the evaluation result is determined to represent the first type.

4. The image signal processing apparatus of claim 2 , wherein the second blend execution unit enlarges a pixel value included in the output image data to generate at least a portion of the visible output image data, when the evaluation result is determined not to represent the first type.

5. The image signal processing apparatus of claim 1 , wherein the at least a portion of the differences in the second and third pixel values result from a change in illumination.

6. The image signal processing apparatus of claim 1 , further comprising a demosaic processing unit that:

receives input of mosaic image data based on signals obtained by an imaging device having an element array including a first element and a second element, the first element being a visible light obtaining element, and the second element being an invisible light obtaining element;

generates a first demosaic image corresponding to a first subset of the signals obtained by the visible light signal obtaining element; and

generates a second demosaic image corresponding to a second subset of the signals obtained by the invisible light obtaining element.

7. The image signal processing apparatus of claim 6 , wherein the first and second subsets of the signals are obtained simultaneously during capturing of an image by the imaging device.

8. The image signal processing apparatus of claim 6 , wherein:

the visible light obtaining element includes RGB elements obtaining R, G, and B color signals to generate the first demosaic image; and

the invisible light obtaining element includes A elements obtaining an A signal, the A signal including R, G, B, and infrared components.

9. The image signal processing apparatus of claim 8 , wherein the noise reduction processing unit corrects at least one of the first pixel values based on the A signal.

10. The image signal processing apparatus of claim 1 , further comprising:

an imaging device having a color array composed of RGB elements and A elements, the RGB elements being visible light obtaining elements, and the A elements being invisible light obtaining elements, wherein the color array obtains R, G, and B color signals and A signals simultaneously during capturing of an image; and

a demosaic processing unit generating a first demosaic image based on the R, G, and B color signals obtained by the RGB elements, and generating a second demosaic image based on the A signals obtained by the A elements.

11. A method, comprising:

establishing, using at least one processor, weights for first pixel values of a first demosaic image based on edge information extracted from a second demosaic image;

generating, using the at least one processor, second pixel values for the first demosaic image based on an application of the established weights to corresponding ones of the first pixel values;

establishing, using the at least one processor, an evaluation result based on differences in the second pixel values and differences in third pixel values of the second demosaic image;

generating, using the at least one processor, output image data based on the evaluation result and a product of the second pixel values and fourth pixel values, the fourth pixel values being generated through an application of a filter to the third pixel values; and

generating, using the at least one processor, visible output image data based on the evaluation result and the generated output image data.

12. The method of claim 11 , further comprising determining whether the evaluation result represents a first type of result.

13. The method of claim 12 , wherein:

the method further comprises generating fifth pixel values based on an application of a filter to the first pixel values; and

generating the visible output image data comprises generating at least a portion of the visible output image data by enlarging at least one of the fifth pixel values, when the evaluation result is determined to represent the first type.

14. The method of claim 12 , wherein generating the visible output image data comprises generating at least a portion of the visible output image data by enlarging a pixel value included in the output image data, when the evaluation result is determined not to represent the first type.

15. The method of claim 11 , wherein the at least a portion of the differences in the second and third pixel values result from a change in illumination.

16. The method of claim 11 , further comprising receiving mosaic image data, the mosaic image data comprising signals obtained by an imaging device having an element array including a first element and a second element, the first element being a visible light obtaining element, and the second element being an invisible light obtaining element.

17. The method of claim 16 , further comprising:

generating a first demosaic image corresponding to a first subset of the signals obtained by the visible light signal obtaining element; and

generating a second demosaic image corresponding to a second subset of the signals obtained by the invisible light obtaining element.

18. The method of claim 17 , wherein:

the first subset of the signals comprises R, G, and B color signals obtained by one or more RGB elements of the visible light obtaining element; and

the second subset of the signals comprises an A signal obtained by one or more A elements of the invisible light obtaining element, the A signal comprising including R, G, B, and infrared components.

19. The method of claim 18 , further comprising correcting at least one of the first pixel values based on the A signal.

20. A non-transitory computer-readable storage medium storing a computer program that, when executed on a processor of an imaging apparatus, causes the processor to perform a method for image signal processing, the method comprising:

establishing weights for first pixel values of a first demosaic image based on edge information extracted from a second demosaic image;

generating second pixel values for the first demosaic image based on an application of the established weights to corresponding ones of the first pixel values;

establishing an evaluation result based on differences in the second pixel values and differences in third pixel values of the second demosaic image;

generating output image data based on the evaluation result and a product of the second pixel values and fourth pixel values, the fourth pixel values being generated through an application of a filter to the third pixel values; and

generating visible output image data based on the evaluation result and the generated output image data.