Color filter array, imaging device, and image processing unit

• US 20070216785A1
• Filed: 03/06/2007
• Published: 09/20/2007
• Est. Priority Date: 03/14/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Mitsunaga, Tomoo, Nomura, Yoshikuni
• Granted Patent: US 7,710,476 B2
• Time in Patent Office: Days
• US Class Current: 348/242
• CPC Class Codes: F21V 9/08 for producing coloured light, e.g. monochromatic; for reducing intensity of light with provision for controlling the colour F21V9/40
• CPC Class Codes: H01L 27/146 Imager structures
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements

Abstract

A color filter array includes a plurality of filters, each having one of a plurality of types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels. The filters of a predetermined type selected from among the plurality of types are arranged at the locations of the pixels in a checkered pattern, and the filters of some or all of the other types are randomly arranged at the pixel locations at which the filters of the predetermined type are not present.

Claims

1. A color filter array comprising:

a plurality of filters, each having one of a plurality of types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels;

wherein the filters of a predetermined type selected from among the plurality of types are arranged at the locations of the pixels in a checkered pattern, and the filters of some or all of the other types are randomly arranged at the pixel locations at which the filters of the predetermined type are not present.

2. The color filter array according to claim 1, wherein the occurrence frequency of the filters of the same type in a region having a predetermined size and including the position of a pixel of interest is within a desired error range.

3. The color filter array according to claim 2, wherein the type of the filters is defined by four colors and wherein the filters having a first color C1 are arranged in a checkered pattern, the filters having a second color C2 are arranged at pixel locations at which the filters having the first color C1 are not present on every other line in a horizontal direction and a vertical direction, and the filters having a third color C3 and a fourth color C4 are randomly arranged at pixel locations at which neither the filters having the first color C1 nor the second color C2 are present.

4. The color filter array according to claim 3, wherein the first color C1 is green, the second color C2 is red, the third color C3 is blue, and the fourth color C4 is a color closer to blue than it is to green and red.

5. The color filter array according to claim 3, wherein the correlation of spectral sensitivity between the third color C3 and the fourth color C4 is higher than the correlation of spectral sensitivity between the other colors.

6. The color filter array according to claim 2, wherein the type of the filters is defined by five colors and wherein the filters having a first color C1 are arranged in a checkered pattern, the filters having a second color C2 or a third color C3 are randomly arranged at pixel locations at which the filters having the first color C1 are not present on every other line in a horizontal direction and a vertical direction, and the filters having a fourth color C4 and a fifth color C5 are randomly arranged at pixel locations at which neither the filters having the first color C1 nor the second color C2 nor the third color C3 are present.

7. The color filter array according to claim 6, wherein the correlation of spectral sensitivity between the second color C2 and the third color C3 and the correlation of spectral sensitivity between the fourth color C4 and the fifth color C5 are higher than the correlation of spectral sensitivity between the other colors.

8. A color filter array comprising:

a plurality of filters, each having one of at least five types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels;

wherein the filters of a first color C1a selected from among the at least five types of color are arranged at the locations of the pixels on every other line in a horizontal direction and a vertical direction, the filters of a second color C1b selected from among the at least five types of color are arranged at the pixel locations at which the filters of the first color C1a are not present on every other line in a horizontal direction and a vertical direction, and the filters of some or all of the other colors are randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b are present.

9. The color filter array according to claim 8, wherein the occurrence frequency of the filters of the same color in a region having a predetermined size and including the position of a pixel of interest is within a desired error range.

10. The color filter array according to claim 9, wherein the type of the filters is defined by five colors and wherein the filters of the first color C1a are arranged at the locations of the pixels on every other line in a horizontal direction and a vertical direction, the filters of the second color C1b are arranged at the pixel locations at which the filters of the first color C1a are not present on every other line in a horizontal direction and a vertical direction, the filters of a third color C2 are arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b are present on every other line in a horizontal direction and a vertical direction, and the filters of a fourth color C3 and a fifth color C4 are randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b nor the third color C2 are present.

11. The color filter array according to claim 10, wherein the correlation of spectral sensitivity between the fourth color C3 and the fifth color C4 is higher than the correlation of spectral sensitivity between the other colors.

12. The color filter array according to claim 9, wherein the type of the filters is defined by six colors and wherein the filters of the first color C1a are arranged at the locations of the pixels on every other line in a horizontal direction and a vertical direction, the filters of the second color C1b are arranged at the pixel locations at which the filters of the first color C1a are not present on every other line in a horizontal direction and a vertical direction, the filters of a third color C2 and a fourth color C3 are randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b are present on every other line in a horizontal direction and a vertical direction, and the filters of a fifth color C4 and a sixth color C5 are randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b nor the third color C2 nor the fourth color C3 are present.

13. The color filter array according to claim 12, wherein the correlation of spectral sensitivity between the third color C2 and the fourth color C3 and the correlation of spectral sensitivity between the fifth color C4 and the sixth color C5 are higher than the correlation of spectral sensitivity between the other colors.

14. The color filter array according to any one of claims 8 to 13, wherein the correlation of spectral sensitivity between the first color C1a and the second color C1b is higher than the correlation of spectral sensitivity between the other colors.

15. An imaging device comprising:

a color filter array including a plurality of filters, each having one of a plurality of types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels;

wherein the filters of a predetermined type selected from among the plurality of types are arranged at the locations of the pixels in a checkered pattern, and the filters of some or all of the other types are randomly arranged at the pixel locations at which the filters of the predetermined type are not present.

16. An imaging device comprising:

a color filter array including a plurality of filters, each having one of at least five types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels;

wherein the filters of a first color C1a selected from among the at least five types of color are arranged at the locations of the pixels on every other line in a horizontal direction and a vertical direction, the filters of a second color C1b selected from among the at least five types of color are arranged at the pixel locations at which the filters of the first color C1a are not present on every other line in a horizontal direction and a vertical direction, and the filters of some or all of the other colors are randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b are present.

17. An image processing unit comprising:

receiving means for receiving image data from an imaging device including a color filter array, the color filter array including a plurality of filters, each having one of a plurality of types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels, the filters of a predetermined type selected from among the plurality of types being arranged at the locations of the pixels in a checkered pattern, the filters of some or all of the other types being randomly arranged at the pixel locations at which the filters of the predetermined type are not present;

first interpolating means for interpolating a pixel value of a first color C1 at a pixel location of the image data received by the receiving means at which the predetermined color is not present using pixels of the first color C1 present in the vicinity of the pixel location so as to generate a first image; and

second interpolating means for interpolating a pixel value of a second color CX different from the first color C1 using pixels of the first color C1 and the second color CX that are present in a local region including a pixel of interest so as to generate a second image.

18. The image processing unit according to claim 17, further comprising:

multiple resolution transforming means for transforming a plurality of images including the first image generated by the first interpolating means and the second image generated by the second interpolating means into a plurality of layered images of a multiple-resolution image;

correcting means for correcting one of the plurality of images in each layered image except for the layered image of the minimum resolution on the basis of the correlation among the plurality of images; and

multiple resolution inverse transforming means for inverse transforming each layered image corrected by the correcting means.

19. An image processing unit comprising:

receiving means for receiving image data from an imaging device including a color filter array, the color filter array including a plurality of filters, each having one of at least five types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels, the filters of a first color C1a selected from among the at least five types of color being arranged at the locations of the pixels on every other;

line in a horizontal direction and a vertical direction, the filters of a second color C1b selected from among the at least five types of color being arranged at the pixel locations at which the filters of the first color C1a are not present on every other line in a horizontal direction and a vertical direction, and the filters of some or all of the other colors being randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b are present;

first interpolating means for interpolating a pixel value of a third color C1c at a pixel location of a pixel of interest using the pixel values of the first color C1a and the second color C1b that are present in a local region including the pixel of interest in the image data received by the receiving means; and

second interpolating means for interpolating a pixel value of each color CX of the plurality of filter colors including the colors C1a and C1b by using pixels of the third color C1c and the color CX that are present in the local region including the pixel of interest.

20. The image processing unit according to claim 19, further comprising:

multiple resolution transforming means for transforming a plurality of images of the colors generated by the second interpolating means into a plurality of layered images of a multiple-resolution image;

correcting means for correcting one of the plurality of images in each layered image except for the layered image of the minimum resolution on the basis of the correlation among the plurality of images; and

multiple resolution inverse transforming means for inverse transforming each layered image corrected by the correcting means.

21. An image processing unit comprising:

a receiving device configured to receive image data from an imaging device including a color filter array, the color filter array including a plurality of filters, each having one of a plurality of types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels, the filters of a predetermined type selected from among the plurality of types being arranged at the locations of the pixels in a checkered pattern, the filters of some or all of the other types being randomly arranged at the pixel locations at which the filters of the predetermined type are not present;

a first interpolating device configured to interpolate a pixel value of a first color C1 at a pixel location of the image data received by the receiving means at which the predetermined color is not present using pixels of the first color C1 present in the vicinity of the pixel location so as to generate a first image; and

a second interpolating device configured to interpolate a pixel value of a second color CX different from the first color C1 using pixels of the first color C1 and the second color CX that are present in a local region including a pixel of interest so as to generate a second image.

22. An image processing unit comprising:

a receiving device configured to receive image data from an imaging device including a color filter array, the color filter array including a plurality of filters, each having one of at least five types of spectral sensitivity and being disposed at the location of a corresponding one of a plurality of pixels, the filters of a first color C1a selected from among the at least five types of color being arranged at the locations of the pixels on every other line in a horizontal direction and a vertical direction, the filters of a second color C1b selected from among the at least five types of color being arranged at the pixel locations at which the filters of the first color C1a are not present on every other line in a horizontal direction and a vertical direction, and the filters of some or all of the other colors being randomly arranged at the pixel locations at which neither the filters of the first color C1a nor the second color C1b are present;

a first interpolating device configured to interpolate a pixel value of a third color C1c at a pixel location of a pixel of interest using the pixel values of the first color C1a and the second color C1b that are present in a local region including the pixel of interest in the image data received by the receiving device; and

a second interpolating device configured to interpolate a pixel value of each color CX of the plurality of filter colors including the color C1a and the color C1b by using pixels of the third color C1c and the color CX that are present in the local region including the pixel of interest.