Imaging method, apparatus and system having extended depth of field

• US 20080080028A1
• Filed: 10/02/2006
• Published: 04/03/2008
• Est. Priority Date: 10/02/2006
• Status: Abandoned Application

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Micron Technology, Inc.
• Inventors: Venkataraman, Kartik, Bakin, Dmitry, Smith, Scott T.
• Application Number:
  US11/540,673
• Publication Number:
  US 20080080028A1
• Time in Patent Office: Days
• US Class Current: 358/514
• CPC Class Codes: G06T 1/0007 Image acquisition
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation
• CPC Class Codes: H04N 25/41 Extracting pixel data from a plurality of image sensors simultaneously picking up an image, e.g. for increasing the field of view by combining the outputs of a plurality of sensors

Abstract

Various exemplary embodiments of the invention provide an extended depth of field. One embodiment provides an image restoration procedure, comprising determining sample point pixels from a pixel array based upon a distance of an object being imaged to the pixel array, and reading intensities of the sample point pixels into a memory. Another embodiment provides an image capture procedure comprising capturing light rays on a pixel array of an imaging sensor, wherein specific sampling point pixels are selected to be evaluated based on spread of an image spot across a based on spread of an image spot across the plurality of pixels of the pixel array plurality of pixels of the pixel array.

Claims

1. An imaging apparatus comprising:

a pixel array comprising a plurality of pixels;

a first lens array comprising a plurality of first lenses over the pixel array; and

a second lens array comprising a plurality of second lenses over the first lens array, wherein each of the plurality of second lenses directs light onto more than one of the plurality of first lenses.

2. The imaging apparatus of claim 1, further comprising an imaging lens over the second lens array.

3. The imaging apparatus of claim 1, wherein each of the plurality of second lenses directs light onto a N×

M cluster of the first lenses, where N and M are integers.

4. The imaging apparatus of claim 3, wherein N and M are equal to 3.

5. The imaging apparatus of claim 3, wherein edges of each of the plurality of second lenses are aligned with edges of the cluster of N×

M first lenses.

6. The imaging apparatus of claim 1, further comprising optical filters disposed between the second lens array and the imaging lens.

7. The imaging apparatus of claim 1, wherein the second lens array is disposed approximately at a focal plane of the imaging lens.

8. The imaging apparatus of claim 1, wherein a numerical aperture of the plurality of second lenses is approximately equal to a numerical aperture of the imaging lens.

9. The imaging apparatus of claim 1, wherein the first lens array is disposed approximately at a focal plane of the plurality of second lenses of the second lens array.

10. The imaging apparatus of claim 1, wherein the pixel array comprises a plurality of pixel arrays on a single chip, and wherein each of the plurality of pixel arrays is a respective color pixel array.

11. The imaging apparatus of claim 9, wherein the plurality of pixel arrays comprises a green pixel array, a red pixel array and a blue pixel array.

12. The imaging apparatus of claim 1, wherein the pixel array comprises a plurality of red, green and blue pixels.

13. The imaging apparatus of claim 1, wherein color filters are provided between the imaging lens and the second lens array.

14. An imaging device, comprising:

a pixel array comprising a plurality of pixels disposed under a first lens array having a plurality of first lenses, wherein each pixel of the pixel array is disposed under a corresponding first lens of the first lens array; and

a second lens array, having a plurality of second lenses, disposed over the first lens array, and wherein said second lenses are larger than said first lenses.

15. The imaging apparatus of claim 14, wherein the pixel array comprises a plurality of pixel arrays on a single chip.

16. The imaging apparatus of claim 15, wherein each of the plurality of pixel arrays is a respective color pixel array.

17. The imaging apparatus of claim 16, wherein the plurality of pixel arrays comprises a green pixel array, a red pixel array and a blue pixel array.

18. The imaging apparatus of claim 14, wherein the pixel array comprises a plurality of red, green and blue pixels.

19. The imaging device of claim 14, further comprising an imaging lens having a focal length from the imaging lens to a focal point of the imaging lens, and wherein the second lens array is disposed approximately at the focal point of the imaging lens.

20. The imaging device of claim 14, further comprising a pixel processing unit for processing pixel signals from the array, the pixel processing unit being configured to form a plurality of different sample point pixels sets for each of a plurality of pixel groups, each of the plurality of sample pixels sets corresponding to a respective pattern of light spread on a pixel array.

21. The imaging device of claim 20, wherein each of the sample point pixel sets comprises a plurality of sample point pixels, and wherein each of the sample point pixel sets comprises a different set of sample point pixels.

22. The imaging device of claim 14, wherein each second lens of the second lens array directs light onto a N×

M cluster of pixels, wherein N and M are integers greater than or equal to 2.

23. The imaging device of claim 14, wherein each second lens of the second lens array directs light onto a N×

N cluster of pixels, wherein N is an integer greater than or equal to 2.

24. The imaging device of claim 23, wherein each second lens of the second lens array directs light onto a 3×

3 cluster of pixels of the pixel array.

25. The imaging device of claim 22, wherein L second lenses direct light onto L clusters of pixels of the pixel array, wherein L is an integer greater or equal to 2.

26. The imaging device of claim 23, wherein L second lenses direct light onto L clusters of pixels of the pixel array, wherein L is an integer greater or equal to 2.

27. The imaging device of claim 24, wherein nine of the second lenses direct light onto nine 3×

3 clusters of pixels of the pixel array.

28. The imaging device of claim 27, wherein the nine 3×

3 clusters of pixels comprise an upper left cluster, an upper center cluster, an upper right cluster, a middle left cluster, a middle center cluster, a middle right cluster, a lower left cluster, a lower center cluster, and a lower right cluster.

29. The imaging device of claim 28, further comprising a pixel processing unit which defines three different sets of sampling point pixels for each 9×

9 pixel group.

30. The imaging device of claim 29, wherein the pixel processing unit is configured to define a first set of sampling point pixels as follows:

an upper left pixel in the middle center cluster;

an upper center pixel in the middle center cluster;

an upper right pixel in the middle center cluster;

a middle left pixel in the middle center cluster;

a middle center pixel in the middle center cluster;

a middle right pixel in the middle center cluster;

a lower left pixel in the middle center cluster;

a lower center pixel in the middle center cluster; and

a lower right pixel in the middle center cluster.

31. The imaging device of claim 30, wherein the pixel processing unit is configured to define a second set of sampling point pixels as follows:

an upper left pixel in the upper left cluster;

an upper center pixel in the upper center cluster;

an upper right pixel in the upper right cluster;

a middle left pixels in the middle left cluster;

a middle center pixel in the middle center cluster;

a middle right pixel in the middle right cluster;

a lower left pixel in the lower left cluster;

a lower center pixel in the lower center cluster; and

a lower right pixel in the lower right cluster.

32. The imaging device of claim 31, wherein the pixel processing unit is configured to define a third set of sampling point pixels as follows:

a lower right pixel in the upper left cluster;

a lower center pixel in the upper center cluster;

a lower left pixel in the upper right cluster;

a middle right pixel in the middle left cluster;

a middle center pixel in the middle center cluster;

a middle left pixel in the middle right cluster;

an upper right pixel in the lower left cluster;

an upper center pixel in the lower center cluster; and

an upper left pixel in the lower right cluster.

33. The imaging device of claim 29, wherein the pixel processing unit is configured to use the first, second and third sets of sample point pixels for:

summing respective intensities of the sample point pixels in each of the first, second and third sets of sample point pixels;

storing the summed values of each set of sample point pixels in respective memories;

applying an edge test to adjacent stored summed values in each memory to find sharpest edges between adjacent summed values, and outputting a respective sharpness value for each memory;

selecting and outputting one stored summed value among three stored summed values in the respective memories, based upon the sharpness values;

creating an image based on the output stored summed values.

34. The imaging device of claim 32, wherein the pixel processing unit is configured to use the first, second and third sets of sample point pixels for:

summing respective intensities of the sample point pixels in each of the first, second and third sets of sample point pixels;

storing the summed values of each set of sample point pixels in respective memories;

applying an edge test to adjacent stored summed values in each memory to find sharpest edges between adjacent summed values, and outputting a respective sharpness value for each memory;

selecting and outputting one stored summed value among three stored summed values in the respective memories, based upon the sharpness values;

creating an image based on the output stored summed values.

35. An imaging device comprising:

at least one pixel array;

a pixel processing unit for processing pixels of the at least one array, the pixel processing unit being configured to form a plurality of sets of sampling pixels, each said set comprising at least one different sampling point pixel, each of the plurality of sets of sampling pixels adapted to detect a respective spread of an image signal on the pixel array.

36. The imaging device of claim 35, wherein the plurality of sets of sampling pixels comprises three sets.

37. The imaging device of claim 35, wherein each set of sampling point pixels comprises nine sampling point pixels.

38. The imaging device of claim 35, wherein the image signal is detected on an N×

M group of pixels of a pixel array, where N and M are integers greater than or equal to 2.

39. The imaging device of claim 35, wherein the image signal is detected on an N×

N group of pixels of a pixel array, where N is an integer greater than or equal to 2.

40. The imaging device of claim 39, wherein the group of pixels is a 9×

9 group of pixels.

41. The imaging device of claim 35, wherein the pixel processing unit is configured to use the plurality of sets of sampling pixels for:

summing respective intensities of the sample point pixels in each of the first, second and third sets of sample point pixels;

storing the summed values of each set of sample point pixels in respective memories;

applying an edge test to adjacent stored summed values in each memory to find sharpest edges between adjacent summed values, and outputting a respective sharpness value for each memory;

selecting and outputting one stored summed value among three stored summed values in the respective memories, based upon the sharpness values;

creating an image based on the output stored summed values.

42. The imaging device of claim 41, wherein the at least one pixel array comprises a green, blue and red pixel array, and the step of applying the edge test is performed on each of the pixel arrays.

43. The imaging device of claim 41, wherein the at least one pixel array comprises a green, blue and red pixel array, and the step of applying the edge test is performed only on of the pixel arrays.

44. The imaging device of claim 41, wherein the pixel array comprises a combined RGB pixel array, and the step of applying the edge test is performed the pixel array.

45. An imager device comprising:

a least a first, second and third pixel array, each for sensing a particular image color and providing respective color pixel output signals;

a pixel processing unit for selecting pixels in at least three different pixel patterns from at least one of the first, second and third pixel arrays, each pattern corresponding to a respective light spread pattern of an image on the at least one of the first, second and third pixel arrays;

the pixel processing unit being configured to sum the selected pixels of the at least three different pixel patterns for selecting one of the summed pixels of each of the at least three different pixel patterns for image construction output in accordance with edge characteristics of adjacent summed pixel patterns.

46. The imager device of claim 45, wherein the pixel processing unit is further configured to apply a respective weighting function to the selected pixels.

47. The imager device of claim 45, wherein the pixel processing unit is further configured to used to use the output summed pixels to reconstruct an image of an object.

48. An imaging device comprising:

at least one pixel array providing pixel signals; and

a pixel processing unit configured to;

receive pixel signals from the at least one pixel array;

divide the received array pixel signals into successive groups of pixels across the at least one pixel array, each successive pixel group comprising pixels in a plurality of rows and columns of the at least one pixel array;

define, for each successive pixel group across the at least one pixel array, a plurality of successive corresponding sampling pixel groups, each corresponding sampling pixel group containing a different group of pixels of said successive pixel group;

sum sampling pixels in each of said plurality of successive sampling pixel groups;

select one of said successive summed groups of sampling pixels corresponding to a pixel group which exhibits a highest edge sharpness with a neighboring summed group of sampling pixels; and

reconstruct an image using said selected groups of summed sampling pixels.

49. The imaging device of claim 48 wherein each said successive pixel group comprises an N×

M group of pixels where N and M are both integers greater than 3, and each said sampling pixel group comprises an O×

P pixel group, where O and P are both integers less than N and M.

50. The imaging device of claim 49 wherein said successive pixel group comprises a group of 9×

9 pixels, and each said sampling pixel group comprises nine pixels of said 9×

9 pixel group.

51. The imaging device of claim 48 wherein said plurality of successive corresponding sampling pixel groups comprise three sampling pixel groups.

52. The imager device of claim 48 wherein each said summed group of sampling pixels has a weighting factor associated with each pixel which is summed.

53. The imager of claim 48, further comprising a plurality of pixel arrays, each of a respective color, and wherein said pixel processing unit is further configured to:

combine pixel signals from the pixel array and process the combined signals as the received pixel signals.

54. The imager of claim 48, further comprising a plurality of pixel arrays, each of a respective color, and wherein said pixel processing unit is further configured to:

separately process pixel signals from each of said plurality of pixel arrays as the received pixel signals; and

combine reconstructed images corresponding to each of the plurality of pixel arrays to form an output image.

55. The imager device of claim 48, wherein the at least one pixel array provides pixel signals of a plurality of colors and the pixel processing unit is further configured to demosaic the pixel signals and provide the demosaided pixel signals as received pixel signals.

56. A method of capturing an image, comprising:

capturing light rays containing image information of an object with an imaging lens;

directing the light rays from the imaging lens to a plurality of first lenses of a first lens array;

directing the light rays from each of the first lenses to a cluster of second lenses of a second lens array; and

directing light from each of the second lenses to respective pixels of a pixel array.

57. The method of claim 56, wherein the directing the light rays from each of the first lenses comprises directing light rays to a cluster of N×

M second lenses, wherein N and M are integers greater than or equal to 2.

58. The method of claim 56, wherein the directing the light rays from each of the first lenses comprises directing light rays to a cluster of N×

N second lenses, wherein N is an integer greater than or equal to 2.

59. The method of claim 58, wherein the cluster of second lenses is a 3×

3 cluster of nine second lenses.

60. The method of claim 56, wherein the pixel array comprises a plurality of pixel arrays.

61. The method of claim 58, wherein each of the plurality of pixel arrays is a respective color pixel array.

62. The method of claim 61, wherein the plurality of pixel arrays comprises a green pixel array, a red pixel array and a blue pixel array.

63. The method of claim 56, wherein the pixel array comprises a plurality of red, green and blue pixels.

64. A method of imaging an object, comprising:

providing an imager device having a pixel array comprising a plurality of pixels;

receiving light rays from an object to be imaged on the pixel array, the light rays originating at different distances from the pixel array; and

creating an image of the object using signals from the pixel array, said signals being from particular sample pixels, and wherein said sample pixels correspond to a spread of an image spot on the pixel array.

65. The method of claim 64, wherein said particular sample pixels comprise a plurality of sample pixels sets, each of the plurality of sample pixels sets corresponding to a respective amount of spread of an image spot on the pixel array.

66. The method of claim 65, wherein each of the sample point pixel sets comprises a plurality of sample pixels, and wherein each of the sample point pixel sets comprises a different set of sample point pixels.

67. The method of claim 64, wherein said sample pixels are determined from a group of M×

N pixels of said pixel array, wherein M and N are integers greater than or equal to 2.

68. The method of claim 64, wherein said sample pixels are determined from a group of M×

M pixels of said pixel array, wherein M is an integer greater than or equal to 2.

69. The method of claim 68, wherein said sample pixels are determined from a group of pixels comprising nine 3×

3 clusters of pixels.

70. The method of claim 69, wherein the nine 3×

3 clusters of pixels comprise an upper left cluster, an upper center cluster, an upper right cluster, a middle left cluster, a middle center cluster, a middle right cluster, a lower left cluster, a lower center cluster, and a lower right cluster.

71. The method of claim 70, further comprising providing a pixel processing unit which defines three different sets of sampling point pixels for each 9×

9 pixel group.

72. The method of claim 71, wherein the pixel processing unit is configured to define a first set of sampling point pixels as follows:

the upper left pixel in the upper left cluster;

the upper center pixel in the upper center cluster;

the upper right pixel in the upper right cluster;

the middle left pixels in the middle left cluster;

the middle center pixel in the middle center cluster;

the middle right pixel in the middle right cluster;

the lower left pixel in the lower left cluster;

the lower center pixel in the lower center cluster; and

the lower right pixel in the lower right cluster.

73. The method of claim 72, wherein the pixel processing unit is configured to define a second set of sampling point pixels as follows:

the lower right pixel in the upper left cluster;

the lower center pixel in the upper center cluster;

the lower left pixel in the upper right cluster;

the middle right pixel in the middle left cluster;

the middle center pixel in the middle center cluster;

the middle left pixel in the middle right cluster;

the upper right pixel in the lower left cluster;

the upper center pixel in the lower center cluster; and

the upper left pixel in the lower right cluster.

74. The method of claim 73, wherein the pixel processing unit is configured to define a third set of sampling point pixels as follows:

an upper left pixel in the middle center cluster;

an upper center pixel in the middle center cluster;

an upper right pixel in the middle center cluster;

a middle left pixel in the middle center cluster;

a middle center pixel in the middle center cluster;

a middle right pixel in the middle center cluster;

a lower left pixel in the middle center cluster;

a lower center pixel in the middle center cluster; and

a lower right pixel in the middle center cluster.

75. The method of claim 71, wherein the pixel processing unit is configured to use the first, second and third sets of sample point pixels for:

summing respective intensities of the sample point pixels in each of the first, second and third sets of sample point pixels;

storing the summed values in buffer memories;

applying an edge test algorithm to each of the stored summed values to find sharpest edges between adjacent summed values, and outputting respective sharpness values to a comparator;

selecting and outputting stored summed values, based upon the sharpness value output to the comparator;

creating an image based on the output stored summed values.

76. The method of claim 74, wherein the pixel processing unit is configured to use the first, second and third sets of sample point pixels for:

summing respective intensities of the sample point pixels in each of the first, second and third sets of sample point pixels;

storing the summed values in buffer memories;

applying an edge test to each of the stored summed values to find sharpest edges between adjacent summed values, and outputting respective sharpness values to a comparator;

selecting and outputting stored summed values, based upon the sharpness value output to the comparator;

creating an image based on the output stored summed values.

77. The method of claim 64, wherein the pixel array comprises a plurality of pixel arrays.

78. The method of claim 77, wherein each of the plurality of pixel arrays is a respective color pixel array.

79. The method of claim 77, wherein the plurality of pixel arrays comprises a green pixel array, a red pixel array and a blue pixel array.

80. The method of claim 64, wherein the pixel array comprises a plurality of red, green and blue pixels.

81. An image creation process, comprising:

selecting sample point pixels with a pixel processing unit from a pixel array for use in creating an image, wherein the selecting comprises selecting a plurality of sets of sample point pixels from a group of pixels of the pixel array, each set having at least one different sample point pixel;

reading signal information from the sample point pixels from the group of pixels into a memory; and

summing the signal information of the sample point pixels from the group of pixels in the memory.

82. The image creation process of claim 81, wherein the selecting step comprises selecting sample point pixels from a plurality of pixel arrays, each of a respective color.

83. The image creation process of claim 82, wherein each of the plurality of pixel arrays is a respective color pixel array.

84. The image creation process of claim 83, wherein the plurality of pixel arrays comprises a green pixel array, a red pixel array and a blue pixel array.

85. The image creation process of claim 81, wherein the selecting step comprises selecting sample point pixels from a pixel array comprising a plurality of red, green and blue pixels.

86. The image creation process of claim 81, wherein summing the signal information comprises summing intensities of the sample point pixels;

and further comprising storing the summed intensities.

87. The image creation process of claim 86, further comprising applying an edge test to the stored summed intensities.

88. The image creation process of claim 81, further comprising:

comparing sharpness of edges of adjacent stored summed intensities;

choosing and outputting one of said summed intensities based on highest edge sharpness; and

restoring an image based on said output of summed intensities.

89. An image capture process, comprising:

capturing light rays on a pixel array of an imaging sensor, the pixel array having a plurality of pixels;

wherein specific sampling point pixels of the plurality of pixels are selected to be evaluated based on spread of an image spot across the plurality of pixels of the pixel array.

90. The image capture process of claim 89, further comprising receiving the light rays at an imaging lens, and directing the light rays from the imaging lens to first lenses of a first lens array.

91. The image capture process of claim 90, further comprising directing the light rays from each of the first lenses onto a plurality of second lenses of a second lens array.

92. The image capture process of claim 91, further comprising directing the light rays from each of the plurality of second lenses onto respective pixels of the pixel array.

93. The image capture process of claim 89, wherein the pixel array comprises a plurality of pixel arrays.

94. The image capture process of claim 93, wherein each of the plurality of pixel arrays is a respective color pixel array.

95. The image capture process of claim 93, wherein the plurality of pixel arrays comprises a green pixel array, a red pixel array and a blue pixel array.

96. The image capture process of claim 89, wherein the pixel array comprises a plurality of red, green and blue pixels.