Alternative Color Image Array And Associated Methods

• US 20110279705A1
• Filed: 02/25/2011
• Published: 11/17/2011
• Est. Priority Date: 05/14/2010
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Wu, Donghui, Shan, Jizhang, Kuang, Jiangtao
• Granted Patent: US 8,624,997 B2
• Time in Patent Office: Days
• US Class Current: 348/229.1
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H04N 2209/045 using mosaic colour filter
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/42 by switching between different modes of operation using different resolutions or aspect ratios, e.g. switching between interlaced and non-interlaced mode
• CPC Class Codes: H04N 25/447 by preserving the colour pattern with or without loss of information

Abstract

An image sensor includes an array of light sensitive elements and a filter array. Each filter element is in optical communication with a respective light sensitive element. The image sensor receives filtered light having a repeating pattern. Light sensitive elements in at least two successive rows alternately receive light having a first color and a second color, and light sensitive elements in common columns of the successive rows alternately receive light having the first color and the second color. Light sensitive elements in at least two additional successive rows alternately receive light having a third and a fourth color, and light sensitive elements in common columns of the additional successive rows alternately receive light having the third color and the fourth color. Output values of pairs of sampled light sensitive elements receiving light of a common color and from successive rows are combined to generate a down-sampled image.

Claims

1. An image sensor, comprising:

an array of light sensitive elements; and

a filter array including a plurality of first, second, third, and fourth filter elements, each filter element in optical communication with a respective light sensitive element,

each first filter element configured to transmit light of a first color,

each second filter element configured to transmit light of a second color,

each third filter element configured to transmit light of a third color,

each fourth filter element configured to transmit light of a fourth color, and

the filter array configured to include a repeating pattern of filter elements characterized by;

at least two successive columns of alternating first and second filter elements where common rows of the at least two successive columns also include alternating first and second filter elements, and

at least two additional successive columns of alternating third and fourth filter elements where common rows of the at least two additional successive columns also include alternating third and fourth filter element elements.

2. The image sensor of claim 1, the first and fourth colors being the color green, the second color being the color blue, and the third color being the color red.

3. The image sensor of claim 1, the first color being the color cyan, the second color being the color yellow, the third color being the color green, and the fourth color being the color magenta.

4. The image sensor of claim 1, the first color being the color red, the second color being the color green, the third color being the color blue, and the fourth color being the color emerald.

5. The image sensor of claim 1, the first color being the color red, the second color being the color green, the third color being the color blue, and the fourth color being the color white.

6. The image sensor of claim 1, the first color being the color red, the second color being the color green, the third color being the color blue, and the fourth color being at least all colors of visible light.

7. A method for down-sampling an image produced by an image sensor including an array of light sensitive elements, comprising:

filtering light incident on the image sensor such that the image sensor receives light having a repeating pattern characterized by;

light sensitive elements in at least two successive columns alternately receiving light having a first color and a second color, and light sensitive elements in common rows of the at least two successive columns alternately receiving light having the first color and the second color, and

light sensitive elements in at least two additional successive columns alternately receive light having a third and a fourth color, and light sensitive elements in common rows of the at least two additional successive columns alternately receiving light having the third color and the fourth color;

sampling output values of the light sensitive elements; and

combining output values of pairs of light sensitive elements receiving light of a common color and from successive rows of the array to generate a down-sampled image.

8. The method of claim 7, the first and fourth colors being the color green, the second color being the color blue, and the third color being the color red.

9. The method of claim 7, further comprising configuring the light sensitive elements to have a common exposure time, wherein the down-sampled image has an increased signal-to-noise ratio.

10. The method of claim 7, further comprising configuring the light sensitive elements such that light sensitive elements of successive rows alternately have long and short exposure times, wherein the down-sampled image has increased dynamic range.

11. The method of claim 10, the step of combining comprising, for each pair of light sensitive elements:

selecting a value from a light sensitive element of the pair having a long exposure time when the light sensitive element having a long exposure time has not saturated; and

selecting a value from a light sensitive element of the pair having a short exposure time when the light sensitive element having a long exposure time has saturated, the value being normalized to the value of the light sensitive element of the pair having the long exposure time.

12. An image sensor, comprising:

an array of light sensitive elements; and

a filter array including a plurality of red, green, and blue filter elements, each filter element in optical communication with a respective light sensitive element,

each red filter element configured to transmit only red colored light,

each green filter element configured to transmit only green colored light,

each blue filter element configured to transmit only blue colored light, and

the filter array arranged such that successive rows of the filter array have alternating first and second configurations, the first configuration characterized by a repeating pattern of successive blue, green, red, and green filter elements, the second configuration characterized by a repeating pattern of successive green, blue, green, and red filter elements.

13. A method for down-sampling an image produced by an image sensor including an array of light sensitive elements, comprising:

filtering light incident on the image sensor such that successive rows of the array of light sensitive elements alternately receive light having a first pattern and a second pattern, the first pattern characterized by each four successive light sensitive elements in a row respectively receiving blue, green, red, and green colored light, and the second pattern characterized by each four successive light sensitive elements in a row respectively receiving green, blue, green, and red colored light;

sampling output values of the light sensitive elements; and

combining output values of pairs of light sensitive elements receiving light of a common color and from successive rows of the array to generate a down-sampled image.

14. The method of claim 13, further comprising configuring the light sensitive elements to have a common exposure time, wherein the down-sampled image has an increased signal-to-noise ratio.

15. The method of claim 13, further comprising configuring the light sensitive elements such that light sensitive elements of successive rows alternately have long and short exposure times, wherein the down-samples image has an increased dynamic range.

16. The method of claim 15, the step of combining comprising, for each pair of light sensitive elements:

selecting a value from a light sensitive element of the pair having a long exposure time when the light sensitive element having a long exposure time has not saturated; and

selecting a value from a light sensitive element of the pair having a short exposure time when the light sensitive element having a long exposure time has saturated, the value being normalized to the value of the light sensitive element of the pair having the long exposure time.