Luminance-priority electronic color image sensor

• US 6,593,558 B1
• Filed: 12/30/1999
• Issued: 07/15/2003
• Est. Priority Date: 05/10/1996
• Status: Expired due to Term

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Applied Science Fiction, Inc.
• Inventors: Edgar, Albert D.
• Primary Examiner(s): Allen, Stephone B.
• Application Number:
  US09/476,164
• Time in Patent Office: 1,293 Days
• Field of Search: 250/208.1, 250/226, 250/214.1, 250/214.R, 348/268, 348/276, 348/269, 348/277, 348/270, 348/280, 348/271, 348/281, 348/272, 348/282, 348/273, 348/283, 348/275, 358/512, 358/513, 358/514, 358/518, 358/500, 430/503, 430/507, 430/508, 430/509, 430/510, 430/511, 430/512, 257/431, 257/432, 257/436, 257/443
• US Class Current: 250/208.1
• CPC Class Codes: G01J 2003/516 with several stacked filters or stacked filter-detector pairs
• CPC Class Codes: G01J 3/465 taking into account the colour perception of the eye; using tristimulus detection
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: H04N 2209/042 having a single pick-up sensor

Abstract

In luminance priority multilayer color film, one of the layers substantially matches the luminance sensitivity of the human eye. This luminance layer distinguishes from prior art color films that have a blue, a green, and a red sensitive layer. This luminance layer has the priority front position to sense light before being diffused and attenuated by other layers, giving the luminance record enhanced speed and clarity compared to prior art blue-priority color film. In another embodiment, a layered CCD sensor has a top silicon layer that is sensitive to all colors, followed by a yellow filter, a second silicon layer responsive to green and red light only because of the yellow filter, a cyan filter, and a bottom silicon layer receiving only green light. An image from a luminance-priority color sensor inputs to a color space conversion to recover full color. In the preferred embodiment, a luminance layer on top maps to a luminance “Y” value, and underlying color sensitive layers are used in conjunction with the luminance to derive the “U” and “V” chrominance vectors of YUV color space.

Claims

1. A luminance priority color sensor comprising:

a semiconductor substrate having a plurality of sensing elements disposed on the semiconductor substrate, where each sensing element comprises;

at least one color sensing layer disposed outwardly from the semiconductor substrate, wherein the color sensing layer is operable to measure an intensity of light within a frequency band corresponding to at least one color of light; and

a luminance sensing layer disposed outwardly from the at least one color sensing layer, wherein the luminance sensing layer is operable to measure luminance.

2. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises a color sensing layer operable to measure an intensity of light within the red and green frequency bands.

3. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises a color sensing layer operable to measure an intensity of light within the green and blue frequency bands.

4. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises a color sensing layer operable to measure an intensity of light within the red and green frequency bands.

5. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises a color sensing layer operable to measure an intensity of light within the red and blue frequency bands.

6. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises a color sensing layer operable to measure an intensity of light within the group of red, green or blue frequency bands.

7. The luminance priority color sensor of claim 1, wherein the plurality of sensing elements comprises a charge coupled device (CCD) array.

8. The luminance priority color sensor of claim 1, wherein each color sensing layer includes a filter layer.

9. The luminance priority color sensor of claim 8, wherein the filter layer comprises a dichroic filter.

10. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises:

a red-green color sensing layer operable to measure an intensity of light within the red and green frequency bands; and

a green color sensing layer operable to measure an intensity of light within the green frequency band.

11. The luminance priority color sensor of claim 1, wherein the at least one color sensing layer comprises:

a red-green color sensing layer operable to measure an intensity of light within the red and green frequency bands; and

a red color sensing layer operable to measure an intensity of light within the red frequency band.

12. The luminance priority color sensor of claim 1, wherein the luminance priority color sensor operates within an imaging system.

13. The luminance priority color sensor of claim 12, wherein the imaging system comprises a digital camera.

14. A method of digitizing a scene comprising:

measuring an intensity of light associated with luminance and outputting luminance data;

measuring an intensity of light associated with at least one color of light to produce color data;

wherein the intensity of light associated with the at least one color of light is measured in at least one color sensing layer and the intensity of light associated with luminance is simultaneously measured in a luminance layer superimposed over the at least one color sensing layer; and

processing the luminance data and color data to produce values representative of the red, green and blue color components of each pixel within the scene.

15. The method of claim 14, wherein at least one color sensing layer comprises:

a red-green color sensing layer operable to measure the intensity of light associated with red and green light; and

a green color sensing layer superimposed under the red-green color sensing layer wherein the green sensing layer is operable to measure the intensity of light associated with green light.

16. The method of claim 15, wherein processing the luminance data and color data to produce values representative of the red, green, and blue components of each pixel within the scene comprises:

calculating the blue component by subtracting the red-green data from the luminance data;

calculating the red component by subtracting the green data from the red-green data; and

the green component is directly measured.

17. The method of claim 16, further comprising processing the red, green, and blue components of each pixel to adjust for luminance.

18. The method of claim 14, wherein at least one color sensing layer comprises:

a red-green color sensing layer operable to measure the intensity of light associated with red and green light; and

a red color sensing layer superimposed under the red-green color sensing layer wherein the red sensing layer is operable to measure the intensity of light associated with red light.

19. The method of claim 14, wherein each color sensing layer includes a filter.

20. The method of claim 19, wherein the filter comprises a dichroic filter.