One chip camera with color sensing capability and high limiting resolution

• US 20060088298A1
• Filed: 12/09/2005
• Published: 04/27/2006
• Est. Priority Date: 05/08/2002
• Status: Active Grant

• Current Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Original Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Inventors: Frame, Wayne W., Heim, Gerald B.
• Granted Patent: US 7,535,504 B2
• Time in Patent Office: Days
• US Class Current: 386/227
• CPC Class Codes: H04N 2209/045 using mosaic colour filter
• CPC Class Codes: H04N 2209/047 using multispectral pick-up elements
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• 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

Abstract

A high sensitivity, single chip, low light level imaging device is provided. The imaging device of the present invention utilizes sparse color sampling, to maximize the luminance information gathered. In particular, color information is gathered by a small proportion of the pixels included in an image sensor, while the remaining pixels operate at full spectrum sensitivity. The present invention allows the correct hue of objects to be determined, while providing high sensitivity to available luminance information in a scene. The imaging device can include a global near infrared blocking filter that can be selectively placed in the optical path of the device. In addition or alternatively, opaque pixels may be included in the image sensor to correct for errors caused by charge diffusion.

Claims

1. A method for controlling characteristics of a camera, comprising:

providing an image sensor comprising a plurality of pixels;

filtering image information to a first portion of the plurality of pixels for sensitivity to a selected first spectral region;

filtering image information to a second portion of the plurality of pixels for sensitivity to a selected second spectral region;

filtering image information to a third portion of the plurality of pixels for sensitivity to a selected third spectral region, wherein less than half of the pixels of the image sensor pixels receive image information filtered to within one of the first, second, or third spectral regions, wherein image information incident on a fourth portion of the plurality of pixels is not filtered to within any one of said first, second, or third spectral regions, and wherein the fourth portion of the plurality of pixels comprises more than half of the plurality of pixels of the image sensor; and

at least one of;

1) filtering image information incident on the plurality of pixels of the image sensor to remove at least near infrared wavelengths from the image information;

2) filtering image information to a fifth portion of the plurality of image sensor pixels, wherein at least visible and near infrared wavelengths are blocked from reaching the fifth portion of pixels.

2. The method of claim 1, wherein the fourth portion of the plurality of pixels of the image sensor are sensitive to at least near infrared wavelengths.

3. The method of claim 2, wherein image information incident on the plurality of pixels of the image sensor is filtered to remove at least near infrared wavelengths from the image information.

4. The method of claim 2, further comprising:

selecting a high visible ambient light mode, wherein in response to selecting the high visible ambient light mode the image information incident on the plurality of pixels of the image sensor is filtered to remove at least near infrared wavelengths from the image information.

5. The method of claim 4, wherein said selecting a high visible ambient light mode comprises placing a filter for removing at least near infrared wavelengths in a path of an optical beam comprising the image information incident on the pixels of the image sensor.

6. The method of claim 5, further comprising:

selecting a low visible ambient light mode, wherein the filter for removing at least near infrared wavelengths is taken out of the path of the optical beam comprising the image information incident on the pixels of the image sensor.

7. The method of claim 6, further comprising:

in response to selecting the low visible ambient light mode, removing a signal from the first, second and third portions of pixels from an output of said image sensor.

8. The method of claim 7, wherein the first, second and third portions of pixels of the image sensor comprise color information pixels.

9. The method of claim 1, wherein image information to a fifth portion of the pixels of the image sensor is filtered, wherein at least visible and near infrared wavelengths are blocked from reaching the fifth portion of pixels.

10. The method of claim 9, further comprising:

using a signal from said fifth portion of pixels to reduce effects of at least one of charge diffusion and dark current.

11. The method of claim 10, wherein said using a signal from the fifth portion of pixels comprises subtracting signals provided by the pixels in the fifth portion of pixels from signals provided by pixels included in the first, second and third portions of pixels.

12. The method of claim 11, wherein each pixel included in the fifth portion of pixels is associated with a group of pixels comprising at least one each of the first, second and third portions of pixels, wherein for each group the signal from the pixel in the fifth portion of pixels is subtracted from the signal from each of the other pixels in the group.

13. The method of claim 1, further comprising:

1) filtering image information incident on the plurality of pixels of the image sensor to remove at least near infrared wavelengths from the image information; and

2) filtering image information to a fifth portion of the plurality of image sensor pixels, wherein at least visible and near infrared wavelengths are blocked from reaching the fifth portion of pixels

14. A camera apparatus, comprising:

an image sensor, wherein said image sensor comprises;

a first plurality of pixels, wherein the first plurality of pixels provides image information including a first range of visible wavelengths;

a second plurality of pixels, wherein the second plurality of pixels provides image information including a second range of visible wavelengths;

a third plurality of pixels, wherein the third plurality of pixels provides image information including a third range of visible wavelengths; and

a fourth plurality of pixels, wherein the fourth plurality of pixels is capable of providing image information including near infrared wavelengths, wherein the number of pixels included in the fourth plurality of pixels is greater than a sum of the pixels included in the first, second and third pluralities of pixels.

15. The apparatus of claim 14, further comprising:

a near infrared blocking filter, wherein in a first mode of operation the near infrared blocking filter is placed in a path of a beam comprising image information incident on the image sensor to prevent near infrared wavelengths from reaching the first, second, third or fourth plurality of pixels, and wherein in a second mode of operation the near infrared blocking filter is removed from the beam comprising image information incident on the image sensor to permit near infrared wavelengths from reaching the first, second, third and fourth plurality of pixels.

16. The apparatus of claim 15, further comprising:

a processor, wherein an image sensor output signal is processed to create a camera output signal.

17. The apparatus of claim 16, wherein in the second mode of operation an output from the first, second and third pluralities of pixels is removed from the camera output signal.

18. The apparatus of claim 16, wherein in the first mode of operation the processor assigns color information to areas of the image comprising the camera output signal corresponding to at least most of the image information by averaging the color information from nearby pixels included in one of the first, second or third pluralities of pixels.

19. The apparatus of claim 14, further comprising:

a fifth plurality of pixels, wherein the fifth plurality of pixels is not provided with image information in visible or near infrared wavelengths; and

a processor, wherein information comprising at least one of charge diffusion signal and a dark current obtained from said fifth plurality of pixels is used by said processor to provide a filtered camera output signal.

20. The apparatus of claim 19, further comprising:

a near infrared blocking filter, wherein in a first mode of operation the near infrared blocking filter is placed in a path of a beam comprising image information incident on the image sensor to prevent near infrared wavelengths from reaching the first, second, third or fourth plurality of pixels, and wherein in a second mode of operation the near infrared blocking filter is removed from the beam comprising image information incident on the image sensor to permit near infrared wavelengths from reaching the first, second, third and fourth plurality of pixels.

21. The apparatus of claim 19, wherein at least most of said first, second, third and fifth pluralities of pixels are arranged in groups consisting of one pixel from each of the first, second, third and fifth pluralities of pixels, wherein said groups of one pixel from each of the first, second, third and fifth pluralities of pixels are surrounded by pixels included in the fourth plurality of pixels.

22. The apparatus of claim 14, wherein at least 90 percent of the total number of pixels comprise pixels included in the fourth plurality of pixels.

23. The apparatus of claim 14, wherein each of the pixels included in the first plurality of pixels is associated with a filter that passes wavelengths included in the first range of visible wavelengths,

wherein each of the pixels included in the second plurality of pixels is associated with a filter that passes wavelengths included in the second range of visible wavelengths,

wherein each of the pixels included in the third plurality of pixels is associated with a filter that passes wavelengths included in the third range of visible wavelengths.

24. An image sensor system, comprising:

a means for collecting image information, including;

a plurality of means for collecting image information primarily in a first range of wavelengths;

a plurality of means for collecting image information primarily in a second range of wavelengths;

a plurality of means for collecting image information primarily in a third range of wavelengths;

a plurality of means for collecting image information primarily in a fourth range of wavelengths comprising near infrared wavelengths;

means for selectively blocking infrared wavelengths from image information incident on said means for collecting image information;

means for processing image information collected by said means for collecting image information;

wherein in a first mode of operation said means for selectively blocking infrared wavelengths is operable to prevent infrared wavelengths from reaching said means for collecting image information, and wherein in a second mode of operation said means for selectively blocking infrared wavelengths is not operable to prevent infrared wavelengths from reaching said means for collecting image information.

25. The system of claim 24, wherein the means for collecting image information further comprises:

a plurality of means for collecting information related to noise in said pluralities of means for collecting image information primarily in said first, second, third and fourth ranges of wavelengths.

26. The system of claim 25, further comprising:

a means for filtering image information into primarily said first range of wavelengths associated with each of said plurality of means for collecting image information primarily in a first range of wavelengths;

a means for filtering image information into primarily said second range of wavelengths associated with each of said plurality of means for collecting image information primarily in a second range of wavelengths;

a means for filtering image information into primarily said third range of wavelengths associated with each of said plurality of means for collecting image information primarily in a third range of wavelengths.

27. The system of claim 24, wherein in said second mode of operation a signal from each of said first, second, and third pluralities of means for collecting image information is not included in an output signal provided to an end user.