IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0078722
(2008-04-03)
|
등록번호 |
US-7733392
(2010-06-29)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
7 인용 특허 :
11 |
초록
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A method and apparatus for identifying and compensating for the effects of defective pixels in high resolution digital cameras having image processing apparatus. The apparatus includes a storage system for storing data corresponding to either a dark current reference image and a white reference imag
A method and apparatus for identifying and compensating for the effects of defective pixels in high resolution digital cameras having image processing apparatus. The apparatus includes a storage system for storing data corresponding to either a dark current reference image and a white reference image and at least one actual image captured by a pixel array, and at least one processor coupled to the storage system for compensating the data corresponding to the actual image based upon the stored data. The method includes capturing and storing both dark and white reference images as well as capturing and storing actual images, identifying pixels that are affected by dark current or are defective pixels, reading data corresponding to pixels of an actual image affected by dark current or that are defective from the storage system and compensating the affected pixels.
대표청구항
▼
What is claimed as new and desired to be protected by Letters Patent of the United States is: 1. An image processing apparatus comprising: a memory apparatus for storing at least one actual image, at least one dark current reference image, and at least one white reference image captured by a pixel
What is claimed as new and desired to be protected by Letters Patent of the United States is: 1. An image processing apparatus comprising: a memory apparatus for storing at least one actual image, at least one dark current reference image, and at least one white reference image captured by a pixel array, the storage system further storing a plurality of gain conditions and a plurality of exposure times associated with the at least one actual image and a plurality of gain conditions and a plurality of exposure times associated with the at least one dark current reference image and the at least one white reference image; and a processor coupled to the storage system for compensating the at least one actual image by identifying defective pixels of the at least one actual image based on at least one gain condition of the stored plurality of gain conditions associated with the at least one dark current reference image and the at least one white reference image, and at least one exposure time of the stored plurality of exposure times associated with the at least one dark current reference image and the at least one white reference image, and applying at least one defective pixel compensation process to the identified defective pixels. 2. The image processing apparatus of claim 1, wherein the processor performs the compensation using an associated gain and exposure time associated with the at least one dark current reference image and the at least one white reference image that substantially match the gain and exposure time associated with the at least one actual image. 3. The image processing apparatus of claim 2, wherein the processor further performs dark current compensation to the at least one actual image. 4. The image processing apparatus of claim 1, wherein the processor identifies defective pixels affected by dark current using the at least one dark current reference image. 5. The image processing apparatus of claim 1, wherein the processor identifies defective pixels affected by white current using the at least one white reference image. 6. The image processing apparatus of claim 1, wherein the processor captures a plurality of dark current reference images under a plurality of gain conditions and exposure times for creating a respective dark current reference image and for each combination of the plurality of gain and exposure conditions, identifies locations of dark current pixels which require compensation; and creates from the captured plurality of dark current reference images the respective dark current reference image and for each gain combination of gain conditions and exposure times, identifies locations of hot pixels that require compensation. 7. The image processing apparatus of claim 6, wherein the processor further selects one of the dark current and hot pixel reference images by selecting one of the plurality of gain condition and exposure time combinations based on the gain condition and exposure time combination that substantially matches the gain condition and exposure time combination of the at least one dark current reference image and the at least one white reference image. 8. The image processing apparatus of claim 7, wherein the processor further smoothes the pixels affected by dark current using signal values from available neighboring pixels, the pixels affected by dark current being identified using the selected dark current and hot pixel reference images, the signal value of each pixel identified as affected by dark current being retrieved from the at least one dark current reference image and the at least one white reference image. 9. The image processing apparatus of claim 7, wherein the processor scales down the signal value of a pixel affected by dark current, the pixels affected by dark current being identified using the selected dark current and hot pixel reference images, the signal value of each pixel identified as affected by dark current being retrieved from the at least one dark current reference image and the at least one white reference image. 10. An image processing apparatus comprising: a memory device for storing at least one actual image, at least one dark current reference image, and at least one white reference image captured by a pixel array, the storage system further storing a plurality of gain conditions and a plurality of exposure times associated with the at least one actual image and a plurality of gain conditions and a plurality of exposure times associated with the at least one dark current reference image and the at least one white reference image; and a processor coupled to the storage system for compensating the at least one actual image by identifying defective pixels of the at least one actual image based on at least one gain condition of the stored plurality of gain conditions associated with the at least one dark current reference image and the at least one white reference image, and at least one exposure time of the stored plurality of exposure times associated with the at least one dark current reference image and the at least one white reference image, applying at least one defective pixel compensation process to the identified defective pixels, capturing a plurality of white reference images under a plurality of gain conditions and exposure times for creating a respective defective pixel reference image, and for each combination of gain conditions and exposure times, identifying locations of defective pixels that need compensation. 11. The image processing apparatus of claim 10, wherein the processor captures the plurality of white reference images under a plurality of light conditions for creating a respective defective pixel reference image. 12. The image processing apparatus of claim 11, wherein the plurality of light conditions comprise a no light condition, a first light condition and a second light condition having a higher Lux value than the first light condition. 13. The image processing apparatus of claim 12, wherein the processor further creates a dark dead pixel reference image, and for each gain condition and exposure time combination, identifies locations of dark dead pixels that require compensation. 14. The image processing apparatus of claim 13, wherein the processor further creates a white dead pixel reference image, and for each gain condition and exposure time combination, identifies locations of white dead pixels that require compensation. 15. The image processing apparatus of claim 11, wherein the processor further creates a saturation dead pixel reference image, and for each gain condition and exposure time combination, identifies locations of saturation dead pixels that require compensation. 16. The image processing apparatus of claim 11, wherein the processor further creates a bad pixel reference image for each gain condition and exposure time combination, and identifies locations of bad pixels that require compensation. 17. The image processing apparatus of claim 13, wherein the processor compensates for dark dead pixels by scaling down the signal level of pixels identified as dark dead pixels to an average signal level for normal pixels under the no light condition using the dark dead pixel reference image to locate the dark dead pixels. 18. The image processing apparatus of claim 14, wherein the processor compensates for white dead pixels by one of scaling up and scaling down the signal level of pixels identified as white dead pixels to an average value for normal pixels under the first light condition using the white dead pixel reference image to locate the white dead pixels. 19. The image processing apparatus of claim 15, wherein the processor compensates for saturation dead pixels by scaling up the signal level of pixels identified as saturation dead pixels to an average value for normal pixels under the second light condition using the saturation dead pixel reference images to locate the saturation dead pixels. 20. A digital camera comprising: an image compensation apparatus having: a memory device for storing at least one actual image, at least one dark current reference image, and at least one white reference image captured by a pixel array, the storage system further storing a plurality of gain conditions and a plurality of exposure times associated with the at least one actual image and a plurality of gain conditions and a plurality of exposure times associated with the at least one dark current reference image and the at least one white reference image; and a processor coupled to the storage system for compensating the at least one actual image by identifying defective pixels of the at least one actual image based on at least one gain condition of the stored plurality of gain conditions associated with the at least one dark current reference image and the at least one white reference image, and at least one exposure time of the stored plurality of exposure times associated with the at least one dark current reference image and the at least one white reference image, and applying at least one defective pixel compensation process to the identified defective pixels.
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